Laser Tracing line between cuts

[Chadb Harvey]

I have a RD644XG. Recently it started creating a thin line between the start of the laser cutting to the first cut in the design and between each cut and back to the beginning when done. The line is thin and not deep. Doesn't matter the file, even files I did not create and there are no thin lines in the file connecting all the actual designs to cause the thin lines.

[Tim Mellor]

If it is not a Gcode error then seems like you have an electronic issue causing the Laser to not switch off completely on travel moves between cuts.

Simple way to check your files is pick one and upload it here and get someone else running the same version of RD Works to try it. At least that will eliminate software and your settings.

Not really something that will be easy to help with debugging the electronics from elsewhere on the planet unless another person has had the exact issue. Without an Oscilloscope (to look at the Laser trigger signal during a move) and some other gear you will be stabbing the air.

Other than that good luck

[Jeffrey Aley]

This is a common sign that your high-voltage power supply has failed. It needs to be replaced.

Sorry.

-Jeff

[Chadb Harvey]

I replaced the power supply and it still is not cutting off the entire beam between cuts. The power supply must not be the issue.

[Tim Mellor]

Unfortunately that leaves only the controller and wiring as likely culprits. Assuming you don't have any test gear or access to it along with a driver to poke the correct bits.

Start with the assumption that as the controller is working and from your description it still is generally at least then wiring is the first thing to look at it is also far cheaper to replace than swapping power supplies or controllers.

Without going into the Physics of it the insulation on wire is a dielectric material that can and does act like a Capacitor more so if it is breaking down of if it is not true HV cable (there is a few threads here). That is it can store a charge or if it has actually broken down allow an arc right through the insulation. Possible this stored charge is showing on your job (some photo would help a lot) as that charge bleeds out. So what sort of power does this job use? What is the material making this trace visible so we can get an idea of the nature of it? Is it constant or does it diminish over the travel move?

So making sure your laser has been off for a while disconnect the HV wire at the Power supply end and physically look along the complete length of it and the metal it contacts for Carbon tracks, spots or any kinks or breaks in the insulation.

The other easy check which I suspect will reveal nothing is disconnect the actual Laser signal from the controller and run a file. Any trace of any sort then at least you eliminate the controller as a fault and go back to wiring.

Flying blind

Have a read of this thread too for some more details on HV wiring issues viewtopic.php?f=127&t=3559&p=20494&hilit=hv+wire#p20494

[Jeffrey Aley]

I feel bad for advising you to spend money on a power supply that doesn't fix the problem. I hope you were able to return it for a refund. Sorry about the trouble!!

The fact that the laser power decreases, but does not shut off, is very interesting.
First, let's have a look at the Vendor settings. Go to File -> Vendor Settings. The password is RD8888 . Select "Laser" in the left-hand pane, and click "Read" at the bottom. Please post the results.

Second, we need to do some research on how the RuiDa controller and the laser power supply communicate. Russ did a thorough analysis (as you'd expect) in (I think) video 97: https://www.youtube.com/watch?v=5CoTrLNUWTM . I haven't re-watched it yet. As I recall, there's a signal that tells the laser tube to turn on or off, and there's a signal that tells how much power to use when it's on. But I think one of them might be PWM (?) -- have to watch the video to be sure. Likely something is wrong with one of these, but until I re-watch the vid, I can't develop a hypothesis.

Sorry,

-Jeff

[Doug Fisher]

>>I feel bad for advising <<

I probably would have posted the same information if you had not done so. Power supplies that are going bad often act the way the original poster described!

[Tim Mellor]

The biggest issue with trying to debug is information and then re interpenetrating the information provided. Logically it is the power supply not behaving properly but is it the supply, stray noise, controller or wiring driving the supply that is actually the fault? So it wasn't a bad call to look at the power supply at all.

As per the linked video it is for most into Electronic nerdishness with gear they don't have or really need to buy to operate a Laser. Even humans with that gear would need to figure out what they need to look for and where without blowing the front end out of there gear due to a lack of Laser knowledge.

I guess I tend to advise looking for no or low cost first and request more from the OP to try and get a proper look at the problem via remote means before spend $ on the likely blocks at fault.

[Elizabeth Bloomfield]

So this thread appears to have died but the problem lives on, except this time in my own laser.

TLDR: New PSU, new laser tube, no changes to vendor settings in RDWorks from when files previously properly cut

A bit of background: I've been using this machine with RDWorks with no issue for two years. I went to cut a file (.ai with both scan and cut) and noticed that it left a burn trail at all the travel lines, including returning to the origin position. It leaves the same trail, although very faint, when I press "Frame" as well.

I poked about the internet and read a suggestion that it was the first signs that a PSU was going bad so I replaced the PSU. The problem appeared to resolve for four more files (all .ai with both scan and cut). I wasn't especially pleased with how a scan turned out on a different file so I figured it was time for routine maintenance (mirrors and alignment, checking everything for square and level, etc) and during alignment noticed that when I turned the master control to the machine off, the laser fired a very small pulse. I emailed the PSU folks. They assured me that this is "completely normal" and to continue using the PSU but that I could also try replacing the laser tube... which I then did.

So since that email, new laser tube, re-realignment, nice clean shiny new mirrors, I finally decided to go ahead and try again. Back to the original issue: a trail whenever it travels and the laser doesn't stop firing when it should during scans.

I've gone through the wiring diagrams at least 5 times to make sure I didn't bungle the PSU install. The wiring all looks good. There's no evidence anywhere that there's visible problems: no discoloration, no kinks, bends, etc. There's no wires in parallel that would produce bizarre behavior from what I can tell.

After the PSU behavior, I had wondered if it was the controller that's at fault but don't have any idea how to test that other than buy a new one.

I've included photos of the travel lines, a scan as it resulted plus what it should look like, as well as all my vendor settings.

Any advice or help would be immensely appreciated.

[Doug Fisher]

>>when I turned the master control to the machine off, the laser fired a very small pulse. I emailed the PSU folks. They assured me that this is "completely normal" <<

I have never seen this. That would be very unsafe. Wait and see what other readers of this thread say when they chime in, but I think your PS people are BSing you.