Training Materials for Metal Chrome-plated Rod Grinders in Jiyuan City

1.0Purpose

Ensure the normal operation of equipment, product processing accuracy, improve production efficiency and product quality; standardize safe operation, eliminate potential safety hazards to achieve safe production.

2.0Scope of application

Suitable for all operators of Cindless Mill.

3.0Powers and responsibilities

3.1Operators: equipment use and daily maintenance, real understanding of equipment performance and safe operation.

3.2Professional technicians: equipment maintenance, training employees to be familiar with and understand the machine performance and potential safety risks.

3.3Technical guidance and supervision of correct operation methods: group leader and supervisor.

4.0Workflow: In order to use the center-less grinder safely and effectively, the operator must comply with the following operating specifications:

4.1Fully understand the performance and structure of the center-less grinder, and abide by the safety production regulations.

4.2Before starting up, you must first do daily maintenance and inspection work, check whether the equipment is normal, check whether the lubrication system and cooling system are normal.

4.3Before processing, it is necessary to carefully check whether the knife plate is in good condition, and check whether the position of the knife plate is perpendicular to the feed and discharge guide wheels in a line.

4.3.1If the wear of the knife plate causes scratches on the ground material, it shall be maintained or replaced in time before grinding.

4.3.2If the knife plate needs to be replaced, the specifications and effective length of the knife plate should be distinguished before replacing the knife plate, so as to avoid using the wrong specifications of the knife plate;

4.3.3Before clamping the cutter plate and the baffle plate, clean the residue in the gap with the air gun;

4.3.4When installing the knife plate, hold the knife plate with one hand and tighten the screw with the other to prevent the knife plate from falling, and check whether the knife plate is placed correctly, and then use the wrench to lock the fixing screw;

4.3.5When placing the materials to be ground, wipe the rack with rags and clean the previously ground materials to avoid mixing with other products.

4.4.0Preparation before starting up

4.4.1Check the grinding wheel for cracks.

4.4.2First check the hydraulic tank, lubrication box, reducer and other oil storage conditions, and water tank storage conditions. In addition, the lubrication of each lubrication point requires the injection of lubricating oil.

4.4.3Then start the machine according to the electrical requirements of the machine tool. When starting the grinding wheel and the guide wheel, it must wait until the lubrication signal lamp is on, otherwise it will cause the bearing bush to hold the shaft without oil.

4.4.4Selection of center height (H) and blade thickness: the center line of grinding wheel of 80 and 83 grinders is 209mm and 285mm respectively from the bottom surface of the bracket. The high installation center of the workpiece has a great influence on the geometric shape accuracy of the workpiece after grinding. In order to improve the roundness of the workpiece to be ground (to reduce the error of triangular and pentagonal edges), the center height of the workpiece should generally be as high as possible. However, if the center of the workpiece is raised too high, it will cause runout and produce axial vibration mosquitoes. Therefore, the center height of the workpiece should be based on the actual situation to prevent the workpiece from runout during grinding. The following table can be used as a reference for selection:

Center height:H=0.04(Dr Dw) Ht = 0.9H H Heart Height Ht Diamond Pen Offset

Θ t = Θ x 0.9 Θ tilt angle Θ t trim angle

Calculation formula:H=0.004*(Diameter of guide wheel+Workpiece diameter)Specific appropriate adjustments according to the situation.

The thickness of the blade must be less than the diameter of the product, and the bearing capacity of the blade must be able to withstand the pressure of the workpiece. Diameter40-60Millimeter workpiece, knife plate thickness must be ≥20mm

 

 

4.4.5According to the center height of the workpiece, adjust the guide wheel dresser to the displacement:diamond pen displacement formula:h=0.9*Workpiece heart height;

4.4.6Adjust the angle of inclination of the wheel carrier and the angle of return of the wheel dresser:1 °-2 ° for guide wheel tilt angle grinding IT5 accuracy; 2 °-2 ° 40 'for IT6 accuracy; 2 ° 30'-3 ° 30 'for IT8 accuracy',The theoretical inclination angle α required to achieve IT3 level accuracy should be within 1 °）

