K40 Laser cutter RAMPS conversion

[tim_n]

Anyone done a RAMPS conversion on the little K40 laser cutters?

I decided as 99% of what I cut in the laser cutter is A4, it'd be handy to have one at home (for the workshop)

Most the problems seem to be around the driver motors etc, but this seems like fun:

http://3dprintzothar.blogspot.co.uk/2014/08/40-watt-chinese-co2-laser-upgrade-with.html

http://www.cnczone.com/forums/general-laser-engraving-cutting-machine-discussion/256422-cnc.html

So we've bit the bullet and bought one to play with and got the RAMPS kit (£20) from eBay to play with.  Doesn't arrive for a few weeks and I fully expect it all to be broken inside, so we'll see how it goes.

Hopefully once we're done, we might build a bigger base area for it, but with 40w tubes & power supply I don't expect it to perform miracles.

I don't expect to be working on it in the space, unless we pop up to talk about it.

[Ian Macdonald]

Have been thinking of buying myself but won't be for a few months,
would therefore be interested in your experiences etc. in carrying out
the upgrade.

All the best

Ian

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[Adrian Godwin]

I'm marginally interested too. I believe JAS are able to supply a cutter without the usual controller, but they're still relatively high quality machines and may be more expensive than buying one of the worst cheap imports and throwing parts of it away. At least your money would be going into the bits that matter though.

There are also a fair few damaged / burnt out ones on ebay, but unfortunately there seems to be a good chance of tube failure so they need to be really cheap (or really good) to be worthwhile.

[tim_n]

Exactly that. We got a pretty good deal so can't complain.

I don't know whether I'll drive up with it to the space - it may actually be easier and in which case people are welcome to come look and poke around. This should have a working tube and if not, its going back!

[Giac0m0]

Thats sounds rather spectacular, even if you keep it and do the work at your multipl- car driveway, would you put together a post/wiki page with it as a project and your findings?  

[tim_n]

There's some really good info about on how to do it, but no complete breakdown. So I'm going to try for that. So fingers crossed it arrives in one piece and isnt lethal out of the box.

[Simon Howes]

I'll put you in contact with my friend whose doing the conversion if you want. It did work out of the box but was surprisingly dire (he showed me something he engraved.)
How bad is it? Doesn't have limit switches and homes by grinding the steppers against the limits of the axis bad! Ho ho!

That said though the *components* you get for the 300 bucks are very good.
Tube & psu (made by another company, so they work)
Optics
Power supply
Big laser cutter shaped casing
Extractor
Water pump

Totally replacing the derptroller with ramps is the way to go. My friend is using some special RAMPS board designed for 36v (or was it 32?). There's some american company that has some complete x/y dropin replacement. Or you can make your own or hack the existing one. The existing design has a tiny cutting area but the axis can move a lot more. The carriages are some sort of massive shitty drawer slidery thing. If you replaced it for something smaller you'd end up with about a4 sized cutting area. If you've built a 3d printer a simple x/y thingamajig ain't too hard :)

My friends reaaaal busy atm, but I can put you in contact if you wanna chat :)

On 8 Oct 2015 6:31 am, "tim_n" <tim.n...@gmail.com> wrote:

There's some really good info about on how to do it, but no complete breakdown. So I'm going to try for that. So fingers crossed it arrives in one piece and isnt lethal out of the box.

[Ian Macdonald]

@Simon H

Grinding the steppers for home is not bad per se, if you think of any
init routine for XY motion you want to step slow and special when
first switched on in case the carriage is blocked(eg new and the
shipping restraint has not been removed, not that that ever happens :)
and test for excess current in the motor drives before you destroy the
drives.

That said you are probably right and it is done bad :-)

Would love to see photos of friends cutting results though, give an
idea of just how much improvement is needed/can be achieved.

Cheers

Ian

On 8 October 2015 at 08:29, 'Simon Howes' via London Hackspace

[Jon Fautley]

On 7 Oct 2015, at 16:46, tim_n wrote:

> Anyone done a RAMPS conversion on the little K40 laser cutters?

Following on from the other thread, I'm seriously thinking about this.
There's seemingly a few different types of 'cheap 40W Chinese laser
cutter', some of which seem to have air assist already built in and a
myriad of different (looking) control interfaces.

Could you link to which one you went for? I'm assuming its one of the
ones with the Moshidraw interface board?

Certainly interested in following your progress on this, and I might
even pick one up myself to 'play along at home'.

Cheers

Jon

[tim_n]

Hi Jon, no the one bought was a coreldraw/mosidraw.  May be the same thing.  It wasn't really a well thought out exercise, merely wondering whether we could laser etch bacon.

[tim_n]

I just got notification that it was out for delivery today.  Which is fairly shocking as I had free delivery and it showed dispatch from China and a 28 day delivery time.   They obviously have stock in the UK and the waiting time is only if they've oversold I guess.

