Ever increasing issues (LS1290)

[MysteryMachine]

Hi there,

I have been coming across an ever increasing issues with my laser cutter (an LS1290) and I'm really starting to struggle with what to do?

The engraving function is non-functioning completely (probably best to save this one for a different thread?) but the cutting seems to be getting worse to the point where my output is almost unusable.

In the absence of the engraving function, for the time-being I've been using the laser on a high speed/low power to engrave lines, which work quite well. Until recently where the line quality has degraded massively. It now produces nothing but wobbly lines and the line often cuts out/disappears mid line.

I've got a couple of example shots of some pieces that I did a little while back and how they look when using the machine now. You can clearly see the difference in the line quality. Both pieces were cut using the same settings and the same material.





I really don't know where to start?

The laser tube is very recent (only about 30 hours use) and so is the power supply. I've cleaned the lenses, checked for bubbles in the tube, checked, double checked and triple checked the alignment and nothing seems to resolve this issue?

I don't know if it's a multitude of issues? I have to regularly align the laser because it goes out of alignments within about 10 mins of cutting! I'm having trouble even cutting 3mm plywood now where it used to slice through it with ease.

If anyone has seen this issue or knows what could be causing it, I'd be really grateful for some advice?

Also, if anyone is in Bristol and fancies taking a look at the machine (I'll pay) I'd love someone with some experience to help me get to the bottom of these issues??

Many thanks for your time

Bruce (at his wits ends!)

[MysteryMachine]

Here is another example of a before/after piece. The original one was done around a month ago, the other one was done this morning, with the same settings as the original.

It didn't even cut through the ply sheet in places and had to be 'snapped' out of the parent material. I'd aligned the laser immediately before carying out this mornings test/comparison cut.

[Daven]

Are all the mirrors bedded correctly especially the one in the head? Is the lens pinched up enough so it is not rattling around? It would be worth cleaning (baby wipes) the bearing bars and the bar the carriage runs on, dry and oil them . I have found sometime this helps with that sort of judder effect (although I've not seen it quite as bad on mine!).

Best
Dave

[PhillyDee]

It looks very much like you have some loose bits! Alignment should never move, so sounds to me like mirrors may be loose, lens may be loose or perhaps carriage etc. I aligned mine a few months ago, and use it daily. As for the engrave not working, the tube will have a minimum 'strike power' on my 80W it is 11%, it will not fire below this, so must be set at 11% or noting will engrave.

[MysteryMachine]

Are all the mirrors bedded correctly especially the one in the head? Is the lens pinched up enough so it is not rattling around? It would be worth cleaning (baby wipes) the bearing bars and the bar the carriage runs on, dry and oil them . I have found sometime this helps with that sort of judder effect (although I've not seen it quite as bad on mine!).

It looks very much like you have some loose bits! Alignment should never move, so sounds to me like mirrors may be loose, lens may be loose or perhaps carriage etc. I aligned mine a few months ago, and use it daily. As for the engrave not working, the tube will have a minimum 'strike power' on my 80W it is 11%, it will not fire below this, so must be set at 11% or noting will engrave.

Well, you learn something new every day.

I have been (frustratingly) trying to solve this issue for weeks and was almost at the point of setting fire to the machine!

The number of times I've 'reset' the mirrors on their spring (and re-tensioned them too) in case they were wobbling, the countless hours cleaning the (already spotless by now) the slide surfaces and oiling them, cleaned the mirrors, cleaned the lens, checked for play in every part of the machine....

Today I discovered something new. It's obvious now, but somehow eluded me!

Despite having removed the lens numerous times, as well as the mirror on the head above the lens, I'd never noticed that the mirror in the 'middle' of the machine (not the one next to the laser, not the one on the head but the one in between, on the end of gantry) was actually removable too? HOW COULD I HAVE MISSED THIS??

I'd cleaned it so many times but never realised that the mirror itself was separate to the copper coloured housing assuming it was just held on with the tensioning screws. I'd always thought this was one item.

Once I'd peered down into the darkness of the hole on the back of the mirror (this part of my workshop is a little dark too which doesn't help), I saw the little notches for removing/tightening. Eureka!

Guess what? Yep, it was loose. Very, VERY loose.

Now that I've given it a good tighten up, the machine is completely transformed. It cuts lovely and neatly now, really accurately and doesn't miss parts of lines or cuts.

It also cuts a lot better on lower powers and more than anything, the alignment seems to stay put. I was literally having to adjust it more than I was cutting and doing whole sheets of repeat design was simply a no no (which defeats the object of having a 1290 really). Now it seems to cut consistently and cleanly at any/every point of the table which it never did before but had got worse and worse over time.

WOOHOO! Faith in the machine restored, I can make the things I've promised people now. I was picturing having to buy a new laser or something equally expensive.


PhillyDee, as for the engraving, it's definitely not the laser power. It fires fine at 11% (especially now that the mirror is stable)

The problem is that when engraving, the laser doesn't actually switch off. it just engraves a massive, solid area. I'll have to upload some shots to explain. It's very strange....

Thanks for the advice though, it's really appreciated.

[MysteryMachine]

As for the engrave not working, the tube will have a minimum 'strike power' on my 80W it is 11%, it will not fire below this, so must be set at 11% or noting will engrave.

Thanks again for the info on this. I have been aware that the laser refuses to fire below 10% but the issue is something a lot stranger and I can't get to the bottom of it.

Basically, in engrave mode, the laser just doesn't switch off between 'pulses' and in fact, stays on even during the speed up/slow down area either side of the part being engraved. The laser is on the WHOLE time it's engraving.

As an example, here are three 10mm circles that I want to engrave in the middle of three 20mm squares (which will be 'cut' on high speed and low power)




Here are the settings for the engrave/circles and for the light cut/squares



Now take a look at this video and see how the laser stays on the whole time it's engraving and only turns off between the cuts on the squares (as it should):

CLICK HERE FOR YOUTUBE VIDEO


Here you can see that the engraved circles are now elongated 'lozenges' where the laser head runs back & forth, speeding up and slowing down for each pass. Because the laser is on the whole time, it basically engraves a huge area, not the bit it should be engraving! I hope this makes sense?



If anyone has any ideas on this, you really would make my year because it's already been three months (or more) that this issue has been affecting my machine. I really, really would like to be able to use the engrave function because I would be using it for about 80% of my work!

Many thanks.

[Daven]

At a guess I would say drop the speed - 200mm/s and see if that makes a difference first of all

Best
Dave

[Tom]

Hi Bruce
What machine is it and what software, lasercut 5.3 5.1 5.0

[MysteryMachine]

Like this you mean?

This was a similar exercise but with squares instead or circles. Engraving speeds: 100, 300, 500 consecutively (power 15).

Obviously, the slower speeds caused more burning than the higher speeds, but I was just trying anything to see if it would work.





[edit] the faster the engrave speed, the further the laser head tracks either side of the engraving area in order to speed up and slow down. [/edit]

[Daven]

OK - next test - what happens if you import a bmp and engrave that?