4.4.7Dressing of guide wheel and grinding wheel:

According to the above, select the displacement of the diamond tool tip and the rotation angle of the guide wheel dresser, trim the guide wheel, and trim the grinding wheel together. Before starting the guide wheel and grinding wheel, the oil pump must be started first, and the guide wheel and grinding wheel shall be started after the normal lubrication signal lamp is on. When dressing the guide wheel, turn the speed regulating handle to the high-speed position, turn on the water nozzle switch of the spray guide wheel, and then trim. In order to ensure the cutting performance of the grinding wheel and the required correct surface, the grinding wheel must be trimmed in time. Fine trimming of the grinding wheel plays a great role in improving the roughness. When trimming, rough trimming is 0.002-0.005; 0005 reciprocating trimming speed: rough trimming is 100 mm/min, fine trimming is 50 mm/min, high precision trimming is 15-25 mm/min.

4.4.8Adjust the installation height of the workpiece and the position of the guide plate or roller:

Move the guide wheel frame to change the height of the pallet so that the center of the finished size of the workpiece is at the required height of the workpiece device, and pay attention to the contact point between the workpiece and the pallet so that the wear debris is not embedded between the workpiece and the pallet. Otherwise, it will affect the surface quality of the workpiece. After the installation position of the workpiece is determined, the guide wheels at both ends of the bracket can be adjusted, and the guide wheels at the inlet and outlet on one side of the guide wheel can be adjusted. Too tight or too loose adjustment will directly affect the flatness of the workpiece bus, so it must be carefully adjusted. The adjustment should be carried out under the low speed rotation of the guide wheel, so as not to damage the surface of the guide wheel. The guide wheel on the side of the grinding wheel is only used for protection, so as to avoid accidents caused by parts falling into the side of the grinding wheel.

D.1

D.

Grinding wheel

1-2mm

Description:Δ-half of the workpiece passes through the grinding at one time; Δ1-slightly lower than the guide wheel The front and rear guide plates on one side of the grinding wheel can be installed loosely (there can be a gap of 0.4-0.8mm between the workpiece and the guide plate) to avoid pressure from the workpiece on the guide plate.

Guide wheel

 

4.4.9Test grinding parts:

For through grinding, if the spark distribution in the grinding area is uneven, the actual situation can be observed for the correction and dressing of the guide wheel and the fine adjustment of the grinding angle of the grinding wheel. For example, if the taper is large, the straightness of the guide frame and the guide wheel bus can be corrected accordingly. Strictly speaking, the first test grinding must track and adjust the material rack to ensure uniform rotation of the workpiece and prevent flying! Until the workpiece tolerance finish normal and then officially put into production.

5.0Work Content

5.1It is strictly forbidden to use machine tools with super energy

5.2Start the lubrication pump first, and after the indicator light is on, start the grinding wheel running for 3-5 minutes. Pre-grinding processing can only be carried out after confirming that the lubrication, hydraulic, cooling and electrical systems are operating normally.

5.3When the grinding wheel is running fast, pay special attention to the moving distance. Prevent the grinding wheel from colliding with the product.

5.4The diamond of wheel dresser and guide wheel dresser should be sharp, and there must be sufficient coolant when dressing.

5.5When replacing the grinding wheel, use a wooden stick to knock the grinding wheel to check whether there are cracks, and the grinding wheel should be statically balanced. The grinding wheel and the chuck tire shall be firmly fastened, and the grinding wheel (or guide wheel) and the flange plate shall be padded with 0.6-2mm rubber pad, and the clamping force shall be uniform.

5.6Install the grinding wheel carefully, and apply force when tightening the nut. It is strictly forbidden to exert too much force to affect the accuracy of the spindle, and the protective plate should be locked after installation.

5.7The pallet bracket must be firmly fixed, and the center of the workpiece must be higher than the center of the grinding wheel and the guide wheel during grinding.

