My $20.00 foray into the world of CNC

[bmac2]

A couple of months ago I stumbled onto a web article titled “MAKE THIS 3D PRINTED LASER ENGRAVER FOR JUST $20” https://3dprint.com/79856/diy-3d-printed-laser-engraver/ created by Stephen Brockett an engineer in New Zealand. He has made all of the information available in the public domain including the .STL files for the 3D parts. Reading it looked like it would be a cool little project to do but:
1) I don’t have access to a 3D printer.
2) I already have more than enough projects on the go so I definitely didn’t need to start another one.

 

[bmac2]

USE EXTREME CAUTION IF YOU ATTEMPT THIS PROJECT! IT INVOLVES MODERATE POWERED LASERS THAT CAN BLIND YOU INSTANTLY, EVEN WHEN SEEN REFLECTED ON A DARK SURFACE

Now that all that is out of the way, we can get on with the more interesting stuff

But I don’t want to start on the Whippet until I get gear cutting down, and I can’t start cutting gears until I get the parts to finish the Arduino indexer for the rotary table. My old bench supply died while I was working on the rotary table and its replacement is on hold waiting for the same “slow boat from China” to arrive as the indexer so . . . . scratch.gif
The engraver is Arduino based using the sleds, stepper motors, and laser diode from a couple of DVD drives. I had everything needed in the basement in the “Dead PC” bone yard so I stripped down a couple of old DVD burners and started messing around with the electronics, G-code and a felt pen.

 

[bmac2]

You can’t tell from the video but it’s a “G” the pen was a sloppy fit in the brass tube so it’s a bit of a mess but it worked.

[ame]https://www.youtube.com/watch?v=wGCGXgvO8GE&feature=youtu.be[/ame]

 

[bmac2]

There are 2 laser diodes in a DVD burner a 200-300mw red that’s dangerous and will blind you given half a chance. And an inferred that’s extremely dangerous and I just binned it before I got tempted to try something stupid.

 

[bmac2]

I’d ordered a pair of 600-700nm safety glasses and a T0-18 laser module and a week later it was time to try out the laser . Ok it’s not Star Wars and it won’t even touch anything white or reflective but it will go through card stock.

Oh . . . . DON’T use your multi meter as a back stop then fooling around with a laser. :wall:

 

[bmac2]

What tipped the scales on this project was when I found out I could get the parts printed dirt cheap at the Public Library. Who knew they had a Makers Market at the library? I downloaded the STL files and two weeks and $14.95 later I picked up my printed parts. The finish was not what I was expecting maybe I was expecting too much and for $15.00 they will work fine.

 

[bmac2]

The first thing I learned about PLA was to not leave it in the sun :fan:. Apparently warping in printed PLA is quite common so after more Google searching and a couple of hours with a heat gun, I could stop kicking myself and start screwing things tougher.

 

[bmac2]

The sides have mounts with a “T” slot to hold the nut for mounting the sleds for the Y axis. I had read that people were having trouble with them breaking when tightening up the screws because of the way the PLA is laid down during printing.
Naturally after reading all the warnings . . . . . I broke one, so back to Google to find what type of glue to use on PLA. After some more searching it look like super glue or epoxy work best on PLA. I added a “U” shaped metal strap that wrapped over the end of the mount and epoxied one on each of them.

 

[bmac2]

The mount for the Y axis work surface is well thought out and I think quite clever. It has 3 hex holes in the bottom that fit 6-32 nuts perfectly and mounts to the sled with a single screw through the middle. A set screw goes into each of the nuts and these are used to level it.


[ame]https://www.youtube.com/watch?v=fAdWHiv0sRw&feature=youtu.be[/ame]

 

[bmac2]

My original plan was to use an Arduino UNO and a development board but it looked like it was going to get a little tight once it was closed in so I decided to use my trusty old Boarduino and some veroboard (strip board).

 

[bmac2]

Squeezed everything in and with the coroplast (that corrugated cardboard but plastic stuff) covering made from a former “Watch for Falling Ice and Snow” sign I think it looks pretty good.

 

[bmac2]

This thing was fun and easy to make and I’ve learned a lot about how G-code and CNC work. In the original they use a driver board off e-bay so everything just plugs in. There was no programing required just download and install the software and it works. The only problem with it is that with a work area of 38 x 38 mm and relatively low power I couldn’t come up with of a practical use for it other than burning “Tomato’s” onto Popsicle sticks for my wife.

But when I finally got it focused properly it will cut 100lb card stock (.014”, .35mm thick) in 2 moderately quick passes. So as long as it will fit the work area, I have my very own CNC laser gasket cutter ;D.
For added ambiance with the roll top down and the lights off it’s like a little fire place in the shop.
The parts for the indexer came in so I can get back to that.

Thanks for looking in.

[ame]https://www.youtube.com/watch?v=Go0H_6OiK6w&feature=youtu.be[/ame]

 

[Wizard69]

USE EXTREME CAUTION IF YOU ATTEMPT THIS PROJECT! IT INVOLVES MODERATE POWERED LASERS THAT CAN BLIND YOU INSTANTLY, EVEN WHEN SEEN REFLECTED ON A DARK SURFACE

This is a bit of an understatement! Anybody thinking about building lasers need to understand all the safety implications. There is nothing faster than the speed of light.

