wear parts of ball mill layout

ball mill maintenance & installation procedure

ball mill maintenance & installation procedure

Am sure your BallMill is considered the finest possible grinding mill available. As such you will find it is designed and constructed according to heavy duty specifications. It is designed along sound engineering principles with quality workmanship and materials used in the construction of the component parts. YourBallMill reflects years of advancement in grinding principles, materials, and manufacturing techniques. It has been designed with both the operators and the erectors viewpoints in mind. Long uninterrupted performance can be expected from it if the instructions covering installation and maintenance of the mill are carried out. You may be familiar with installing mills of other designs and manufacture much lighter in construction. YourBallis heavy and rugged. It should, therefore, be treated accordingly with due respect for its heavier construction.

The purpose of this manual is to assist you in the proper installation and to acquaint you a bit further with the assembly and care of this equipment. We suggest that these instructions be read carefully and reviewed by everyone whenever involved in the actual installation and operation of the mill. In reading these general instructions, you may at times feel that they cover items which are elementary and perhaps not worthy of mention; however in studying hundreds of installations, it has been found that very often minor points are overlooked due to pressure being exerted by outside influences to get the job done in a hurry. The erection phase of this mill is actually no place to attempt cost savings by taking short cuts, or by-passing some of the work. A good installation will pay dividends for many years to come by reduced maintenance cost.With the modern practice of specialized skills and trades, there is often a line drawn between responsibilities of one crew of erectors and another. Actually the responsibility of installation does not cease with the completion of one phase nor does it begin with the starting of another. Perhaps a simple rule to adopt would be DO NOT TAKE ANYTHING FOR GRANTED. This policy of rechecking previously done work will help guarantee each step of the erection and it will carefully coordinate and tie it into subsequent erection work. To clarify or illustrate this point, take the example of concrete workers completing their job and turning it over to the machinist or millwright. The latter group should carefully check the foundation for soundness and correctness prior to starting their work.

Sound planning and good judgement will, to a great extent, be instrumental in avoiding many of the troublesome occurrences especially at the beginning of operations. While it is virtually impossible to anticipate every eventuality, nevertheless it is the intention of this manual to outline a general procedure to follow in erecting the mill, and at the same time, point out some of the pitfalls which should be avoided.

Before starting the erection of the mill, adequate handling facilities should be provided or made available, bearing in mind the weights and proportions of the various parts and sub-assemblies. This information can be ascertained from the drawings and shipping papers.

The gearing, bearings, and other machined surfaces have been coated with a protective compound, and should be cleaned thoroughly with a solvent, such as Chlorothene, (made by Dow Chemical). Judgement should be exercised as to the correct time and place for cleaning the various parts. Do not permit solvents, oil or grease to come in contact with the roughened top surfaces of the concrete foundation where grouting is to be applied; otherwise proper bonding will not result.

After cleaning the various parts, the gear and pinion teeth, trunnion journals and bearings, shafting and such, should be protected against rusting or pitting as well as against damage from falling objects or weld splatter. All burrs should be carefully removed by filing or honing.

Unless otherwise arranged for, the mill has been completely assembled in our shop. Before dismantling, the closely fitted parts were match marked, and it will greatly facilitate field assembly to adhere to these match marks.

The surfaces of all connecting joints or fits, such as shell and head flanges, trunnion flanges, trunnion liner and feeder connecting joints, should be coated with a NON-SETTING elastic compound, such as Quigley O-Seal, or Permatex to insure against leakage and to assist in drawing them up tight. DO NOT USE WHITE LEAD OR GREASE.

Parts which are affected by the hand of the mill are easily identified by referring to the parts list. In general they include the feeder, feed trunnion liner, discharge trunnion liner if it is equipped with a spiral, spiral type helical splitter, and in some cases the pan liners when they are of the spiral type. When both right and left hand mills are being assembled, it is imperative that these parts which involve hand be assembled in the correct mill.

Adequate foundations for any heavy equipment, and in particular grinding mills, are extremely important to assure proper operation. The foundation should preferably be in one piece, that is, with a reinforced slab footing (so called mat) extending under both trunnion bearing foundations as well as the pinion bearing foundation. If possible or practical, it should be extended to include also the motor and drive. With this design, in the event of some movement, the mill and foundation will tend to move as a unit. ANY SLIGHT SETTLING OF FOUNDATIONS WILL CAUSE BEARING AND GEAR MISALIGNMENT, resulting in excessive wear and higher maintenance costs. It has been found that concrete foundations on a weight basis should be at least 1 times the total weight of the grinding mill with its grinding media.

Allowable bearing pressure between concrete footings and the soil upon which the foundation rests should first be considered. The center of pressure must always pass through the center of the footing. Foundations subject to shock should be designed with less unit pressure than foundations for stationary loads. High moisture content in soils reduces the amount of allowable specific pressure that the ground can support. The following figures may be used for preliminary foundation calculations.

Portland cement mixed with sand and aggregate in the proper proportions has come to be standard practice in making concrete. For general reference cement is usually shipped in sacks containing one cubic foot of material. A barrel usually holds 4 cubic feet. Cement will deteriorate with age and will quickly absorb moisture so it should be stored in a dry place. For best results the sand and gravel used should be carefully cleaned free of humus, clay, vegetal matter, etc.

Concrete may be made up in different mixtures having different proportions of sand and aggregate. These are expressed in parts for example a 1:2:4 mixture indicates one bag of cement, 2 cubic feet of sand, and 4 cubic feet of gravel. We recommend a mixture of 1:2:3 for ball mill and rod mill foundations. The proper water to sand ratio should be carefully regulated since excess water increases the shrinkage in the concrete and lends to weaken it even more than a corresponding increase in the aggregate. Between 5 to 8 gallons of water to a sack of cement is usually recommended, the lower amount to be used where higher strength is required or where the concrete will be subject to severe weathering conditions.

Detailed dimensions for the concrete foundation are covered by the foundation plan drawing submitted separately. The drawing also carries special instructions as to the allowance for grouting, steel reinforcements, pier batter, foundation bolts and pipes. During concrete work, care should be taken to prevent concrete entering the pipes, surrounding the foundations bolts, which would limit the positioning of the bolts when erecting the various assemblies. Forms should be adequately constructed and reinforced to prevent swell, particularly where clearance is critical such as at the drive end where the gear should clear the trunnion bearing and pinion bearing piers.

For convenience in maintenance, the mill foundations should be equipped with jacking piers. These will allow the lifting of one end of the mill by use of jacks in the event maintenance must be carried out under these conditions.

Adequate foundations for any heavy equipment, and in particular Marcy grinding mills, are extremely important to assure proper operation of that equipment. Any slight settling of foundations will cause bearing and gear misalignment, resulting in excessive wear and higher maintenance costs. It has been found that concrete foundations on a weight basis should be approximately 1 times the total weight of the grinding mill with its grinding media.

Allowable bearing pressure between concrete footings and the soil upon which the foundation rests should first be considered. The center of pressure must always pass through the center of the footing. Foundations subject to shock should be designed with less unit pressures than foundations for stationary loads. High moisture content in soils reduces the amount of allowable pressure that that material can support. The following figures may be used for quick foundation calculations:

Portland cement mixed with sand and aggregate in the proper proportions has come to be standard practice in making concrete. For general reference cement is usually shipped in sacks containing one cubic foot of material. A barrel usually consists of 4 cubic feet. Cement will deteriorate with age and will quickly absorb moisture so it should be stored in a cool, dry place. The sand and gravel used should be carefully cleaned for best results to be sure of minimizing the amount of sedimentation in that material.

