Maintenance for Z-Axis Ball Screws

Alloy Wheel Repair CNC Machine

In previous article, we have had discussions about one of the most important maintenance jobs for mechanical components installed on all Alloy Wheel Repair CNC lathes, that is, to keep both X-axis ball screw and Z-axis ball screw clean and lubricated. When ball screws are not cleaned and not lubricated as required, the work life span for these ball screws can be dropped as much as 85%.

wheel repair machine

Lehigh MR-2540 Alloy Wheel Repair Diamond Cutting CNC lathe

All electrical power must be turned OFF first.
We will provide the instructions as to how to provide maintenance to Z-axis ball screw on Lehigh Alloy Wheel Repair CNC lathe. The Z-axis ball screw is located in the front of the alloy wheel repair CNC lathe along longitudinal direction on which the tool post can travel from left to the right or from right to the left. In order to have the access to the Z-axis ball screw, one must remove the long sheet metal cover in the front with the following simple steps.
1. Alloy Wheel Repair CNC Lathe –Maintenance of Z-axis – Front Access
One can easily locate and remove the sheet metal cover at the front of the cross slide.  This sheet metal cover is about 6’-0” long in total length between the headstock construction on the left hand side and end of casting bed on the right hand side.
Z ball screw cover

After removing the front cover, you will have full access to Z-axis ball screw.

Before removing this sheet metal cover with full length, one must locate and remove all locking bolts at the top of this sheet metal cover one by one until they are all removed. During this procedure, the cross slide must be moved from left to right for a couple of time so that you can locate some locking bolts hidden behind it.
wheel repair machine

View at the left end: Multiple locking screws circled in red shall be removed.

2. Alloy Wheel Repair CNC Lathe –Maintenance of Z-axis: Lubrications
After removing all locking screws between the long sheet metal cover and the casting bed, the entire sheet metal cover only can be slided out from the right hand side of this alloy wheel repair CNC lathe so long as there is enough space to allow this sheet metal cover being removed.
In case that there is very limited space on the right hand side of the CNC lathe, use Allen Wrench (10 mm) at the very end of Z-axis ball screw to move the cross slide table towards the left hand side as much as it can until it is stopped.
Wheel Repair CNC machine

The end view of the Z-axis ball screw and its sheet metal cover in full length.

wheel repair machine

Moving the cross slide to the other end before removing sheet metal cover.

After removing the top sheet metal cover of the Z-axis ball screw, it would be very easy to remove all the chips and dust along the full length of the Z-axis ball screw. In particular, it is important to remove the piles of the chips and dirt inside of the housing of the Z-axis ball nut.  They must be removed carefully.
z axis ball screw

Close look of piles of chips and dusts

z-axis ball screws

Z-axis ball screw without top cover

It is also very important to verify and confirm that the automatic lubrication system is fully functional and the oil pipe from oil terminal going to the Z-axis ball screw provides enough oil on the Z-axis ball screw after cleaning job. Once again, in order to keep alloy wheel repair diamond cutting CNC lathe working correctly, both X-axis and Z-axis ball screws must be properly lubricated and kept clean all the time. For good machine shop practice, it requires full inspection on both X-axis ball screw & Z-axis ball screw every three month.

3. Alloy Wheel Repair CNC Lathe –Maintenance of Z-axis Servo Motor
To get access for Z-axis servo motor on Lehigh MR-2540 or MR-2940 Alloy Wheel Repair diamond cutting CNC Lathe, one needs to remove the sheet metal cover on left hand side of the sliding door first (see picture below).
To do so, one should close the sliding doors so that you will have the complete access to the large sheet metal cover for Z-axis servo motor.
Wheel refinishing lathe

The large sheet metal cover on the top of Z-axis servo motor

After removing this sheet metal cover on the top, you can locate the housing for Z-axis servo motor.  The first thing to do is to clean all the small chips and dusts in this area. Then, the timing belt should be removed and replaced as part of the maintenance procedures

z-axis servo motor

View after removing the cover.

z-axis servo motor

Enlarged view for Z-axis servo motor.

main motor

View for old Z-servo motor timing belt

motor belt

View of new Z-servo motor timing belt

As a short summary, Ball Screws play a critical role in the feed drive system of Alloy Wheel Repair CNC lathes which require higher precision delivering motion due to higher accuracy requirement of the machining quality. Therefore, it is very important to remember that the reliability and performance are critical standard for both X-axis ball screw and Z-axis ball screw. Furthermore, the proper maintenance on alloy wheel repair diamond cutting CNC lathe is critical to its performance over the long term. Keeping ball screws lubricated and free from contaminants extends their working lift and reduce the down time for your alloy wheel repair CNC lathe. The recommended maintenance schedule for both X-axis ball screw and Z-axis ball screw is every 3 months.

alloy wheel repait CNC lathe

The large sheet metal cover on the top of Z-axis servo motor