5.8After the grinding wheel is dull, it should be trimmed in time and cannot be used continuously.

5.9When the machine is running, the operator shall not leave the job without authorization.

5.10When the straightness of the processed workpiece exceeds the requirements of the process regulations, it shall not be processed.

5.11Check lubrication, hydraulic, cooling, mechanical, electrical and other devices frequently. Found abnormal imagination should be immediately shut down, find out the cause, timely treatment.

6.0After work

6.1Before stopping the machine, turn off the coolant and run the grinding wheel empty for more than 2 minutes to dry it.

6.2All operating handles, switches and knobs must be placed in the shutdown position to cut off the power supply.

6.3Before leaving work, the processed products must be cleaned up and placed in the designated area, and the lighting facilities and doors and windows of the workshop must be closed before leaving the workshop.

7.0Precautions

7.1The operator must be familiar with the performance of the grinder, and must be trained and qualified before taking up the post.

7.2Except for professional operators, it is strictly forbidden for others to operate the machine to prevent other accidents.

7.3When operating the grinding machine, you must pay attention to the gap distance between the grinding wheel and the knife plate before turning on the spindle motor.

7.4During the operation of the grinding machine, attention should be paid to safe operation. During the operation of the grinding machine, the grinding wheel and the guide wheel should not be touched at will to prevent the material from splashing and hurting people.

7.5The materials to be ground shall not be incomplete, scratched or pinched, and shall be straight during feeding to prevent the feeding track from being stuck.

7.6During the grinding process, the product size should be tested regularly to carefully confirm whether the product size meets the requirements. If there is any problem, stop grinding and deal with it in time.

7.8Regularly check the knife plate of the grinding machine, if there is wear and tear, the knife edge must be replaced in time.

7.9The residual debris on the grinding wheel and cutter plate must be cleaned to avoid the presence of debris during product processing to prevent the grinding material from being stuck and affecting the service life of the cutter plate.

Common problems and solutions of long axis grinding:                             

1. Burn

Cause:1Grinding area too short Small mouth of grinding wheel2Insufficient cooling water 3The grinding wheel does not match the material4Angle mismatch between grinding wheel and guide wheel5The amount of grinding is too large.

Solution:

1.1Reasonably adjust the grinding area and increase the opening to make the grinding wheel backward from the inlet.60%To participate in grinding, only fine-tuning the angle of the grinding wheel corrector can be used to trim the grinding wheel for trial grinding. The inlet end of the grinding wheel will not be ground for one centimeter, and it cannot be formally produced until it is adjusted to the appropriate grinding angle. (The grinding zone will become longer when the grinding allowance increases. The grinding wheel must be flattened!)

1.2The coolant must be sufficient, because the grinding zone of the grinding wheel will instantly reach a high temperature of nearly 1,000 degrees during the grinding process. If the grinding surface cannot be fully cooled, burns will occur and changes in metal surface performance will occur.

1.3It is very important to match the material of the grinding wheel with the product to be processed, ordinary carbon steel. Soft (hrc60A) alloy steel generally uses brown corundum grinding wheel grinding, stainless steel High speed steel using diamond best, boron nitride Single crystal corundum and green carbon are also good choices. The higher the hardness of the material, the softer the grinding wheel (according to the current company's existing product structure brown corundumMlevel, basically can be satisfied).

Other reasons: dressing the guide wheel makes the workpiece walk downhill; When grinding large-size shafts, improper rotation speed of the guide wheel will also cause burns, grinding deviation and bending. Too fast-will increase the unit grinding volume to produce higher temperature will burn. Too slow-the contact time between the grinding wheel and the grinding point is too long, and the single point cannot be cooled.

2. grinding bending

Cause1Grinding wheel grinding area too far forward No mouth 2The guide wheel is used at an inappropriate angle. 3Rear shelf low4Guide wheel speed mismatch. Solution:

2.1If the grinding area of the grinding wheel is too far forward, the grinding is concentrated at one point and the instantaneous temperature difference is too large, which will produce a slight straightness change and cause the material to swing and make the subsequent part of the grinding deviate and bend more and more.

