Laser Cut Safety Lock-Out Tags

Lock-out tags are used by factory workers to clearly identify broken or damaged equipment.  Milwaukee Makerspace is no exception.  A set of stop sign-shaped, 3″ wide, 3/16″ thick, red plastic tags have been created with the words “STOP – NEEDS REPAIR” in bold, white letters.  Tags are hanging over the first aid file cabinet by the light switches in the Workshop.  If you find a machine is out of service, please zip-tie a tag to the machine, preferably over its ON/OFF switch so people can easily spot it and refrain from using a potentially unsafe tool.

Easy and Free 3D

Its no huge secret that learning to make something in a 3D CAD program has been a bit challenging before now. Programs such as Blender are quite powerful, but the learning curve is a bit steep and you could spend days working in tutorials before you actualy got around to making anything. Well, the world turns and the people with the big brains are slowly learning that the best way to get more people involved is to create tools that don’t require a masters in computer design to understand.

In the old days, you needed a high end workstation with advanced graphics capabilities to do this kind of work. I can remember going to my friends work place and marveling at his 386 workstation built into a desk with a pen based touch screen. These days we can do so much more, and in a web browser. The recommendations below won’t meet everyone’s needs, but it’s a great starting point to learn what works and what does not. Its also hella fun.

Back in November I bought a Printrbot during their Kickstarter campaign. Since then I have been trying out different combinations of programs and processes for generating 3D designs and slicing them for use on the printer. I had a short list of requirements for things I absolutely needed:

  • Short learning curve, nothing overly complicated. I just need to make straight 3D designs. I don’t need textures, colors or animation.
  • Free. I was looking to keep this as low cost as possible. I am a huge fan of open source solutions.
  • Ability to export STL files.

I ran through Blender, 123D, Google (now Trimble) sketchup and a few other programs. They were all quite functional, but each had some small quirks or non-intuitive interface problems and I was routinely somewhat frustrated and defeated. I kept poking around and finally stumbled upon a winning combination.

TinkerCad is a free 3d design app. It runs within your browser and has a strong preference for Chrome. All your designs are assembled with a simple tool set and saved to the web automatically. The site allows you to download your designs as STL, VRML or 2D SVG. It also allows you to imidiately submit your designs to several 3D printing services such as Shapeways and Sculpteo.

Although the tools are somewhat limited, you are able to do a surprising amount of real work. All of the tools are quite intuitive and I was able to jump in without needing to run through the tutorial. In fact, my 12 year old daughter jumped in after I was done and was designing her own things without any input from me. I’m going to be needing a lot more filament at this rate. The ruler and measurement tools are better than any other program I tried. In less than 20 minutes I was able to assemble a small robot design.

Once I had the design, I was able to easily export the STL file and immediately print one using the printrbot. I added a small raft to the back and drilled out a hole for a button. This is now going to be my new doorbell. I also added a few LEDs to the back for lighting.

Once I was done, I was really excited by the prospect of actually being able to make virtual things. I decided to see what else I could do. One dream has been to find a way to easily create cardboard sliced designs. A fairly new app from Autodesk called 123D MAKE can do just that. It’s not open source, but it is a free 100+ MB download. I was able to take the STL file I downloaded and upload it to the 123D MAKE program. From within the tool, I was able to set material thickness, slice type, output format, stage size and dozens of other options. I was then able to export EPS files containing all the pieces laid out and numbered for assembly.

I was able to take these over to the laser cutter and cut some slices from cardboard I had laying around. I assembled them per directions and wound up with this bad boy.

If you don’t have a laser cutter, you can always just print the design and cut the pieces by hand.

I think we are seeing start of a huge shift in production of one-off items. 3D printers are getting cheaper, and more importantly, printing services are able to produce items in almost any material you can imagine. As the design tools get easier and easier to use you are going to see these services become more and more prevalent. Need a replacement part? Print it yourself. Have an idea for a game, have it printed, boxed and shipped overnight. Its the definition of a disruptive technology.

