Remedies for Troubles of Hydraulic System

1	Oil does not enter into the pump	Inversion of the motor	Reverse the terminals
		No oil in the oil pump	Remove the oil-pipe and add oil into the pump
		Oil level is too low in the tank	Add oil into the tank
Oil filter is blocked	Clean the oil filter
Oil pump is damaged	Replace the oil pump
2	Oil pressure is insufficient	Over-flow valve is jammed	Repair the valve
		Oil pump is seriously worn	Replace the oil pump
Oil plug falls down	Fix the oil plug
3	Creep of worktable	There is air in hydraulic system	Exhaust air
		Air leakage in oil supply system	Seal the air leakage point
		Guideway contact is not good	Rescrape the guideway
Lubrication of the guideway is insufficient	Strengthen the lubrication of the guideway
Centers of the hydraulic cylinder and guideway are  unparalleled	Readjust
Guideway oil is not qualified	Replace the oil
4	Dwell time is not stable	Throttle valve for dwelling is blocked	Clean the throttle valve
Dwell time is set too long	Reset
5	Worktable does not reverse	Speed of worktable is too low	Adjust the speed
		Stop-nut of the pilot valve is maladjusted	Readjust
Rod of reverse valve is stuck or rusty	Clean the rod
Gap of pilot valve is too large	Replace the pilot valve
6	Noise and vibration in the system	Air remained in the system	Exhaust air
Oil pump or the clutch is damaged	Replace
7	Function of automatic recycle fails to work	Electrical system or solenoid does not work well	Check the system depending on the diagram
8	Periodic feed is incorrect	Air is remained in the oil-pine	Exhaust air
Note: No.7 and No.8 are only suitable for semi-automatic model.

 
 
 
 
Remedies for Grinding Defects
 

No.	Grinding Defects	Possible Causes	Remedies
1.	Straight waves on the surface of workpiece	Vibration comes from outside of the machine	Eliminate or isolate the vibration
		Clearance of the spindle is too large	Readjust the clearance
		Grinding wheel is not balanced	Rebalance the wheel
		Grinding wheel is too hard	Replace a softer one
		Grinding is blunt	Redress the wheel
Workpiece is supported loosely between centers	Adjust the tailstock
Do not use center rest for thin and long workpiece, or the support force of the center rest is not enough	Mount or readjust the center rest
The center holes of workpiece do not contact well with the centers	Redress the holes or the centers
Cross feed is to large	Readjust
Rotary speed of the workpiece is too high	Readjust
2.	Spiral line on the surface of workpiece	Due to the large clearance, the spindle is forced to displace and only half area of the wheel is in working	Readjust the clearance
		Due to the thermal deformations of the grinding carriage and headstock, only one side of the grinding wheel is in working	Operate the machine when the temperature is stable
		The out-of-straight of the feeding guideway makes the grinding position inconsonant with the dressed position, so only half area of the wheel is in working	Make the two positions conform with each other as much as possible
Rigidity of headstock and tailstock is not enough	Find out the reason of weak rigidity and eliminate it
Generatrix of the grinding wheel is not straight after dressing	Readjust
Speed of worktable is too high	Appropriately adjust it
3.	Workpiece is convex	The workpiece bent over to the feeding direction	Mount a center rest
		Supporting force of the center rest is not enough, or do not adjust the rest when the workpiece becomes smaller	Readjust the center rest
Grinding wheel feeds too much, or the dwell time is too long at both ends of workpiece	Readjust
Original accuracy of longitudinal guideway is lost	Rescrape the guideway
4.	Workpiece is concave	Supporting force of center rest is too much	Readjust the center rest
		Grinding time for the middle part is longer than that of two ends	Decrease the grinding time at two ends
Original accuracy of longitudinal guideway is lost	Rescrape the guideway
5.	Inner hole of workpiece is horn-shaped	The grinding wheel is too harder or too fine	Replace with the softer or rougher wheel
The amount of feed is not proper or the the dwell is occurred at one end of workpiece	Readjust the feed amount
6.	Generatrix of taper hole is not straight after grinding	Equal-height difference between centers of workpiece and grinding wheel is too much	Readjust the machine bed or replace with a smaller wheel
Original accuracy of longitudinal guideway is lost	Rescrape the guideway
7.	Scratches on the surface of  workpiece	Coolant liquid is not clear	Replace the coolant  liquid and filter it finely
Grains fall down on the workpiece	Increase the liquid flow when dressing the wheel
8.	Burnt marks or cracks on the surface of workpiece	Grinding wheel is too hard	Replace with a softer one
		Feeding amount is too much	Decrease the feeding amount
Grinding wheel is not dressed well or becomes blunt	Redress the grinding wheel
Coolant liquid is not supplied sufficiently	Increase the coolant liquid
9.	Surface of workpiece is rough and in fish-scale shape	Grinding wheel is not dressed well or becomes blunt, or the surface of wheel is dirty	Redress or clean the wheel
		The hardness of wheel is not even	Dress the uneven layer or replace with a new one
The wheel is not dressed well due to the unshaped diamond or the shaking of diamond when dressing	Sharpen the diamond or eliminate the shaking
10.	Roundness of the cylindrical surface is bad	Center hole of workpiece or centers are not round, or they do not match well, or the contact area is dirty	Reshape the center holes or clean the centers or replace with new centers
		Workpiece is not balanced	Balance the workpiece
Original accuracy of bearing bore of headstock or center sleeve bore of tailstock is lost	Check and repair, or replace with new ones

 
 
 
 
 
 
 
Maintenance of the Machine

1. Daily maintenance
   1. Before starting
   2. Fill the specified lubricant into oil basin and all lubricating positions
   3. Check the make sure that the electrical switches are in zero point and connections are in normal condition.
   4. Check and make sure that all clamping screws and protecting shields are tightened.
   5. Make sure that the machine is supplied with sufficient coolant.
   6. After starting
   7.  Check and make sure that the working pressure is normal.
   8.  Make sure that the spindle oil is sufficient.
   9.  Sufficiently lubricate the guideway.
   10.  Idle running for ten minutes before normal operation.
   11.  In terms of semi-automatic machines, turn the switches to specified points and cycle the movements several times before the semi-automatic cycle grinding.
   12.  Before shutting down the machine, stop the coolant firstly, run idly for about five minutes and then stop the grinding motor.
   13.  Clean each part of machine to prevent rust after using.
2. Weekly maintenance
   1. Change the coolant.

Clean the coolant tank thoroughly before filling new coolant.

1. Clean all parts of the machine and smear the rust-proof grease, and cut the power at weekend.
2. Keep motors clean.
3. Seasonally maintenance
   1. Change the spindle lubricant.
   2. Change the lubricant in the tank of headstock.
4. Half-yearly maintenance
   1. Change the hydraulic oil in the tank of machine bed.

Do not use the cotton yarn but fine rag or foamed plastic to clean the oil tank.

1. Clean the radiator of hydraulic system. (Only for high-precision machine)
2. Check the condition of electrical parts.
3. Yearly maintenance
   1. Remove and clean all rolling bearings in the machine and motors.

Coat lubricating grease on the bearings and mount them again, and replace the worn ones.

1. Change the old fuse wires with the same current ones. Never change the current of fuse wires.
2. Check the quick-wear parts and replace them if necessary.
3. When changing the nodulized copper filter of workhead, cement the new one to the filter body with glue 402.

Change the filter if it is blocked.