CO2 laser - the learning curve

[PaulT]

Simond asked me to appear here.

 

I have just bought a Chinese 40w CO2 laser after carefully researching the many clones on offer.

The history of these machines is very chequered so my eyes were wide open when I dived in.

I think mine is good wrt hardware, it came working and with several of the recommended enhancements at a sensible price.

Sorting software has been harder than setting up the hardware but I reckon I am nearly there.

 

Test engraves and cuts have looked promising so I have started on my first proper job which is cutting 3/16" Bass wood sheet to make baulk roads for complex mixed gauge turnouts.

 

I got cut thru' with 2 passes but several issues are needing attention as I learn to optimise settings and get correct scaling through the software.

When I am there I will post pix and settings.

 

Thanks to Giles for his brick bog files. Once I have cracked my baulks' settings I will have a pop ( should that be poop?) at one of his.

 

My second job for the machine is lots of buildings.......

[Simond]

Paul,

 

Welcome & thanks for joining us.

 

Which machine do you have and which software are you encumbered with?

 

As you'll have seen earlier in the thread, my machine is an HPC, bought second-hand, and equipped with the extraordinarily unimpressive Newlydraw software. I draw using a copy of TurboCad which I bought at least 22 years ago, and I suspect nearer 25 - it does everything I need in 2D, although I do have access to PTC Creo through work if I want to do 3D stuff. I transfer drawings to the laser in DXF format.

 

I pondered an upgrade to the laser control hardware & software, but I don't think it's worth the effort, as I now seem to have a reasonably reliable method of etching & cutting. I'd rather make models than upgrade machine tools, but I suspect the milling machine is due a bit of work in the not-too-distant...

 

I also have benefitted from Giles generosity with the brick outhouse

 

Best

Simon

[PaulT]

Paul,

 

Welcome & thanks for joining us.

 

Which machine do you have and which software are you encumbered with?

 

I didn't like the price that HPC charge to tart up the basic K40 machine, as I reckoned I could do what was needed. In any case during this Spring they discontinued their cheapest model so I bought at 1/3 the price they now offer.

My K40 came from bgadepot on Ebay at £640 including delivery to UK, duty was < £20

It is very good value as it includes enhancements that other bods had to do as aftersales, viz, air assist, redspot focus aid,  interlocks on lid and no water supply.

 

The  X and Y axis slides, belts and pulley system are better than average. See below for Z axis comments.,

 

The controller card is latest version, called M2. This does lock me into using Corel Draw 11 as supplied under Win XP or other versions up to CD X5 which I bought cheaply.  This works perfectly under Win7  with the supplied dongle and "Corel-Laser " software to drive the laser and adequately under Win10 on another machine , not tried cutting with that.. In Win10 the minor problem with invisible menu bar is well written up and work arounds provided.

 

Many users of the earlier cheap versions of the K40 have gone through hoops upgrading the driver board for Mach3 etc. I don't see the need for that...yet!

 

I also have CD X7 but this is NOT compatible.

 

I had to set up the mirrors alignment but that is only a day's work.

 

The weakest part is that the table Z-axis leadscrews are a bit basic so stiff to adjust, If I find I am using that a lot I will modify these 4 corner rise and fall leadscrews and may even add stepper to Z axis.

 

The other mods I expect to consider will be:

 

Improved air/smoke extract...plenty of advice available on easy improvements on Yahoo group.

 

Cutting a slot in front of casing to allow longer bits of wood to "pass-through" .  As supplied the largest work piece is 330 x 220mm.  The internal layout shows this mod is feasible although it will limit focus range for such long work pieces. I only want 10mm range out of the 75 available for A4 sheets.

 

I am still learning how to optimise speed, passes and power settings for various materials, currently using 3/16" bass wood, 3mm ply and mdf.

 

Much advice out there quotes x mA power levels; mine is calibrated in % of Maximum but I can't relate that to mA value...does anyone know?

Edited June 13, 2016 by PaulT

[Simond]

Paul

 

I don't "know" but my machine is quoted as being 35W.