Concrete may be made up in different mixtures having different proportions of sand and aggregate. These are expressed in parts for example a 1:2:4 mixture indicates one bag of cement, 2 cubic feet of sand, and 4 cubic feet of gravel. We recommend a mixture of 1:2:3 for ball mill and rod mill foundations. The proper water to sand ratio should be carefully regulated since excess water will tend to weaken the concrete even more than corresponding variations in other material ratios. Between 5 to 8 gallons of water to a sack of cement is usually recommended, the lower amount to be used where higher strength is required or where the concrete will be subject to severe weathering conditions.

We recommend the use of a non-shrinking grout, and preferably of the pre-mixed type, such as Embeco, made by the Master Builders Company of Cleveland, Ohio. Thoroughly clean the top surfaces of the concrete piers, and comply with the instructions of the grouting supplier.

1. Establish vertical and horizontal centerline of mill and pinion shaftagainst the effects of this, we recommend that the trunnion bearing sole plate be crowned so as to be higher at the center line of the mill. This is done by using a higher shim at the center than at the endsand tightening the foundation bolts of both ends.

After all shimming is completed, the sole plate and bases should be grouted in position. Grouting should be well tamped and should completely fill the underside of the sole plate and bases. DO NOT REMOVE THE SHIMS AFTER OR DURING GROUTING. When the grout has hardened sufficiently it is advisable to paint the top surfaces of the concrete so as to protect it against disintegration due to the absorption of oil or grease.

If it is felt that sufficient accuracy in level between trunnion bearing piers cannot be maintained, we recommend that the grouting of the sole plate under the trunnion bearing opposite the gear end be delayed until after the mill is in place. In this way, the adjustment by shimming at this end can be made later to correct for any errors in elevation. Depending on local climatic conditions, two to seven days should he allowed for the grouting to dry and set, before painting or applying further loads to the piers.

Pinion bearings are provided of either the sleeve type or anti-friction type. Twin bearing construction may use either individual sole plates or a cast common sole plate. The unit with a common sole plate is completely assembled in our shop and is ready for installation. Normal inspection and cleaning procedure should be followed. Refer to the parts list for general assembly. These units are to be permanently grouted in position and, therefore, care should be taken to assure correct alignment.

The trunnion bearing assemblies can now be mounted on their sole plates. If the bearings are of the swivel type, a heavy industrial water-proof grease should be applied to the spherical surfaces of both the swivels and the bases. Move the trunnion bearings to their approximate position by adjustment of the set screws provided for this purpose.

In the case of ball mills, all internal wearing parts will pass through the manhole, whereas in the case of open end rod mills they will pass through the discharge trunnion opening. When lining the shell, start with the odd shaped pieces around the manhole opening if manholes are furnished. Rubber shell liner backing should be used with all cast type rod mills shell liners. If the shell liners are of the step type, they should be assembled with the thin portion, or toe, as the leading edge with respect to rotation of the mill.

Lorain liners for the shell are provided with special round head bolts, with a waterproof washer and nut. All other cast type liners for the head and shell are provided with oval head bolts with a cut washer and nuts. Except when water proof washers are used, it is advisable to wrap four or five turns of candle wicking around the shank of the bolt under the cut washer. Dip the candle wicking in white lead. All liner bolt threads should be dipped in graphite and oil before assembly. All liner bolt cuts should be firmly tightened by use of a pipe extension on a wrench, or better yet, by use of a torque wrench. The bolt heads should be driven firmly into the bolt holes with a hammer.

In order to minimise the effect of pulp race, we recommend that the spaces between the ends of the shell liners and the head liners or grates be filled with suitable packing. This packing may be in the form of rubber belting, hose, rope or wood.

If adequate overhead crane facilities are available, the heads can be assembled to the shell with the flange connecting bolts drawn tightly. Furthermore, the liners can be in place, as stated above, and the gear can be mounted, as covered by separate instructions. Then the mill can be taken to its location and set in place in the trunnion bearings.

If on the other hand the handling facilities are limited it is recommended that the bare shell and heads be assembled together in a slightly higher position than normal. After the flange bolts are tightened, the mill proper should be lowered into position. Other intermediate methods may be used, depending on local conditions.

In any event, just prior to the lowering of the mill into the bearings the trunnion journal and bushing and bases should be thoroughly cleaned and greased. Care should be taken not to foul the teeth in the gear or pinion. Trunnion bearing caps should be immediately installed, although not necessarily tightened, to prevent dirt settling on the trunnions. The gear should be at least tentatively covered for protection.

IMPORTANT. Unless the millwright or operator is familiar with this type of seal, there is a tendency to assume that the oil seal is too long because of its appearance when held firmly around the trunnion. It is not the function of the brass oil seal band to provide tension for effective sealing. This is accomplished by the garter spring which is provided with the oil seal.

Assemble the oil seal with the spring in place, and with the split at the top. Encircle the oil seal with the band, keeping the blocks on the side of the bearing at or near the horizontal center line so that when in place they will fit between the two dowel pins on the bearing, which are used to prevent rotation of the seal.

Moderately tighten up the cap screws at the blocks, pulling them together to thus hold the seal with its spring in place. If the blocks cannot be pulled snuggly together, then the oil seal may be cut accordingly. Oil the trunnion surface and slide the entire seal assembly back into place against the shoulder of the bearing and finish tightening. Install the retainer ring and splash ring as shown.

In most cases the trunnion liners are already mounted in the trunnions of the mills. If not, they should be assembled with attention being given to match marks or in some cases to dowel pins which are used to locate the trunnion liners in their proper relation to other parts.

If a scoop feeder, combination drum scoop feeder or drum feeder is supplied with the mill, it should be mounted on the extended flange of the feed trunnion liner, matching the dowel pin with its respective hole. The dowel pin arrangement is provided only where there is a spiral in the feed trunnion liner. This matching is important as it fixes the relationship between the discharge from the scoop and the internal spiral of the trunnion liner. Tighten the bolts attaching the feeder to the trunnion liner evenly, all around the circle, seating the feeder tightly and squarely on its bevelled seat. Check the bolts holding the lips and other bolts that may require tightening. The beveled seat design is used primarily where a feeder is provided for the trunnion to trunnion liner connection, and the trunnion liner to feeder connection. When a feeder is not used these connecting joints are usually provided by a simple cylindrical or male and female joint.

If a spout feeder is to be used, it is generally supplied by the user, and should be mounted independently of the mill. The spout should project inside the feed trunnion liner, but must not touch the liner or spiral.

Ordinarily the feed box for a scoop tender is designed and supplied by the user. The feed box should be so constructed that it has at least 6 clearance on both sides and at the bottom of the scoop. This clearance is measured from the outside of the feed scoop.

The feed box may be constructed of 2 wood, but more often is made of 3/16 or plate steel reinforced with angles. In the larger size mills, the lower portion is sometimes made of concrete. Necessary openings should be provided for the original feed and the sand returns from the classifiers when in closed circuit.

A plate steel gear guard is furnished with the mill for safety in operation and to protect the gear and pinion from dirt or grit. As soon as the gear and pinion have been cleaned and coated with the proper lubricant, the gear guard should be assembled and set on its foundation.

