Cheap Chinese Laser Cutter

[FlyinFlynn]

Andy - if you go for the eleksmaker pro without a laser I can recommend this 6W laser. I have recently fitted one to my engraver and it has just been reduced in price to $37.50 delivered using ali standard shipping (20 days). If you still need more power they also do a 20 Watt version for $108!...

As for the make or type of frame they all have their drawbacks which become apparent when you use them and most people seem to modify the basic frame to improve matters.....but that is half the fun! If you have a cnc router or a 3D printer you can design and make your own with the aluminium profiles readily available. The electronics also.. I would recommend an arduino uno and a cnc shield and run GRBL firmware but many manage very well with the stock eleksmaker firmware and electronics.

[Andy J]

Thanks Flynn

Was tempted to go down the Eleskmaker route if only to ensure I could get working software. However down loaded their application last night and the input requires gcode.

At a loss at the moment as how to produce gcode files on the cheap. My version of autocad 2104, freecad, inkscape nor wintopo appear not to have the ability to produce the required output.

Thanks for the link re the 6W laser as was going to buy a GNC without a laser first just to see if I could get a working interface going, with perhaps a mod to add a 3rd axis for cutting slightly thicker objects.

[alex nicol]

Hi Robert,

I hope you can help. I'm considering the purchase of the eleksmaker a3 2.5mw laser (USB version) and am interested in how you expanded the cut area.

Was it a kit of parts, or did you just purchase longer rails?

would I be correct in assuming a longer servo belt would be required?

are there any Settings/parameters which need changed to reflect the longer cutting area?

Thanks in Advance

Alex

[Phil Olson - Model Technics]

Hi Alex - to increase the size you just need longer ally sections - there are no end stops so the size is dictated by the size of what you are cutting. Just be aware that bigger things take longer to cut so cooling may be a problem and the ally extrusions will eventually flex if made long enough

[Phil Olson - Model Technics]

any recommendations for safety goggles or are the eleksmaker ones ok ?

[FlyinFlynn]

Posted by Andy Joyce on 13/11/2019 18:56:26:

Thanks Flynn

Was tempted to go down the Eleskmaker route if only to ensure I could get working software. However down loaded their application last night and the input requires gcode.

At a loss at the moment as how to produce gcode files on the cheap. My version of autocad 2104, freecad, inkscape nor wintopo appear not to have the ability to produce the required output.

Thanks for the link re the 6W laser as was going to buy a GNC without a laser first just to see if I could get a working interface going, with perhaps a mod to add a 3rd axis for cutting slightly thicker objects.

I think Inkscape has a plugin to generate gcode (https://www.youtube.com/watch?v=Ny5IURC7gfs). There is also a free program called 3dpBurner Image2Gcode to generate gcode from graphic images. Also for free there is program called dfx2gcode which does what it says on the tin!. There are not too many other free CAM programs that I am aware of. I use Vetric Aspire but that is a paid for application and not yet specifically for laser work although writing a post processor to convert the 'router' gcode into 'laser' gcode is pretty simple. Of the paid for applications, Lightburn seems to be what most people are using.

I took a day designing this in 123DDesign (which is still available for free even though it has been superceded by Fusion 360)

from a picture of a commercial offering from aliexpress. Available for about $38 without a laser..not sure that it would accomodate a z axis though...too much mass on the cantilevered x axis!

Alex.....yes, you would need a longer toothed belt if you lengthen any of the rails...Also perhaps you may need to change the maximum travel parameter if your application uses that parameter and soft limits is enabled (GRBL definitely has these parameters - not sure if eleksmaker software does)

[alex nicol]

Hi Gents,

Thanks for the info, I guess it looks like I'll need to just do some more homework and take the plunge and 'suck it and see' as they say

Cheers

Alex

[Andy J]

Thanks Flynn, Re installed inkscape and followed a set of instructions I found on the web to generate gcode which it did, but what a faff.

Will go looking for dfx2gcode as Inkscape does not seem to be a User friendly interface at all.

Andy

[Andy Meade]

I'm using Lightburn and the controller has GRBL on it, and I'm having a laser power problem. I've changed $31 (or was it 32? can't remember but it fixed it) to turn the laser off on moves, but now that laser seems to be stuck at 10% power, no matter what I change on the cut path settings. Anyone got any ideas?

[FlyinFlynn]

Posted by Andy Meade on 19/11/2019 10:40:42:

I'm using Lightburn and the controller has GRBL on it, and I'm having a laser power problem. I've changed $31 (or was it 32? can't remember but it fixed it) to turn the laser off on moves, but now that laser seems to be stuck at 10% power, no matter what I change on the cut path settings. Anyone got any ideas?