Now, go make something!


Free 3D design web app

How do you make the BADASS more badass?

Simple.  Add lasers.

Video of Vectorized Laser PCB Fabrication

The next generation BADASS board was too big to fit through the card laminator, so I figured I’d try my hand at Tom’s laser etching method.  By using the trace program included with CorelDraw I was able to make a vectorized path for the board.  One pass takes about 5 min at 50% speed.

Gradient Reference for the 25 Watt Laser Cutter

A map of how deep and/or dark the laser cutter etches based on the percentage of power and percentage of speed.

So, I was just getting in to the ‘Space when Jason G. and I started talking about the laser cutter.  I had planned on doing some simple tests to determine the level of shading that I could get for an as-yet unnamed project when he mentioned that he (and others) were talking about doing a full map of different settings and the results.

I thought that I might as well give it a shot.  The set up was interesting.  I created a grid of rectangles in CorelDraw (oh, how I hate you!) and then used the preferences dialogue in the laser cutter driver to adjust the speed and power for each little square.

I should explain that the driver recognizes 8 colors and for each color in your image you can assign different settings.  It was a little trying given that the grid is 10×10 but, eight at a time, I assigned the appropriate colors, then settings and let it cut.

After the charring became significant on the low speed/high power settings, I decided to omit the rest of them because, honestly, who wants their project to turn into charcoal?  If you can’t read the Olde English font, it says, “Here Be Fire! (not suitable for etching).”

As you can see, there is a very nice gradient that results from many of these settings used in conjunction with one another.  I also left the tar/smoke-damage on because I wanted people to know what their project would look like immediately after using these settings.  I suspect that most of that can simply be sanded off.

I had forgotten my camera, but a big thanks to Kevin B. for taking a few shots and emailing them to me via his phone.

Next, a cutting template similar to this one.  Oh, and a gradient rainbow.  Yeah, a monochromatic, smells-like-a-forest-fire rainbow should do the trick.  Maybe I’ll even make it a double. :)

Makers, assemble!

Yeah.  Having access to a laser cutter is pretty boss.  I’m planning to wear this to the premiere of a certain movie this weekend.  Four layers of acrylic; two diffuse, two opaque.  11 LEDs, 11 100 Ohm resistors, some phone cord, some solder, and a 9V battery.  There’s no lack of great pages on Instructables about how to make your own.

PCB with Lasered Paint Resist and Fast Sponge Etching

TomG shows how he etches PCB boards using paint, a 25W laser cutter, Muratic Acid, 30% H2O2 and a sponge. Much frothing ensues.

The technique is a neat one, given the presence of a laser cutter, because it can take you from copper clad to etched board in a pretty quick amount of time.

One note, the Muratic Acid is actually from a pool supply store, not Home Depot. It is, of course, dangerous. Wear safety goggles, use gloves, use in a well ventilated area. (The acid smells like a punch to the nose, don’t inhale it)

Fun with Lasers!

Just about the only thing I don’t love about the Open ReVolt motor controller is the case.

As cool as an Open Source Motor Controller is, it’s just not shown off with a basic metal cover. In fact, I actually drilled through the original cover (and put clear packaging tape over the holes!) to see the power and troubleshooting LEDs through the lid.

Recently, the Milwaukee Makerspace got itself a laser cutter. It’s not all that powerful, but more than capable for cutting plastics. One of the Makers posted a blog entry about making a wood box on the laser. He used a program called BOXMAKER which helps you layout the size of your box, including overlapping cut edges to put the whole thing together.

This got me started on the idea of building a clear plastic case for my 500 amp Open ReVolt controller. But I had never even used the laser before. I sat down with the member who owns the laser, and he took me through the basics of importing files, exporting to the laser, and modifying power and speed settings. With that, I was able to start making a few test items on the laser. I figured that since I already had the Open ReVolt logo as a vector file, it couldn’t be easier to try out etching some plastic with it.

