Commission new laser cutter.

[magman2112]

Now that the new laser cutter has been positioned in the laser room, it is time to evaluate it’s condition and bring it in to service.

Here’s an initial list of the items I expect we will need to undertake to complete this task

1. Re-assemble the machine
2. Clean the machine inside and out
3. Do an initial power on test to see what works
4. Test the motor mechanism and see what works
5. Install the laser tube and cooling system
6. Test laser tube and measure it’s power output if it works.
7. Align laser tube and mirrors
8. Evaluate new working practices for the new machine
9. Document all key details on Wiki

If we think of any other key steps we can add them as necessary.

@DoESLiverpool/laser-maintenance

[magman2112]

We were able to make some initial tests last night with some good progress.

All panels have been re-fitted to the machine and the bed slats fitted, so the re-assembly (Item 1) is now complete.

The inside of the bed has had an initial clean, though there are a few area’s I would like to go over again.

We did an initial power on test and after a bit of hunting found the main power switch on the side of the machine (labelled as PC). Power came up OK and the controller powered up as well. Using the controller position controls we were able to move the drive mechanisms successfully. This clears items 3 and 4 from the list, though we do still need to check the alignment once the laser is working.

Overall, a very good start with the new machine, with verification that a number of the key systems are in good working order.

[magman2112]

The laser tube was installed by Sean on Maker Night, but the existing coolant tubes are perished and incomplete.

I have ordered some new silicone tubing along with a missing panel connection for the cooling. This should be with me today (Saturday) so we can progress with the commissioning next week.

[magman2112]

The new coolant tubing and panel connection have arrived, along with some jubilee clips for the coolant connections. Sean fitted these on Maker Night, along with the extraction connection.

Initial tests found that the laser wasn’t working, but then we remembered that there was a second IEC power connection on the back of the machine, this apparently supplies the laser power supply. Sean then also found that the missing switch on the front panel is also needed to enable the laser power supply, which is to be expected on a laser cutter.

With the switch held on manually, the laser tube fired.

I obtained a replacement switch barrel and fitted it today. I also cleaned the main lens and two of the main mirrors. All of these will work sufficiently for now but will likely need replacement in the near future.

The laser now fires, as expected and after some initial alignment, tests cuts were successfully made. I have made an initial attempt to find the correct focal length, but this likely still needs refinement. I also expect that a full alignment is still needed to ensure accurate cuts across the whole bed.

The Air assist still needs to be connected as well.

Good progress though. I anticipate that we will get the final alignment completed in the next week, then we can work on the operational aspects.

[magman2112]

Last Maker Night, Sean and I connected up the air assist and started experimenting with settings in Lightburn, though not fully satisfactory. We suspected that some alignment issues were to blame, but we ran out of time to make any adjustments. The cutting power seemed low as well.

During Maker Day, I was able to undertake some more tests. I found that the primary mirror was very dirty. The current mirrors are the molybdenum type, so require more cleaning than the Silicon type we used in Gerald. With the mirrors all cleaned, I then did a further alignment which is still not perfect, but much better.

It appears that the current lens has a focal length of 62.5mm for the primary focus. Until we make a focus guide of the right size, focus can be checked by measuring 65mm from the workpiece to the first ring on the laser head.

Cutting power is now as expected and settings similar to Tony appear to cut and engrave well.

One new parameter in the Lightburn settings of note is the minimum power in the laser power settings. This is effectively how corner power is set for the Ruida controller (this parameter is not required with our previous controller). I found that a setting of half of the full power setting is required for successful cutting of 3mm MDF (so 40% Minimum power for a 80% high power setting).

I have also glued the mount for the visible spotter laser, though this may not last a long time. I have taken measurements of the bracket though, so that we can 3D print a replacement if required.

A couple of measurements for future reference. The mirrors are 25mm diameter. The lens is 20mm in diameter with a focal length of 62.5mm.

The new machine is now ready to be used by more users. Once we have agreed on the new name for this machine I will build a Wiki page for it and add a tag for it in GitHub.

[DaveBenji]

1. Do the quality of the mirrors contribute to the lack of power?
2. If the mirrors need more frequent cleaning will there be a shared methodology ?
3. Will we have a demo day for users?
4. How happy are we with the old Gerald tube?
5. Will the new lense guide look like those for Gerald or Sheila ?

[magman2112]

In response to you queries Dave.

1. The quality of the mirrors does affect the laser power, but so does the cleanliness. The main issue with the new laser is that it had not been used for years and had also had a small fire at some stage apparently. After cleaning the mirrors thoroughly, they now look quite good. We will have to see how frequently they need to be cleaned in the coming weeks and months. If they tend to get dirty too quickly, we can replace them relatively inexpensively (£35 from Amazon for all 3), but if they work OK we don’t need to replace them. Only time will tell.

2. If more frequent cleaning is required, then a regular routine will likely be required. There are lens cleaning cloths in the laser spares cupboard for this purpose, so it’s just documenting a process and inviting interested folk to a show and tell to implement some better working practices.

3. That’s not a bad idea. We need to get the name agreed for the new machine and work out a few of the working practices and peculiarities as well, but this should be doable in early December perhaps. I will post something on the Google Group with a couple of dates for people to come and have a look methinks. Or you can come on a Maker Night as well if you want to find out earlier. There are also some new bed cleaning processes we want to implement as well, which fit into this “demo day” idea quite well.

4. Gerald’s old tube was working quite well, though there are a few other outstanding issues with Gerald that will have to be worked out with its new owner. Luckily, the tube that came with the new laser also appears to be working well, though we still need to check this with our laser power meter.

5. I suspect you are talking about the focus guide for the laser. A basic focus stick will look very much like the one we used to use on Gerald. I am tempted to make a larger focus object, so it’s more obvious what it is for, as people have thrown away other examples by mistake in the past. We will get a stick on hook for the new machine as a home for the new focus item, whichever form it ends up being.

I hope that is a little clearer, but by all means ask more questions if it isn’t.

[magman2112]

One thing I forgot to mention in previous comments. I found a connector inside the new laser cutter that is compatible with Rotary attachment that we were given a couple of years ago. A quick test shows that the connector is compatible and the tool basically works.

Once we have completed the commissioning of the new machine, we will more thoroughly test this attachment, then work out some use processes and document them on the wiki. I will raise a separate issue for this once this new laser commissioning process has been completed.

Yet another interesting enhancement to the capabilities in DoES methinks.

[JackiePease]

I've been using the new laser cutter this morning and generally it seems really good.

A couple of issues:

• The laser head height had to be changed before to focus on the mount board, then after restarting the cutter, it had to be reset again.
• when cutting hardboard, a faint cutting line is visible, out of alignment with the main cutting line, maybe suggesting damage to the mirror
  

[magman2112]

I re-checked the alignment on the laser today and found that it was out for the final mirror, which cause the laser beam to catch the rim of the air assist cone, giving the double line on some of the cuts. I also noted that the new mirror mounts have lock screws that need to unset and set for each adjustment, to reduce the chance of vibrations altering the alignment.

The previous alignment was also set of 3mm material, with the bed pretty much at its maximum height. I have now reset the alignment to focus as 0 on the bed itself at its maximum height. This should solve Jackie's issue in the previous comment. As a working practice, i would say that all focus adjustment should be done with the bed height adjustment switch rather than adjusting the laser head, as it is much more reliable to adjust the focus this way consistently for all users.

I also determined that the focus stick height needed is 21mm as a first pass. I will make a couple of these up today for people to use, we can then monitor how this works.