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Cheap Chinese Laser Cutter

experiences with a Chinese laser cutter

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Geoff Gardiner30/11/2019 10:01:16
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543 forum posts
916 photos

Joshua.

I have just built a laser cutter with the dimensions that you are after.

Have a look at my build log here.

It will also take a dremel for cutting thicker ply.

Geoff...

FlyinFlynn01/12/2019 15:04:18
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151 forum posts
95 photos
Posted by Joshua Henderson 1 on 30/11/2019 09:51:59:

Flyinfynn

Please put a link on here when gig start building.

what size are you building and with what components?

I like the idea of being able to cut a full kit hence the sizing as the Eleksmaker A3 only have a small cutting area.

Im sure some way with the Extended frames they can be supported somehow? Just don’t know what to buy as a start for the laser cutter/ setup to then tinker with?

Link is https://www.modelflying.co.uk/forums/postings.asp?th=147510

I have a 1.2 meter length of 20x40 lying around (as you do!!) so i will build it that long, probably be about 30cms wide. As it is a simple design and quite light on the cantilevered gantry it should not suffer too much from vibrations. Buying an eleksmaker and possibly modding it to your requirements would be the less traumatic way to go but where is the fun in that? There is no magic in these engraver/cutters, you just need to arrange for the laser to be in the right place at the right time..and most of that is done by the microprocessor, if there is any magic in this process it is in being able to master the software to get your design in a machine readable form.

Andy Joyce04/12/2019 19:27:51
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265 forum posts
54 photos

Let the fun begin!

dsc01090 (medium).jpg

Andy Joyce06/12/2019 17:35:06
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265 forum posts
54 photos

Flynn

How are you getting on with your 6W cheap laser? Tempted to purchase the same model but thinking you only get what you pay for given similar models are upwards of £70.

FlyinFlynn06/12/2019 18:44:20
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151 forum posts
95 photos

I have two of them now and they seem ok. I don't think that the 6 Watts they claim for the laser is realistic as the performance I am getting from them is about on a par with the results others have had from 3.5Watt lasers. Perhaps the laser module is 6 watts input power...... Having said that $40 delivered is still a really good price for a 3.5 Watt laser and there is no external power brick needed....the regulator board is internal and the fan cools both the board and the laser heatsink. It makes for a neat installation. I have just uploaded a video to YouTube of one of mine working in my fuz side cutter .here on YouTube.

This lasers are appearing on Ebay now... the word is out!

You don't see expensive hard disks any more now do you!

Enjoy the build.

Edited By FlyinFlynn on 06/12/2019 18:44:49

Andy Joyce06/12/2019 19:28:29
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265 forum posts
54 photos

More inclined to go with this laser link given those cheap units are not rated correctly. Plus its suppose to be from the UK.

Edited By Andy Joyce on 06/12/2019 19:48:29

Andy Joyce06/12/2019 19:54:25
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265 forum posts
54 photos

Just spotted this laser seems to indicate it requires and external driver so unsure what is supplied for the price quoted.

FlyinFlynn07/12/2019 11:48:05
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151 forum posts
95 photos

Yes Andy..it is a bit confusing with there being 3 different lasers on offer in the same listing.

The rating on the laser I bought is only my estimation based on practical results and the Chinese penchant for overstating specs....

My take on your laser is that the picture of the 5500mW one has the regulator board mounted above the fan, they describe this as 'external', this has a 2 pin and a 3 pin XH connector on it. The 3 pin connector is for +12v,GND and PWM and the 2 pin connector would be just +12v and GND for use if your controller board didn't support PWM. The 500mW laser does not have the PWM function,so just a 12v power cable and a simple regulator must be inside the heatsink.

It is quite a good price IF it is a 5.5W laser...but you should ask yourself how likely is it that this Chinese manufacturer/seller is quoting the output power of the laser diode, or, along with all the other Chinese suppliers, quoting you how many Chinese Watts are being consumed by the diode, the electronics and the fan combined.

The only way to be sure is to measure the current and voltage going to the laser diode.

I did see on a listing for the NEJE 20Watt module that the actual light output was quoted as 5.5 Watts. I suspect if you buy just a laser diode the specs will tell you the actual output power of the diode but if you buy a laser module you will be told the input power of the module.....

Death and taxes is all you can rely on!

Andy Joyce07/12/2019 14:25:42
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265 forum posts
54 photos

Flynn

Looks like I pay my money and just hope you get something that works!

Currently stuck as how to calibrate the Arduino Uno with GRBL installed to match the output of a Gcode file output from Inkscape.

Inkscape measures a simple box as 70x10mm but for some reason LaserGRBL cuts a box far bigger in size

 

Edited By Andy Joyce on 07/12/2019 14:30:15

Edited By Andy Joyce on 07/12/2019 14:30:35

Andy Joyce07/12/2019 17:59:42
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265 forum posts
54 photos

Think I have now cracked the scaling issue by using the $$ command to ascertain the settings and then scaling $100 and $101 to 80.