2.2The use angle of the guide wheel is inappropriate, and the diameter of the guide wheel is adjusted to be larger before than after.20-60Silk. In the adjustment, it is mainly to ensure that the sample rod is not interfered by the grinding wheel too seriously. The correct adjustment method is that the grinding wheel can hold the sample rod not too tightly, and gently shake the sample rod to make it connect with the guide wheel bus.100%Contact can be tested with thin paper.

2.3The low material of the front rack will warp up and leave the support of the knife plate in the rear half of the knife plate, resulting in swing. The vibration produces a grinding bend. After the material rack is ground to the rear of the material, it will leave the support of the knife plate and produce grinding bending. The solution is to track and adjust the material rack during the first few grinding so that each group of rollers will exert the same force.

3. spiral pattern (only the long axis is mentioned here)

Cause:1The knife plate is used too close to the top..  2Wear or damage of the cutter plate alloy.  3Severe grinding wheel threshing.   4The knife plate does not match the produced material.5The guide wheel angle does not match the grinding wheel. Solution:

3.1When the grinding machine is adjusted, the workpiece will contact with the middle line of the knife plate alloy as much as possible, so that the swing caused by the straightness problem of the material will not be scratched by the corner of the knife plate alloy during the work, and the back of the convex point will be scratched once it is scratched. Therefore, during normal adjustment, the distance between the knife plate and the grinding wheel should be reduced as much as possible.,The material is best in the middle of the knife plate alloy.

3.2Check whether the knife plate is damaged before use, and replace the lost knife plate directly. If the wear is not obvious, the adjustment is to use a straight line to avoid the wear position as much as possible.

3.3The number of grinding wheel sanding scratches occurs when the processing material is soft and the center of use is low. For soft materials, only the sand grains with higher hardness of the bonding agent are not easy to fall off the grinding wheel. For general materials, the methods of increasing the center height, increasing the rotation speed of the guide wheel and extending the grinding zone can be used to reduce the pressure of the workpiece on the cutter plate so that fine sand grains can be easily removed.

3.4Some materials should not use alloy knife plate, such as high nickel The grinding viscosity of high chromium steel is too high to form a hard block on the knife plate and scratch the product.

3.5Redress the guide wheel pull frame to match the cutting angle of the guide wheel and the grinding wheel.

4. end ellipse and product ellipse out of tolerance

Cause1Material ends are bent.2Poor straightness. 3The guide wheel is not rounded.4Grinding wheel guide wheel spindle clearance is too large.5The longitudinal feed is too large, the speed of the guide wheel is high or low, and the grinding wheel is small. Solution:

4.1Straightness of raw materials shall be0.15mm/EverymWithin, the straightness difference will cause the material to swing when entering the grinding area to produce flat grinding, which can increase the number of grinding to ease or straighten before grinding.

4.2Retrim the guide wheel to ensure that the use of template trimming to reduce the impact of vibration, each trimming should allow the dresser to stay in the same position.

4.3When the gap between the grinding wheel shaft is large, the product will be flattened by swinging during operation. This situation must be solved by professional maintenance and adjustment of the shaft gap.

4.4Speed up the speed of the grinding wheel, reduce the amount of longitudinal feed, adjust the linear speed of the guide wheel.0.3-0.53Meters/between seconds.

5. products have taper

Cause: the material rack is not adjusted properly.

Solution: There are two types of size head here.1Two big or small 2The whole only gets bigger or smaller in turn.

5.1Since the material rack is not adjusted to one side and the front rack is biased to one side of the guide wheel, one end of the material will grind small and the reverse will become larger during grinding. The rear material rack is biased to the direction of the guide wheel, and the rear end of the workpiece is small, and the rear end of the grinding wheel is large. In this case, the dressing rack should be rearranged and attention should be paid to making each group of rollers exert force consistently.     5.2After the material rack is gradually adjusted lower, the ground workpiece gradually becomes larger, which can be solved without readjustment and only by following the bar adjustment roller support force.

