HMC - Ballscrew - Backlash Test

Applies to machines built from:
January, 1989

HMC - Axis Ballscrew - Backlash Test - Introduction

This procedure tells you how to test for axis backlash on the X, Y, and Z axes of a horizontal mill.

Prerequisites

Jog each axis to the center of its range of travel.
Tools Required:
• Dial indicator that can measure 0.0001" (0.003 mm)

Step 1

Put the dial indicator so that it touches the side of the spindle housing.

Push X.

Push HAND JOG.

Push .001/1..

Jog the X Axis until the dial shows approximately 0.015" (0.38 mm).

Set the indicator dial to 0.

Step 2

Push POSITION.

Push ORIGIN.

In the display, the X value for OPERATOR shows 0.

Step 3

Jog the X Axis 0.010" (0.25 mm) in the positive (+) direction.

Jog the X Axis 0.010" (0.25 mm) in the negative (-) direction.

Record the difference between these two values:

• the indicator value
• the X-Axis position on the control

If the difference is more than 0.0002" (0.005 mm), the backlash is too large.

caution: Before you do the manual backlash test, make sure the machine is not in an alarm condition: Release EMERGENCY STOP, and push RESET to stop each alarm.

Do a manual test of the backlash as follows:

1. With your hands, push on the right side of the table.
2. Set the indicator to 0.
3. With your hands, push on the left side of the table.

If the indicator shows more than 0.0002" (0.005 mm), the backlash is too large.

Step 1

Put the dial indicator so that it touches the bottom of the spindle housing.

Push Y.

Push HAND JOG.

Push .001/1..

Jog the Y Axis until the dial shows approximately 0.015" (0.38 mm).

Set the indicator dial to 0.

Step 2

The values for DISTANCE TO GO in the lower right-hand corner of the screen show: X = 0, Y = 0, Z = 0.

Step 3

Jog the Y Axis 0.010" (0.25 mm) in the positive (+) direction.

Jog the Y Axis 0.010" (0.25 mm) in the negative (-) direction.

Record the difference between these two values:

• the indicator value
• the Y-Axis position on the control

If the difference is more than 0.0002" (0.005 mm), the backlash is too large.

Step 1

Put the dial indicator so that it touches the face of the spindle cap.

Push MDI.

Push Z.

Push HAND JOG.

Push .001/1..

Jog the Z Axis until the dial shows approximately 0.015" (0.38 mm).

Set the indicator dial to 0.

Step 2

The values for DISTANCE TO GO in the lower right-hand corner of the screen show: X = 0, Y = 0, Z = 0.

Step 3

Jog the Z Axis 0.010" (0.25 mm) in the positive (+) direction.

Jog the Z Axis 0.010" (0.25 mm) in the negative (-) direction.

Record the difference between these two values:

• the indicator value
• the Z-Axis position on the control

If the difference is more than 0.0002" (0.005 mm), the backlash is too large.

caution: Before you do the manual backlash test, make sure the machine is not in an alarm condition: Release EMERGENCY STOP, and push RESET to stop each alarm.

Do a manual test of the backlash as follows:

1. With your hands, push on the front of the table.
2. Set the indicator to 0.
3. With your hands, push on the back of the table.

If the indicator shows more than 0.0002" (0.005 mm), the backlash is too large.

Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.