3d printer to laser cutting/engraving

[Martian]

Any of you clever people thought about or have converted their 3D printer to a laser cutter/engraver ?

[Mark J]

I have made a laser mount for my ender 3 and have a laser. I've not used it yet due to the smoke issues in the house. If you go down this route be very careful use, a screen and buy the correct eyeware from a reputable source, expect to pay a lot for these, and make sure they block the wavelength of the laser. Do not use the ones supplied with lasers bought cheap online.

[Bob Smitham]

Give this thread by FylinFinn a look over if you already have a 3D printer the build comes in at around £100.

A lot of playing around with bits of software is required but within a week I was cutting ply and balsa.But being printer owners I'm sure you are familiar with that.

 

[FlyinFlynn]

Thanks for the mention Bob. In my opinion there is one main problem with using a 3D printer with a laser and that is Marlin. Marlin is the firmware driving your 3D printer and while it is capable of actually driving a laser too it is not the best choice if you intend to do engraving as well as cutting soft woods. GRBL is a much better choice because with v1.1 release it has a laser mode implemented - read all about it here. It transforms the results you will get. 

/2p 

[Martian]

2 hours ago, FlyinFlynn said:

Thanks for the mention Bob. In my opinion there is one main problem with using a 3D printer with a laser and that is Marlin. Marlin is the firmware driving your 3D printer and while it is capable of actually driving a laser too it is not the best choice if you intend to do engraving as well as cutting soft woods. GRBL is a much better choice because with v1.1 release it has a laser mode implemented - read all about it here. It transforms the results you will get. 

/2p 

So FlyinFlynn are you saying dump Marlin and use GRBL instead ? 

[Mark J]

Interesting to see the cost of the parts as around £100. But as I mentioned before a good pair of certified laser goggles are over the £100 pound mark. With a 5w laser it would only take one flash. I used to work with lasers so am aware of the potential hazards and consequences.  

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=762

[FlyinFlynn]

18 hours ago, Martian said:

So FlyinFlynn are you saying dump Marlin and use GRBL instead ? 

For a laser application, yes, that is what I would recommend. Marlin is excellent for 3D printers, it is the application Marlin is primarily developed for, but laser operations require a different emphasis that I feel is better served by GRBL. The mere fact that you need a different configuration in Marlin for the two disciplines (3d printing and laser engraving)  means having a single machine to do both becomes problematic, and at the hobby level, a simple two or possibly three axis machine without extruders, hotends, heated mats, fans, large psu's and the like mean only a simple controller board running a simpler but more effective operating system work better. I am now switching over from Uno/Mega2560 running vanilla GRBL to ESP32 based controller boards, running GRBL_ESP32 which allow wireless access via ESP32-Webui or the excellent LaserGRBL , which will also connect wirelessly using telnet, although some work is still needed to improve connectivity and features there I feel. 

 

I put together a new controller board layout and had them made at JLCPCB for $4 or $5 for 5 boards plus shipping, running GRBL_ESP32 it has all you need for laser operations.

 

I would also recommend GRBL over Marlin for cnc work too - routing, hot wire cutters, needle cutters, drag knife, drawing robots and so on. In all there disciplines you have to hobble Marlin to get it to work (hotend temperature disable, constant temperature retrieval)

 

[Martian]

Thank you very much flyingfinn . I am going to use my Anet 8 3d printer stripped down as the basis for the cutter . 

[Martian]

22 hours ago, Mark J said:

Interesting to see the cost of the parts as around £100. But as I mentioned before a good pair of certified laser goggles are over the £100 pound mark. With a 5w laser it would only take one flash. I used to work with lasers so am aware of the potential hazards and consequences.  

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=762

Sorry Mark I missed your comment appreciate your knowledge thank you

[Martian]

After extensive research I have come to the conclusion that converting an Anet a8 to a laser cutter at least for me is a non starter. First the 3d printer is designed  for just that 3d printing although it can be made to work it will not produce a very usable cutter/engraver the work area is to small the height is unnecessary and a nuisance also the laser once burning starts stays on.whilst these things are not insurmountable I felt it a waste of time to cap it all the Anet control board with Marlin firmware could not be made to work with my chosen burning software Lightburn ,not that there is a huge number available. So I have opted to strip the Anet for what I can reuse ,stepper motors power supply motor wiring etc. I purchased a GRBL board from Amazon ( Jeff was pleased) it came with some bits which are useful, I had already bought a 7.5watt laser an NJE unit that came with adapter and wiring. Test with the bits I am going to use proved more than capable and the GRBL board hooked straight up to Lightburn and a quickly drawn outline was easily tracked and burnt well into ply. Now the electronics are working i searched out a design for the frame and found 1 on thingiverse parts are printing now and extrusion etc have been ordered. The frame will be about 24inches by 15 inches which will allow for cutting into a 1/8th 24x12 ply sheet with 2 or 3 passes . I should point out a frame and motors plus v wheels can be bought as a kit from e-bay supposedly from the UK but I had no way of knowing how long it would take to arrive nor how good it would be.i could probably get the cost down by long winded shopping around or buying from China as yet i haven't added it up. If anybody is interested  i will post the progress ,more to come. Happy flying ,P.S all  this so i can carry on with my Tigercat ?