 

The meter is 0 to 30mA full scale, and when the pot is fully wound up the meter reads 25mA

 

I guess you could scale from that

 

Best

Simon

[Simond]

Been quite busy since June - there are lots of updates, including some laser work, in my PD thread, link below.

 

I have, however, run into an issue, and I fear it will require a fairly drastic solution. Following some discussions on the Emblaser thread, I tried to "etch" my way through some plastic by making multiple passes - this was actually a prototype I was making for my day job, nothing to do with models, so no photos, I'm afraid, but what I discovered that the laser was not returning to its origin after each pass, and the error was cumulative, and somewhat random, in that it did not occur every time. I'd had similar issues during my first few tests with the machine, and thought it was just my ineptitude, but it seems there are other issues (possibly augmented by my incompetence!).

 

The perplexing issue is that the software seems to think it's right, so performing a soft reset after each cycle doesn't help. I suspect that a hard reset might fix it, but at a hugely increased cycle time.

 

As far as I can tell, it only happens on the X axis, and it always increases the X value, by a very small, but visible amount, say 0.1 to 0.3mm. There doesn't seem to be any obvious mechanical cause, nothing binding, no obstructions.

 

My options seem to centre around replacing the main driver board with either a new HPC board, or an aftermarket alternative, lots of which seem to have become available with the rise in hobby robotics & digital products. I hope to find time during the day to talk to HPC, and get their comments, recommendations, etc. Will post more in due course.

 

There is, of course, a further benefit, in replacing the loathsome Newlydraw software with something a bit more twenty-first century.

 

Best

Simon

Edited November 10, 2016 by Simond

[Simond]

Hi all

 

Does anyone have any experience of replacement driver boards for lasers?

 

I'm fed up with Newlydraw, and the laser is not really behaving properly, it loses registration between cuts, which rather limits what you can achieve with it.

 

I'm thinking "Smoothieboard" - http://www.andornot.co.uk/product/smoothie-board-5xc/

 

And "Visicut" - https://github.com/t-oster/VisiCut/wiki

 

Any thought, comments or experience would be most welcome!

 

Cheers

Simon

[Simond]

New toys alert!!

 

I have recently spent some spare time playing with Visicut, and the Smoothieboard arrived today!

 

 

 

Doubt I'll do much with it for a day or two, but hopefully, we'll be rocking & rolling next week.

 

Best

Simon

[Giles]

Good luck with that - I hope it sorts the Problems!

[Simond]

Slow start, but I though that yesterday afternoon, after work, it was a nice day, but not "out in the garden", the kids didn't need Dad's taxi, & MrsD was happily WFH in the study. What could possibly go wrong...?

 

So I started to trace the wiring on the laser, (I'll eventually draw the diagrams a bit more legibly and post here for anyone else) and then removed the motion controller board. At this point, I hit snag #1, in that the X-axis motor is connected to a 12-way ribbon cable rather than the expected 4 wires. A bit of checking with the multimeter located two pairs of tracks, but the resistance of the windings is around 20R, rather than the expected 5R5 of the Y-axis motor.

 

Further checking located the motor type number, and it's a "high impedance" motor - 20R & 25mH, which is not recommended for the Smoothieboard. This needs to be replaced with a lowZ version, which. In itself , is not difficult, but requires almost total dismantling of the moving parts of the machine.

 

I was trying to avoid this, as it implies a full realignment after reassembly, but hey-ho, in for a penny.

 

This wasn't as simple as you might hope, but having dismantled the lift system, I could access the fixing bolts at the back, and the X-Y assembly is now loose in the case.

 

At that point the garage phoned to say the car was ready, MrsD decided to go shopping, and MsD called to be collected, so progress ground to a halt.

 

So current state of play is that the machine is half dismantled, and the schematics are very rough in my notebook.

 

Next step is to get the carriage assembly upended, find the specs for the Y-axis motor and buy one or both replacements, depending. I'm hopeful the Y-axis motor will be ok, and I possibly have a replacement for the X, so we might make more progress today.

