Common Causes of Ball Screw Failure

ISO 9001:2000 CERTIFIED

Lead Screws International

2101 Precision Drive

Traverse City, MI 49686 USA

Toll Free: (800) 678-0726

Phone: (231) 947-4124

Fax: (231) 947-3851

39-foot long precision ground two-nut ballscrew.

The LSI team stands behind its work!

CAUSES OF BALL SCREW FAILURE

A. Misalignment will cause a higher than normal running torque.

Check for:

1. Bent Screw.

2. Alignment of screw in relation to journals.

3. Alignment of screw in relation to nut housing.

4. Alignment of screw in relation to slides, gibs, and roller cages.

B. Improper lubrication can cause poor running and high wear.

Check for:

1. Proper maintenance of machine lubrication system.

2. Correct type of lubricant (follow manufacturer's recommendations).

3. Make sure lubricant is clean.

4. Remember synthetic lubricants can cause varnish deposits.

5. DO NOT USE GRAPHITE BASED LUBRICANTS.

C. Dirty environments can cause poor running and high wear.

1. Make sure proper wipers are installed and in good working condition.

2. Consider installing a bellow type protective cover.

3. Consider lubrication system filters or strainers.

4. Check coolants for rust and gum content.

5. Be careful with soaps and high pressure cleaning so that lubricants are not washed away.

D. Store extra ball screws properly.

1. Lubricate and rotate nuts periodically.

2. Keep screws protected with tubular plastic sheeting.

3. Hang ball screws vertically to keep them straight.

4. Keep units from excessive vibration.

E. Be aware of the following potential problems.

1. Ball screws can be overloaded.

2. Hardness of screw and nut may be substandard.

3. There may be a mismatch of leads between the screw and the nut.

4. A screw may have been crashed and not look like it.

5. A unit may be partially disassembled and not look like it.

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