Makes me regret purchasing my RAMPS from China on the slow boat.  That'll probably take much longer to get here.

For anyone following, I've got an emergency mushroom style shutoff switch on order, flow sensor, limit switch, RAMPS bits and bobs, heatsinks for the drivers which weren't included in the RAMPS kit.  I'm going to document the build on www.waark.com, probably write an instructable and I'll take plenty of pics.

[Ian Henderson]

Tim

I'm very interested in following your documentation of this.

Many thanks

--Ian

[Brendan Sleight]

Related - http://3dprintzothar.blogspot.co.uk/2014/08/40-watt-chinese-co2-laser-upgrade-with.html
Via dangerousprototypes
http://dangerousprototypes.com/2015/10/01/40-watt-chinese-co2-laser-upgrade-with-ramps-arudino/

BMS

[tim_n]

Thanks Brendan.  Yes I've been reading them extensively.

I'm thinking of bringing the box into the space weekend after next to have a play & test it with default configuration.  If any of the bits have arrived (unlikely but who knows!) we may also make modifications.

I'm also quite interested in rastering logos onto bacon just because.  Perhaps the hackspace logo.

I'm earmarking Sunday 25th October for laser cutter fun as it looks like the camp I was supposed to be on is cancelled.

[MSRaynsford]

Last time I checked these setups weren't capable of doing raster engraving with a 40W tube.

They can handle it with a 2W diode but they're not fast enough so once upgraded to 40W it just results in flaming death.

It's also only black/white engraving so some creativity is needed for anything with more than 2 colours.

Please correct me if I'm wrong, it's something I'm currently working on.

[tim_n]

Probably not wrong! I'm probably mixing terminology of stuff I don't understand properly.  I mean to say I'll be shading in logos in an engraving way.

[tim_n]

Decided to go camping on the 23-25th October, so provisionally Sat 7th Nov.

[tim_n]

As the cutter had been with us for 14 days and I'd only done a cursory inspection (no live testing) we decided to give it a try.

As expected the laser was not particularly well aligned.  After a couple of tests we realised it was bad enough that it was smacking into the side where the control panel was.

I left the adjustment to the guy with the most patience and after about 10-15 minutes we had a well aligned laser.

Attached is pics of Rule 0 test and engraved bacon.

[tim_n]

OK all the bits are arriving from China, but I've been told that the 7th is a bad day as it's bonfire night.  Ooops!

So, it'll be Sat 14th! For definite!  I'd prefer earlier, but camping/halloween/bonfire night all inbetween! 

[tim_n]

Couldn't get Imgur apps to upload photos from the build on Saturday, so i've added them to google photos.

https://goo.gl/photos/ka3zDhUgRiju9c259 should hopefully work!

Ben/Gary/Steve and I appeared about 10:30am on the Saturday.  Took us about half an hour to get setup and the first job was to have a good hard look at it.  No-one had read the build logs I'd encouraged them to read before we started, so it took a while to get us all in the right mindset.

The biggest problem (and what took a lot of time) was modifying the ribbon cable.  We took the bed of the laser out which gave me an opportunity to get all the metal swarf out.  By having a good look, we could see the optical end stops and how the mechanics all worked.  It would have been best if we'd got an adapter for the ribbon cable, but instead we crimped on ends to it and used some coloured pin wires to connect everything up.

Having done this, the next 4-6 hours were spent swearing at stepper motors that didn't want to step.  During this time I did what I do best which was help put up the projector screen in the class room, fetch bacon sandwiches, cleaned the toilets and do some non-essential poor quality soldering.  When I returned I read through some blogs and found some others having the same problem and it appeared to be the speed of the steppers.  with that fixed it was just a case of working out why now the steppers when instructed to move 1mm moved 1cm.  This was eventually rooted down to some older random manual modifications we made to the EPROM with tgreer which seems to be prioritised over the firmware on the arduino (? I was too tired to question this so may be wrong).

We reassembled the bed system and attempted to get the lasers aligned but found the base of the laser was too badly misaligned, so we ended up taking it out again and realigning it.  We got it down to a fair bit of accuracy, but needs further work.  The laser would fire, but at this point it was 2am and patience was running a little thin.  Our only windows laptop had suddenly fizzed earlier in the day and we were trying to run inkscape and the plugin on a windows surface and couldn't get the g-code to compile for a simple square.

The plus is that this is all now software issues, the RAMPS controller seems to be doing its job.  We do definitely need a new laser bed, the current one shares heritage with a banana.  Thinking of getting the Z-kit in from lightobjects.

Still need to add safety features and a new panel.  Getting close though, probably another long day of mods left to do on it, so may be back.

Thanks for all the help, suggestions and laughs on the Sat, good fun and I consumed a fair bit of the pinkish drink in the fridge. A few people saw me pouring out money from the sweet box - I was breaking a few notes not pinching stuff, though the sweet box is in need of some wood glue by the looks of it.