Tarkin is Red Tagged. It has been performing inconsistently recently and has resulted in a number of wasted materials and delayed projects. We will work on this to get it back up and running to a reliable state.
Robert
Thank you for this note, @Rolo. I booked time for Saturday but responding here to keep track of updates.
Thanks for the notice. I thought the red tag on Skedda went through to next friday. I’m not sure what happened there. I am going to move your booking to Dorian for the same time.
I don’t expect Tarkin will be up by tomorrow or within the next few days.
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It will be ready Sunday
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I improved the alignment, but there’s still too much heat on the #2 mirror for the mounting. Kind of goes with having this much power going through it.
I’ve got a new mount machined out and will get it in Monday.
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There are improvements! But still not ready for removing the red tag yet.
Danny checked everything from mirror, alignment, lens alignment, few other little things that certainly made a difference. However, in testing a cut of a design on a large sheet, there was enough wide beam flakiness for me to not be okay with opening this tool back up yet to others.
We’re still working on it will and we’ll keep y’all posted.
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I don’t agree with this conclusion at this time.
The plywood being cut was nearly useless. Instead of 120, it was down to like 30 mm/s, sooting up, and catching fire. I’ve only seen plywood that bad few times. The plywood was bad, that was clear and agreed.
Putting in a regular piece of plywood, it was a bit thinner but went back to cutting at 120 mm/s and giving a really clean cut with extensive detail and clean top surface that took a few minutes to run. We both saw the earlier test piece on the “bad” stuff and it was also cutting worse in the middle where there was some warpage. It didn’t feel that dramatically warped to be honest, but that was compounded with ridiculously slow cutting due to the plywood type. It was consistently cutting badly in areas that then we put good plywood on the same spot on the bed and it cut beautifully there. The beam is going to make a messy cut if it’s out of focus and taking far too long to run.
Occam’s Razor there. We know the plywood we pulled out was bad, so that info isn’t useful one way or the other. Good plywood cut great.
More to the point, I ran extended power testing and the mirror alignment did not shift with the new mirror over extended running at full power. It did shift with the old one under those conditions, now it doesn’t. That cuts to the core of the problem and shows that’s been effectively corrected.
I do not see evidence to justify keeping this machine offline at this time. We both saw it, the bad plywood doesn’t cut and the stuff we normally use cut quick, beautifully, and consistently on the same spot on the bed. The probs we saw on bad stock was bad stock, and that behavior could fully be explained.
It was power tested for longer term runs and showed no changes, the cuts on good stock were excellent. If there’s any other problem, I don’t have evidence showing it or even suggesting it, and I can’t think of any additional testing that would be of value at this time.
The #2 mirror has been replaced with a gold-over-silicon instead of moly. Moly is slightly more lossy than GOS, but has a higher damage threshold overall. There has only been one case over many years where a GOS #2 mirror spontaneously blew up on Tarkin, and it was more than a year ago. It didn’t even look like it had gotten dirty, seems like it just wasn’t up to handling a 200W beam. I don’t expect any prob but if anything did come up, look at #2 first. I won’t go into detail other than “if it’s bad, you’ll know it”. It won’t look like a mirror any more.
I think the only concern now is the mismatch on the most recent test cut. I’m headed up in a few minutes to see if it’s a recurring problem or a one off fluke. Details in Slack.
While I agree that the type of wood effects the cut or engraving quite a bit, I find it hard to believe it has something to do with what appears to be the beam getting wider, or less focused, at certain parts of the cut, when it’s fine and thin at other parts.
This is a big problem folks have been having and I’d like this to be fixed before we open it up
I’m downgrading Tarkin from Red to Yellow this evening.
After extensive testing this week by @dannym , @NickE, and some from me, there’s a few things to note.
Danny made a handful of improvements and tuneups in the hardware as well as in the controller to add stability and accuracy in the cuts. Nick’s cuts from last week vs yesterday were night and day different while using the same plywood and settings. I saw similar results with mine. While small patterns and tests were able to show smaller issues, the more consistent issues that have been popping up showed when we ran longer cuts spanning the bed.
Additionally, we were able to nail down a problem with some of the 1/4" plywood sheets.
TLDR; There is absolutely a difference in laser-able quality when it comes to plywood: Use interior rated plywood, not exterior. If you’re not sure, ask the lumber sales-folks.
There was one order that included some Baltic Birch 1/4" from a 4’x’8’ sheet. Normally I’d pick up the standard “Birch” 4’x8’ sheets which have not had any significant issues. The BB from 4’x8’ sheets however is the stuff that charred a lot and was hard to cut through. After a trip to Fine Lumber today with Danny, we learned the BB 4’x8’ sheets are intended for exterior use. This means it had a significantly different amount or composition of glue that ultimately inhibited a good laser cut. We tried a sheet of the Baltic Birch rated for interior use which comes in 5’x’5’ sheets. Despite being the same thickness, I saw a significant improvement in etching and cutting. I was able to move at speeds between 35 and 40 rather than the 15-20 for exterior rated BB.
Going forward we’ll continue to stock the standard Birch plywood 1/4" and Baltic Birch 1/8". When I make runs or order for delivery, I’ll be sure to ask that we’re getting interior rated plywood, just in case the manufacturer ever decides to change up their formula some day.
Why the Yellow Tag?
There are still some inconsistencies that can be seen detailed in this post:
While not a show stopper, these are signs to lookout for. It is not obvious what is causing this so please do report any issues seen as well as any signs of good runs. We are committed to a good quality laser for you all that can be used for your lasering needs.
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Skedda still shows red tag on Monday, prevents reservation of Tarkin.
There was an issue with the bed being unlevel- it is now fixed and the red tag should be removed by morning.
There is no reason for this to be in yellow or red tag.
Please return this to green-tag status on Skedda.
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I added this note to the tarkin wiki page. Is there anything else we’ve learned that would be of help to add?
“Ask for interior grade plywood - it has a different amount or composition of glue than exterior grade and produces significantly better results.”
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Thanks Sid.
@dannym there are still signs of imperfections last we were on this topic which is why this is considered a yellow tag, still usable state, but we’re acknowledging there is something off.
There are no indications of any problems I am aware of.
In fact it is performing at a very high level on all the benchmark tests. Even better than it has done in the past.
What are you referring to here?
if you look at the picture It still has those weird squiggly lines at some angles.
maybe the belt ? a slightly loose bolt on a bearing block?
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