Note nothing is set for $0 through $27, is this correct?

Edited By Andy Joyce on 07/12/2019 18:02:40

FlyinFlynn07/12/2019 18:43:23
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151 forum posts
95 photos

Errr....no! Here is my GRBL configuration -

grbl_1.jpg

You probably can't read that, does your software allow config file imports? My config file can be downloaded from here. There are entries in $0,1,10,11,12,22,23,24,2526 and 27 although some of those are to do with homing. Let me know if you cannot upload a config to your controller. Alter my config to suit your speeds,rates and accelerations ( and set $22 homing cycle enable to 0 if you don't use homing)

The 80 steps per mm is correct if you are using a 1.8 degree per step motor set to x16 and a 20 tooth gt2 pulley

360/1.8 * 16/40 = 80 degrees per motor revolution/degrees per step * microsteps/ mm per pulley revolution smiley

How are you getting on with Inkscape?...

Andy Joyce07/12/2019 19:45:25
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265 forum posts
54 photos

Well I certainly have multiple files loaded for controlling the controller but not sure if any allow upload of the configs although I assume I did this when downloading the GRBL sketch.

Just downloaded universal gcode sender and can now see all the settings so will see if I can download your settings using that programme.

Andy Joyce07/12/2019 20:09:36
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265 forum posts
54 photos

Did get errors in downloading your file but now can see all the full range of settings in CNCjs so thanks very much for your help.

Andy

FlyinFlynn07/12/2019 22:08:00
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151 forum posts
95 photos

Glad you got it sorted. Strange about the file download..it works for me.

Andy Joyce09/12/2019 18:23:36
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265 forum posts
54 photos

Can anyone advise how I should connect my laser as pictured. Assuming it must be as depicted although the graphics on the PCB are not easily understood.

arduino.jpg

s-l1600 (small).jpg

FlyinFlynn10/12/2019 18:37:08
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151 forum posts
95 photos

OK..well, I don't have one of those lasers but.....your diagram looks right to me. I suspect, from the silk layer printing, that the two wire connector is for use if your control board outputs a negative going pwm pulse and the red 3 wire connector is for use when your controller outputs a positive going pwm pulse, which your arduino does. If there is continuity between the - pin in the red connector and A+ in the white one that would reinforce my belief.

If anyone actually has one of these lasers and can state definitively then that obviously overrides my suspicions!

I do sometimes wonder if there is anyone else interested in this laser stuff. dont know

Andy Joyce10/12/2019 19:13:52
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265 forum posts
54 photos

Thanks Flynn we modelers do like to make things difficult for ourselves. Think it would have been cheaper to get my parts cut from an external supplier but my last set of dxf files I sent one company failed to be able to be read, hence the desire to try cutting my own parts.

Suspect tomorrow nights job is to fit some limit switches to the cutter hardware rails, provided of course that I receive the limit switches in the post. Laser should arrive over the weekend.

Continue to play around with the drawing packages I have to try to get the various ribs I want cut, but not finding an easy method to auto trace pdf drawings. Did try one of the web based services for pdf to dxf but the quality was not there, so continue to try various tools in both Inkscape and Autocad 2014. In the past I have used Power Point to generate plans but again the output format of that package limits its ability to be loaded into a SW tool that can generate the necessary gcode.

FlyinFlynn11/12/2019 11:44:00
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151 forum posts
95 photos

I have never found an acceptable result from automatic tracing. My best results have been obtained by using LibreCAD, which I believe is suitable for linux. I import an image file, which is usually downloaded as a jpg or png (- but sadly not pdf) and manually trace lines on a new layer and, when finished, save that layer as a DXF. That way you get to decide where to place the lines. The software allows uniform shapes to be created, such as 10mm triangular fillets which differ from the plan slightly and allow you to line up the dowel holes in the horizontal plane, altogether a bit more accurately than just freehand tracing. There are also all the usual abilities for measuring and trimming as well as a shedload of features I will never understand.....

librecad.jpg

librecad_2.jpg

I use DeskProto as my CAM software but that is Windows only and I have no experience with linux......keep lookingyes

When you get this working you will a) have learnt a new skill or two, and b) have the kit to make loads more airframes! c) not have to wait on anyone for freshly cut parts.smiley

CREDITS...free plan from AeroFred no rights reserved!

Edited By FlyinFlynn on 11/12/2019 11:46:36

Andy Joyce12/12/2019 19:21:51
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265 forum posts
54 photos

Can someone please advise how the carriage limit switches should be set/wired. Have set $20 & $21 to 1 with the switches wired to NO but cant seem to get then function as expected.

alex nicol12/12/2019 19:52:27
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388 forum posts
17 photos

I've just taken the plunge and ordered an Alphawise C30 DIY kit and have absolutely no experience in cad or what software to use or even what works with what etc. Very steep learning curve ahead methinks

Is there an idiots guide somewhere that outlines the basics of how it all works

Thanks in advance

Alex

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