[FlyinFlynn]

I think you are on the right path Martian, GRBL, Lightburn and a NEJE laser.

Ensure you have laser mode on ($32=1) and use M4 and not M3 when engraving, for cutting it does not matter so much as you will generally be at 100% power all the time.

I appreciate you have recently bought your laser module but you might be interested in this video reporting on the NEJE40 watt laser module and its capabilities. It employs two 7 watt blue laser diodes in a single module....maybe something to consider in a future purchase?

 

Which frame did you go for from thingiverse?

[Martian]

1 hour ago, FlyinFlynn said:

I think you are on the right path Martian, GRBL, Lightburn and a NEJE laser.

Ensure you have laser mode on ($32=1) and use M4 and not M3 when engraving, for cutting it does not matter so much as you will generally be at 100% power all the time.

I appreciate you have recently bought your laser module but you might be interested in this video reporting on the NEJE40 watt laser module and its capabilities. It employs two 7 watt blue laser diodes in a single module....maybe something to consider in a future purchase?

 

Which frame did you go for from thingiverse?

 

[Martian]

Thank you Flying Flynn. I will look at that link. I opted for one titled Laser cut 15w is is much larger than I want but I will change extrusion lengths to suit my needs . My GRBL board has a link for laser or spindle maybe I will fit an interchangeable  head with spindle just for some more head pain.

[Martian]

Hi FlyinFlynn, could do with some guidance if you can please 

[FlyinFlynn]

13 hours ago, Martian said:

Hi FlyinFlynn, could do with some guidance if you can please 

 

What specific pointers do you feel you need Martian?

 

If you post a link to the board you bought from Amazon it might be possible to confirm what I suspect - 

 

Normally these boards have a PWM output pin, this pin can be directly connected to the pwm in pin of your laser module, which makes it simple. You could also utilise that same pin to drive an external MoSFET board (I use one of these) to drive a DC spindle motor, just watch the temperature build up and the current. While there are many people that successfully and happily swap between spindle and laser operations on the same machine I prefer to keep them separated on two different machines, mainly because the settings for laser work are quite different to the requirements for spindles, there is laser mode, feed rates, Z operations and different software workflows to manipulate. After a while you kind of just build up the component parts to build new machines ?

As far as the laser goes, build the frame, fit the laser, the wiring should be +12V, GND and PWM, you can ignore the 4th wire from the laser module, it is a thermistor output for measuring the temperature of the laser diode. If you are comfortable with Lightburn then getting your first engravings should be straightforward, however LaserGRBL is much simpler to configure as it has fewer options and therefore capabilities but it is a good starting point.

 

 

[Martian]

Hi Flyinflynn at the moment it's the x y configuration the travel exceeds the set limits and causes the motors to judder violently.  I'm still getting to grips with the terminology. I will get to my laptop tomorrow  and download some pics. My chosen software is Lightburn but that doesn't give full config access so am using GRBLRD to do that I suspect I need to determine the distance traveled per motor rotation, it's all confusing 

[FlyinFlynn]

It might feel confusing at first, but it is all quite logical and you will find it soon starts falling into place.

 

First you will need to sort out the direction of travel for each axis, manually move your carriages into the middle of their travel, then switch everything on and instruct a X axis move, if it moves the wrong way then you can simply reverse the plug on the controller rather than mess with the $3 (Step Direction Invert Mask), once both X and Y  are moving in the right direction you need to set up the steps per mm for both axis', you can either work it out using This as a guide or you can just wing it by instructing a move of a set distance and then measuring how far it actually travelled and then adjusting $100 (for X) $101 (for Y) upwards or downwards depending if it moved too far or too little. The final number will be a regular number.. like 25 or 200 or something like that. It depends upon the number of teeth on your pulley, the number of microsteps you have set and the pitch of your belts/threaded rod. Once you have it moving in the right direction and the right amount you can play with the speed ($110 for X and $111 for Y) you can increase the value until your carriage starts skipping steps on a longish run and then back it down 10% or a bit more, you can also play with acceleration but again, if you push it too high it will start skipping steps. The last thing to do is set your maximum travel on each axis with $130 and $131, you don't actually need this parameter yet but if you enable  soft limits you will need those values to be correct.

