Product

• Lotem™ 800 Fiber Head
• Lotem 400 Fiber Head
• Lotem XL

Background

When removing the Lotem's filter, the lens, which is inside the head/lens casing, stays attached to the filter and is also removed. When this happens, it is necessary to disassemble the head/lens assembly in order to tighten the lens. To do this, open the back of the head/lens casing, and remove the laser head to gain access to the lens; then poke a long, custom-designed jig inside the casing and tighten the lens.

Creo Israel would like to extend its appreciation to Mr. Paul Gallimore of Creo England for his help in preparing this procedure.

Requirements

In addition to the above, include a bottle of Acetone and an assortment of:

• Allan^® keys
• Screwdrivers
• Cable ties

Procedure

Implement this procedure on rare occasions (for example, to remove an overly tightened lens filter).

• Overview
• Tightening the lens
• Reassembling the lens and testing

Overview

Figure 1, shown below, provides an at-a-glance, six-step overview of the lens tightening procedure. Basically, all you need to do is remove everything from the head/lens casing, insert the jig into the casing, then tighten the lens. The entire procedure is detailed in Tightening the lens.

Figure 1

Tightening the Lens

1. Open the rear door of the Lotem; then remove both the unloading tray and the top back cover.
2. Insert a cheater; then, using the carriage motor menu, move the carriage to a position where you can work comfortably on the head (for example, position 700).
3. Shut down and power-off the Lotem.
4. Remove the four screws at the top back of the head assembly on the resolution motor; then remove the two detector connectors and the motor power connector, as shown in Figure 2.

Figure 2

With the motor and mounting bracket released, unhook the two springs underneath the motor that provide tension to the head rotation arm. The arm and springs are shown in Figure 1.
Note: When removing the motor and springs, mentally note how to reassemble them. Pay close attention to how the resolution motor meshes with the head rotation arm. This must be reassembled properly.

5. Set the resolution motor aside; then, using a screwdriver, remove the head rotation arm from where it protrudes from the head/lens assembly casing, as shown in Figure 1.
6. Remove the locking screw from the head/lens assembly casing, and put the screw to one side:
   
   
   
   
7. At the back of the head/lens assembly casing, cut and remove the various cable wraps that secure the black plastic tubing in place, as shown in Figure 3.

Figure 3

Note: Before removing the cable ties, pay attention to how they are threaded through the two brackets. You will need to put them back in the same way.

Important: From this point on in the procedure, the fibers are unsupported. You must be very careful with them.

8. Remove the screws from the fiber cable support bracket (Figure 3) and set the cable support bracket aside.
9. From the back of the head/lens casing, remove the black retaining ring, using the optic head outer key (P/N 291B7B867), as shown in Figure 4.

Figure 4

Note: You may need to temporarily position the head rotation arm back through the casing so that you can hold it to prevent rotation as you unscrew. There is a large spring washer directly behind the retaining ring, which will fall out when you remove the retaining ring. Remember to put it back at the end of the procedure.

10. With the head/lens casing retaining ring set to one set, remove the bearing behind it (see Figure 1); then carefully pull out the laser head. When it is out of the casing, lay the laser head over the V-block, as shown in Figure 5.

Figure 5

Note: If you look at the end of the laser head (above), you can see where the fibers terminate.

This picture also shows the bearing, which is removed during the next stage of the procedure, and the spring washer, which was removed together with the retaining ring in step 9. Both the bearing and washer appear in this picture only to show you what they look like. At this stage in the actual procedure, they will have already been removed.

11. Hold the laser head in one hand; then, using the other hand, wipe the front, shiny V-groove (holding the edge of the fibers) with a cotton tip soaked in acetone, as shown in Figure 6.

Figure 6

Note: Wipe the V-groove with the soaked cotton tip in one direction only; then throw the cotton tip away and use a new one.

12. From the top of the casing, remove the screw that reaches down into the casing, preventing the immediate removal of the second bearing.
    Note: To see how this screw causes an obstruction, refer back to Figure 1; then look into the head/lens casing.
13. When you have removed the screw, reach a finger into the casing (if your fingers are long enough) and pull the bearing out. You may need to hook the bearing out with an Allan^® key. If you use an Allan^® key, be very careful, because just beyond the bearing is the lens (see Figure 1).
14. Look into the casing to see the lens and the pinholes in which the jig fits. Very carefully insert the optic head inner key
    (P/N 293B7B866) into the head/lens casing, and fit the jig pins into the holes on either side of the lens (see Figure 1). Rotate the jig clockwise to ensure that the lens is securely tightened.

Reassembling the lens and testing

1. Replace the bearing.
2. Tighten the screw back down into the casing.
3. Place the laser head very carefully back into position, and orientate it so that the rotation arm can be passed through the head/lens casing and screwed into it.
4. Replace the spring washer and the retaining ring. The retaining ring protrudes slightly, as shown in Figure 1. 
   Note: Do not overly tighten the retaining ring: it will cause an unsmooth resolution rotation.
5. Replace the fiber/tubing support bracket. Use cable wraps to secure the black tubing to the bracket, as described in step 7 of the lens tightening procedure.
6. Screw the rotation arm back into the head assembly by first passing it through the head/lens casing; then hook the two springs back onto the rotation arm.
7. Re-insert the locking screw removed in step 6.
8. Replace the resolution motor assembly by screwing the motor block into place. Ensure that it connects properly to the head rotation arm.
   Note: Remember to place the exposed earth wire under one of the motor fixing screws.
9. Put the detector and motor power connectors back in place.
10. Check whether the resolution motor moves freely. To do this, power on the Lotem and launch the application. From the Resolution Motor menu, move the motor back and forth a few times between the home position (HP) and the max pos app value (found under the Properties tab of the Resolution Motor menu).
11. Check whether the focus motor moves freely. From the Focus Motor menu, move the motor back and forth a few times between the HP and the max pos app value. To find the max pos app value, select hardware>database>focus motor; then
    double-click the res 60 option.
    Note: If both motors are not moving freely, find out why.
12. Fully calibrate the Lotem, including focus, intensity, resolution, delay and elevation.

Technical contact(s)

Itai Peperovich
See the Escalation page for escalation contacts.

Date submitted

13 Jan 2003