Drive Belt Replacement: MIRA and NOVA

Applies to: MIRA and NOVA

This guide shows how to replace the X and Y drive belts in a MIRA or NOVA laser, and how to recalibrate the machine afterward.

Drive belts are a wear item and should be replaced as needed. If a belt squeaks, shows visible damage, or you notice slipping in your score lines or engravings, it may be time to replace it.

What you need

• Replacement drive belt
• Allen key set
• Cabinet key
• Compressed air
• 1/8” masked acrylic
• Magnifying glass
• Computer with LightBurn

Belt sizes

MIRA: replace the X drive belt

1. Power the machine off and unplug it.

2. Open the lid and gently push the gantry all the way to the back of the machine.

3. Use a cabinet key to unlatch the upper access panel on the right of the machine. Remove the panel and set it aside.

   

4. Find the underside of the keypad inside the motor cabinet. Gently push up on the bottom of the keypad to pop it out. Pull the keypad all the way out and lay it carefully out of the way. You can disconnect the HMI cable from the keypad if you need to.

   

   

   

5. Gently move the gantry to the front of the machine so it sits under the keypad opening. Reach into the motor cabinet and carefully squeeze the belt between your thumb and index finger to feel its tension. Make a mental note of the tension and resistance.

6. Look through the keypad opening to find the X motor mounting bolts. Use a 4 mm Allen key to loosen the 4 mounting bolts. Do not remove them: they only need to be loose enough for the motor to slide forward and back in the bracket.

   

   

7. Gently move the gantry to the center of the machine. Looking at the motor assembly through the right side of the machine, find the tensioner bolt on the left side of the X motor. Use a 3 mm Allen key to loosen the tensioner bolt about 1/2”. The key and bolt size can vary with the generation of the machine.

   

   

   

8. With all the bolts loose, pull the motor towards the front of the machine. Slip the drive belt off the pulleys and discard it. If there is not enough room, loosen the tensioner bolt further.

   

9. While the belt is off, use compressed air to clear dust and debris from around the pulleys. Clean the pulleys themselves with a small paint brush or toothbrush if needed.

10. Fit the new belt on the pulleys with the teeth towards the pulley. Check that the belt is the right size: 99MXL.

    

11. Tighten the belt tensioner while squeezing the belt between your fingers to check the tension. If you did not move the nut, tightening the tensioner bolt until the nut touches the bracket should be close to the right tension. Make sure the tensioner bolt sits above the black bracket and touches the motor directly.

    

    

12. Once the tension is right, tighten the 4 motor mounting bolts.

    

13. Put the keypad back in its housing and reinstall the upper access panel.

14. Go to Verify the belt tension.

MIRA: replace the Y drive belt

1. Power the machine off and unplug it.

2. Use the cabinet key to open the laser tube hatch at the rear of the machine.

   

3. Use a Phillips screwdriver to remove the small, square access panel on the left side of the machine. Set the screws and panel aside.

   

   

4. Find the Y motor and drive belt, directly in front of the Mirror 1 bracket. Carefully squeeze the belt between your thumb and index finger to feel its tension.

5. Find the Y motor mounting bolts. Use a 4 mm Allen key to loosen the 4 bolts. Do not remove them: they only need to be loose enough for the motor to slide forward and back in the bracket.

   

   

6. Find the belt tensioner bolt on the side of the Y motor. Use a 4 mm Allen key to loosen it about 1/2”. The key and bolt size can vary with the generation of the machine.

   

   

7. With all the bolts loose, push the motor towards the front of the machine. Slip the drive belt off the pulleys and discard it. If there is not enough room, loosen the tensioner bolt further.

   

   

8. While the belt is off, use a small paint brush or toothbrush to clear dust and debris from around the pulleys. Clean the pulleys themselves if needed.

9. Fit the new belt on the pulleys with the teeth towards the pulley. Check that the belt is the right size: 110MXL.

   

10. Tighten the belt tensioner while squeezing the belt between your fingers to check the tension. If you did not move the nut, tightening the tensioner bolt until the nut touches the bracket should be close to the right tension.