 

It is $32 for laser mode on.....which must be set to 1. Go to the console...type in $$... what do you have in $30 (maximum spindle speed) and $31 (minimum spindle speed). typical values will be $30=255, $31=0 or $30=1000, $31=0....... then type

G1F1000S[whatever value you have for $30] [enter]

....then type M3 and the laser should come on AT FULL POWER.... M5 will turn the laser off .

If the laser only comes on at 10% then the problem lies in the laser and/or its power supply and not the software.

edit.....just noticed....

There is a setting in Lightburn --Edit-Device Settings S-value max that must be set to the same value as GRBL $30. t5his will set the max power that lightburn will use.

Edited By FlyinFlynn on 19/11/2019 12:14:10

[Andy Meade]

Excellent, some things to try there FF. I do like Lightburn as it's "all in one" as compared to my other choices where I'm passing gcode to something else etc.

[FlyinFlynn]

I use LaserGRBL. I did download and install Lightburn and am now nearing the end of the free trial period. I quite like Lightburn too, but not enough for me to pay the asking price, I don't feel it gives me enough over and above LaserGRBL.

All of the artwork editing I do in Vetric Aspire and if I didn't already have that software then the asking price for LightBurn would be more reasonable for me.

Incidentally, you can find your GRBL $30 settings in LightBurns machine settings tab and you can configure GRBL from there instead of dealing with the command line in the control console if you prefer.

[Andy Meade]

$30 was indeed at 1000, and turning the laser on via M codes gave a good 100% beam. Yet when running a cut program, I'm still at less than 10% I'd say.

I double checked machine settings everything matches as you'd expect. Strange.

[FlyinFlynn]

Posted by Andy Meade on 19/11/2019 22:10:53:

$30 was indeed at 1000, and turning the laser on via M codes gave a good 100% beam. Yet when running a cut program, I'm still at less than 10% I'd say.

I double checked machine settings everything matches as you'd expect. Strange.

OK..well I would suggest you take a look at the gcode file that LightBurn generates. Upload a file and save the gcode, take a look in notepad or notepad+ near the top of the file and look for the Sxxxx entry..here is an example ..

; LightBurn 0.9.07
; GRBL device profile, absolute coords
G00 G17 G40 G21 G54
G90
M4
; Cut @ 1000 mm/min, 5% power
M9
G0X88.09Y88.43
G1X88.57S50F1000
G1X89.33Y91.16
G1X89.39Y91.36
G1X89.43Y91.57

; Cut @ 1000 mm/min, 75% power
M8
G0X150.05Y89.74
G1X146.3S750
G1X145.05
G1Y86.03
G1Y84.8
G1X144.24Y84.67
G1X141.81Y84.27
G1X140.57Y84.07
G1X136.85Y83.49

you can see the % power is set to 5% and the S command is S50..a bit further down Lightburn was set to 75% the S command is S750

You can also see Lightburn is set to use a speed of 1000mm/min and the F1000 tells GRBL to do just that. Check both GRBL and lightBurn are set to the same units (mm or inches) .

What version of GRBL have you got loaded?

[Andy Meade]

Good idea, I'll check the gcode output. GRBL is at version 1.1f I believe.

[Andy J]

Flynn out of interest what program are you using to produce aerofoils wing ribs. My version of Profili will not produce dxf files so semi stumped how to get a suitable output ready for cutting.

[FlyinFlynn]

It is a bit convoluted...but it is free!

Not really a program to produce the aerofoils...just a site where you can select, or even plot your own aerofoil, then send it to the aerofoil plotter where you can enter your parameters for chord and thickness etc. and then download as an SVG. Once I have the SVG I upload it into 123DDesign (also free) as a sketch where I remove the chord and section lines, then extrude it into a 1mm thick solid and re-export it as an SVG into LaserGRBL. 123DDesign can also export in 2D as DWG/DXF although I have never tried it .

Airfoiltools 123DDesign Lasergrbl

 

what file format does Profili output?.. perhaps you just need a conversion utility?

Edited By FlyinFlynn on 23/11/2019 12:16:47

[FlyinFlynn]

Just had a look at Profili and it would seem that the free unregistered version allows export to DXF..

[Andy J]

Yes Profili 2.30 does allow dxf files but only for a simple rib. Ribs created in the wing panel management tad which has far more options can only be exported in the professional registered version. In addition when you export an Profili dxf file to Inkscape, it flags an error message and then fails to load. This can be corrected by exporting Profili dxf files to Autocad and then exporting a new dxf output file to inkscape to generate the cutting file.