6. gnawing injury

Cause: basically produced in the workpiece head and tail20About cm, the material shakes and causes gnawing of the grinding wheel.

Cause analysis: This situation basically has three reasons1The contact surface between the guide wheel and the workpiece is small, and the workpiece is not supported by the guide wheel in the front and rear half of the guide wheel, which is mostly used in small and medium diameter products.2The material is too fine out of the grinding wheel ten centimeters in length without support.

6.1The low workpiece of the front material rack is separated from the knife plate support at the outlet: the grinding diameter is ≤25Millimeter diameter products, to the knife plate5There must be a guide support or roller within a centimeter to ensure that the material does not shake in the air. The shaking caused by the low front material rack can be solved by readjusting.

6.2The loss of circle of the guide wheel causes too much grinding of individual points to form scars: solutions

6.3The dressing guide wheel ensures smooth contact with the workpiece without losing roundabout.

6.4If the grinding zone is concentrated at one point, the use of a center-high and slightly lower cutter plate and the workpiece subjected to high pressure under the grinding wheel will also produce workpiece chattering, which may occur in some uncertain positions or even edge circles.

7. guide wheel and grinding wheel dressing:

Adjusting the inclination angle of the guide wheelaGrinding1.5He ︒-2He ︒And the turning angle of the guide wheel dresser is slightly smaller than the inclination angle, turn the speed regulating hand to the high-speed position, turn on the water nozzle switch of the spray guide wheel, and then carry out dressing. in order to ensure the cutting performance of the grinding wheel and the required correct surface, the grinding wheel must be trimmed in time. fine grinding wheel dressing plays a great role in improving roughness. during dressing, rough trimming0.002-0.005; fine trimming0.002-0.0005Reciprocating speed: rough trimming100mm/min,Fine trimming50mm/minHigh-precision repair15-25mm/min.

Table of influence of guide wheel dressing parameters on spark distribution in grinding area:

Parameters	too big	Small
hDiamond pen displacement right shift right deviation	Hard sparks at the front of the grinding wheel (at the workpiece inlet)	Sparks at the rear of the grinding wheel (at the exit of the workpiece) are hard.
	Sparks at the rear of the grinding wheel (at the workpiece exit) are soft	The front part of the grinding wheel (at the workpiece inlet) has a soft spark.
atranslation angle	The spark in the middle of the grinding wheel is soft, and both ends are hard.	The spark in the middle of the grinding wheel is hard, and both ends are soft.

When the adjustment and improper operation may produce defects:

Adjust operation condition	Possible defects	Remarks
Workpiece center high too low	Poor edge roundness
Workpiece center too high	Small edge produced by workpiece beating
The workpiece outlet spark is too hard	easy to burn, roundness\Poor finish, spiral lines and other defects on the surface of the workpiece in severe cases	To perform a guide wheel alignment or turn the guide wheel frame horizontally
Grinding wheel drive belt runout	Easy to produce edge degree	Pull the belt in is expected to improve
The grinding wheel has worn out	Burn occurs when the surface roughness is severe	Blunt is the appearance of a cry
Large vibration of grinding wheel	There are small edges on the surface of the workpiece, the surface quality is poor, and the workpiece has runout in severe cases.	Sometimes the cooling water seeps into the grinding wheel.
Poor contact between guide wheel bus and workpiece	Taper or uneven generatrix of workpiece, small edge or other defects at both ends of workpiece	Guide Wheel Calibration Repair Required
Bracket-Rear deviation of guide wheel connection	Taper, drum-type or saddle-type surface defects
Diamond pen blunt	The durability of the grinding wheel is reduced, and the surface quality of the workpiece is poor.

