Install a 4” Lens: NOVA

Applies to: NOVA 10, NOVA 14 and NOVA 16

This guide shows how to install the 4” lens safely on your NOVA and calibrate the auto focus for it. Use the 4” lens to cut thicker materials. It also gives more clearance between the laser head and the material when you engrave items with high sides, such as serving bowls or trays.

What you need

• Allen keys
• Microfiber cloth
• 4” (101.6 mm) lens
• NOVA lens tool
• Powder-free nitrile gloves
• Flat piece of scrap material
• Pen or marker

Remove the 2.5” lens

1. Place a microfiber cloth under the laser head, on the honeycomb or blades, to catch small pieces that would otherwise drop into the bed.

2. Remove the air hose from the air fitting on the laser head: push on the blue retainer ring and pull the hose free.

   

3. On the left side of the laser head, loosen the thumb screw until the lens housing is released.

   

4. Remove the lens housing from the laser head and turn it upside down.

   

5. Using the NOVA lens tool from the tool kit, gently unscrew the retainer ring inside the lens housing until the retainer ring, silicone O-ring and lens are fully removed.

   

6. Reinstall the empty sliding lens housing in the laser head. Set the slider to about marker 10 on the housing.

7. Tighten the thumb screw until the lens housing is firmly in place.

8. Push the air hose back into the air fitting on the lens housing, and tug it lightly to check that it is fully seated.

Install the 4” lens

1. Find the 4” lens housing at the top of the laser head. It looks like a small red rectangle.

   

2. Use an Allen key (1.5 mm or 2 mm, depending on the generation of the machine) to remove the mounting bolts on each side of the 4” lens housing. Set the bolts aside.

   

3. Carefully remove the 4” lens housing from its slot in the laser head.

   

4. Use a 1.5 mm Allen key to remove the tiny lens mounting bolts and white plastic washers from the housing, and set them aside.

   

5. Carefully place the 4” (101.6 mm) lens in the 4” lens housing, dome side up. Looking at the lens from the top of the housing, you should see your reflection right side up, like looking into a tiny mirror. There may also be an arrow on the ridge of the lens that shows the correct orientation.

   

6. Reinstall the tiny lens mounting bolts with a 1.5 mm Allen key, with the white washers in place. Thread all three bolts before you fully seat any of them, which helps the lens seat correctly. Do not overtighten the bolts, which can damage the lens.

   

7. Return the 4” lens housing to its original position in the laser head.

   

8. Push firmly on the housing so it is fully seated in the laser head. Then reinstall the mounting bolts from step 2 on each side of the laser head to secure the housing.

   

   

The 4” lens is now installed. We recommend a 5 point test, to check that the alignment through the new lens lets the beam fully exit the nozzle. See 5 Point Test: NOVA.

Calibrate the auto focus

The 4” lens can use the auto focus function on the NOVA, but only once the sliding lens housing is set to the right position. Marker 10 is a starting depth that should be close. A short focal ramp test finds the exact setting.

This calibration is needed because of where each lens sits. The 2.5” lens is fixed inside the sliding housing, which also carries the auto focus sensor, so it stays a constant distance from the sensor. The 4” lens is mounted in the chassis of the laser head, so its distance from the material depends on the depth setting of the sliding housing.

Run a focal ramp test

1. Place a flat piece of scrap material on the bed.

2. Auto focus onto the material.

   

3. Close the lid and quickly tap the pulse button on the keypad.

4. Take the scrap material off the bed and inspect the pulse mark. Do not move the laser head or the bed.

5. Read the Z value on the keypad and write it under the pulse mark. Put the material back so the laser will pulse on a fresh area. Keep all the pulse marks in a line, to avoid confusion.

   

6. Use the Z DOWN arrow to lower the bed by 1 mm. Pulse, inspect and label the mark as in steps 3 to 5.

7. Lower the bed another 1 mm and repeat, for a total of 3 pulse marks.

8. With the material repositioned, auto focus onto it again.

9. Use the Z UP arrow to raise the bed by 1 mm. Pulse, inspect and label the mark.

10. Raise the bed another 1 mm and repeat, for a grand total of 5 pulse marks.

    

Read the result and set the slider

Inspect the pulse marks closely. If the current setting is close, the dots form a gradient, with the dot size growing towards the outer ends.

1. Find the Z value with the finest pulse mark. In the example photo, the mark at a Z depth of 7 is smaller than the marks at 6 and 8.

2. Work out the difference between that Z value and the Z value at auto focus.

3. Move the slider by that amount in the matching direction. For example, if the auto focus Z value is 8 and the best mark is at 7, slide the housing from 10 to 9.

For more precision, repeat the focal ramp test in 0.5 mm steps instead of 1 mm steps.

Note the marker value that works for your setup. You can use it as the standard setting for the sliding housing whenever you fit the 4” lens.