Most Rod Mills are provided with a discharge housing mechanism mounted independently of the mill. This unit consists of the housing proper, plug door, plug shaft, arm, and various hinge pins and pivot and lock pins. The door mechanism is extra heavy throughout and is subject to adjustment as regard location. Place the housing proper on the foundation, level with steel shims and tighten the foundation bolts. The various parts may now be assembled to the housing proper and the door plug can be swung into place, securing it with the necessary lock pins.

After the mill has been completely assembled and aligned, the door mechanism centered and adjusted, and all clearances checked, the housing base can be grouted. The unit should be so located both vertically and horizontally so as to provide a uniform annular opening between the discharge plug door and the head liners.

In some cases because of space limitation, economy reasons, etc., the mill is not equipped with separate discharge housing. In such a case, the open end low discharge principal is accomplished by means of the same size opening through the discharge trunnion but with the plug door attached to lugs on the head liner segments or lugs on the discharge trunnion liner proper. In still other cases, it is sometimes effected by means of an arm holding the plug and mounted on a cross member which is attached to the bell of the discharge trunnion liner. In such cases as those, a light weight sheet steel discharge housing is supplied by the user to accommodate the local plant layout in conjunction with the discharge launder.

TRUNNION BEARING LUBRICATION. For the larger mills with trunnion bearings provided with oil seals, we recommend flood oil lubrication. This can be accomplished by a centralized system for two or more mills, or by an individual system for each mill. We recommend the individual system for each mill, except where six or more mills are involved, or when economy reasons may dictate otherwise.

In any event oil flow to each trunnion bearing should be between 3 to 5 gallons per minute. The oil should be adequately filtered and heaters may be used to maintain a temperature which will provide proper filtration and maintain the necessary viscosity for adequate flow. The lines leading from the filter to the bearing should be of copper tubing or pickled piping. The drain line leading from the bearings to the storage or sump tank should be of adequate size for proper flow, and they should be set at a minimum slope of per foot, perferably per foot. Avoid unnecessary elbows and fittings wherever possible. Avoid bends which create traps and which might accumulate impurities. All lines should be thoroughly cleaned and flushed with a solvent, and then blown free with air, before oil is added.

It is advisable to interlock the oil pump motor with the mill motor in such a way that the mill cannot be started until after the oil pump is operating. We recommend the use of a non-adjuslable valve at each bearing to prevent tampering.

When using the drip oil system it is advisable to place wool yarn or waste inside a canvas porous bag to prevent small pieces of the wool being drawn down into the trunnion journal. If brick grease is used, care should be taken in its selection with regard to the range of its effective temperature. In other words, it should be pointed out that brick grease is generally designed for a specific temperature range. Where the bearing temperature does not come up to the minimum temperature rating of the brick grease, the oil will not flow from it, and on the other hand if the temperature of the bearing exceeds the maximum temperature rating of the brick grease, the brick is subject to glazing; therefore, blinding off of the oil. This brick should be trimmed so that it rests freely on the trunnion journal, and does not hang up, or bind on the sides of the grease box.

When replacing the brick grease, remove the old grease completely. Due to the extended running time of brick grease, there is usually an accumulation of impurities and foreign matter on the top surface, which is detrimental to the bearing.

Where anti-friction bearings are supplied, they are adequately sealed for either grease or oil lubrication. If a flood system is used for the trunnion bearings and it is adequately filtered, it can then be used for pinion bearings with the same precautions taken as mentioned above, with a flow of to 1 gallons per minute to each bearing.

These lubricants can be applied by hand, but we highly recommend some type of spray system, whether it be automatic, semi-automatic or manually operated. It has been found that it is best to lubricate gears frequently with small quantities.

Start the lubrication system and run it for about ten minutes, adjusting the oil flow at each bearing. Check all of the bolts and nuts on the mill for tightness and remove all ladders, tools and other obstructions prior to starting the mill.

Before starting the mill, even though it is empty, we recommend that it be jogged one or two revolutions for a check as to clearance of the gear and its guard, splash rings, etc. The trunnion journal should also be checked for uniform oil film and for any evidence of foreign material which might manifest itself through the appearance of scratches on the journal. If there are any scratches, it is very possible that some foreign material such as weld splatter may have been drawn down into the bushing, and can be found imbedded there. These particles should be removed before proceeding further.

If everything is found to be satisfactory, then the mill should be run for ten to fifteen minutes, and stopped. The trunnion bearings should be checked for any undue temperature and the gear grease pattern can be observed for uniformity which would indicate correct alignment.

It should be noted that with an empty mill the reactions and operating characteristics of the bearings and gearing at this point are somewhat different than when operating with a ball or rod charge. Gear noises will be prominent and some vibration will occur due to no load and normal back-lash. Furthermore, it will be found that the mill will continue to rotate for some time after the power is shut off. Safety precautions should therefore he observed, and no work should be done on the mill until it has come to a complete stop.

We have now reached the point where a half ball or rod charge can be added, and the mill run for another six to eight hours, feeding approximately half the anticipated tonnage. The mill should now be stopped, end the gear grease pattern checked, and gear and pinion mesh corrected, if necessary, according to separate instructions.

The full charge of balls or rods can now be added, as well as the full amount of feed, and after a run of about four to six days, ALL BOLTS SHOULD AGAIN BE RETIGHTENED, and the gear and pinion checked again, and adjusted if necessary.

Where starting jacks are provided for the trunnion bearings of the larger sized mills, they should be filled with the same oil that is used for the lubrication of the trunnion bearings. Before starting the mill they should be pumped so as to insure having an oil film between the journal and the bushing.

When relining any part of the mill, clean away all sand from the parts to be relined before putting in the new liners. For the head liners and shell liners you may then proceed in the same manner used at the time of the initial assembly.

Before relining the grate type discharge head, it is advisable to refer to the assembly drawings and the parts list.Because of such limitations as the size of the manhole opening, and for various other reasons, it will be found that the center discharge liner and cone designs vary. The cone may be a separate piece or integral with either the trunnion liner, or the router discharge liner. Furthermore, it will be found in some mills that the center discharge liner is held by bolts through the discharge head, whereas in other cases it depends upon the clamping effect of grates to hold it in position. In any event, the primary thing to remember in assembling the discharge grate head parts is the fact that the grate should be first drawn up tightly towards the center discharge liner by adjusting the grate set screws located at the periphery of the discharge head. This adjustment should be carried out in progressive steps, alternating at about 180 if possible and in such a manner that, the center discharge liner does not become dislodged from its proper position at the center of the mill. These grate set screws should be adjusted with the side clamp bar bolts loosened. After the grates have been completely tightened with the set screws, check for correct and uniform position of each grate section. The side clamp bar bolts may now be lightened, again using an alternate process. This should result in the side clamp bars firmly bearing against the beveled sides of the grates. The side clamp bars should not hear against the lifter liners.

When new pan liners are installed, they should be grouted in position so as to prevent pulp race in the void space between the discharge head and the pan liner. Another good method of preventing this pulp race is the use of the sponge rubber which can be cemented in place.