 

I'm grateful to M Wright (workwright) who has posted some useful links on the Emblaser forum, I'll be following those : http://www.rmweb.co.uk/community/index.php?/topic/108310-darkly-labs-emblaser-affordable-laser-cutter-review/?p=2752970

 

This series of videos on you tube is very good - starts with the machine arriving and by video 7 he's had it 4 months and made some modifications, and reviews them too.

 

I've also been reading through http://donsthings.blogspot.co.uk/2016/11/k40-s-interlock-breakout-board.html (sorry, that's not the home page) where he talks about converting a similar machine.

 

The K40 series machines are mechanically ok, but electrically rather dodgy, and variable - no two appear identical! Many machines apparently do not have interlocks preventing the tube firing whilst the doors are open. This is a poor state of affairs, happily mine is interlocked, but I'll join the throng and urge anyone who has a non-interlocked machine to fix it before it fixes you...

 

As most people are aware, gas lasers run on high voltages, well in excess of 20kV and at currents that will make your eyes water (it's only milliamps, but it'll stop your heart. Got the defibrillator handy, and someone who knows how to use it?)

 

More to follow!

Simon

Edited June 17, 2017 by Simond

[Simond]

Dismantled the gantry assembly from the chassis this afternoon, in spite of gardening enthusiasm from Madame. The lattter resulted in 4 trips to the local tip, which, thankfully, was not closed and relocated to Ashford, a mere twenty mile drive each way, by a local government initiative a few years back. Count your blessings...

 

Anyway, the stepper I have from the turntable experiments a couple of years back is not suitable, and the one that was fitted has been removed. I will order a new one tonight.

 

I now understand why the ribbon cable is 12-way. Photos have been taken. There are two limit stops fitted to the machine, and these are connected to the old controller through the same ribbon cable (it's probably clearer to refer to the ribbon cable as a flexible printed circuit) : these are the led/phototransistor type, but, bizarrely are fitted to detect full right, and full down. The newlydraw software uses full up and full left as zero-zero, so that's odd... given that they are optical and could easily be configured to detect both limits of each axis, it's a bit of a conundrum to understand why they are as they are. Damn shame they didn't do both extremes of travel, would have hugely improved the machine, probably saving me all this palaver.

 

I've cleaned & reassembled the lifting table thingy. Acetone does dissolve the gunk formed from the vaporised & recondensed MDF glues, with some aggressive abrasion. I want to motorise this. Watch this spade.

 

Then I went for a beer or two, so no further progress anticipated today!

Best

Simon

Edited June 17, 2017 by Simond

[Giles]

Spade will be watched avidly.....

[EKR]

Only four trips to the tip, you were lucky....

It takes weeks to eject the spiders.

[Simond]

I haven't hoovered the car yet...

[Simond]

New stepper arrived today

 

Removed old stepper, started to make a puller to get the toothed sprocket off.

 

Lathe broke - don't know why but I suspect the Ward Leonard drive system - the primary motor is running, but there ain't no drive...

 

Managed to get sprocket off

 

Bent flange

 

Straightened flange

 

Fitted motor but it was not at all smooth

 

Removed motor, took sprocket off again, turned it upside down refitted it.

 

Smooth

 

Every b....y screw is obscured by part of the frame. It's a bit tedious. Anyway, I think I can move on to the electrickery now.

 

Hopefully the next session will be a bit less fraught!

 

Best

Simon

[M Wright]

Hi, you seem to be having fun with your upcycling project. One  little set of tools I purchased for a totally diiferent job has proved a couple of times the cats wiskers when dealing with Chinese metal case and fixture design.  It is made by their ex friends across the Sea of Japan.  It is a minature ratchet drive and assorted bits + Hex and torx. It is made By Makita and is of very high quality. It is amazing with the little ratchet wrench in your fist what you can get into and undo .  http://www.powertoolworld.co.uk/makita-p-79158-39-pcs-screwdriver-set#gref (cheapest I could find, no endorsment of poduct or supplier intended)  The other essential on the 50w machine is my mountain bikers headlamp. Hands free and lots of light where you want it. The mounting of the electronic components in my machine is really c..p. Just put a self taspper through the case, woops, missed the wire, I think I will have another go. Never mind the razor sharp screw ends hiding under one of the beams that makes cleaning up cutting a rather bloody task.  It will be interesting to hear how you fair with better quality components. Make sure all the components are earth bonded.  Earthing seems little understood by their designers Regards, Workwright.