 

Also set laser mode on with $32=1, set your minimum spindle speed to 0 with $31=0 and the maximum spindle speed to ----- either 255 OR 1000, I'm not sure what Lightburn expects, I use 1000 but 255 works equally well, you just need to remember which you selected.

 

Leave homing off for the time being ($22=0), it adds complexity and really isn't needed in laser workings.

 

Leave Soft limits and hard limits both off for the time being ($20=0 and $21=0)

 

That's it.....done.

 

If you are using LaserGRBL it gives you notes on what each parameter is under GRBL/GRBL configuration.

If you get stuck come back!

[Martian]

Hi FF 

after you have input $ values in LaserGRBL does it need to be saved or written to the control board firmware ? 

A bit each day is making it clearer ? 

[Martian]

Hi FF here is the control board

JADAZI GRBL CNC Controller Control Board 3 Axis Stepper Motor Spindle Driver Board

 

Edited June 14, 2021 by Martian

[FlyinFlynn]

11 hours ago, Martian said:

Hi FF 

after you have input $ values in LaserGRBL does it need to be saved or written to the control board firmware ? 

A bit each day is making it clearer ? 

 

Yes. Your controller has to be connected to the computer usb and in an 'idle' condition. If the 'alarm' indicator is lit in the bottom right corner of laserGRBL then you need to send a $X by entering $X in the box where it says 'type gcode here', then press enter, the alarm should extinguish, then go to GRBL/GRBL Configuration, make the changes in the 'value' field you want and then press 'write', you should get a notice saying 'config written successfully'.

 

The Jadazi controller board you have has a couple of sockets to drive your laser, this is because some lasers come with two separate connectors, one for just power and one for the signal and ground and some lasers come with a single 3 wire connector. Your laser actually has 4 wires but the green wire is a temperature sensor and can be left disconnected for the time being.  I suggest you use the 3 wire connector on your board labelled 3PLaser. Follow the colour info on the boards advert on Amazon with the blue wire going to the lasers yellow wire - that is the PWM signal line.

[Martian]

Hi FlyinFlynn thanks for your help I have made a lot of progress machine is tracking ok now just need to fine tune settings. But when I power up machine the laser is on straight away is this normal if so I will have to put a switch in power feed. P.S module is connected as advised .thanks in anticipation

[FlyinFlynn]

1 hour ago, Martian said:

Hi FlyinFlynn thanks for your help I have made a lot of progress machine is tracking ok now just need to fine tune settings. But when I power up machine the laser is on straight away is this normal if so I will have to put a switch in power feed. P.S module is connected as advised .thanks in anticipation

There are two possibilities as to why the  laser firing during boot, the first is some GRBL controller boards utilise a Mega2560 processor and some of the output pins on that processor do some funny things during the boot sequence, if the designer has selected one of those funny pins as the PWM output pin it can cause the laser to fire. I don't think your board suffers from this problem though as I believe it uses a 328 processor, the same as an Uno, which does not suffer from the 'funny pin during boot' syndrome, so I think your board doesn't have a pull down resistor on the PWM signal line so when the processor is booting the PWM pin 'floats', allowing the laser to activate to noise. This can quite easily be rectified by fitting a 10K resistor between the black and yellow pins on the laser plug, this will pull the signal line down keeping the laser off until the signal switches it on with a 3v3 pwm signal.

 

Glad you are making progress.

[Martian]

Thanks FF on to the next stage ?

[Martian]

First thank you FlyinFlyn thanks for all your help I have successfully calibrated and got my laser cutter working  using it to cut beech ply formers and engrave images and lettering , I have also built a CNC router and am trying to calibrate this using the same control board as the cutter and again GRBL software. What I need to be able to do is convert PDF files to cad files then Gcode files so I can extract individual former patterns from a plan any Ideas also to anyone who knows how to do this.

thank you

[FlyinFlynn]

I believe Lightburn has a PDF import option, however, that costs money, and there are free options out there although I think it will require more than one piece of software to get from .PDF to .gcode. All of the free software I am aware of that convert an image to gcode require a raster file like .bmp, .png, .jpg or a vector file like a .svg

 

I think laserGRBL does a really good job at generating gcode with any of those formats but you will need to save your PDF in a raster file first.  Adobe Acrobat can export a PDF as a .PNG or .JPEG which can be cleaned up in 'Paint' so that is one option, I'm not sure if the free Adobe software can do the same though.

 

You could also use your web browser to display a PDF and screen capture it to 'Paint' but you will lose all the scaling by doing that - not a problem if you can scale your raster file afterwards though.