A BRM Laser has three timing belts that require regular checking and tensioning. There are 2 Y-axis belts and 1 X-axis belt. The Y-axis belts are located to the left and right of the work area. The X-axis belt is on the bridge, from left to right, starting and ending at the laser head.

Check the timing belts regularly to make sure they still have the correct tension. If a belt is adjusted too loosely or too tightly, you will notice your machine does not cut or engrave as well as it should. Improper tension can also cause the belt to malfunction.

How do I know if the timing belt has the correct tension?

Position the bridge at the front or rear of the machine. Move the laser head to the left or right. Twist the belt at a 90° angle. Can the belt rotate more than 90°? Then the tension is too low. The tension is too high when it can rotate less than 90°. Repeat this procedure for all belts.

How do I adjust the tension of the belt?

The timing belts are fastened with clamps. There are 2 Allen bolts recessed in the clamp. These can be used to tighten or loosen the belt.

To adjust the Y-axis belt(s), use the small clamps on the front side. To adjust the X-axis belt, use the small clamp on the left of the laser head.

By turning the Allen bolts in, you tighten the belt; turning them out loosens the belt. Make sure to turn both bolts in or out by the same amount. That ensures tension on the belt remains even. If you notice that the belt is twisting, you will need to turn the Allen bolts in and out until the belt itself is straight. That will prevent it from tearing.

Turn in or out a little and check the tension again. Continue this process until the belt has the correct tension. The belt has a clamp at both ends. Adjust the belt with one of the clamps, not with both of them. If you need to use the rear clamp to adjust the Y-axis, use the rear clamp for the other Y-axis belt also. If you adjust one side in front and the other in back, the bridge may become slightly misaligned. That will result in a deviation in the dimensions of your work.

Unable to tighten anymore, but this seems necessary? Unscrew the Allen bolts of one clamp completely. Loosen the bolts on top of the clamp. That allows you to open the clamp. Move the belt 1 tooth further into the clamp and tighten the clamp again. Tighten the Allen bolts again to adjust the belt.

When you need an extra tooth next time, it is time to replace the belt(s). The belt has lost its proper tension and you can start to see effects in your work.

My timing belt is damaged or has lost tension, how do I replace a belt?

If, for example, your belt is missing a tooth, has lost its elasticity or is defective in some other way, you will have to replace it. When replacing a Y-axis belt, it is advisable to replace the other Y-axis belt as well.

Loosen both clamps with the 2 Allen bolts. Leave the belt in the clamps. Undo one of the clamps. Ideally, remove the belt from the clamp on the front (Y-axis) or left (X-axis). Leave the other clamp on the belt.

If possible, use tape to stick the new belt to the end of the old one. Try to do this as well as possible but do not build up the tape too much. Then you can pull on the old belt. Keep the belt as flat as possible. By doing this, you pull the new belt along, making it easier to position it in the right place. Make sure to do this carefully to ensure the belts stay together.

Once the new belt is visible and can be easily reached, you can separate the belts. Remove the clamp from the old belt and attach it to the new one. Attach the clamp to the side of the belt you just pulled through the machine.

If you replace both belts on the Y-axis, you first replace one, then the other. Once you have done this, proceed to the next steps.

Y-axis. Place the belt flat on the bridge. Keep the clamp side against the panel where the clamp is to be attached. At the front, place the belt against the small panel where the clamp will be mounted. Pull the belt a little tighter by hand. Then hold the tooth that just touches the panel. Cut the belt here.

X-axis. Place the belt flat on the bridge. Keep the clamp side against the panel on the left side of the laser head in which the clamp is mounted. On the right side of the head, place the belt against the head. Tighten the belt a little by hand. Then hold the tooth that just touches the panel. Cut the belt here.

Once the belt is at its correct length, take hold of the cut end of the belt. Place the second clamp on the belt at the third tooth from the beginning of the belt. The belt will therefore stick out a little through the clamp. Fasten the clamp.

Now mount the side of the belt where you first mounted the clamp. For the Y-axis this is at the back. For the X-axis, this is on the left side of the head. Leave about a centimeter of space between the clamp and the mounting panel. Make sure that the clamp is not set against the mounting panel! For an Open Bed laser machine (portal), leave about 1.5 centimeters of space.

When the clamp is properly mounted, move the bridge all the way back (Y-axis) or the head all the way to the left ( X-axis). Move the clamp that is not yet fixed to the attachment point. The belt will now be tensioned and you can tighten the clamp with the two Allen bolts. Because you have moved the bridge backwards and/or the laser head to the left, they give counter pressure so that you can easily fasten the clamp without pushing away the bridge / head.

Rotate the Allen bolts half a turn each, until you obtain the correct tension.

If you have trouble getting it done or would like a technician to do it, please send us a ticket so we can help you out.