11. Once the tension is right, tighten the 4 motor mounting bolts.

12. Close the laser tube hatch and reinstall the small cover panel.

13. Go to Verify the belt tension.

NOVA: replace the X drive belt

1. Power the machine off and unplug it.

2. Use a cabinet key to unlatch the large E-stop side access panel on the right of the machine. Remove the panel and set it aside.

   

3. Gently move the gantry towards the front of the machine so there is plenty of room to work on either side. Find the X motor and drive belt. Reach into the motor cabinet and carefully squeeze the belt between your thumb and index finger to feel its tension. Make a mental note of the tension and resistance.

   

4. Find the X motor mounting bolts. Use a 4 mm Allen key to loosen the 4 bolts. Do not remove them: they only need to be loose enough for the motor to slide forward and back in the bracket.

   

   

5. Find the tensioner bolt on the right side of the X motor. Use a 4 mm Allen key to loosen it about 1/2”. The key and bolt size can vary with the generation of the machine.

   

   

6. With all the bolts loose, push the motor towards the front of the machine. Slip the drive belt off the pulleys and discard it. If there is not enough room, loosen the tensioner bolt further.

   

7. While the belt is off, use compressed air to clear dust and debris from around the pulleys. Clean the pulleys themselves with a small paint brush or toothbrush if needed.

8. Fit the new belt on the pulleys with the teeth towards the pulley. Check that the belt is the right size: S2M-284.

   

9. Tighten the belt tensioner while squeezing the belt between your fingers to check the tension. If you did not move the nut, tightening the tensioner bolt until the nut touches the bracket should be close to the right tension.

10. Once the tension is right, tighten the 4 motor mounting bolts.

11. Reinstall the large E-stop side access panel.

12. Go to Verify the belt tension.

NOVA: replace the Y drive belt

1. Power the machine off and unplug it.

2. Use a cabinet key to unlatch the large E-stop side access panel on the right of the machine. Remove the panel and set it aside.

   

3. Use a Phillips head screwdriver to remove the 3 mounting bolts around the nearest rear corner panel. Remove the corner panel and set it aside. A long Phillips head screwdriver reaches the recessed screw through the small access hole on the back edge of either rear corner panel.

   

   

4. Find the Y motor and drive belt, towards the top rear corner of the cabinet. Reach in and carefully squeeze the belt between your thumb and index finger to feel its tension. Make a mental note of the tension and resistance.

   

5. Find the Y motor mounting bolts. Use a 4 mm Allen key to loosen the 4 bolts. Do not remove them: they only need to be loose enough for the motor to slide in the bracket.

   

   

6. Find the tensioner bolt on the top side of the Y motor. Use a 4 mm Allen key to loosen it about 1/2”. The key and bolt size can vary with the generation of the machine.

   

   

7. With all the bolts loose, push the motor down towards the bottom of the machine. Slip the drive belt off the pulleys and discard it. If there is not enough room, loosen the tensioner bolt further.

   

8. While the belt is off, use compressed air to clear dust and debris from around the pulleys. Clean the pulleys themselves with a small paint brush or toothbrush if needed.

9. Fit the new belt on the pulleys with the teeth towards the pulley. Check that the belt is the right size: 294-3M.

   

10. Tighten the belt tensioner while squeezing the belt between your fingers to check the tension. If you did not move the nut, tightening the tensioner bolt until the nut touches the bracket should be close to the right tension.

11. Once the tension is right, tighten the 4 motor mounting bolts.

12. Reinstall both cover panels.

13. Go to Verify the belt tension.

Verify the belt tension

After a drive belt is replaced, test it to make sure the tension is right. If it needs adjusting, follow the matching process above and tighten or loosen the tensioner bolt.

1. Move the laser head and gantry to the center of the bed by hand.

2. Power the machine on and let it reset fully.

3. Listen to the machine while it resets:

   • Everything sounds normal: the tension is probably about right. Let the machine finish resetting and go on to the scanning offset settings below.
   • A higher pitched squeal, or the axis with the new belt does not move at all: the belt may be too tight. Power the machine off and loosen the new belt slightly.
   • A clunking sound, or the laser head jitters and jumps: the belt may be too loose. Power the machine off and tighten the new belt slightly.

