Centerless Grinding machines

1、 Parts are not round

Reason for occurrence

（1）The guide wheel has not been rounded

（2）The grinding frequency is low or the ellipse in the previous process is too large.

（3）Blunt grinding wheel

（4）Excessive grinding or cutting amount

Elimination methods

（1）Repair the guide wheel and wait for it to finish rounding (usually until there is no intermittent sound)

（2）Appropriately increase the number of grinding cycles

（3）Repair the grinding wheel

（4）Reduce wear and heavy tool speed

2、 The parts have a polygonal shape (polygon)

Reason for occurrence

（1）The center height of the parts is not high enough

（2）The axial thrust of the component is too large, causing it to tightly press against the stop pin and unable to rotate evenly

（3）Unbalanced grinding wheel

（4）The center of the component is too high

Elimination methods

（1）Accurate forward centering of parts

（2）Reduce the inclination angle of the grinder guide wheel to 0.5 ° or 0.25 °. If blocking cannot be solved, the balance of the pivot point needs to be checked.

（3）Balanced grinding wheel

（4）Properly reduce the center height of the parts

3、 Vibration marks on the surface of the parts (i.e. fish colored and straight white lines appearing on the surface of the parts)

Reason for occurrence

（1）Machine tool vibration caused by unbalanced grinding wheel surface

（2）Moving forward at the center of the component causes it to bounce

（3）The grinding wheel is dull or the surface of the grinding wheel is too polished

（4）The rotation speed of the guide wheel is too fast

Elimination methods

（1）Carefully balance the grinding wheel

（2）Properly reduce the center of the parts

（3）Grinding wheel or appropriately increasing the grinding wheel dressing speed

（4）Reduce the speed appropriately

4、 The parts have a taper

Reason for occurrence

（1）Due to excessive low busbars on the front guide plate or the inclined surface of the front guide plate towards the guide wheel, the front part of the component is small

（2）Due to the low surface of the rear guide plate and the guide wheel busbar, or the inclination of the rear guide plate towards the guide wheel, the rear of the part is small

（3）Due to the following reasons, the front or rear of the component may experience a taper

　　① The grinding wheel has a taper due to incorrect dressing

　　② The surface of the grinding wheel and guide wheel is worn out

Elimination methods

（1）Properly move the front guide plate and adjust it to be parallel to the guide wheel busbar

（2）The guide surface of the adjusted guide plate is parallel to the guide wheel busbar and on the same line.

　　①Adjust the angle of the grinding wheel modification according to the direction of the taper of the part

　　②Grinding wheel and guide wheel [WeChat for metal processing, good content, worth paying attention to]

5、 The center of the component is larger and the two ends are smaller

Reason for occurrence

（1）The front and rear guide plates are evenly inclined towards one side of the grinding wheel

（2）Grind the grinding wheel into a waist drum shape

Elimination methods

（1）Adjust the front and rear guide plates

（2）Modify the grinding wheel, and do not make excessive adjustments each time

6、 There are circular thread lines on the surface of the parts

Reason for occurrence

（1）The front and rear guide plates protrude from the surface of the guide wheel, causing the parts to be scraped by the edge of the guide wheel at the outlet or inlet

（2）The support ratio is too soft, and the ground cutting is embedded on the support ratio bearing surface to form protruding burrs, which are engraved into thread lines on the surface of the part

（3）The coolant is not clean and there are chips or sand particles inside

（4）At the exit, due to the large amount of grinding, it is scraped and ground by the edge of the grinding wheel

（5）The center of the part is lower than the center of the grinding wheel, resulting in greater pressure and causing sand particles and chips to stick to the support hair

（6）Blunt grinding wheel

（7）Excessive allowance or rough grinding of the grinding wheel, resulting in extremely fine thread lines on the surface of another component

Elimination methods

（1）Adjust the front and rear guide plates

（2）Replace the surface lubrication with higher hardness bristles

（3）Replace the coolant

（4）Make the edge of the grinding wheel rounded, so that the 20mm radius at the exit of the part is not ground

（5）Appropriately advance the center height of the component

（6）Grinding wheel

（7）Properly reduce wear and slow down modification speed

7、 Cut off a small piece at the front of the part

Reason for occurrence

（1）The front guide plate protrudes from the surface of the guide wheel

（2）The front end of the grinding wheel and the guide wheel are not in a straight line and differ greatly.

（3）Too much grinding at the entrance

Elimination methods

（1）Move the front guide plate back a bit

（2）Replace or modify the longest of the two

（3）Reduce the amount of grinding at the entrance

8、 The middle or tail of the part is cut, and there are several types of cuts:

1. The incision is rectangular

Reason for occurrence

（1）The excellent surface of the rear guide plate prevents the rotation of the parts and the grinding of the tread surface from continuing

（2）The extension of the rear support pad is too long, and the worn parts have not fallen off, which prevents the rotation and advancement of the worn parts

Elimination methods

（1）Move the rear guide plate back appropriately

（2）Reinstall the support pad

2. There are angular or many micro shaped marks on the incision

Reason for occurrence

（1）The rear guide plate is behind the surface of the guide wheel

（2）The center of the component is moving too high, causing the component to bounce at the exit

Elimination methods

（1）Move the rear guide plate slightly forward

（2）Properly reduce the center height of the parts

9、 The surface brightness of the component is not zero enough

Reason for occurrence

（1）The inclination angle of the guide wheel is too large, causing the cutting amount of the parts to be too fast.

（2）The speed of modifying the grinding wheel is too fast, and the surface of the grinding wheel is not shiny after modification

（3）The modification of the guide wheel is too thick

Elimination methods

（1）Reduce the inclination angle

（2）Reduce modification speed and modify the grinding wheel from scratch

（3）Repair the guide wheel

Note: When the grinding wheel is not started, it is forbidden to open the coolant. If the coolant is opened first, in order to prevent the occurrence of faults, intermittent driving (i.e. on, off, on, off) should be adopted to wait for the coolant to dissipate from the surroundings before starting work.