Jump to content

Cheap Chinese Laser Cutter


ROBERT BURLACE
 Share

Recommended Posts

A small blower will definitely help I use a pond air pump and machine lubricant hose - the fan behind probably isn't directional enough to clear debris from the cut path. In addition, try raising your material off the cutting bed. I use 10cm long pieces of aluminium angle. Air is a better insulator than wood, so will stop some of the energy being conducted out of your cut piece. In addition it will reduce the distance from the laser to the piece, increasing the intensity of the beam (assuming you can focus it at that distance).

Link to comment
Share on other sites

Chris, I have just been setting up my homemade CNC/Laser cutter. I am using Inkscape with a laser extension installed. This creates G-Code to send to the cutter (M03 to turn on and M05 to turn off). My first cuts were also burning at the corners - where the laser speed slows to change direction. I have found that if I use M04 to turn on the laser instead of the M03 command, then the laser power reduces when it slows and you don't get the burnt corners.

This may be of help to you.

Geoff...

Link to comment
Share on other sites

I have a small fan placed about 6 inches away as that's all I have for now, I have ordered a pond pump which I will run through some thin tube so that it's close to the wood. I am using 9mm MDF for the baseboard which is working well so far although I've only done a few cuts.

I was using the thin plastic pieces to raise the wood up, but they are only about 1.5mm thick so perhaps I'll try something thicker, it would be nice for the cut pieces to drop down so that I know I'm all the way through.

On the pictures below I was cutting an F1 former for a Peter Miller 'The Ohmen', it took 13 passes to get all the way through, I am hoping that when the pump arrives it will be a cleaner cut.

Thanks Geoff, I'll try playing with the G-code. I am also using Inkscape and I did download an extension to generate the G-code, however I am not using this and instead I am using Lightburn to control the laser.

VIDEO LINK

f1 final resized.jpg

f1 cut resized.jpg

f1 sheet resized.jpg

Link to comment
Share on other sites


Posted by chris larkins on 25/10/2019 11:33:32:

Success, I did as Robert suggested and tried again but this time raised up on 8mm rails, this time the parts dropped through once cut.

drop cut.jpg

drop final.jpg

Great stuff, glad it worked for your Chris. How many passes were you down to? What software are you on? If using Lightburn there is a setting in the device settings called “smax” this seems to default to 250 but can in fact be set to 1000. It controls the maximum power of your laser. The power on cut settings is relative to your smax setting. You may not be getting what you think is full power. Where did you find the plan? I do like Peter Miller’s models.

Link to comment
Share on other sites

I am using Lightburn, at first the laser would not cut at all but the smax was set to 255, after changing it to 1000 I was in business. Then whatever I was cutting was coming out WAY bigger than it should have, after searching the web I discovered that the steps were out, after changing the X and Y axis to 80 it was back to the correct scale.

It still took 13 passes at 2700 mm/min, but I guess that is the price for having just a 3000mw laser, maybe slowing it down would reduce the amount of passes.

The plan was a freebie in RCM&E, Peter was kind enough to send me the PDF.

Link to comment
Share on other sites

I have got an interesting problem..

Using Benbox, which I gave to admit I am not impressed with. All the buttons are in Chinese.

Anyway, I did manage to etch an image although it was reversed. X and y drives seemed to work perfectly.

I then tried to cut a cockpit panel out of balsa and just succeeded in burning a hole in the wood so tried playing with the laser and step settings. I now seem to have lost the y drive or rather pressing up and down on Benbox gets translated to left and right. Reset, powered off etc. Looks like a software problem but Benbox seems useless for cutting. The scale seems wrong for a start. Is lightburn the way to go? 40usd doesn't seem too expensive if it will work with this. Would I have to make any changes to the hardware? I am not sure just what lightburn actually does apart from laser control. I suspect that it reads a gcode file and coverts that to x, y and laser control.

Any thoughts on my immediate problem though?

