Band Alignment Excel 51X - 2500 and Tightening the Idler Tension Bolt

Band Alignment

1.

Clean the band with acetone.

Thread the Y band through the capstan drive assembly. Each band has a more ‘rounded’ side if you look closely. Install the rounded side towards the shaft attached to the motor.

Install the Y band into the Y band slotted holder on the front and back. Secure it with four socket head caps 4 mm x 12 mm. See the image below:

Open

2.

Loosen the front and back M10 band tensioners.

Hand tighten both Y Band tensioners. The band should be tightened but not torqued.

Open

M10 band tensioner.

Make sure there is enough space between the band holder and the base of the band holder as displayed in the next image:

3.

Open the capstan idler to see the band on the capstan drive shaft. The band should be approximately centered on the capstan drive shaft.

Run the Y-axis back and forth by hand, observing the band position on the capstan idler bearing by looking through the open idler door and adjust the top M6 screws on the band tensioner which are push-pull bolts that raise and lower the band on each end. Again, try to keep the band about 2 mm from the top capstan shaft shoulder as shown:

4.

Follow the same procedure used for the Y band to center the X band. The X band also needs to be centered side to side on each end. Center the band so it appears centered in the slots on the capstan using the two M6 pull screws on the front and back of the X band tensioners.

5.

Tighten the M10 tension bolts for both the X and Y axes to the following specification:

TORQUE SPECIFICATION: 18 NM

6.

Double-check that the bands look centered over the entire travel for each axis.

Tightening the Idler Tension Bolt

Ensure the band is correctly aligned before proceeding.

1. Turn the machine off and clean the band with acetone.

2. Loosen the tension bolt on the capstan drive.

3. Finger tighten the tension bolt.

4. Place a 2.5 L key in one of the bolts on the coupler shaft (This will lock the drive).

5. Use a force gauge to fine-tune this process because often the idler tension Bolt is overtightened.

6. Using the force gauge push on the locked drive until it slips.

7. Read the peak force on the force gauge.

   1. For the X-axis it should be between 50-75 lbs.

   2. For the Y-axis it should be between 75-100 lbs.

8. If the value displayed in the force gage is below the minimum accepted value, then tighten the idler tension bolt. If the value is higher than the maximum accepted value, then loosen the idler tension bolt.

9. Make sure to move the drive to a different spot after testing with the force gauge this will prevent isolated damage to the band.

10. Repeat steps 6 through 10 as needed.