After the mill is erected, in order to avoid overlooking both obvious and obscure installation details, we recommend the use of a check list. This is particularly recommended for multiple mill installations where it is difficult to control the different phases of installation for each and every mill. Such a check list can be modeled after the following:

No. 1 Connecting Bolts drawn tight. A. Head and Shell flange bolts. B. Gear Connecting, bolts. No. 2 Trunnion studs or bolts drawn up tight. No. 3 Trunnion liner and feeder connecting bolts or studs drawn up tight. No. 4 Feeder lip bolts tightened. No. 5 Liner bolts drawn up tight. No. 6 Gear. A. Concentric B. Backlash C. Runout D. Joint bolts drawn up tight. No. 7 Coupling and Drive alignment and lubrication. No. 8 Bearings and Gearing cleaned and lubricated. No. 9 Lubrication system in working order with automatic devices including alarms and interlocking systems.

We further recommend that during the first thirty to sixty days of operation, particular attention be given to bolt tightness, foundation settlement and condition of the grouting. We suggest any unusual occurrence be recorded so that should trouble develop later there may be a clue which would simplify diagnosing and rectifying the situation.

As a safety precaution, and in many cases in order to comply with local safety regulations, guards should be used to protect the operators and mechanics from contact with moving parts. However, these guards should not be of such a design that will prevent or hinder the close inspection of the vital parts. Frequent inspection should be made at regular intervals with particular attention being given to the condition of the wearing parts in the mill. In this way, you will be better able to anticipate your needs for liners and other parts in time to comply with the current delivery schedules.

When ordering repair or replacement parts for your mill, be sure to identify the parts with the number and description as shown on the repair parts list, and specify the hand and serial number of the mill.

By following the instructions outlined in this manual, mechanical malfunctions will be eliminated. However, inadvertent errors may occur even under, the most careful supervision. With this in mind, it is possible that some difficulties may arise. Whenever any abnormal mechanical reactions are found, invariably they can be attributed to causes which though sometimes obvious are often hidden. We sight herewith the most common problems, with their solutions.

Cause A GROUT DISINTEGRATION. Very often when the grouting is not up to specification the vibration from the mill tends to disintegrate the grouting. In most instances the disintegration starts between the sole plate and the top surface of the grouting near or at the vertical centerline of the mill. As this continues, the weight of the mill causes the sole plate and trunnion bearing base to bend with a resultant pinching action at the side of the bearing near the horizontal center line of the mill. This pinching will cut off and wipe the oil film from the journal and will manifest itself in the same manner as if the lubrication supply had been cut off. If the grout disintegration is limited to about . 050 and does not appear to be progressing further, the situation can be corrected by applying a corresponding amount of shimming between the trunnion bearing base and the sole plate near the centerline of the mill in such a fashion that the trunnion bearing base has been returned to its normal dimensional position. If, on the other hand, the grouting is in excess of . 050 and appears to be progressing further, it is advisable to shut down operations until the sole plate has been re grouted.

Cause B HIGH SPOT ON THE BUSHING. While all BallMill bushings are scraped in the shop to fit either a jig mandrel or the head proper to which it is to be fitted, nevertheless there is a certain amount of seasoning and dimensional change which goes on in the type of metals used. Therefore if high spots are found, the mill should be raised, the bushings removed and rescraped. Bluing may be used to assist in detecting high spots.

Cause C INSUFFICIENT OIL FLOW. Increase the oil supply if it is a flood oil system. If brick grease is used, it is possible that the particular grade of brick may not be applicable to the actual bearing temperature. Refer to the remarks in this manual under the paragraph entitled Lubrication.

Cause E EXCESSIVE RUBBING ON THE SIDE OF THE BUSHING. This comes about due to the improper setting of the bearings in the longitudinal plane. In some cases, particularly on dry grinding or hot clinker grinding mills, the expansion of the mills proper may account for this condition. In any event, it can be remedied by re-adjusting the bearing base on the sole plate longitudinally at the end opposite the drive.

There are many more lubricant suppliers, such as E. F. Houghton and Co. , or Lubriplate Division of Fiske Bros. Refining Co. In making your final selection of lubricants, you should consider the actual plant conditions as well as the standardization of lubricants. New and improved lubricants are being marketed, and we, therefore, suggest that you consult your local suppliers.

diy desktop 5-axis cnc mill : 9 steps (with pictures) - instructables

diy desktop 5-axis cnc mill : 9 steps (with pictures) - instructables

I bought the CNC 2417 Mini. There are lots of different models out there. Some of them come with a Laser module too. Just mind to pick one that matches these table slots, if you do not want to re-design my 3D parts.

If you feel like going with the linear to rotary y-axis conversion (the one that moves the table back and forth), I can give you some ideas with this picture. You can also see it in action in the video. If you need further info just ask me in the comments.

So I thought, OK, I have to use a trunnion. Then I thought, why build a 3D printer (prior years project) if you are only to use it for fancy stuff. I have to 3D print something really useful: a trunnion table!

Apologies for being such an infidel using OnShape for that, but I like using different platforms when designing new ideas. So I did a first design, then a second and I ended up with something that might actually work.

It consists of many parts that are mostly printed flat on the bed to be sturdy enough for this application. Of course lots of bolts and nuts (all are M3) were used to assemble the thing together. I also used some 608 roller bearings and 8mm diameter smooth shafts.

For the printed parts (all greens and reds) I used ABS plastic. Grab the attached STLs and print all of them 2 times, except for Part3 which is needed only once and Part9 4 times. Mind to align Part9 with the T shape flat face on the bed (screw hole aligned with Z).

The belts though, you can not avoid, you have to buy them. I tried printing some ninjaflex material but it is not suitable for this application, you need the belts to be really stiff in terms of tension to increase the machine's accuracy.

Of course I knew that the board that came with the router is only for 3 axis and I should replace it. So I found out that the closest thing to making 5 axis work simultaneously (other than using any old-fashioned parallel ports) is a MACH3 usb board.

So I got the BL-UsbMach-v2.1 and five stepper motor drivers TB6600. I know, these drivers are an overkill for the small NEMA 17 motors, but these were the ones I found to be plug and play for the MACH3 board.

For this thing to work, you need some serious power. The power supply that came with the router would not suffice. So I got one of my old ATX power supplies and used the 12v output. An intermediate board to supply 12v to all stepper drivers and the spindle was custom made. Really simple stuff just connect + with + and - with - for all components (parallel power supply of 12v to all drives).

But if you are an engineer you know you have to think deeper. You need to get involved with CAM (Computer Aided Manufacturing) and aim for the 5-axis tutorials to see if the software you are targeting is even capable of producing code for such machines.

Some minor changes are needed in terms of machine layout settings and post-processor coding, to match the machine geometry and axis layout. But thanks to some really good tutorials online I was able to overcome this and generate 5-axis code!

Some testing needed to be done now. I quickly made a simple but really easy to debug geometry when looking at the g-code. I tried the Flow toolpath with multiaxis enabled and the code looked really good. So I sent it to the machine and... success!

So I imported it in Fusion 360. Unfortunately the Flow toolpath only works on geometry, not on mesh. So I had to use some basic toolpaths, but OK this is still 5-axis. I did some adaptive cleaning and parallel finishing toolpaths and tested the simulation.

5-axis Milling is not an easy thing to do. I know I still need to find a robust way to zero the machine before I start cutting. Maybe add probes to make some basic homing and calibration possible. But I think overall this project was a nice and productive way of putting some really advanced CNC techniques to the test.