Thanks

Martyn

Link to comment
Share on other sites

My experience with benbox lasted all of 30 seconds when I realised just how useless it probably was. It is really a program for etching rather than cutting but the UI is terrible. Lightburn is fairly intuitive and allows you to do quite a lot. I do mainly use it for running the cutting, while Inkscape helps me to draw, design, take measurements, etc. Honestly they do everything between them that I think we could wish for in doing what we do. Try the Lightburn free trial. No changes to your hardware, no.

I presume you have done all the initial trouble shooting.... wire connections etc? Were your stepper cables connected and tidied away securely? Possible the laser has cut one if not?

Link to comment
Share on other sites

Thanks Robert

I use Draftsight but migrating to QCAD for my drawings, save to DXF so I would need to translate the DXF files to gcode.

Nothing obviously wrong with the lasercut tee. I think the software has got screwed up somehow, probably due to me tweaking the settings.

I'll try lightburn and see if that fixes it.

What file format does inkscape save as? How do you generate the gcode?

Martyn

Link to comment
Share on other sites

Came across this thread and it sparked my interest in laser cutters again. Looked at one of the far east 40W units some time ago, so now surprised that a 3W laser can cut ply. If I was to purchase a cheap kit to give it a go, what should I be looking at purchasing?

Link to comment
Share on other sites

@ Martyn K, there is a small flag icon in the box at the top left hand corner ......select EN.

For those not happy with Benbox you might like to try LaserGRBL for free. It also has the advantage of supporting PWM for the laser for when you want to try engraving and not just cutting. You will have to flash grbl_v1.1f onto your controller, or buy an R3 Uno and a cnc shield and keep the old controller as a back up. There are no editing features in LaserGRBL however so you will need to use an external graphics program if you need to edit your formers/ribs etc.

Link to comment
Share on other sites

Anyone any hints on general machine setup in Lightburn? I've flashed the controller with GRBL via xLoader, and now Lightburn recognises the machine. I can steer it around and have sent a DXF file to be cut, although it comes out at about 3 or 4 times scale! I guess this is a steps / mm issue?

Link to comment
Share on other sites

Posted by Andy Meade on 27/10/2019 17:22:21:

OK well I calibrated mine myself - 80 steps per mm on X and Y axes, also had to invert the X pin as it was backwards. Just need to figure out how to reset origin 0,0 position now and focus the laser.

Mine was the same, set it to 80 steps and it's working fine now

Link to comment
Share on other sites

I have started to make an enclosure to deal with the fumes problem, my machine is 65cm x 50cm but with the extra room required each side for the stepper motors the enclosure ends up being quite big.

For the sides I have used some left over laminate flooring (so I have a nice faux wood finish laugh), I have yet to make the top but I will probably make this from some 5mm foamboard that I have left over from another project which will make it light enough to lift on and off, I have also ordered some A3 sized 3mm orange tinted acrylic to give a 'viewing window'.

In one side I have installed a 100mm extractor fan which I will vent outside, in the back there are a couple of small 20mm holes to allow air to enter.

I am still waiting on my air pump so that I can provide a flow of air to the workpiece, I am thinking to mount some brass tube to the side of the laser module which will direct the airflow, in a similar way to on some scroll saws. The question is how close does this need to be? Does it need to be within a centimetre or so of the workpiece or is an inch or two close enough?

enclosure.jpg

enclosure1.jpg

Link to comment
Share on other sites

Posted by ROBERT BURLACE on 22/09/2019 08:35:56:

A balsa rib - cut before I installed the air assist which really helps clean up cut edges.58871355182__91ee32f2-7914-4564-8d50-524d9da617a9.jpg

Air assist - fed by a small pond air pump

ac7fbec8-42db-4d19-b27c-667032a26fac.jpg

Clean cut in some sample bits of 4mm ply - leaves a bit of a burnt edge but sands off easily enough and have had as bad on short kits purchased online before now.

img_0309.jpg

And this is the setup - the bare aluminium rails are stock from the kit, i extended the cutting area using the black ones to 1100mm- giving a workable cutting area of about 400mm x 1000mm

img_0334.jpg

Hi

have a link to buy the profiles of the building to enlarge the machine.

Christophe

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...