Once the machine resets properly, check the scanning offset settings and confirm the belt tension.

Scanning offset settings

Any time a belt is replaced, the scanning offset (SO) settings must be checked, and they will likely need a slight adjustment. Other engraving software calls these “Reverse Interval” settings. This guide follows the process and settings in LightBurn.

SO settings compensate for the natural deviations of a running machine. Motors take time to accelerate and decelerate, belts flex a little, and the tube and power supply take time to respond when the controller tells them to fire. Together these can cause “ghosting” at the edges of an image. The SO settings make the edges of an engraving line up, and the edges are only ever as crisp as those settings. At AEON Laser USA, we calibrate this setting to a tolerance of +/- 0.01 mm.

Create the SO test file

MIRA: make 3 rectangles, each 20 mm wide by 10 mm tall, stacked and aligned vertically with 2 mm between them. Each rectangle must be on its own layer.

Set each layer as shown:

NOVA: make 4 rectangles, each 20 mm wide by 10 mm tall, stacked and aligned vertically with 2 mm between them. Each rectangle must be on its own layer. Use the three layer settings above, plus this fourth layer:

Choose the test material

We recommend masked 1/8” transparent acrylic for SO testing. Thin, clear acrylic lets light pass through the engraved surface, which helps when you look at the ends of the lines. Any material can be used, but consider how it burns. Wood, for example, is a poor choice because of its large burnout: it is barely noticeable on a large project, but it badly affects precision in this test. If you use another material, you may need to adjust the power settings, but do not change the speeds.

The test is the same on a MIRA and a NOVA. A NOVA has one more box and speed setting, because it has a higher top speed.

Run the SO test

1. Power the machine on and let it reset fully.

2. Put the material in the bed and focus on it as you normally would.

3. Send the file to the machine, set the origin and frame the job to make sure it will not run off the material. Leave about 1 mm of untouched space around the edge of the frame for the overswing.

4. Run the test file and inspect the results. A magnifying glass or loupe helps, and so does shining a light behind the lines. Always adjust based on how the left side of the file looks, though by the end both sides should line up.

5. Look at the lines in pairs, starting from the top: lines 1 and 2 are a pair, then 3 and 4, and so on. The edges will look like one of these:

   All edges line up at every speed. Nothing to adjust. The machine is ready to run jobs.

   

   Line 1 ends to the left of line 2 (and line 3 to the left of line 4, and so on). The SO setting is too high and needs to be lowered.

   

   Line 1 ends to the right of line 2 (and line 3 to the right of line 4, and so on). The SO setting is too low and needs to be raised.

   

   Those pictures are exaggerated for clarity. Your settings will most likely not be this far out. A more realistic example of a setting that needs adjusting:

   

6. Once you know which way to adjust, go back to LightBurn. Click the wrench and screwdriver icon on the top toolbar, next to the little gears, to open the “Device Settings” window. If the window has no values in the white box, check that your device profiles were imported correctly. See the LightBurn setup guide, where importing device profiles is covered with the connection methods.

   

7. Double click the speed value that needs adjusting.

8. Change the “Line Shift” value only, based on the test. Do not change any other value in this window. If line 1 was left of line 2, decrease the value. If line 1 was right of line 2, increase it.

   

9. Click “OK” on both windows once the value is changed. On a NOVA, you must click “Write” in the “Device Settings” window after making a change and before clicking “OK”. Otherwise the values are not updated for this file or for future jobs.

   

10. Resend the file to the machine and run the test again. The file must be resent after any SO change. Otherwise the machine runs the old, incorrect settings from the file already on the controller.

11. Repeat steps 4 to 10 until all the ends line up within tolerance.

12. Save the settings as a backup. Open the “Device Settings” window again and click “Export” at the bottom. Save the file where you want it. The USB that came with the machine is a good place.

Your belt is now replaced and tensioned, and the SO settings are tuned to match it. Your machine is ready to get back to work.