Andy Meade Posted October 24, 2019 Share Posted October 24, 2019 Looks like you're getting a lot of reflection - have you got a blower fan installed to clear the debris? Quote Link to comment Share on other sites More sharing options...
ROBERT BURLACE Posted October 24, 2019 Author Share Posted October 24, 2019 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). Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 24, 2019 Share Posted October 24, 2019 These things are meant to be engravers. I gave just finished assembling mine. If you are cutting, what do you use as a baseboard? Martyn Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted October 24, 2019 Share Posted October 24, 2019 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... Quote Link to comment Share on other sites More sharing options...
chris larkins Posted October 25, 2019 Share Posted October 25, 2019 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 Quote Link to comment Share on other sites More sharing options...
chris larkins Posted October 25, 2019 Share Posted October 25, 2019 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. Quote Link to comment Share on other sites More sharing options...
ROBERT BURLACE Posted October 25, 2019 Author Share Posted October 25, 2019 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. 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. Quote Link to comment Share on other sites More sharing options...
ROBERT BURLACE Posted October 25, 2019 Author Share Posted October 25, 2019 Additional thought- the fumes from MDF are not pleasant or good for you. I would suggest a swap for a piece of softwood ply for your waste board when you get round to it. Still not great but the resin in mdf is mean stuff. Quote Link to comment Share on other sites More sharing options...
chris larkins Posted October 25, 2019 Share Posted October 25, 2019 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. Quote Link to comment Share on other sites More sharing options...
ROBERT BURLACE Posted October 25, 2019 Author Share Posted October 25, 2019 Ahhh Ok- not sure how much of a difference it will make to your overall cutting time, but if you drop cutting speed down to something more like 120-180mm/minute it takes fewer passes. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 25, 2019 Share Posted October 25, 2019 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 Quote Link to comment Share on other sites More sharing options...
ROBERT BURLACE Posted October 25, 2019 Author Share Posted October 25, 2019 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? Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 25, 2019 Share Posted October 25, 2019 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 Quote Link to comment Share on other sites More sharing options...
ROBERT BURLACE Posted October 25, 2019 Author Share Posted October 25, 2019 No need to generate a Gcode as such with Lightburn. It can talk directly to your laser using gbrl. Inkscape can save and open dxf, Dwg, svg, pdf, amongst others. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 25, 2019 Share Posted October 25, 2019 I have installed Lightburn but it doesn't detect the laser cutter. Has anyone else got lightburn working with the bang good laser? Quote Link to comment Share on other sites More sharing options...
chris larkins Posted October 25, 2019 Share Posted October 25, 2019 Yes I have, when I'm home I'll send you the details of what I did. First off you will need to download the GRBL hex file, just go onto the GRBL website and download it, I think it was version 1.1 Edited By chris larkins on 25/10/2019 21:18:46 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 25, 2019 Share Posted October 25, 2019 Thanks Chris No rush, I am away for a few days from tomorrow Martyn Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted October 25, 2019 Share Posted October 25, 2019 I've been using a free program called CNCjs for controlling my laser. Quote Link to comment Share on other sites More sharing options...
Andy J Posted October 26, 2019 Share Posted October 26, 2019 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? Quote Link to comment Share on other sites More sharing options...
FlyinFlynn Posted October 26, 2019 Share Posted October 26, 2019 @ 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. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted October 27, 2019 Share Posted October 27, 2019 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? Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted October 27, 2019 Share Posted October 27, 2019 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. Quote Link to comment Share on other sites More sharing options...
chris larkins Posted October 29, 2019 Share Posted October 29, 2019 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 Quote Link to comment Share on other sites More sharing options...
chris larkins Posted October 30, 2019 Share Posted October 30, 2019 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 ), 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? Quote Link to comment Share on other sites More sharing options...
christophe dauvergne Posted October 31, 2019 Share Posted October 31, 2019 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. Air assist - fed by a small pond air pump 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. 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 Hi have a link to buy the profiles of the building to enlarge the machine. Christophe Quote Link to comment Share on other sites More sharing options...
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