[Simond]

Mine was "CE-ed" by HPC, I think, so it's got interlocks and earth bonding, and seems mercifully free of self-tappers sticking out. That said, there's the odd sharp edge.

 

The micro-ratchet is great, but, for example, won't help when the flange is a mere 10mm from the screw head, and it's edge is about half a millimetre over the centre line thereof. Screwdriver engaged with screw head at absurd angle - happily didn't wreck the screw heads, and the screws were reused to fit the new motor.

 

Couldn't face it tonight. Playing with the Unimat 3 to make some brake hanger spacers for the Dukedog.

 

Best

Simon

[M Wright]

Hi, I thought this might interest you.  It is a project one of the guys who helped me fix my power supply is crowd sourcing.  I am sure he would be interested in your project to fit a better processor to your machine. https://www.kickstarter.com/projects/2118335444/gerbil-the-open-upgrade-for-your-k40-laser?ref=creator_nav.  Regards, Malcolm Wright (workwright)

[Simond]

Malcolm,

 

Thanks for the link. Timely! (Though it does appear that it might have been an easier option)

 

Today I finished stripping out the original endstops. My laser is a k40, but with some extras - it had optical endstops for "right" and "down", which, given zero-zero appears in the horrid Chinese software to be up and left, probably isn't the best starting point....

 

As I mentioned earlier, it has some interlocks and safety stuff too. Good...

 

Today I installed "up" and "left" microswitches, I'm going to put another two on for "down" & "right".

 

I got a cable chain last week but it's too big, need to get a slimmer one.

 

When these things are done, and working, I will install the Smoothieboard. And hope I haven't mis-connected something, and confirm that I am weasel-free, so we don't have a CERN-like melt-down.

 

Still loads of metalwork to do.

 

Best

Simon

[nick_bastable]

 

When these things are done, and working, I will install the Smoothieboard. And hope I haven't mis-connected something, and confirm that I am weasel-free, so we don't have a CERN-like melt-down.

 

 

Best

Simon

i guess at 20 miles away I will be safe   

 

good luck with the upgrade

 

Nick

[Simond]

Well, a bit of progress, the Smoothieboard is installed, and driving the steppers.

 

Next step, which I anticipate tomorrow after work, will be to edit the config file, and to couple up the laser to provide the PWM to give the intensity setting. Only then I'll be confident that it all works.

 

I haven't done loads of photos, but will provide a few in the next couple of posts. I'll also outline the steps I've taken and the links to the various websites where I've found some help.

 

Best

Simon

[Simond]

Well, the sporadic progress has led me to a point where there is control of the steppers from the laptop, and, there is control of the laser... this is the objective of course, so feeling quite pleased with myself yesterday evening.

 

However, the works that I had to do to get the endstops in, and the lifting table out, cleaned and reinstalled, and the additional cable chain meant that the alignments are completely shot away... this was always a risk, but it looks like a long and tedious process to get things sorted, and I'm not currently in the mood, so I'll update these notes instead.

 

What I did...

=========

 

Took photos of everything.

 

Went online, see below.

 

Took out the motion control board from the laser, identified wires, followed them.

 

Dismantled the optical endstops that were fitted, along with flexible printed circuit that connected the endstops & x-axis stepper to the control board.

 

Changed the x-axis (that's horizontal, the cutter is A4 landscape, approx) stepper motor as the supplied one was high impedance and the Smoothie prefers low impedance motors.

 

Checked the y-axis (vertical) motor and found it to be low impedance. Bonus.

 

Fitted microswitches to the base, for y-min & y-max travels. The y-max needed a support bracket from 2mm ally strip, the switch was screwed to the ally with a couple of 8BA screws, and the ally to the machine to with a couple of 6BA screws into tapped holes. The y-min was simply screwed to two tapped holed drilled in the top of the machine. The nice aluminium top is plastic, despite appearances.

