Laserscript user forum

Hi guys, I'm Leon, based up in Middlesbrough.

I'm hoping that my newbie questions don't sound too daft! I purchase the 3020 last November, to cut squares/rectangles out of 2mm MDF, from 15x15mm upto 80x80mm. It took a while for me to get to grips with the machine, but once I was up and running, everything was great. However, 5 months down the line, I'm getting some little niggly problems which I'm hoping someone can help me with?

Speed/Power
I originally set the machine to Sp 20 / Pow 20 as Chris recommended, and this worked great. An A4 sheet of MDF took around 4 minutes to get through, clean cuts, no bother. Gradually the cuts stopped going all the way through, so I increased the power and slowed the speed. I'm currently cutting at Sp 8 / Pow 45%, which has put an A4 sheet up to 9 minutes. Does this sound right? Does the machine/laser take a bit of time to bed-in and this is the kind of speed I should be expecting?

Cutting Accuracy
When I first started, every cut was perfect, the squares all matched, and I didn't have to check them much at all. I'm now getting odd sized ones though, with upto 2mm difference between them? The template I'm using hasn't changed, but on a full grid of 40x40mm squares, some are 40x38, 40x39, etc. I have a lot of different templates set up for different size squares, and the same thing happens on all of them. Strangely, the vertical cuts are fine, it's the horizontals which are either too high or too low. Any idea what's causing this?

Cuts
Really an extension of the above, a lot of the cuts aren't vertical (90 degrees to the cutting bed), some are probably around 30 degrees off vertical?

Flame
From day one, there's been a flame while I'm cutting. It doesn't seem to do any real damage, but it's blackened the cable ties around the laser head, and when I've tried doing circular cuts, I get very worried that the flame is going to damage something. Should I be worrying about this? And is there anything I can do to reduce the flame?

Cleaning
I've always tried to clean regularly. The machine has only been used for 5 hours per week since I got it, probably even less. I bought some alcohol and cotton swabs, and I've been cleaning the end of the laser tube, the 3 mirrors, and the cone where the laser comes out. It's only really the cone which shows any dirt on the swab, but, will dirt build up inside the cone, and should I be taking it apart to clean inside? I've washed the honeycomb a couple of times as well, but that's about it. I've not cleaned the running tracks or anything like that.

Apologies again if the any of the above is something obvious. Before buying the machine, I'd never even seen one before, so it's been a steep learning curve. I've been reading the other threads, and there's some good info I've picked up, but nothing quite explains the problems I seem to be having. I've gone from getting a full perfect sheet of squares in 4 minutes, to getting 60-70% worth of squares in 9 minutes. Any help would be really appreciated.

Cheers!

Hi Leon,

Welcome to the forum!

I have had my 3020 since October last year so no expert, I suspect Spooky (Dave) will be along soon and give you the answers to your problems.

Out of interest what extraction do you use?
It sounds like the belts and mirrors need adjusting - the tubes do de-grade over time but not sure if the demand you have put on it would be enough just yet. Cleaning and lubricating the tracks may help as well.

Cooling can also be a cause - maybe think about adding a chiller unit. The air assist on the 3020 should blow the flame away from the head - wonder if that needs adjusting?

I would be cutting at a lower speed using less power to be honest - I try not to use more than 15 if I can help it, that will keep the flame down and put less demand on the tube.

Hope this helps until Spooky pops in

Dave

As if by magic the shopkeeper appeared (for those with long memories)

Hiya Leon,

Lets see what can be done

Speed / Power:

The issues you are experiencing is quite normal for tubes, lemme see if I can explain,
A tube has a life of around 1000 hours but this can vary buy as much as 50% depending on the load placed on it and the quality of the cooling system. If the tube has gotten hot on a regular basis or has been deprived of water (by bubbles forming in it) this can reduce tube life by quite a bit, tubes don't often just die they tend to get weaker and weaker until it takes just too long to get anything done. The first 60 hours are the best tube time with a slow degradation in performance from there on. Whilst this can be annoying it is a product of all gas CO2 laser tubes, RF tubes don't suffer the same way but when you take into account an RF tube can cost upwards of £5000 replacing the occasional CO2 tube doesn't seem quite so bad.It can also be caused by the alignment of the beam causing beam scatter and reduced cutting efficiency.