Hi. I made it really well! I also couldn't try, so I'm in a tentative state now. If there is a problem with the motor and the controller, there are 3 axes, but the 5 axis is not looking for a solution because the deceleration ratio is too much compared to the problem or the processing area..

really nice build... there is a grbl version for 5/6 axis... works with the Arduino mega and a ramps 1.4 board... it's really sweet... https://github.com/fra589/grbl-Mega-5Xi use it in conjunction with cncJS https://cnc.js.org/

Thank you!I was aware of this project but I am not sure it was ready for 5axis by the time I started working on mine. I had the rapms with 5 stepper controllers (xyz and two extruders was one of my 3d printer tests). But searching for firmware I only found grbl for 4 axis. I also got the grbl 4 axis shield for arduino uno but never tested it, as after I did the switch from linear Y to rotary A, I did not change the electronics to move Y and A together. It was the time I got the idea of the 3d printed trunnion and ended up with the mach3 electronics.Hopefully I will do something in the future!

I am a bit confused by the wiring of the spindle: why the relais. In this way you can not control the spindle speed.Did I mis something, or............?Edit. I just saw another lttle detail which I think is not very handy. The two rotating axes are belt driven withitout a protection against dust. This wil wear down your belts and pulleys in a very short time.I would strongly suggest to cover them up against all kinds of dust.Accrylic dust is especially very interseting: I have seen belts and puleys just vapourise within days when working in this kind of stuff.

Try CNC-toolkit http://cnc-toolkit.com/But be aware: you also have to configure your cnc-router for Tool path compensation. Personaly I would sugest Linuxcnc (it's also free). It's not the most complicated software to configure for TCP.

operational and maintenance of cement plant vertical roller mill

operational and maintenance of cement plant vertical roller mill

The VRM for cement grinding offers a significant advantage in power savings. Typically, the VRM uses 50% less power than a ball mill when grinding the same clinker to 3900 Blaine. VRMs are also much more adept at handling hot feed compared to ball mills. The simple and compact vertical mill layout is cost competitive to build and offers many options for layout, even in existing plants. Today significant operating experience has been accumulated with vertical mills ranging from plant design and layout to operation with multiple types of product. One of the main focus points regarding cement VRM operation in the USA has been product quality and the product compatibility with existing ball mill systems.

The vertical roller mill design allows the option of rotating the roller segments 180 degrees before replacing. They can also be hardfaced in place with a standard rewelding procedure. The table liners can also be replaced or hardfaced. As of this time both methods have been undertaken. After the mill was in operation for over 10,000 hours the roller and table wear rates have been measured 2 times, once through each method

Described above, roller segment rotation and rewelding of both the table and roller liners. The actual wear rate for both the roller and table liners before hardfacing was 0.30 g/T. The measured wear rate with hardfaced liners was 0.12 g/T. The 50% reduction in wear rate with hardfaced liners was expected as data from other vertical cement mills indicated such a savings could be expected. In either case the wear rate has exceeded expectations and operation has not been detrimentally effected by wear.

The VRM continuously demonstrates the ability to make product equal to or better than existing ball mills with the tendency towards the better. The VRM product meets all market requirements in terms of both output and quality.

A higher level of operational flexibility and improved consistency has been maintained. Overall better efficiency allows for lower operating costs. And easy, predictable maintenance add further benefit to the bottom line. The Phoenix based cement producer is completely satisfied with the installation of a VRM for cement grinding.

increase capacity and cut co2 emissions with calcined clay | flsmidth

increase capacity and cut co2 emissions with calcined clay | flsmidth

Manufacturing clinker is energy and emissions intensive. The less clinker you can use, the less impact you have on the environment. With our clay calciner system you can reduce process emissions by up to 40% and get a cost-effective, quality product that meets your strength and colour expectations all while reducing your operating costs.

Clay is a naturally occurring material found almost everywhere around the world. With the right treatment, it makes a perfect SCM and can be used to replace up to 40% of the clinker in your product. With our clay calciner system, you maximise your return on your investment. With lower capital costs as compared to a new clinker line, you get an energy efficient process that delivers a high quality product and can maximise your substitution rates.

The process begins with the dryercrusher, designed specifically to manage the high moisture content of your clay. Material is then fed to the 2-stage preheater/calciner system where it is preheated and activated in the calciner.

A cyclone at the outlet of the calciner separates the gas and material. The temperature and other process conditions can be tightly controlled. This allows for a consistent operation, resulting in uniform product quality and emission control. Furthermore, because the stable process delivers a highly consistent product, you can substitute more clinker as compared to calcined clay produced in a rotary kiln.

Our flash calciner system costs less to set up than a rotary kiln and is more energy efficient by approx. 20% as compared to a rotary kiln. Furthermore, it produces highly reactive clay that can be used as a clinker substitute in the range of 30 40%, resulting in a huge CO2 reduction for the finished cement product. In contrast, only 15 25% substitution can be achieved with product produced in a rotary kiln because the calcined clay is less reactive and therefore less suitable as a clinker substitute.

By applying the right settings and conditions during activation and cooling, we have developed a unique, patent-pending process to achieve the standard grey cement colour in your clay. This ensures end users will be happy with the look of the product, as well as its performance.

Clays suitability as a clinker substitute depends on its chemical content (in particular, its oxide and mineralogical content), how amorphous its structure is, particle fineness, strength development and emissions.

We will help you confirm that you have a suitable clay source as well as the right equipment design to process it. Our laboratory testing services include full chemistry as well as clay reactivity analysis. A pilot scale system is also available to produce calcined clay in a larger scale to allow a full quality and strength test of the blended cement product if desired.

If you have an unused kiln available, we can develop a site-specific concept for a system that produces calcined clay. This will have a lower capital cost than a new clay calciner system, but also limits the potential clinker substitution to ~20% due to quality.

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

ball mill liner function | wear parts for industry | qiming casting

ball mill liner function | wear parts for industry | qiming casting

Ball mill is a major equipment in the production of power plants, cement plants, mines, chemical industry, metallurgy and other industries, the liner is one of the components of the mill, the main role is to protect the cylinder, the cylinder from the grinding body and Material direct impact and friction, help to improve the mill grinding efficiency, increase production and reduce metal consumption. As the liner in the harsh conditions of long-term conditions, maintenance and replacement of considerable volume, not only requires human, material and financial resources, but also a direct impact on productivity.

Ball mill liner plays a major role in protecting the inner wall of the anchor windlass. Different shapes of the ball mill lining plate can improve the grinding effect of the ball mill and improve the working efficiency of the ball mill. 1, flat ball mill liner, the surface smooth, suitable for installation in the fine grinding warehouse. 2, the pressure of the type of ball mill liner, suitable for coarse grinding warehouse, for low speed ball mill. 3, ladder-type ball mill liner, ladder liner is better than the pressure liner, suitable for installation in the coarse grinding warehouse. 4, small corrugated liner crest and pitch are small, suitable for fine grinding and coal mill. 5, end cover liner installed in the grinding head cover or cylinder cover to protect the end cover from wear and tear. 6, ring groove liner in the lining of the T surface for casting a circular groove, after installation to form a circular groove, suitable for multi-warehouse grinding of the first and second positions, dry, wet grinding Machine can be. 7, grading liner, grinding mill for the ideal state should be large particles of material with a large diameter grinding body to impact and crush, that is, in the direction of the mill feed with large diameter grinding body, with the material The direction of the material to the gradual reduction of the grinding body should be sequentially reduced.