 

Fitted microswitches to the carriage for x-min & x-max. Small piece of ally angle at the left, with the switch screwed on, x-min sorted. Easy-peasy. X-max was slightly more bother. In the end I made a "U" shape from tufnol, and drilled and tapped a hole in one of the legs. This is then effectively a g-cramp, which locks onto the carriage. The microswitch was fixed to the tufnol. A further piece of ally was cut, drilled & tapped to allow it be fixed to the carriage to prod the switch from a distance.

 

Made a piece of ally to support the cable-chain on the right of the mechanism, to carry the wires from the x-max limit switch and the x-axis stepper. Fitted a 10x10mm cable chain from Amazon, about one third of the metre length supplied was enough. Drilled & tapped the bottom of the machine housing to fix the other end.

 

Reinstalled the mechanism in the housing. This brief phrase covers a multitude of niggly problems and quite atrocious use of some formidably bad language. I have no idea how these machines are assembled in the factory, because to get at one screw you have to take out another, and to tighten that one, the other needs to be removed... A little "design for assembly" would have gone a long way. Anyway, I made some oblongs of steel, approx 30x25mm, and tapped an M6 hole through, 10mm in from the middle of a long side. These were sprayed with red oxide primer, and then used to allow the fixing screws to be put in from underneath, and tightened "blind", as it is simply impossible to get a spanner on the conventional nuts that were fitted, when the lifting table is installed. Then the whole thing had to come out again because the lifting table needed to go in first, and you can't install that as a unit because you'd have to dismantle the whole x-motion assembly and that was simply a dismantling too far. Anyway, persevere, got there in the end.

 

Wired the switches. Where there was a risk of the wires touching metal (y-max & x-min) I cut a bit of plastiglaze and sandwiched it between the microswitches and the ally. Made a mistake in the wiring. See below.

 

Powered up the board before I installed it in the laser, on the laptop USB, Copied the config files, confirmed that the various software talks to the board. Watched the pretty flashing lights "dance"

 

Made a "shelf" from Perspex, on which the Smoothieboard was mounted. Fixed this to the plate where the old controller was, cut a hole in the outside of the machine to clear the Lan and USB sockets on the board.

 

Verified the 24V supply from the laser power supply, connected it to the plug for the Smoothieboard. Labelled the plug & socket.

 

Spiral wrapped the limit switch wires. Plugged them into the board. Reconnected the USB, failed to get the board to work. No dancing lights. Oh 'eck! Disaster! No, not quite, but close. Discovered that despite making the four sets of two-core wires for the limit switches at the same time and all identical and checking them, I'd put one wire in the plug in the wrong hole, and it was shorting the board by connecting 5V live to ground. Luckily, the laptop USB can't push enough current into the board to do any harm, so it just didn't work. I found my mistake and fixed it, and then reconnected, sigh of relief, all well. Had I connected the 24V input, the instructions suggest that I'd have killed the board. Luck was on my side. And maybe a bit of caution too.

 

Checked the stepper connections as recommended in the Smoothieboard instructions, all ok. Plugged the steppers into the board. Board & computer still talking.

 

Deep breath. Plugged in 24V, powered up the laser mains. Fired up Pronterface (see below) on the laptop and made the steppers move! Hurrah! They went the right way! Double hurrah!! Endstops all work! Triple hurrah!!!

 

Yesterday, I connected the laser "L" wire and the extra ground to the Smoothieboard, and proved that the PWM was able to drive the laser.

 

I then started the realignment process, but I've a way to go on that yet. That's not difficult or complex, just tedious (and potentially dangerous if you do it the way some of the you-tube clowns do it!) Anyway, I have done the difficult stuff, and I'm pleased so far. The proof of the pudding will be when I start cutting, maybe in a week or maybe tomorrow...

 

Software, Hardware, Links & things.