I used the laser to make a few small test pieces on various materials. The two logos turned out pretty well. They were both etched AND cut out with the laser. On the orange medallion, I mirrored the image, so it would be a design on the “back” of the piece. That keeps the upside nice and shiny and clean.

Plastics cut on the laser


After practicing a bit on the laser, I started wondering what else I could cut, mark, or etch with the laser. Last night, I forgot something at the Makerspace, so I had to return there this morning to retrieve it. And I am NOT a morning person, so I had my trusty travel coffee mug with me. It’s stainless steel with an anodized dark gun metal finish to it. “I bet that would laser engrave nice!” I though to myself. Sure enough, it only took a little tinkering to figure out how to keep the mug from rolling sideways inside the laser before I could engrave it.

Also, when I came in this morning, all the lights were off, except for one – Tom’s LED lit plexiglass desk drawer. I asked him for some advice last night about how to engrave and then edge-light in clear plastic. He plugged in his project to show me a sample, and had left it on. It was eerily awesome to see the Makerspace lab lit up by green LED power! It’s a good example of how I would like to engrave the top of the controller case and light it up.

Well, that’s it for now. Next, I’ll have to take careful measurements of the controller, lay out the box, find some material to work with, and figure out where and how big the cuts in the end plates will need to be for the bus bars.

Unexpected Detour

When I arrived at the space Sunday, I had planned to work on a circuit board design in DipTrace.  After I left, I had spent six hours rewiring a golf cart.  Allow me to explain…

It all started when I went to take the trash out.  I used the golf cart with the flatbed to ferry the cans out to the dumpster.  After emptying the cans, I rode back and decided to charge the cart’s batteries.  Tom and Rich had just returned from lunch and Tom suggested we swap out batteries instead.  While swapping them out, we decided to also rewire them.  While rewiring them, part of the cart broke.  There’s a small white plate under the driver’s seat.  It’s about 4″ x 6″, likely made of asbestos, and holds a series of copper contacts that a lever attached to the gas pedal slides over to select the speed of the cart.  And it broke in two when we tried to tighten fix a wire on it.

We had a few options: try to mend the old, brittle plate, replace it with something new, rewire the whole thing, or scrap everything out for a solid state motor controller.  Not wanting to adopt a new project or sacrifice a motor controller that could be better used elsewhere, I volunteered to try and fabricate a replacement for the broken part.

First I documented everything just the way it was.  I labeled wires, took photos, scribbled down notes, etc.  Next I went about removing the broken plate.  There was probably more rust than metal on those bolts.  Then I took a pair of digital calipers and a ruler and measured the locations and sizes of holes for each component.  I considered using the CNC router or drilling a plate by hand, but the laser cutter seemed to be a much faster and precise approach.  I drew up my replacement plate in CorelDraw and found a scrap of 1/4″ acrylic that matched the size and thickness of the old plate.  After some tinkering with the printer driver and a dozen passes with the laser, I had a copy of the original in plastic form.

The next few hours were spent migrating the old parts over to the new one and wiring it back in.  Right around 7:00 PM, I tied some batteries together and the thing leaped forward.  A few more tests and it should be as good as new.  Someone suggested that maybe the plate was asbestos to avoid heating issues so we’ll keep an eye on that too.

Easter at the Makerspace


As we think about Easter, we can’t help but think about all the cool stuff we could do at the Makerspace. Oh sure, we’ve got the Egg-Bot, to plot art onto eggs (and other spherical objects) but hey, that’s almost too easy, right? What else can we do?

wood bunnies

Maybe some laser-cut bunnies! We could use the Laser Cutter to cut out some bunnies and do something interesting with them. (Or the CNC Router could be used for bigger pieces.) Hmmm, I bet we could even make some sort of crazy laser-cut Easter baskets, maybe using living hinges.

Speaking of bunnies, what is Easter without chocolate, put them together and you’ve got chocolate bunnies, which I’d consider the pinnacle of Easter treats.


With the Makerbot we could print these awesome chocolate bunny molds and kick out our own chocolate bunnies!

So… what will you be making for Easter?