Qiming Casting is one of the largest manganese steel, chromium steel, and alloy steel foundry in China. Products include crusher wear parts, Crusher spare parts, mill liners, shredder wear parts, apron feeder pans, and electric rope shovel parts.

simaie sanate spadana

simaie sanate spadana

The SIMA mill combines the drying, grinding and separation processes into just one unit, which simplifies the plant layout. And because it operates at a low noise level, outdoor installation is feasible substantially reducing civil construction costs and improving the working environment. Compared to ball mills, the SIMA mill can produce better or equivalent cement quality.

flexible milling and grinding solutions that last | flsmidth

flexible milling and grinding solutions that last | flsmidth

With years of experience in the cement and mining industries and over 3000 mills sold worldwide, FLSmidth continues to develop its range of efficient milling and grinding solutions. This experience and know-how, as well as close collaboration with our customers, means we can deliver advanced milling and grinding technology solutions that puts us at the forefront as a partner.

We know that you strive to increase production while saving on CAPEX, operation and maintenance costs. Further, consideration for the environment is a priority for production industries, making energy-efficient designs highly sought after. So, these are our priorities when designing milling and grinding equipment to meet your needs.

Milling and grinding of raw material, minerals and cement is a rough process, with highly abrasive and hard feed materials that can accelerate equipment wear and tear. This leads to increased costs for equipment and spare parts replacement, and costly maintenance. It is crucial that the equipment used for milling and grinding can withstand such harsh materials. Our range of milling and grinding technologies have been tried and tested around the globe. Our vertical roller mills, horizontal mills, hydraulic roller presses and stirred mills have for many years offered efficient milling and grinding, flexibility, cost savings and easier maintenance. Whatever the application, one of our robust milling and grinding solutions will be suitable for grinding all types of feed materials including hard rock ores, raw, cement or slag. We work closely with you to realise the potential of the technology that will benefit you. Some of the features you can benefit from in our milling and grinding solutions include:

With the knowledge and experience gained throughout the years, we ensure that you have the best milling or grinding solution possible, whether you are working in the cement industry or mining industry.

For the cement industry, our Hydraulic Roller Press is suitable for water-scarce locations as it does not require water for deagglomeration of feed material in the roller press. It is also adaptable to three different types of grinding setups: pre-grinding, semi-finish grinding and finish grinding. The OKTM mill can skilfully grind raw or cement feed material and offers parts commonality, simplifying spare parts inventory and facilitating easy switching of parts between vertical roller mills. Our ATOX coal mill has large rollers with great grinding capability of all types of coal, tolerating moisture levels up to 20 percent.

For the mining industry, our semi-autogenous (SAG) grinding mill uses a minimal ball charge in the range of 6-15 percent. It is primarily used in the gold, copper and platinum industries as well as in the lead, zinc, silver, and nickel industries. Autogenous (AG) grinding mills involve no grinding media as the ore itself acts as the grinding media.

Our ball mills are the most robust design in the industry, available with either geared or gearless drive arrangements. The cost-effective FT Series mills are smaller, gear driven and feature hydrodynamic lubrication.

Understanding the challenges you face when milling and grinding hard feed material, we have built our technologies to last. We have paid particular attention to the wear parts because they are right there where the action is, making it all happen. We hardface them with the toughest

There is no doubt that milling and grinding cement and other feed material is tough work. We offer well-designed technologies to endure virtually any hard rock ore or raw material, with differing moisture levels and particle size. Whatever your milling and grinding needs are, FLSmidth is your trusted partner.

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

low alloy steel ball mill liners design | wear parts for industry | qiming casting

low alloy steel ball mill liners design | wear parts for industry | qiming casting

The main function of the ball mill liner is to protect the mill and use the convex peak of the liner to play the ball to grind and crush the material. Therefore, the main failure mode of the liner is abrasive wear under the repeated impact of small energy. Under the condition of abrasive wear, wear resistance directly affects the service life of parts, so the research on wear resistance is also an important technical problem. This project is put forward for the failure of liner under abrasive wear conditions, and the purpose is to improve the comprehensive performance of low alloy steel wear-resistant material under this condition.

Wear-resistant low alloy steel materials usually contain alloying elements such as silicon, manganese, chromium, molybdenum, nickel, etc. The strong influence of these alloying elements on the matrix structure and hardenability of the material can be brought into full play, which can make the material have better wear resistance.

Carbon: Carbon is an important element that affects the strength, hardness, toughness, hardenability, and wear resistance of cast steel. If the carbon content is too high, the hardness of the high carbon martensite formed after heat treatment is high, but the toughness is low, and cracks are easy to form during heat treatment; if the carbon content is too low, the hardenability and hardness of the casting are poor, and the wear resistance is poor. Considering the combination of hardness and toughness, two different carbon contents (mass fraction, the same below) were adopted in this material, which was 0.30% 0.35% and 0.40% 0.45%, respectively. The effects of two carbon contents on the microstructure and properties of low alloy steel were studied.

Chromium: Chromium is one of the basic elements of wear-resistant materials. Its main function is to improve the hardenability of steel, strengthen the matrix by solution, improve the oxidation resistance of steel and increase its corrosion resistance. Chromium and iron form continuous solid solution and form a variety of compounds with carbon. The complex carbide of chromium has a significant effect on the properties of steel, especially the improvement of wear resistance. Cr and Fe form intermetallic compound FeCr. Chromium can significantly increase the hardenability of steel, but it also tends to increase the temper brittleness of steel. Chromium improves the temper brittleness of the steel and reduces the martensite point ms of the steel. When chromium is added into pure iron and steel, the strength and hardness can be improved at a certain chromium content. Considering the effect of chromium on Microstructure and properties of steel, the content of chromium is 1.0% ~ 1.4%. The effect of chromium on Microstructure and properties of steel is observed by experiment.

Nickel: Nickel and carbon do not form carbides. They are the main alloying elements for forming and stabilizing austenite. In this respect, the role is second only to carbon and nitrogen. Nickel and iron exist in the phase and phase of steel in the form of mutual solubility, which makes them strengthen. By refining the grain size of the phase, the low-temperature properties, especially the toughness of steel are improved. Nickel can improve the hardenability of steel by reducing the critical transformation temperature and the diffusion rate of elements in steel. Some physical properties of steel and alloy can be significantly improved when nickel content is high. The effect of nickel on toughness, plasticity, and other process properties of steel is less than that of other alloy elements. In addition, as nickel is a rare element and an important strategic material, the nickel content is set at 0.4% based on the above factors.

Molybdenum: Molybdenum belongs to the element of the closed phase region. Molybdenum exists in the solid solution phase and carbide phase in steel. In the carbide phase, when the content of Mo is low, it forms composite cementite with iron and carbon; when the content is high, it forms its own special carbide. The effect of molybdenum in steel can be summarized as improving hardenability, improving thermal strength, preventing temper brittleness, increasing remanence and coercivity, improving the corrosion resistance of alloy in some media and preventing pitting corrosion tendency. Molybdenum has a solid solution strengthening effect on ferrite and improves the stability of carbides, so it has a favorable effect on the strength of steel. The effect of molybdenum on the Temper Embrittlement of steel is quite complicated. As a single alloy element, Mo increases the temper brittleness of steel, but when it coexists with other elements, such as chromium and manganese, molybdenum reduces or suppresses the temper brittleness caused by other elements. Because the different content of molybdenum may have different effects on the properties of steel, we decided to select the content of molybdenum in the experiment as 0.25% 0.35% and 0.45% 0.60%.