============================

 

Smoothieboard - open source project. Well impressed with the product, documentation and everything else. The website is http://smoothieware.org/smoothieboard, which links to all the documentation, etc. I bought my board from Andrew Wade at And Or Not, very helpful, usual disclaimers. Andrew@andornot.co.uk http://www.andornot.co.uk

 

Visicut is a recommended software package for conversion of DXF files to g-code. It's free, here: https://hci.rwth-aachen.de/visicut

 

Pronterface is a slicer program, I presume for 3D printing. If offers a useful control interface. It's free too: http://www.pronterface.com

 

Editing the config file - apparently, don't use the windows text editors as they can confuse matters. The recommended package is Gedit, https://wiki.gnome.org/Apps/Gedit

 

Stepper motor came from one of the usual robotics online shops, forgot which one, but it was a tenner or so.

 

I'll post some photos as and when, any questions, ask away.

 

I'm confident that when I've finished the laser, I could do a milling machine or a lathe. Indeed, I might...

 

Best

Simon

Edited August 8, 2017 by Simond

[Giles]

I'm very impressed, but I suspect I might have lost the will to live by now, if it were me....i can only cope with the simpler things in life.....

 

Well done!

[Simond]

Thanks Giles,

 

I was getting a little stressed by it, which isn't the point of a hobby, after all, however, most of the hassle was due to the way the damn laser was built originally. That wasn't stressful, just b----y annoying. And most of the stress was the fear of the risk of killing a £160 PCB, but that's inevitable if you're doing something where you're a total novice. Reminds me of first time on a motorbike. And if you want a laugh, look at that subject on you-tube!

 

Having done it once, (and, assuming it does work as expected, when it's finally finished) I'd do it again, only this time, I'd a) start with a brand new one, b) not disturb the mechanism fixings, and thus not be faced with a complete realignment, c) probably try to have all the microswitch supports & other modifications 3D printed so they clip or glue on, and d) try to fit the Smoothieboard so it used the existing hole in the housing.

 

Obviously hindsight is (at least potentially) 20:20, so these observations are the result of the learning curve. What it means is that anyone who is put off by the price of the Emblaser, but wants to have a go anyway, can do so for around £500, if they're prepared to go down this route. And into the bargain, you get a 40W machine, which may or may not make a difference to what you want to make with it, how long each item takes, etc.

 

One link I forgot to add to the above post was http://donsthings.blogspot.co.uk/search/label/K40%20A%20Index. Credit where due!

 

As an aside, I see there are 0.5W diode lasers for sale on eBay at £139.

 

Best

Simon

[Simond]

Monkeysarefun directed me to the link for Laserweb, I have tried it, but I'm trying to stick to Visicut for the time being.

 

I have achieved the exciting feat of cutting out a rectangle. Whoopee! The scaling is wrong, marginally, it's about 204mm for 200 required, in X, not sure in Y as the rectangle was rather narrow! This scaling issue can be corrected easily in the config files, as there is a setting for "steps per mm" (several hundred, so a 2% change is not going to significantly diminish the accuracy of the beast).

 

My copy of TurboCAD is positively ancient, it must be nearly 30 years since I bought it, and it seems that some kind of artefacts appear in DXF files, and they rather mess up the scaling. I had blamed Newlydraw for that, unfairly, it seems (mind you it has enough other issues to be criticised!), we have a more up-to-date version of TC at work, and it doesn't do it, so I'll have to spend more money or my cunning plan will work... we'll see. I have no idea what they are, they don't appear in TC, but if I open the drawing in LibreCAD or Visicut, they are there, and have to be removed, in order to get an A4 drawing to fit onto an A4 cutting area.

 

 

 

Haven't quite sorted homing, or cutting speeds. It's dreadfully slow at the moment, but I think that's just me being conservative. I'll wind it up a bit next time I have a go.

 

Apparently, it is possible to have a double com port on the Smoothieboard. This allows two programs to access together, so I could run Pronterface and Visicut simultaneously, if I have correctly understood. This will help with the homing issue, and allows resets without power off, which will speed thing up a bit.

 

Best

Simon

[Giles]

Simon, have you considered Draftsight? It's a free version of Autocad Light, and free.... it's very good, and will do anything you will want. Obviously it will export at DWG or DXF.