 

Eight The relationship between the shape of the guide wheel and the workpiece

8.1In the through grinding operation, the function of the guide wheel is to drive the workpiece to rotate while giving the workpiece a radial thrust, so the guide wheel should be inclined at an angle. In order to increase the contact length between the guide wheel bus and the workpiece, the guide wheel should be built into a single-page hyperboloid shape with large middle and small middle at both ends,A straight line on the face of a single-page hyperboloid is an oblique straight line.This requires translating the guide wheel corrector by an angle to trim the guide wheel to achieve the ideal contact bus.The inclination angle of the inclination angle of the guide wheel can be close to the angle of the straight line of the curved surface, so that the contact between the guide wheel surface and the workpiece can be ensured to be in a line contact state.

8.2Since the grinding speed of different workpieces is different, the larger the diameter of the workpiece, the slower the grinding speed. Therefore, the larger the diameter of the material, the smaller the inclination angle, the smaller the translation angle, and the larger the displacement of the diamond pen.

Nine The problem of the rough processing of the center-less grinding: the cause of the rough surface of the product,1.Grinding wheel mesh is too small.2Center height too high or low 3Short grinding area.4Whether the cutting fluid has slick oil or has deteriorated.5The center height of the product is too low 6 The grinding area of the product is too short; the vibration of the grinding wheel is too large 7 The quality of the guide wheel is too poor.

Solution:

9.1The greater the choice of grinding wheel when the product roughness requirement is high, the greater the choice of grinding wheel when the product roughness requirement is high.Ra0.4When the following80The mesh grinding wheel can be met, the roughness of the high selection of finer grinding wheel and the use of a polishing effect of the resin bond grinding wheel.

9.2The high center of the workpiece will cause the workpiece to jump and produce white spots and rough spots, and the low center will cause the wire pattern to increase the pressure of the knife plate.

9.3The grinding wheel working area of the product grinding process can be divided into three areas, namely the grinding area Grind to proper size. Light repair area Is the grinding area coarse light grinding fine light. Polishing area Grinding without grinding amount is equivalent to reactive polishing. Therefore, with a reasonable area length, the roughness of the product will be poor when only the grinding area is not polished and polished.

9.4Coolant must have lubricating effect, only full lubrication can achieve the ideal roughness, general materials use emulsified oil3%That's it.

9.5Spiral lines appear on the grinding surface: 1. The outlet end of the grinding wheel is "convex". The method of elimination is that this "convex" part should be trimmed more when the grinding wheel is trimmed. 2,2The pallet has been chipped to produce sharp edges or a surface with napping. The method of elimination is to grind the pallet or replace the pallet. 3,1 page 6 page: 2 page 8 talk)|$ talk! '3,Appropriately adjust the speed of export and feed to make the workpiece feed and export speed consistent with the grinding zone. 4. The grinding wheel binder has uneven hardness, resulting in uneven threshing of the grinding wheel. At this time, the new sand grinding wheel 5 must be replaced. There is a deviation in the relative position of the axis of the grinding wheel and the guide wheel, and it must be re-aligned as required.

9.6There are vibration marks on the surface (Axial striation marks with the same light and shade are vibrato marks.）：1The grinding wheel or some other parts are unbalanced, and the clamping of the grinding wheel is incorrect, which causes the machine to vibrate when the grinding wheel rotates. At this time, the grinding wheel and chuck should be rebalanced. When installing the grinding wheel, pay attention to the correct grinding wheel clamping method. 2,2,The vibration of other machine tools or vehicles is transmitted to the machine tool. At this time, the machine tool should be kept away from these vibration sources, or anti-vibration trenches should be dug to isolate and weaken the incoming vibration. 3. If the center of the workpiece is too high, the grinding wheel reduces the component force of the workpiece pressing against the pallet and the guide wheel through the grinding force, causing the workpiece to be unable to maintain good contact with the pallet and the guide wheel smoothly, causing the grinding to vibrate. At this point, the pallet should be lowered. 4, the pallet installation is not strong, so that the workpiece through the pallet vibration. Reinstall or reinforce the pallet at this time. 5, the length of the transmission triangle belt is different, causing machine vibration. At this time, the length of the triangle belt should be readjusted or replaced. 6. The spindle bearing is improperly adjusted or worn, causing the grinding wheel to vibrate. At this time, the bearing adjustment screw should be opened to readjust the clearance of the bearing. 7. The machine tool motor vibrates, causing the machine tool to vibrate.