Manganese: Manganese is a good deoxidizer and desulfurized. Manganese and iron form solid solution, which improves the hardness and strength of ferrite and austenite in steel; at the same time, it is a carbide forming element, which enters cementite to replace some iron atoms. Manganese can refine pearlite and improve the strength of pearlite steel indirectly by reducing the critical transformation temperature. Manganese can also significantly reduce the AR1 temperature and the austenite decomposition rate of steel. Manganese has a significant effect on improving the strength of low and medium carbon pearlite steels. However, as an alloying element, manganese has its disadvantages. When the content of Mn is higher, the grain size of the steel tends to be coarsened and the sensitivity of temper brittleness is increased. It is easy to produce white spots in steel due to improper cooling after smelting, casting, and forging. Considering the effects of manganese on the microstructure and properties of steel, the content of manganese is 1.1% 1.4%.

Silicon: Silicon is one of the common elements of steel. As an alloying element, the content of silicon in steel should not be less than 0.40%. Silicon does not form carbide in steel, but exists in ferrite or austenite in the form of solid solution. It improves the strength of the solid solution in steel, and its cold work deformation hardening rate is very strong, second only to phosphorus, but also reduces the toughness and plasticity of steel to a certain extent. If the content of silicon is more than 3%, the plasticity, toughness, and ductility of the steel will be significantly reduced. Silicon can improve the elastic limit, yield limit, yield ratio, fatigue strength, and fatigue ratio of steel. Silicon can increase the annealing, normalizing, and quenching temperatures of steel, reduce the diffusion rate of carbon in ferrite, and increase the tempering stability of steel. Considering the effects of silicon on properties and microstructure of steel, the content range of silicon is 1.1% 1.4%.

Rare earth: There are two main functions of rare earth in steel, one is purification and the other is alloying. Re can improve as-cast microstructure, refine grain size, purify molten steel, modify non-metallic inclusions, improve their morphology and distribution, and play a role in microalloying. Improve toughness and casting properties (hot cracking resistance and fluidity), improve strength. However, due to the uncertainty of adding method and amount, if the rare earth content is too much, it may have an adverse effect on the properties of steel. Therefore, the content of rare earth in this material is determined to be 0.04% 0.06%.

Boron: The outstanding function of boron in steel is that the hardenability of steel can be increased by a small amount of boron (0.001%). When the content of boron is more than 0.007%, it will lead to hot embrittlement of steel. Therefore, the boron content in this material is determined to be 0.003%.

The main elements of the experimental materials were selected according to the above analysis. The carbon content of sample #1 and #2 is 0.30% 0.35%, and the content of molybdenum is 0.25% 0.35%; the carbon content of sample #3 and #4 is 0.40% 0.45%, and the molybdenum content is 0.45% 0.60%.

In this experiment, a 50 kW medium frequency induction furnace is used for smelting. In order to reduce the oxidation of the furnace charge, the stirring of molten metal should be avoided as far as possible. In the later stage of smelting, the feeding block should not be too large and should be dried to a certain temperature to prevent splashing at the furnaces mouth. The feeding sequence is scrap steel, pig iron nickel plate, ferrochrome, ferromolybdenum ferrosilicon, ferromanganese rare earth ferrosilicon, and finally adding aluminum for deoxidation.

After dry mixing for 2-3 min, the molding sand was mixed with water and glass for 4-6 min. After the mold is made, the mold is hardened by blowing carbon dioxide (blowing pressure is 0.15-0.25 MPa, blowing time is 1-2 min). Before pouring, the sand mold and alloy are preheated in the furnace and kept dry. The preheating temperature is about 100 .

The properties of as-cast materials must be properly heat treated. In the actual working condition, the martensite structure with high hardness, high strength, and good toughness should be obtained, and the heat treatment process of quenching and tempering is adopted. The undercooled austenite of low alloy wear-resistant steel is relatively stable, and the cooling rate of oil in the low-temperature zone is much smaller than that of water, so oil is the most suitable quenching medium. Tempering is to reduce or eliminate the residual stress caused by quenching, improve the plasticity and toughness of the material, reduce its brittleness, and obtain the appropriate combination of plasticity, toughness, and hardness. Therefore, the quenching temperatures of 850, 880, 910, and 930 are selected for 1 h. The tempering temperature is 200, 230, 260, and 290 , and the holding time is 2 h.

It can be seen from Fig. 1 that, on each quenching temperature curve, with the increase of tempering temperature, the hardness value of #1 sample basically shows a downward trend, but the decrease range is not very large, and the downward trend is relatively gentle; on the impact toughness curve, with the increase of quenching temperature, the value decreases, but with the increase of tempering temperature, its value increases. With the increase of tempering temperature, the carbon content, alloying element content, dislocation density, and twinning number in the martensite matrix decrease, so the amount of strengthening also decreases, so the hardness decreases. With the increase of tempering temperature, the matrix recrystallization and carbide point coarsening and spheroidizing. Because the carbide spheroidization reduces the dislocation slip distance and makes the slip distance shorter, the dislocation can not cut them, so the toughness shows an upward trend.

Figure 3 shows the metallographic structure of the sample after quenching at 910 and tempering at 230 . It can be seen that the microstructure and matrix of the two kinds of samples are lath martensite. The microstructure of the sample is uniform and the grain size is fine.

It can be seen from Table 2 that with the increase of hardness, the wear resistance of #1 #4 samples increases in turn. Therefore, it can be concluded that the wear loss of materials is directly related to the hardness of materials. The higher the hardness is, the smaller the weight loss is, the better the wear resistance of materials is. In addition, the dispersed carbides in the matrix also contribute to the wear resistance of the materials, but the effect is less than that of the hardness because of the few carbides precipitated.

China Mill liners manufacturer, Qiming Machinery is a leader in the design, manufacture, and supply of mill liners for mineral processing and quarrying industries. It offers customers complete wear liner solutions for mills that increase performance, equipment availability, and lower maintenance costs. Its mill liners are also tested to withstand the acidity level of different elements that may be present in the milling process. Longer milling life to your machine means fewer expenses and more profit or income to your company.

Qiming Casting is one of the largest manganese steel, chromium steel, and alloy steel foundry in China. Products include crusher wear parts, Crusher spare parts, mill liners, shredder wear parts, apron feeder pans, and electric rope shovel parts.

tic insert jaw plate feedback archives - tic insert wear parts

tic insert jaw plate feedback archives - tic insert wear parts

The news investigated the usage of the liner for the shell of domestic large SAG mills and combined the actual production and the failure type of the liner in Yichun Luming Mining Co., Ltd. to identify the main direction of the profile optimization of the SAG mill shell liner. In addition, the analysis of impact energy of grinding media in SAG mill based on DEM and the computation technology for throwing trajectory of grinding media in SAG mill based on Milltraj were applied to conduct the profile optimization of the liner for the shell of the SAG mill. Actual production indicated excellent application results.

The design scale of the molybdenum mining and dressing project of Yichun Luming Mining Co., Ltd. (hereinafter referred to as Luming mining) is 50000 T / D, with an annual ore processing capacity of 15 million tons. The grinding process adopts the process of semi-autogenous mill + hard rock crusher + ball mill (i.e. SABC process). The semi-autogenous mill is of 10.97 m 7.16 m, driven by bilateral small gears, with an installed power of 2 8 500 kW and power frequency operation.

