Sophia cutting inaccurately

[JackiePease]

I tested Sophia on Sunday by cutting a Permission to Make badge. The badge wasn't as circular as it should have been. There were slight flat edges.
I didn't take a photo, but it would be worth doing some test cuts to see if it needs adjusting.

[Sean-anotherone]

X any Y both need fully rebuilding with new belts and bearings. Rather like the new X on Gerald, the machine will probably be like new after the work, but needs to be torn down and some bits ordered (and probably a few bits made. The front-end Y pulley holder I made ( a year ago or so?) was only a temporary fix and needs reinforcement or replacing for a start, and both X axes are on their last legs - they only work at all when the tension is a fraction of what it should be..

Sophia probably does not need a lot of money spent, but time is required, and it'll need to be in bits for a while.

Without wishing to sound like a broken record, the best solution is sitting at the end of the laser room, as if there was no pressure/demand, the repairs could be given the attention needed without impact.

[MatthewCroughan]

Is this related to #1399 ?

[JackiePease]

I tried to test Sophia today.
I first tried a grade engrave - the laser jumped from one part of the bed to another.
I then tried cutting a rectangle - 3/4 was fine, then the laser cut out. On @magman2112 advice I filled up the chiller unit with water (approx. 1 and a half jugs).
This didn't make any difference, although the laser cutter is making a strange bubbling noise which apparently suggests this is chiller related - I can't tell if water is getting through but the inlet pipe does feel slightly cold.

[magman2112]

With Sophia now moved in to the Meeting Room. I re-assembled the machine, but noticed quite a few issues with the carriage.

The single bearing on the left of the carriage is binding slightly, possibly due to using an M5 screw rather than the M6 that the bearing is specified for. Unfortunately we don’t currently have any bolts long enough to replace this at the moment.

Also, the rear bearing on the right side was loose in the carriage, due to the thread being stripped on the grub screw. I found another screw to replace this, though I have not cut this down to size at the moment, as I want to see how it behaves.

I refitted and slightly shortened the x-axis drive belt, though this belt is due for replacement as it is getting a little stiff. The carriage was moving relatively smoothly after these fixes though.

There is an issue with the datum not working, with the motor buzzing when trying to go to the home position. I suspect that the proximity sensor may not be working, this needs a bit more testing to verify this and possibly identify a replacement. Just to be clear, the datum is not working at the moment.

I next completed an alignment and clean, which had Sophia cutting 3mm plywood at a speed of 12mm/sec successfully.

Finally, I addressed the issue of cutting issues originally noted in this issue. Testing with a 40mm square, it was found that the x-axis was too long, cutting a 47mm side instead of 40mm. I adjusted the pulse count for this axis and got Sophia cutting again at the right dimensions.

As Jackie has identified a couple more issues since I completed these changes, it is apparent that Sophia is not ready for general use at the moment.

[amcewen]

I had a look at it this evening.

Good news: I fixed the datum. The metal tab was too high, which was why the induction sensor wasn't detecting it. I bent it back into the right position, and have configured it to auto-datum at power on again.

Bad news: I think Sophia needs a new tube. I'm not 100% sure, but it looks to me like the inner laser tube is full of water. The outer water-cooling jacket isn't filling up totally with water either. It'd be good to get a second opinion, but I think a new tube will be in order. We don't have a spare for Sophia right now do we?

[Sean-anotherone]

Wow, that's a pretty serious failure !   This might take out the HV psu too if it isn't short circuit protected. Sean On Tuesday, 3 November 2020, 23:08:44 GMT, Adrian McEwen <notifications@github.com> wrote: I had a look at it this evening. Good news: I fixed the datum. The metal tab was too high, which was why the induction sensor wasn't detecting it. I bent it back into the right position, and have configured it to auto-datum at power on again. Bad news: I think Sophia needs a new tube. I'm not 100% sure, but it looks to me like the inner laser tube is full of water. The outer water-cooling jacket isn't filling up totally with water either. It'd be good to get a second opinion, but I think a new tube will be in order. We don't have a spare for Sophia right now do we? — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or unsubscribe.

[JackiePease]

I have left a message with Smoke and Mirrors to ask which laser tube we need (not that clear from #676)

[JackiePease]

The laser tube was fitted by @Sean-anotherone and works fine.
AJ has since cut out some signs.
However, today Andy Green was trying to engrave several lines of lettering on to a slate coaster - the lettering started at an increasing distance from the left hand side on each line (although the letters themselves look ok).
The distance wasn't consistent between attempts. It seems unusable, at least for engraving, at the moment. Probably worth someone doing some more tests.

[magman2112]

It looks like there are issues with the idler wheel in the carriage. This was 3D printed a while ago and has worn down quite a bit, so the belt slips off and binds up. I will print some new wheels on my SLA print, which should be a bit more robust than the current PLA ones. I will also look to see if we can make an improved belt tensioner.

[Sean-anotherone]

This would be a good time to take the bed out entirely and refurb it - the tensioning mechanism on both X and Y is ropey and a few of the bearings need replacement.  The replacement sled I made could than also be fitted, restoring the last 30mm of available bed. Sean On Friday, 4 December 2020, 00:49:17 GMT, Mike Gorman <notifications@github.com> wrote: It looks like there are issues with the idler wheel in the carriage. This was 3D printed a while ago and has worn down quite a bit, so the belt slips off and binds up. I will print some new wheels on my SLA print, which should be a bit more robust than the current PLA ones. I will also look to see if we can make an improved belt tensioner. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.