Cutting Accuracy:

I'd tend to agree with Dave N on this one, it sounds like your belts may be causing the problem, it can also be a lack of lubrication on the slideways as well as beam scatter so that will be worth checking. Belts are cheap and replacing them once a year is a good idea anyway in case they have suffered from the fumes the machine is producing.

Cuts:

Ahhhh, now this makes a bit more sense, that sounds like mirror alignment on the final lens could be causing all the above. If the beam isn't in the centre of the cone as it exits it will be scattered or deflected causing the cut line to be generated in an offset to the actual programmed position.

Flames:

Double check your air assist is working, Dave is quite right, the air assist should reduce pretty much all the flame to near zero.The fact it's cooking the cable ties suggests not enough air is getting through.

Be VERY careful cleaning the end of the actual laser tube, the smallest fleck of dirt on that mirror (in the actual tube end) can cause a massive overheat and a cracked mirror instantly.

A quick check for final lens alignment,

Stick a sheet of ply or MDF in the machine, bring it as close as possible to the cone end, press the laser button for a split second (enough to make a mark, no more) then visually check to see if the spot it has made looks central to the cone end. This should be your first port of call as all the problems you are having sound very much like Beam scatter.

Let us know how that quick test goes and I'm sure we can get your sorted out

best wishes

Dave

Spooky wrote:As if by magic the shopkeeper appeared (for those with long memories)

'Spooky' AKA Mr Ben Sadly I can remember and then add a decade or so before the program!


Just a thought - if the flame has got as far as the cable ties, check the flame hasn't burned a hole in to the air assist tube!

Dave

Good point Dave, it does sound a little unusual for the flaming to be so pronounced, although sometimes different grades of MDF will cause that kind of problem.

I tried some stuff from B&Q and it was aweful, switched to Medite and had no more problems.
I've only ever seen flames on the 6840 when I turn the air off alltogether but I'm not familiar with the 3020 so I don't know what it runs like as a base line.

Is the air adjustable on the 3020? on the 6840 there is a screw at the back of the nozzle that increases or reduces airflow? wonder if that has shaken lose?

best wishes

Dave

Dave - As far as I can see the tube is connected direct to the cone without any adjustment!

Dave

Looks like it's going to be the old "finger over the end" test then mate

best wishes

Dave

I have the 6040 and also after a few months there are a few things that need checked and tighten up, from looking at photo’s of Dave’s machine (spooky) the quality of the hardware on these budget machines is a lock nut or two short compared to the more expensive ones, obviously.

I have just tightened up the laser head that runs on the nylon wheels, this was affecting the accuracy of the cuts and engraving.
Make sure its not too loose. The flame heat could have damaged the nylon wheels too, worsening the system.

Cleaning all the running bars and guides is critical to keeping the machine running accurately.

Your belts should be fine since you are running at such low speeds and short durations, the only issue I think you may have with the belt is that it has loosened or you have burnt it/stretched it with your flames. The belt adjusting screws on my machine did not have any locking nuts, so loosening is likely. If your belt is too loose your cuts will again be less accurate, just don’t over tighten it as you could end up damaging other parts.

It sounds like you have some mirror alignment issues too, check this carefully.

I also run the water through the tube continuously, it really helps keep the bubbles away compared to when you turn the water on and off with the machine. You still have to check it.. as I have found out…..

Firstly, thanks for the quick replies!

I'll try and answer everything as best I can:

Daven wrote: Out of interest what extraction do you use?
Dave

Just the fan and blue tubing which came with the machine, which goes out of a window.

Daven wrote: It sounds like the belts and mirrors need adjusting - the tubes do de-grade over time but not sure if the demand you have put on it would be enough just yet. Cleaning and lubricating the tracks may help as well.
Dave

I've had a quick look, and they look OK. The rails under the bed are still oiled.

Daven wrote: Cooling can also be a cause - maybe think about adding a chiller unit. The air assist on the 3020 should blow the flame away from the head - wonder if that needs adjusting?
Dave

Righty then, did I mention I was a newbie! The air assist has never been turned on. I don't know if I missed it in the manual, but I've just clicked it on and I now have air. I'll try cutting a sheet with it on, but I'm sure that'll solve my flame issues! What kind of issues will that have caused, if I've been using it without air all this time?

