WildCircuits Laser HackLog

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Re: WildCircuits Laser HackLog

Postby timogiles » Fri Jan 20, 2012 2:56 am

I haven't posted any updates in a while, so I've got a back log of things to talk about. Here is my rotational adapter:
P1020715s.jpg

My brother likes to homebrew his own beer so I thought that it would be a great Christmas present to give him a set of custom engraved bottles. Unfortunately that meant that I couldn't post about my progress in case he was reading. The bottles came out awesome and he really liked his Christmas present! My wife helped design 5 custom altered logos. She has serious photoshop skills. We took 5 of his favorite brands and incorporated the words "Homebrew" and his name, the 6th label was a totally custom design. The bottle in the picture has a modified Stone Brewing logo on it.
P1020716.JPG


P1020717s.jpg


The rotational adapter cost only a few dollars to make. I harvested the stepper motor, drive belt, pulleys and 2 shafts from an old photo printer. The two wood side plates I designed up to the correct dimensions to fit my printer hardware and cut out with the laser cutter. The two wood sides are held together with 3 pieces of 1/4-20 threaded rod and a few nuts and bolts. The whole process of part scavenging/designing/fabricating took a whole Saturday including a trip to Lowes for the threaded rod. Not bad for a day's work. I have to say that it is incredibly rewarding to design something and be able to make the parts myself and by the end of the day have a working mechanism.

I got lucky with this stepper motor. It is a bipolar motor and was compatible with the moshi driver board that I'm using on my machine. I've replaced the brains of my moshi control board with a PIC running my own code. If I didn't have discrete control of the motor driver this wouldn't have worked. I unplugged the Y axis motor and plugged in the rotational adapter motor. The problem with the moshi controller is that on power up it finds home. the Y axis doesn't find home when the motor is unplugged :D . Another quirk is that DPI of the rotational adapter ends up being 3000 with the standard gearing that was in the laser printer. That is easily fixed, all my Y moves are multiplied by 3 when I'm using the rotational adapter. Lastly, the plug that was on the stepper motor cable was the correct size to fit into the moshi board, but the windings were not pinned out correctly. I think it was wired A-B-/A-/B but needed to be A-/A-B-/B.

I have lots to say about my PIC moshi controller, I'll have to save it for another post.
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Re: WildCircuits Laser HackLog

Postby twehr » Fri Jan 20, 2012 1:08 pm

Please share your Moshi/PIC conversion. Lot's of folks would be interested in that.
tim
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Re: WildCircuits Laser HackLog

Postby mondo50m » Fri Jan 20, 2012 6:22 pm

Here is hoping that you have some good news on the conversion of the Moshi board. I would suppose that there are many who are waiting for this.

Milt
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Re: WildCircuits Laser HackLog

Postby HegerService » Sat Sep 15, 2012 3:52 pm

twehr wrote:Please share your Moshi/PIC conversion. Lot's of folks would be interested in that.

Yes please Share. But i have a Idea. Why not use a Arduino Board as Pic? Think with a little Addon, the Laser PWN can controlled with the Arduino Board too. And some other Cool Feature Addons. Like Autofokus. Z Table, Water Temp and Flow Check... And and and.
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Re: WildCircuits Laser HackLog

Postby timogiles » Tue Jan 22, 2013 12:11 am

It has been a very long time since I've posted here, but life has calmed down enough that I can get back to my build log. I decided to change direction a little on the electronics and built my own board with the motor drivers built in. Hacking the moshi board like I did worked fine, but the allegro motor driver chips that everyone is using on the pololu boards are so cheap it doesn't even make sense to keep any of the moshi electronics.

I designed up a board using a PIC16F1937 (that's my favorite PIC right now), using an MCP2200 USB to Serial converter and 4 Allegro A4984s. The Pololu boards that everyone is using use the A4988. I chose the A4984 instead because I could get it in a TSSOP package (easier to solder) and the A4988s had a super long lead time. The laser is only using 2 of the motor drivers right now. I put down 4 so that I could use this same board to build a 3D printer in the future. I also have a header on board to get to my E-Stop and limit switches. I bought my boards from iteadstudio.com. I'm very happy with the quality of their 2 sided boards, and they are very low cost. Shipping takes a long time to NY.

StepperDriverCropped.jpg
Stepper Driver


I originally bought my DC-KIII with the intention of building a much bigger laser. I wanted a 2' x 4' work area and planned to transition all the electronics, tube, mirrors and power supply to the new laser. That plan ended up panning out quite well. I spent the month of September designing up my dream laser and buying parts. The month of October was consumed with building. By the middle of November I was back up with an operational laser. Here is the computer rendering of my design:

ProD_CompleteLaserDesign.png
ProD Complete Laser Design


All the aluminum extrusion is from misumi. The total bill was $913 at misumi. I didn't expect it to cost that much, but I did use a lot of it. I decided to build a complete base so that that laser would be free standing, which drove the cost up. I decided to swap out the DC-KIII's focusing optics for a one of the adjustable ones that LightObject.com sells. That allowed me to have a fixed table, which I think is a terrific idea if you are going to build a 2'x4' laser. My linear rails are maker slide that I purchased from inventables. I bought 2 1800mm rails and cut one of them in half to make the y axis. The gantry is just a solid piece of makerslide. When I bought it I wasn't sure it would hold up running the whole 4' of the table ( I thought it might sag) but it has worked out great.

