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CP642 Ballscrew Replacement

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CP642 Ballscrew Replacement | 23 June, 2009

Hi All,

The x-axis ballscrew on the x-y table of our Fuji CP642 is getting very noisy. Could someone in the know please run me through the procedure for changing the ballscrew and will any calibration be required after fitting?

Any help much appreciated, thanks.

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CP642 Ballscrew Replacement | 24 June, 2009


Procedure how to replace the x-ballscrew of CP642.

1. Before you remove the x-motor, remember the pulse of x-axis motor just it turn ON the zero set sensor. Pulse usually at 1000pls. +/-50pls. 2. Turn Off the machine. 3. Compress the two ballscrew covers. Fix it with tie wrap 4. Loosen the coupling connecting the x-motor and ballscrew. 5. Remove the x-motor. 6. Remove the 4 big allen screw fixing the x-motor bracket. 7. Remove the 2 positioning pins of x-motor bracket. 8. Loosen the other side of the bracket. Then, remove the bracket by tapping with soft mallet. 9. Remove the cover of the ballscrew. 10. Remove the 4 bolts from ballscrew. 11. Position the x/y table at the rear and leftmost of the machine. 12. Get a position wherein you can pull-out the ballscrew from the machine. 13. After successfull pull-out. Remove the ballscrew from the bracket. 14. Remove the angular bearing. 15. Clean the brackets. Put AFC grease on the bearings. Install the angular bearing. Note: For angular bearing, their is a V-shape mark. The V-shape mark must pointing the motor. If the bearing orientation is wrong, unusual sound will heard during table movement. And the life of the bearing will shorten. 16. Assemble the ballscrew and the x-motor bracket respectively. Put all the parts, such as bracket, ballscrew cover, and collars. Tighten all the screws and set screws. 17. Install the ballscrew. 18. Fix the ballscrew to the table. 19. Put the end bracket of the ballcrew. Note: Before connecting the end bracket, see to it, you put the ballscrew cover. Do not fix yet the bracket (Hand tight only). 20. Fix the x-motor bracket. Do not forget to put the 2 positioning pins. 21. Install the coulping. 22. Install the x-motor. Note: Coupling must be sliding smooth from the ballscrew shaft and the motor shaft. 23. Perform ballscrew alignment using dial gauge. Z and Y position of the ballscrew must be 0.1mm. After getting the right alignment fix the end bracket. 24. Check for heavyload on the ballscrew when travelling it manually from right to left or vise versa. Note: if you feel the ballscrew is heavy conduct again the alignment. 25. Power on the machine. Conduct zero setting. 26. After machine is zero set, Inch the motor to the pulse you recorded earlier. 27. Position the table wherein the zero set sensor just turned-ON. 28. Position the x-axis coupling where you can easily tighten the screws. 29. Remove the tie wrap from the ballscrew covers. 30. Double check all the bolts. Be sure all are tighten. Ballscrew replacement is DONE!!!

Good Luck.


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CP642 Ballscrew Replacement | 24 June, 2009

Eagle eyes, unless you are having placing accuracy issues I would not replace the ball screw.

I have heard brand new ball screws make noise. We have a CP6 that has a noisy screw from the factory.It has ran for years with no accuracy issues.

Save your money if you can deal with the noise.

Nice post Jaslen. One quick side note to add.. Be careful when you compress and uncompress the ball screw covers. Make sure you have them captured very securely, or you will be going to the emergency room for stitches.

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CP642 Ballscrew Replacement | 24 June, 2009

I have a used CP642 ball screw - in good condition

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CP642 Ballscrew Replacement | 25 June, 2009

Hi and thank you for your replies,

I feel a lot more confident about tackling the job with your instructions, many thanks. We haven't seen any accuracy issues, and the ballscrew has been making the same banging/knocking noise when changing direction quickly for at least a couple of years. The play in the ballscrew is about 0.1mm, and the edges of the screw feel rough. On our other CP6 there is no more than 0.02mm play and the ballscrew is smooth. Do you think it could fail completely and take out the x-y table or will it just get louder over time?

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CP642 Ballscrew Replacement | 25 June, 2009

Banging and knocking is not good. The noise that we hear on ours is more of a whining.

.1mm runout and rough edges = time to replace in my opinion.

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