[Andy J]

Posted by FlyinFlynn on 12/11/2019 14:32:19:

Andy - if you go for the eleksmaker pro without a laser I can recommend this 6W laser. I have recently fitted one to my engraver and it has just been reduced in price to $37.50 delivered using ali standard shipping (20 days). If you still need more power they also do a 20 Watt version for $108!...

As for the make or type of frame they all have their drawbacks which become apparent when you use them and most people seem to modify the basic frame to improve matters.....but that is half the fun! If you have a cnc router or a 3D printer you can design and make your own with the aluminium profiles readily available. The electronics also.. I would recommend an arduino uno and a cnc shield and run GRBL firmware but many manage very well with the stock eleksmaker firmware and electronics.

Taking your advice Flynn and ordered a Uno + CNC shield. Have used Arduino's before for a glider vario so will first verify I can interface to the board, before I purchase a frame.

[FlyinFlynn]

Good choice. There are some tricky bits to circumvent as you are probably aware of if you have played with arduino before. most of the controller boards I see all use some form of 328p processor even if they are not 'arduinos' per se. they will all work as though they are arduinos.

If you get stuck give a shout out.

One thing to note - you should not power the cncshield up with the stepper drivers in place without first connecting the stepper motors....which you wont yet have!....so either don't fit the shield to the uno while testing your comms. or remove the A4988 (or DRV8825) drivers first. This is true for all the controller boards

Fit all three jumpers to the pins under the stepper drivers.

Once you have connected the stepper motors adjust the stepper driver potentiometer to give ~0.8v on the potentiometer wiper (the screwdriver slot). Check to see if the motors or the drivers get too hot in use.

Let the fun begin!!

[Andy J]

Thanks for the advice Flynn. Need to find a circuit diagram of the shield as have never worked with stepper motors before.

Also just noted those shorting links under each driver board. Out of interest what do these control?

Was doing a search tonight to also understand how to connect 2 motors for one axis but have yet to see an example of the wiring.

Anyway the first task is to get the Uno programmed with GRBL.

[FlyinFlynn]

The shorting links multiply the number of steps per millimeter, in effect the higher the number the higher the resolution. With no links being fitted the resolution is at it's lowest so fit all the links... I don't even bother with the links on the boards I design and make..I just connect the three stepper driver pins MS1,2 &3 to 5volts giving me the highest resolution.

There is loads of info on the cncshield out there....google cncshield pinouts.

You just parallel the connection for the two motors to the same stepper driver output. If one motor tries to run backwards just reverse the 4 pin motor connector.

There is no facility on the cncshield to fit the second motor on a single axis so you will either have to make up a wiring harness or solder up two 4 way pin headers with a 4 way socket and use that between the shield and the motors..

Here is a pic of a 3 axis board I designed which has twin paralleled outputs on the X and Y axes - it makes it a bit clearer.

You can either use the Arduino IDE to program the Uno or you can use Xloader. You are familiar with arduino IDE. The GRBL code is available from Github. You will need to download the source code for use in Arduino IDE (install the grbl-1.1f.20170801.zip file as a library in the IDE) or the hex file if you want to use XLoader. The advantage with using the arduino IDE is that you can modify the configuration of GRBL and then compile and upload it which you cant do when downloading the already compiled hex file. I needed to alter the way GRBL handled homing as there was no Z axis on my 'Klingon' laser and I wanted to enable homing.

[FlyinFlynn]

I should perhaps mention that there are pin headers on the cncshield that allow you to 'clone' a second stepper driver to the X,Y or Z stepper driver. You place a driver in the 'A' socket and place two jumpers on the 4x4 block of header pins corresponding to which axis you want to clone.

I should also perhaps mention that there is a later release of GRBL out now v1.1h, one of the extra features this release has is a self squaring ability on your dual motor axis. This feature will only work in laser mode with PWM if you have a pukka original cncshield from its' developer Protoneer (and not a Chinese clone) and limit switches fitted. I doubt this extra feature is of any use for a laser machine as there are little to no frame distorting loads whilst in operation and limit switches are of little use as absolute zero is not needed.

Edited By FlyinFlynn on 28/11/2019 13:32:05

[Joshua Henderson 1]

Good evening Everyone.

I am looking to put together one of these with a cutting area of around 1m by 0.5m

What is the best way of going about this for bits and pieces? Buy the 2.5w A3 kit and modify? If so what is needed to make it work or maybe another way?

will post the build on here for help and tips.

Thanks

Josh