In 2014, the semi-autogenous mill was put into operation with an average operating power of about 15.6 MW, a ball filling rate of about 15%, and a ball diameter of 150 mm. Due to the high filling rate of steel ball, the large diameter of mill and steel ball, high impact probability and impact energy of steel ball, the liner of semi-autogenous mill cylinder is damaged abnormally, such as fragmentation and block dropping, which results in the shortening of average service life. About 6 sets of cylinder liners are replaced every year, and the production cost is high, which seriously restricts the improvement of the operation rate of the semi-autogenous mill. Therefore, in order to improve the operation rate of the semi-autogenous mill, reduce the operating cost of the mill and improve the economic benefits, it is necessary to optimize the cylinder liner of the semi-autogenous mill.

Based on the comprehensive analysis of the ore properties, mill operation conditions, process parameters, structure, and material of the lining plate and heat treatment process, the optimization objective of shell liner modification for the semi-autogenous mill is determined, which is more than 50% longer than the original service life.

Since there are a large number of steel balls, ores, and pulp in the semi-autogenous mill, various types of lining plates are installed on the cylinder body and the end. These lining plates, especially the lining plates arranged along the axial direction of the cylinder body, on the one hand, protect the mill cylinder from slurry erosion and direct impact of steel balls; on the other hand, the raised lifting strips on the liner continuously lift the grinding medium and materials, which will be thrown or discharged It can crush and grind the material. This grinding form of the semi-autogenous mill determines that the liner and lifting bar will wear continuously. The shape of the worn liner and lifting bar will not only change obviously but also affect the energy transmission characteristics inside the mill and the grinding efficiency. After the liner wear failure, the liner may be broken due to the direct impact of the dropped steel ball, or the convex edge may be reduced due to the shapewear of the lifting strip, resulting in sliding movement between the material and the liner plate of the cylinder, which will aggravate the wear of the liner. Once the lifting strip is worn off, the liner will not only lose the lifting effect on the material, but also aggravate the sliding between the material and the liner, and the liner will be worn out quickly, damaging the mill barrel.

There are many factors that affect the service life of the SAG mill shell liner, including the liner structure itself and field operation. The unreasonable structure of the liner will cause the steel ball to be lifted too high, throw backward and directly hit the opposite liner, which will cause impact fracture of the liner; the improper manufacturing process and material selection of the liner will cause the impact toughness and hardness can not match with the working conditions, resulting in abnormal fracture and early wear; semi-automatic If the filling rate of the mill is too low, the ball will contact with the liner frequently, which will cause the liner to break abnormally and wear ahead of time. Therefore, reasonable dropping point of steel ball, mechanical properties and wear capacity of the liner is the main research directions of liner modification and optimization of the semi-autogenous mill.

The layout of the original SAG mill shell liner is as follows: there are three circles of lining plates along the axial direction of the cylinder, and each ring of lining plates is 48 full height structural lining plates. The cross-section of the lining plates is the same, all of which are of the chevron symmetrical structure. In the middle of the section, the main lifting strip is 288 mm in height, and the thickness of the bottom plate is 85 mm. Small lifting strips are arranged on both sides, with a height of 155 mm, as shown in Fig. 1. There are 72 rows of liner bolt holes on the circumference of the cylinder section. Therefore, the arrangement scheme of 48 rows of liner bolt holes per circle is different from that of the conventional mill, that is, one-liner occupies two rows of bolt holes symmetrically on the bottom plate, while the adjacent liner occupies a row of bolt holes in the middle of the lifting bar, that is, one section form and two-bolt hole arrangement modes.

According to the operating power and ball filling rate of the mill in the early stage, the average comprehensive filling rate of the mill is about 26%. Combined with the structure of the liner, the diameter and filling rate of the steel ball, and the rotation speed and diameter of the mill, the material running state of the semi-autogenous mill is simulated by using special software, as shown in Fig. 2.

It can be seen from Fig. 2 that when the SAG mill is running, the dropping point of the steel ball is about 47 in the fourth quadrant, while the edge of the material is at 42 in the fourth quadrant. Obviously, the falling point of steel ball is located at the edge of the material, which causes a large and frequent impact on the SAG mill shell liner. Therefore, it is necessary to adjust the structure and mechanical properties of the liner to improve the material throwing curve and the impact resistance of the liner.

When the ball size, mill speed, and diameter are fixed, the main factors affecting the material throwing curve in the semi-autogenous mill are the lifting surface angle of the cylinder liner, the ratio between the height of the lifting strip and the spacing (s / h). The change of S / h value can be realized by changing the structure of the cylinder liner, including the number and height of the lifting strip, and the height of the lifting strip can directly affect the wear amount of liner. The analysis, calculation, and research show that the height of the lifting strip can be increased to 320 mm, and the 72 rows of holes in the circumferential direction of the cylinder can be fully utilized. The layout of the lining plate adopts the scheme of high-flat-high, as shown in Fig. 3.

After determining the structure of the liner, the special software is used to simulate the dropping curve of the steel ball in the cylinder again, as shown in Fig. 4. It can be seen from Figure 4 that the dropping point of steel ball is about 40 in the fourth quadrant, while the edge of the material is still 42 in the fourth quadrant. The throwing point of steel ball is near the toe of the material pile, which does not directly impact the cylinder liner, but also helps to improve the grinding efficiency.

In this new liner structure, the original circumference of 48 liners is changed to 72, the number of lifting strips is changed from 48 to 36, and the height of lifting strips is changed from 288 mm to 320 mm, which is divided into high plate and low plate. The cross-section of the liner is single and mutation is small, and the casting and heat treatment technology is simpler than the original one, so it is easier to obtain uniformity and excellence The increase of the height of the lifting strip also increases the wear capacity of the liner, and the overall quality of the liner is reduced by 14% (42t), which is beneficial to reduce the grinding power consumption of the semi-autogenous mill.

In addition, through the analysis of the early failure mode of the liner, it is found that the first bolt hole of the liner at the feed end is more likely to fracture than other positions, but the wear amount is not large. This is because the front end of the cylinder liner at the feeding end is at the joint position of the end cover and the cylinder. The steel balls at the first bolt hole are not easy to accumulate due to the influence of the material flow, resulting in slow wear of the lifting bar at the first bolt hole, but there is less ore at this position and the impact is more serious. The strength of the bolt hole is relatively weak due to the opening at other positions. Therefore, the performance of the lining plate can be ensured by reducing the height of the lifting bar and strengthening the local structure of the bolt hole position. The shape of the improved liner is shown in Fig. 5.

The modification and optimization scheme of the shell liner of the semi-autogenous mill was demonstrated in March 2015 and put into production in the same month. In June 2015, the first set of liner plates was installed and used on the semi-autogenous mill, and nine sets of liners have been applied continuously. After installation and application, the service life of the liner is increased by 47.3% 56.52% compared with the original one, basically eliminating the lining plate fracture problem and greatly reducing the purchase price of the liner; the workable rate and actual operation rate of the semi-autogenous mill are greatly increased, the maximum monthly operation rate is 99.62%, and the grinding efficiency is improved; the quality of the lining plate is reduced, and the average operating power of the semi-autogenous mill is reduced from the original 15.6 4 MW, and the filling rate of steel ball is reduced from 15% to 13.5%.

Qiming Machinery is a leader in the design, manufacture, and supply of mill liners for mineral processing and quarrying industries. They offer our customers complete wear liner solutions for mills that increase performance, equipment availability, and lower maintenance costs. They mill liners are also tested to withstand the acidity level of different elements that may be present in the milling process. Longer milling life to your machine means fewer expenses and more profit or income to your company.

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