Now that all that is out of the way, we can get on with the more interesting stuff



But I don’t want to start on the Whippet until I get gear cutting down, and I can’t start cutting gears until I get the parts to finish the Arduino indexer for the rotary table. My old bench supply died while I was working on the rotary table and its replacement is on hold waiting for the same “slow boat from China” to arrive as the indexer so . . . . scratch.gif

The engraver is Arduino based using the sleds, stepper motors, and laser diode from a couple of DVD drives. I had everything needed in the basement in the “Dead PC” bone yard so I stripped down a couple of old DVD burners and started messing around with the electronics, G-code and a felt pen.

The number one safety measure is to make sure the lasers work area is completely enclosed and that all windows are optically opaque at the wavelength you are operating at.

 

[Wizard69]

There are 2 laser diodes in a DVD burner a 200-300mw red that’s dangerous and will blind you given half a chance. And an inferred that’s extremely dangerous and I just binned it before I got tempted to try something stupid.

The problem with the red laser is that red will transmit through most common window materials. As for the other laser I thought that was ultraviolet (UV). Doesn't matter from a safety stand point as you can't see the beams. However some way nodding materials will block UV. You need to know the specifics of the window material and the wavelength the laser operates at.

The thing here is that you might actually get better performance from a UV laser. I know that many of the industrial lasers at work operate in the UV part of the spectrum.

 

[RonGinger]

I think that is about as slick a small CNC project as I have seen. Not the most useful one in the world, but for what it cost it is great. How would you like to come to http://TheCNCworkshop.com in Detroit in June and talk about it?

 

[bmac2]

Hi Ron thanks.
Ya the little beast is just too small to really be useful but for the cost I couldn’t resist. I paid 7.85 for a 2 pack of the T0-18 diode mounts and the 14.95 for the printed parts so my out of pocket cash was 22.80. The rest of the stuff I had around.
I think where it shines is as a tool to use G-code and learn some of the abilities and limitations of a CNC machine. Everything that’s going on is fully scalable. Use some real stepper motors, extend the X and Y axis, pop on a more powerful laser or add a Z axis with an engraving spindle or router and you have a real tool.
That workshop looks like it definitely would be something I’d be interested in. Even with the exchange rate the registration fee is a deal after looking at what’s being offered. Unfortunately the 3100 km is a bit of a drive.

 

[RonGinger]

Oops, I saw the Canada part but missed Alberta. Yes, that would be ab it of a trip. There are a couple guys from around Toronto that have been to previous workshops.

 

[GailInNM]

Great project Bob.
You may be surprised at how many little jobs will fit in that small envelope. I have a much larger laser that I got used about 15 years ago and probably 1/3 of the things that I engrave would fit. I build small engines and I can think of only one gasket in the last 65 years that would not fit.

For materials, I l use 0.006 inch thick vegetable fiber gasket material which should cut about the same as the card stock you have cut. For name plates

I think you can should be able to engrave standard engravers stock made for lasers. Hard to say as it is made for IR laters. It has a very thin, about 0.002 inch, layer of colored plastic on top of a different colored base plastic so all that is necessary is to remove the top layer to expose the substrate which can be had in thicknesses from 0.020 up to 1/8 inch thick. I mostly use 1/16 inch thick.Of course with my larger laser I just engrave the part at a low power setting and then cut it out with a higher power setting, but you could cut blanks to feed it with machine tools.

Current project is making high visibility key board for my Bridgeport CNC controller. It has 40 engraved keys, all of which would fit your machine. I am about 1/2 way done with it. Last weed I made badges for an upcoming steam-up next month. I made 25. They are 24mm diameter and will have a pin and clasp back glued on them to go on hats or steam-up aprons. They were made from 1/16 inch thick white on black engravers laminate. I also made a few from black on white stock so they would show up better on light colored items like white hats. Photo attached of a black on white one.
Gail in NM

 

[bmac2]

Hi Gail thanks. I love the badge. I guess Poison Creek isn’t much for fishing Rof}.
Steam+Beer+People that like steam and beer? . . . . Can’t think of anything missing, sign me up! Thm:
Your keyboard project sounds interesting, any pictures?
One thing I’ve seen a few guys using small lasers for is laying out printed circuit boards for etching. They coat the copper clad (saw one guy that just used acrylic spray paint) and use the laser to remove the areas they want etched away. I want to try this on brass. It would be cool to be able to make small plaques and number plates for model engines.

 

[GailInNM]

Bob,
The Poison Creek Steam-up is a collection of about 25 friends who get together for a few days to a week to play with live steam Gauge 1 trains about 20 miles east of Salt Lake City, Utah. Poison Creek had numerous mines located on it in the late 1800's and was quite likely severely polluted by mine operations. But today it is suitable for fishing. The beer festival is that every one who can brings a fare amount of of local beer from their part of the country, which ranges from BC, Canada to Florida,USA. So we play trains, drink beer and swap lies.

I just finished cutting the last of the keys for the control panel and will mount the last of them on the control panel in the morning. I will post a photo of it soon as it is finished.

In the past I laser cut resist (paint) on PCB and etched them. Did quite a few. If you want to try it I can pass along some hints that will save you some time and grief. Now I do my PCBs with a high RPM mechanical engraving head with a floating spindle and and vee engraving bits with a tip width of 0.1 or 0.2 mm. Then swap the bit for a drill and drill the board at the same time. All this is done in the Bridgeport CNC mill that the control panel is for. I had marginal results trying to etch brass and aluminum number plates. Mostly because of undercutting of the resist. A spray etcher probably would have cured the problem but I did not continue on with it.
Gail in NM