9.7Irregular scratches on the surface: The main reason for irregular scratches on the surface is the problem of the coolant. One is that the coolant is not clean, and the other is that the coolant has poor performance, resulting in shedding abrasive particles or wear debris staying in the grinding area. Scrap the workpiece. If the former, you can replace the new coolant or add a coolant filter device; if the latter, replace the coolant with good lubrication and cleaning performance.

9.8Surface burn: The main reason is that the temperature of the cutting place is too high, and the grinding heat generated by grinding cannot be discharged immediately, causing the surface of the workpiece to burn. It may be that the cutting depth is too large, the cutting speed is too fast, the grinding wheel is too hard or dull, and the cooling is not enough. The solution is to reduce the cutting depth, reduce the cutting speed, choose a softer grinding wheel, trim the surface of the grinding wheel, improve the structure of the cooling device, so that the coolant can reach the grinding area to the maximum extent, and increase the cooling device in the cooling system. Coolant flow.

9.9The workpiece produces polygonal shapes, such as triangles, pentagons, heptagons, etc,. G. D/ C) q7 u" _6 j NThe main reason is that the workpiece rotation is poor or rough roundness error is too large. 1. The center of the workpiece is not high enough, which increases the component force of the grinding wheel pressed to the pallet and the guide wheel through the grinding force, causing the friction force between the workpiece and the pallet to increase, preventing the workpiece from rotating, causing the workpiece to run poorly in the grinding process, resulting in roundness tolerance. At this time, the center height of the workpiece should be increased, but it should be noted that the high center height of the workpiece will cause the workpiece to jump during grinding, and it will also produce processing errors, which will make the grinding impossible in severe cases. Therefore, attention should be paid to selecting the appropriate center height. 2,2The inclination angle of the guide wheel is too large, which makes the workpiece run poorly during processing. The solution is to reduce the guide wheel inclination, at this time to keep the feed speed unchanged, you should increase the guide wheel speed. 3. The roundness error of the blank is too large. Under normal circumstances, the roundness error of the blank cannot exceed 50% of the grinding allowance. The solution can be to add a process before centerless grinding to improve the roundness of the blank, or to grind several times during centerless grinding. 4, the poor operation of the guide wheel, resulting in poor operation of the workpiece, the guide wheel must be trimmed at this time to keep the guide wheel running well, in addition to check and adjust the guide wheel bearing to maintain good contact between the guide wheel spindle and the bearing.

The diameter of the 10. at both ends of the grinding bar is smaller than that of other places: this is mainly due to the insufficient rigidity of the grinding wheel or the guide wheel, which is caused by the change of cutting depth when the load changes. This requires re-adjustment of the grinding wheel or guide wheel bearings.

11. The axis of long workpiece parts is not straight: this may be caused by poor adjustment of the machine tool and feeding mechanism and the workpiece itself is not straight before processing. One solution is that the machine tool and the feeding mechanism need to be carefully readjusted. Second, the workpiece must be straightened before processing, in addition to the heat treatment to eliminate stress, the workpiece must also be straightened between the two grinding. Three is to increase the coolant flow. In the grinding process, the bad shape of the workpiece is also related to the machine guide plate. Correctly adjust the position of the guide plate, it is not difficult to find the corresponding solution.