Daven wrote: I would be cutting at a lower speed using less power to be honest - I try not to use more than 15 if I can help it, that will keep the flame down and put less demand on the tube.
Dave

Unfortunately, any slower would make it a non-starter commercially.

Spooky wrote: Speed / Power:
The issues you are experiencing is quite normal for tubes, lemme see if I can explain,
A tube has a life of around 1000 hours but this can vary buy as much as 50% depending on the load placed on it and the quality of the cooling system. If the tube has gotten hot on a regular basis or has been deprived of water (by bubbles forming in it) this can reduce tube life by quite a bit, tubes don't often just die they tend to get weaker and weaker until it takes just too long to get anything done. The first 60 hours are the best tube time with a slow degradation in performance from there on. Whilst this can be annoying it is a product of all gas CO2 laser tubes, RF tubes don't suffer the same way but when you take into account an RF tube can cost upwards of £5000 replacing the occasional CO2 tube doesn't seem quite so bad.It can also be caused by the alignment of the beam causing beam scatter and reduced cutting efficiency.

I'm OK with replacing the tubes, I was expecting that to happen anyway. Is there anything I can do to get a quicker cut though?

Spooky wrote: Cuts:
Ahhhh, now this makes a bit more sense, that sounds like mirror alignment on the final lens could be causing all the above. If the beam isn't in the centre of the cone as it exits it will be scattered or deflected causing the cut line to be generated in an offset to the actual programmed position.

OK.

Spooky wrote: Flames:
Double check your air assist is working, Dave is quite right, the air assist should reduce pretty much all the flame to near zero.The fact it's cooking the cable ties suggests not enough air is getting through.

See Massive Newbie Fail above...

Spooky wrote: Be VERY careful cleaning the end of the actual laser tube, the smallest fleck of dirt on that mirror (in the actual tube end) can cause a massive overheat and a cracked mirror instantly.

I am quite careful when cleaning, but how do I actually get to the mirror in the cone? I can feel the opening at the end, but I'm just running a swab around that.

Spooky wrote: A quick check for final lens alignment,
Stick a sheet of ply or MDF in the machine, bring it as close as possible to the cone end, press the laser button for a split second (enough to make a mark, no more) then visually check to see if the spot it has made looks central to the cone end. This should be your first port of call as all the problems you are having sound very much like Beam scatter.

I've just done this, and the spot looks to be higher up the sheet than the cone end.

Mike wrote: It sounds like you have some mirror alignment issues too, check this carefully.

Is there a video for this anywhere, as I've no idea what I'm doing, and the manual isn't the clearest explanation?

Mike wrote: I also run the water through the tube continuously, it really helps keep the bubbles away compared to when you turn the water on and off with the machine. You still have to check it.. as I have found out…..

What do you mean by continuously? As far as I was aware, the water pump is only on when the machine is on.


And one more thing I forgot last night:

Bubbles

There's always a big bubble when I turn the machine on, at the right hand side. It sometimes goes, but I often have to tilt the machine slightly to get it out. I'm also now getting really tiny bubbles appearing at the right hand end of the tube and then increasing as they travel down it, collecting at the left end?

Hiya Leon,

Bubbles!! avoid at ALL costs, they kill tubes VERY quick (as Mike can attest) it's often best to leave the machine on but unplug the extraction to reduce noise. That way the bubbles tend to form a lot less.

I can't over emphasise this, bubbles in the tubes cause more issues than all the other reasons put together!

It sounds like your alignment is indeed out, I don't have the same model as yours so Dave N will probably be able to assist better with alignment instructions (in essence they are all the same but the 3020 has slightly different screw layout)

Running without air assist, this is going to soot up the final lens, and it will require cleaning, this has to be done very carefully as they have a fine coating on them (they look like glass but they are in fact a metallic salt) Zinc Selenium.

Very light touches with a virgin cotton bud and some Isopro alco will sort it though.

I don't know how the lens assembly strips on your model so again Dave N is the man to help

A sooty lens and bad alignment will cause the slow down in cutting you are experiencing for sure.

Let me see if I can get something drawn that will help with the alignment

back in a bit

best wishes

Dave