P1030489.JPG
Laser Frame


One of the key pieces of my design is that all the custom brackets and connectors were designed to be laser cut on my DC-KIII to build the new bigger laser. This saved a lot of money as several of the parts had to be remade a few times when I changed my mind during the build or something wasn't measured correctly. I remade the gantry mounts several times when I found that acceleration of the gantry was causing the brackets to flex. I had to widen them quite a bit and changed from 3 v wheels to 4 v wheels.

Original gantry mount - only 3 vwheels and not wide enough:
P1030464.JPG
Original gantry mount


Wider gantry mount and laser head mount:
P1030493.JPG
Laser Head Close


Trouble Shooting Electronics:
P1030502.JPG
Trouble Shooting Electronics


Everything is finised enough to get back to production!
Laser Complete - no plexi.jpg
Laser Complete before installing the lid panels


I decided to skip the expense of Alupanel and skin the laser with luan plywood. I bought to alumium foil to cover the insides of the wood panels with in case of a beam alignment problem. I don't really want the sides to start on fire. I haven't actually installed my safety aluminum foil yet though.

I'll save the rest of the info of my build for another post.
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Re: WildCircuits Laser HackLog

Postby evokanivo » Thu Jan 24, 2013 6:54 am

I'm planning a 2'x4' and am worried about a few issues. Would you mind covering in your next post:

-beam divergence: does the spot size or cutting strength vary noticeably based on the XY coordinates?
-do you use a beam expander?
-laser wattage (or better yet, beam width at the tube exit point, if you know it)?

Thanks
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Re: WildCircuits Laser HackLog

Postby j@son » Sat Jan 26, 2013 4:41 pm

is this the laser head mount you got? http://www.lightobject.com/Special-Pro- ... -P787.aspx
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Re: WildCircuits Laser HackLog

Postby timogiles » Mon Jan 28, 2013 10:52 pm

evokanivo wrote:I'm planning a 2'x4' and am worried about a few issues. Would you mind covering in your next post:

-beam divergence: does the spot size or cutting strength vary noticeably based on the XY coordinates?
-do you use a beam expander?
-laser wattage (or better yet, beam width at the tube exit point, if you know it)?


evokanivo,
1. the beam does diverge a bit, but it's not extreme and not really a problem. I never tried to measure beam convergence before, so I just went out and had a look at it. I used a piece of scrap plywood and held it on the opening of the focusing head when it was in the home position and the repeated for when it was in the farthest-from-home position. Measuring the two burns that were created, I have: 4.55mm in the home position and 6.65mm in the other position.
2. no beam expanders or any other tricks. Just mirrors
3. my laser is 40watts. I'm using the laser tube and laser powersupply from my DC-KIII. Beam width must be around 4.5mm at the exit of the tube.

j@son wrote:is this the laser head mount you got? http://www.lightobject.com/Special-Pro- ... -P787.aspx


j@son,
I bought this one: http://www.lightobject.com/Pro-laser-he ... -P587.aspx And I have to say that I love it. It is very well made and adjusting it is very easy. You do have to buy a lens and mirror for it. The lens from my DC-KIII was too small as was the mirror. I also bought them from light object.
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Re: WildCircuits Laser HackLog

Postby Robin Hewitt » Mon Feb 04, 2013 3:25 pm

Many thanks for the hack info. I just bought one of these little 40W lasers on impulse and am having serious doubts about MoshiWare even before it arrives.
I am already thinking to replace the processor. Like most people I use whatever my head is currently set up to program, right now that is ARM Coretex.

A couple of questions. I hear good things about Leadshine stepper drivers, is their 1.5A model overkill for this machine or not quite enough?

If you aren't using Moshi, do you have an alternative for the engraving or do I need to write my own?
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Re: WildCircuits Laser HackLog

Postby timogiles » Mon Feb 18, 2013 5:40 pm

Robin,

I don't recall if i ever measured what the coil current is that the Moshi driver board applies to the motors. I think that you would be fine with a 1.5A driver, but i don't know anything about Leadshine. Right now on my 2'x4' laser my motor current is 1.1A

I built my own control board based on a PIC microcontroller. I wrote my own program in python to get designs from the PC to the laser, as well as an inkscape extension. I'm planning on doing a detailed writeup about it soon and opensourcing it all, I just haven't gotten around to it yet. A lot of the guys on this forum are using DSPs from FullSpectrum Engineering or LightObject. They sound like they are full featured and do a good job with engraving / cutting, but I don't have any experience with them. I wanted the challenge of doing my own. :D
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