XII,Disassembly and replacement of grinding wheel:

First remove the grinding wheel cover of the grinding frame, then pull out the floating clutch of the pulley part to disengage the coupling on the main shaft, so that the grinding wheel can be removed from the grinding frame together with the main shaft bearing, and the grinding wheel removal device can be installed to make the main shaft stand upright, and the grinding wheel can be removed and replaced by the end cover of the grinding wheel chuck. If the new grinding wheel needs to be statically balanced after installing, the coupling screw between the grinding wheel chuck and the spindle can be removed, and the corrugated tightening bolt can be loosened, the grinding wheel and the grinding wheel chuck can be removed from the spindle, and then the grinding wheel balance mandrel can be installed for static balance. If the vibration of the new grinding wheel is great after the first dressing, the new grinding wheel should be statically balanced again, or balance on the machine tool by experience, conditional support is best to use the vibration balance meter to balance the whole machine.

XIII. Removal and Replacement of Guide Wheel

First, screw the diamond cutter bar of the guide wheel dresser to the highest position, remove the water baffle, remove the cooling nozzle device, then loosen the hexagonal fastening screws of the two glands, so that the two glands can be removed, then disconnect the gearbox and the clutch of the main shaft, then lift the guide wheel and the main shaft bearing together, then use the same method as the grinding wheel to make the main shaft upright, and then loosen the guide wheel pressure cover, then directly take out the guide wheel and replace.

Fourteen, the adjustment of the grinding wheel spindle

Put the spindle (with grinding wheel) on a shelf so that it cannot rotate, place a magnetic table on the spindle or chuck, loosen the locking screw of the spherical support screw, and then adjust the tightness of the spherical support screw with an Allen wrench. In order to keep the spindle from skewing in the two sleeves, when the supporting sleeve is rotated (its end face should be attached to the shoulder of the spindle shaft, and pay attention to the direction of the disk), the oscillation of the dial indicator should not be greater than 0.01mm, and it is better to have the same direction of the oscillation of the two supports to minimize the error. Then tighten the locking screw and measure the clearance of the bearing. When lifting the support sleeve up and down by hand, the position error value of the dial indicator should be between 0.015-0.02mm, and the clearance of each bearing bush (that is, the five directions of the bearing) Should be equal, and finally check whether the vibration of the support sleeve is within 0.01mm. The bearings adjusted according to the above methods can be officially used after two hours of trial operation on the machine tool.

Fifteen, guide wheel spindle adjustment

The adjustment method of the guide wheel spindle is the same as that of the grinding wheel spindle. In order to ensure high working accuracy, the clearance of the guide wheel bearing should be within 0.003-0.005.

Conclusion:

Grinding by centreless grinder is a key process in the whole processing of chrome-plated rods. Grinding is often required several times from the blank rod diameter to the finished rod diameter. To meet the IT3- IT5 accuracy requirements, the grinding times of centreless grinder will not be less than 3 times (rough grinding, smooth grinding and fine grinding), because grinding by centreless grinder will complete and meet the following requirements: ① Grinding shaft must meet the geometric dimension and tolerance requirements. ② Roundness meets the requirements. ③ The cylindricity meets the requirements. ④ The surface roughness meets the requirements. ⑤ The appearance meets the requirements. The operator level of the center-less grinder in the production of chrome-plated rods is also the highest. When implementing the post salary, the type of fine grinding rod is the highest level, which shows its importance. When talking about the numerous technical requirements of centerless grinding, it generally refers to the requirements of the fine grinding process, that is, the last grinding. The rough grinding rod and semi-fine grinding are the foundation for fine grinding, especially the roundness. The roundness of the bars transported from the steel plant is poor, and can only be corrected after grinding again and again to meet the requirements. We believe that anyone who can operate the fine grinding process will operate the coarse grinding or semi-fine grinding (semi-coarse grinding) process. Therefore, the purpose of the training is to train a group of operators who can operate fine grinding. This is a high-grade requirement and our company's requirement. Please work hard! I also remind the operator that after the shift is over, the machine tool must be cleaned, daily maintenance must be carried out, and the equipment must be taken care of, so that the machine tool can not lose accuracy.

 

 

 

 

 

 

Shape and matching angle of grinding wheel and guide wheel: