Build Thread- Cheap laser cutter modifications.

[mowcius]

I've just bought a cheap Chinese laser cutter and I have lots of modifications in progress and lots planned so I thought I'd get it documented.

There will be lots of pictures and I'm happy to (try and) answer any questions you have.
For those who don't want to read the whole thread (although I'd recommend you do), all pictures will be on my Google+ here with captions: http://plus.google.com/photos/114914...30806001?hl=en
(There will also be extra pictures on there)

First off I want to thank the writers/owners of the following (in no particular order):

Laser Cutting
Upgrading a Laser Cutter from China (Part Two)…
CO2 laser cutter
My cheap Chinese laser experience
madbodger: Laser cutter, part I

All have been very helpful in convincing me to take the plunge and go ahead and buy one of these cheap machines so cheers guys!


Ok so the story:
I've wanted a laser cutter for years but never actually got round to buying one then last week I decided it was time.
I looked on eBay and found various machines sold by various different sellers all looking very similar, some with different software etc. These ranged from about £800 to well over £1500 all for basically the same machine.
I then (completely by accident) clicked on page 16 or something and found a few for around £450 including postage. I was dubious but with the sellers having 99.#% ratings with a few thousand items sold I thought I was pretty safe with that.

Right, web browser's gone borked so I'll start with pics and mod info in next post.

[mowcius]

So I purchased this laser cutter, after a day and a half of no dispatch notification I was getting ready to send the ebay seller a message that evening and then while I was out of the office I got an email saying that a very large box had arrived for me!
Forget 2 day dispatch - 2 day postage! I had presumed it'd be a few weeks waiting for it to come from China but the eBay seller had obviously already imported them into the UK and then sold them on from there.


It arrived in a box completely covered in tape, with lots of foam, a secondary box, lots of bubblewrap and the laser cutter inside all of that.
It all seemed a bit excessive but nothing was broken and I'd take excess packaging and everything in one piece over broken parts any day.


The tube all in one piece! Although I've seen 60 and 80W tubes before, this was larger than I expected for a 40W tube.

The rear of the unit with power, fuse holder, separate grounding connection (for two pin plugged countries presumably as it links straight to the IEC ground pin), extraction hole and water cooling inlet and outlet with silicone hose (6mm ID I think).

The fan's ridiculous - hole's far too small for it.
But I was prepared for this and had ordered 2x 120 SickleFlow Coolermaster fans off ebay (they were cheap and push quite a bit of air for the noise).

The laser cutter control panel complete with some direct translation english.
"The non-professionals are forbidden to adjust route of light"
Professionals can bend it with their mind...


So that's as it came, so far no issues - delivery was fast and nothing was broken. Better than I expected.

[mowcius]

As soon as I had ordered the laser cutter I had also ordered a number of other things I knew I would want for mods so I'm reasonably kitted out for doing things when I have the time rather than waiting for things to be delivered.
I'd recommend this way of working - have a list of things to do and order parts for a few weeks ahead. It can obviously backfire sometimes but stock's always good to have.

So the first mod I knew I was going to do was replace the naff amber coloured window with a nice clear one.
For anyone who thinks that makes it dangerous, it doesn't. Then orange colour only stops the glare, it's the acrylic that stops the IR. All laser cutters such as Universal or Epilog ones have clear acrylic windows.


The acrylic had also become mottled as if the plastic wrapping had reacted with it in some way so it wasn't even a nice clear orange window.

Window removed and it's already looking better!

New 6mm clear piece in place - A3 is the perfect size (just a guess when I ordered it - that's approx 594x420mm for those not in the UK)

As the old mounts were dubious and rusty (and I wanted to add 2 more for stiffness), I cut and ground off the old mounts with my trusty £15 Woolworths mini drill.

I then marked up, drilled through the steel (with 3mm) and the acrylic (with 3.5mm), cleaned up and attached the plastic on.
As I marked up to the hole in the metal, it's not completely square so the acrylic only goes on one way round.

Much better!

I'm probably going to replace the screws with button head ones so they're lower profile but I like it with them visible (even if it does stop me putting acrylic sheets on top of the machine)

The underside's a bit of a mess from my marking out, and where I ground off the mounts needs painting as it's all steel but the lid is much stiffer now and I'm happy with it for the time being.


I then removed the bed with the rubbish spring loaded bit (designed for holding things for engraving) and had a look at how much larger I think I can get the cutting area. The bed is stated as 300x200 in the specs but you can get slightly more than that as standard (although the engraving area they expect you to use most of the time is tiny - about 180x100 is the largest you can fit in it)
With some minor cutting, filing and slight modifications I think I should be able to get about 340 x 250 but I had a brainwave last night that if I move the laser lens and secondary mirror to behind the X axis track (and a few other mods) then I should be able to get all the space I can see (about 360x300). If I can get 300x300 then that's only half the bed size of a typical universal laser cutter (600x300) and I can produce useful sized parts with a bed that size.
The white thing is for extraction (from the engraving area) and I'm going to have to take the whole XY assembly out to remove and modify it.

After looking at the bed size I moved onto lighting - lots of laser cutters don't have any but it makes it so much easier to see what you're doing when setting things up.
A few weeks back I'd saved some self adhesive LED tape ends from the scrap - these are 12V with an LED every 20mm or so and give off a decent amount of light.

With one strip at the front...

and one strip at the back...

the lighting was much improved.
Because they're not a single point light source they're also perfect for this application as when you stick your hand or an object in, there are hardly any visible shadows so you can still see everything.

I did run them off the laser cutter logic board's 24V supply in series but then decided as it's probably a feeble excuse for a power supply and I'll have a fan or two (plus some other electronic stuff) to power off it as well I'd give it a dedicated power supply (which is currently a 12V brick connected externally through one of the many holes in the case)


A final image for today - the laser cutter in the dark with the LEDs on.

Lots more mods and pictures to come!

[mowcius]

Just a quick update today - I received my air compressor for air assist.

It's not too loud and pushes a half decent amount of air through (20L/min up to around 95PSI max)

I also had a further look at the home sensors - looks like it's going to be really easy to modify them - just modify the bit of metal that passes through the photo-interrupter gate.



My aluminium honeycomb for the new bed should be arriving in a day or two (unexpanded so it'll be fun trying to evenly expand that I bet) but my cable chain is likely to turn up beginning of next week (a little annoying as I'm ready for it now but I can't do anything about that).

[mowcius]

So yesterday I removed the tertiary mirror and lens attachment...

And found that my lens was damaged - I've requested a new one and we'll see how that goes.

Turning the mount round 180deg should give me almost the full bed size to work with, the laser won't currently be quite at the back because the mount hits the metal section which houses the laser tube at the back of the machine (but I'm working on that)

After removing the whole X/Y I can see how much space I have to work with.
The ribbon cable is for the X&Y home sensors as well as the X axis stepper motor.

Bit easier to see everything now its out of the chassis.

I've got a bit of cutting and modifying to do to this and hopefully my alu honeycomb will come soon and I can start working on my new bed and figuring out how I'm going to make it height adjustable (if anyone has any suggestions then please speak up)

[Tweakie]

Mowcius,

What make and model is your new air compressor please ??

Tweakie.

[mowcius]

Originally Posted by Tweakie What make and model is your new air compressor please ??

It's just a cheapo one off eBay - AC18B but no idea on the make (I don't think it said on the box). £39.99 posted.They're normally used for airbrushing.
Seems pretty good for the price though.

[mowcius]

So yesterday my aluminium honeycomb arrived wrapped in bubblewrap in a cardboard tube with a bit of paper packaging.

Unexpanded it just looks like a 10mm thick aluminium bar (but a bit lighter maybe)

Looking at the edge you can see some slivers of aluminium.

I'm sure going to have fun expanding it... not. I think the best plan will be cutting it to the right width first (as expanding half will be easier and it'll be easier to store the other half unexpanded as well) and then using two pieces of wood with lots of nails in on each end and simply pulling it apart and seeing what happens.
I've got some aluminium U-section ordered which should be with me before the end of the week along with some flat bar as I think the bed will need some extra support in the middle as the honeycomb's only 10mm thick.

With the X/Y assembly out I gave it a clean and had a look at the rollers (among other things). A few observations/comments:

The bottom rollers/bearings for the X axis track don't actually touch the Y axis track and the top roller has also been put on bent which might mess up my focusing if the track's not level.

There's a right mess under the laser carriage but I suppose I couldn't expect them to clean up for the price it was.

The hole where the extraction vent went through is also rather 'rough and ready' but as I'm probably cutting that out larger anyway it doesn't really matter.

The stepper motor wires are also shoved next to it which won't help with keeping it cool so I'll be moving them.

After seeing this article on hackaday about a crosshair aiming system modification on a laser cutter that was what I'd decided to do for my laser cutter as I already had line generators, 1mW red lasers etc but then after reading a comment stating that having it with a beam combiner along the same path as the IR beam made aligning much easier I decided that would be the way to go (it makes sense!).
Beam combiner was cheap off eBay, ordered today, probably be arriving early next week.
I am a bit tight for space between the laser tube end and the first mirror (got roughly 15-20mm) but I should be able to fit it in and then after aligning it once to the same path as the IR laser it should make future alignment much easier.
I'm tempted to try the crosshair idea as well though as it would give something to line square things up to if they're not in the corner of the cutting bed.

[bpoulin]

I'm trying to develop a mount for my CNC router that uses those cross hairs. Check out Cool Gadgets at the Right Price - Worldwide Free Shipping - DealExtreme I think I paid $3 or $4 for a laser line module. I bought a bunch of them. I want to make a cross hair module for my CNC router, drill press, and laser.

[mowcius]

Well that post looks a little bit like spam but I did say above I already have plenty of laser modules and line generators
I don't personally use dealextreme much, being in the UK I normally find I can get things cheaper delivered here from alternative sources than I can get from DX.

Assuming it's not a spam post I would be interested on how you get on with your laser crosshair marker.

[bpoulin]

No it's not spam... I'm slightly offended by that actually... I was going over your thread on my phone, I missed the part about you having plenty of laser modules. I would like to know of some alternative sources for cheap junk Dealextreme annoys me sometimes because you order something and a week later you'll receive an email saying it's out of stock. I waited 2 months on a camera once before I canceled the order. They don't keep track of their current stock well.

[bpoulin]

And as far as the build, it's a wannabe project. I have too many bigger projects under way to deal with that one right now. But someday when I have nothing to do I'll build it lol.