MKE 3D Printing Meetup – August 2012

MKE3DP

Remember that 3D Printing Meetup we had? You probably read all about it. Well, people liked it, so we’re doing it again.

If you’ve got a MakerBot, RepRap, Mendel90, Solidoodle, Bukobot, Quantum ORD Bot, or some other oddly named CNC machine that spits out melted plastic, pack it up and join us… if you don’t know what the heck those names mean, but you’ve heard the phrase “3D printing” you can join us too, and we’ll answer all your questions.

We’ll be meeting on Sunday, August 12th, 2012 at 1:00pm. We won’t be at our space because we’ve partnered with our friends at Bucketworks for this one! Details are below.

Bucketworks
706 South 5th Street
Milwaukee WI

Note: This event is FREE and open to the public! Everyone is invited.

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.

MegaMax 3D Printer

MegaMax 3D Printer

MegaMax 3D printer based on MendelMax but bigger and minus plastic parts.

This is my on-going project at the Milwaukee Makerspace.  It is a 3D extruded plastic printer with about 1 cuft build envelope.  I want to print life-size human skulls (among other things) from CT scan data.  The printer is made mostly from salvaged parts and materials so the cost has been very low.  When it’s finished it will have a heated 12″x12″ bed (13″x13″ if I can find an aluminum plate that big) and dual extruder so it can print in two colors.

I have learned a lot on this project- some things that work and others that don’t work so well, and how to use a milling machine to drill holes precisely and square the ends of the 8020 extrusion pieces used to build up the frame of the machine.

I could not have done any of this without access to the people, materials, and tools at Milwaukee Makerspace.  Every time I go there to do some work on this project someone says something that gives me new ideas for improvements to the design.   I frequently find materials and parts left for me on the machine’s cart by other members who know what I’m trying to do.  If you have a project idea find your local Makerspace and get busy- there is nothing that will get your creative juices flowing like being around a bunch of people with similar interests and different skills and experience!

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

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.

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

eggs

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.

bunny

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?

My neverending quest for quick turnaround prototype PCBs

For years I have dreamed of a fast way to prototype PCB for projects I am designing.

20 years ago I was using rub on drafting tape and stencils – slow and spotty results.

I tried to modify a plotter to plot resist directly to a PCB – no luck.

Magic markers – I’m no artist.

5 years ago I hacked a laminate router by tapping into the stepper controllers and adding a better Z axis – It can rout boards ok, but takes some tweaking.  It only does fairly wide traces.  But its great at drilling holes!

2 years ago I tried the inkjet printing systems – lots of smeared wet ink and poor registration, not very effective.

I opened up a laser printer and tried to get a board to go through it – almost worked, but the fuser was to narrow to take the board.

Although I haven’t found a fast system yet, I get by with the PNP Blue material and a good laminator.  Although I am regularly disappointed when dust, not quite clean boards, minor wrinkles and other issues leave gaps in traces that need touching up.

Which brings us to the latest attempt:

Now that the maker space has a small laser cutter I am trying to find something I can coat a board with and either burn away or melt onto the board to act as an etch resist.

Early attempts with paint had moderate results – our laser cutters on only 25W so it didn’t burn it cleanly.  I have heard that using flat black paint and a more powerful laser works.

Paste wax and markup fluid weren’t dark enough for the laser to vaporize (thinking of trying black crayons)

The latest attempt uses laser printer toner (just like the PNP only skipping the printing and iron on steps.)

The problem is how to get an even coat on a board without it blowing around.  Static electricity has potential (just like what they do inside a laser printer) but I don’t like the idea of a 5KV power supply exposed and handling powered toner is an automatic mess.

So for the first attempt I mixed the toner with rubbing alcohol (30% water).

Messy stuff!

I painted it on with the tongue depressor but it seemed to coat evenly and took only a few minutes to dry:

It mixes well and paints on fairly easily, here are some sample prints I did at various power and speed settings.  I cleaned the board fairly aggressively with paper towel and rubbing alcohol.

None are quite clean enough to become PCBs but they are getting close.

Although the toner paint looked dry, it may still have had some water in it.  I plan on trying a batch with denatured alcohol (100% – no water) and see if it works better.

 

2/16/2012

Updated progress

I have been trying a number of materials and methods to make my fast turn circuit boards.

I’ve decided that last toner is too messy and there are too many variables to create a repeatable process.  So now I’m trying various other masking materials:

 

Black and white spray paint – it works ok, but the ash left behind by the laser resists the etchant and leaves you with a poor etch.

I also tried tape:  Painters tape, electrical tape, clear and brown box tape.  The masking tape worked ok until the etch was slow and the tape started to dissolve.

I held a few of the boards up to the light so you can see how it etched:

 

 

 

 

 

 

One of the other members of the space found someone who had made the black paint work.  The process is to do 2 passes with the laser – the first burns off the paint, the second burns off the ash!  Then you wipe the board down with rubbing alcohol to clean off any residue.   Here is a set of 3 projects I lasered and etched at once:

This board turned out rather well, I had some trouble with the etchant taking for ever so lost some of the detail on the lettering, but the boards came out nicely.  I should get even better results on the next project.

In an attempt to speed the entire process up I tried to drill holes with the laser cutter from the back of the board:

   Not very good results!  After about 6 passes it still didn’t cut through thin PCB material and stunk and smoked the whole time!

 

 

 

 

 

 

So instead, I used the laser to cut wholes in a small piece of acrylic to use as drill guide:

 

 

 

This gives you a pattern to follow using a Dremel and the holes wind up in the right places and nicely lined up.  I drilled 2 holes in opposite corners of the board and used the leads from resistor to line up the template and board and hold them together while drilling.

 

 

 

This image shows the template attached to the board and about half the holes drilled.  This worked very nicely!  The only problems was small disks of acrylic getting stuck to the drill bit (you can see little craters on the left side of the board where these came from)  I had to clean the drill bit twice to drill the whole thing.  Either bigger holes or a different plastic might fix this.

 

This is first of the 3 boards I put together and it works just fine.  It is a level translator for the encoder you see in the holder.  The encoder will be attached to the drive motor in my electric car and feed back motor position to the controller.  The encoder is 5V and the controller wants a 15V signal.  The test bed uses a 15V power supply and LEDs on the 4 quaderature outputs.

Encoder test video

BoxMaker

We’ve got a Laser Cutter! We can cut things… like boxes. So head on over to BoxMaker and make a box!

As far as materials, that’s a little trickier. I tried wood, but currently the laser cutter can’t handle cutting your standard 1/4″ plywood. (Update: 3mm Baltic Birch plywood works great though!) Here you can see the results of me trying.

Wood

No matter… I moved on to acrylic, since we’ve got a lot of acrylic scrap to play with…

Acrylic

That worked much better! Hopefully once we do some laser maintenance (cleaning and what not) it might be able to cut wood. Of course you could always use BoxMaker to create your box and cut it on the CNC Router instead.

So here’s my laser-cut acrylic box. Notice anything? The tabs are way too big! In my frustration of not being able to cut wood, I switched to the acrylic, but didn’t measure the thickness and create a new file, and since it was not as thick as the wood, I got the tabs all wrong.

Box

Still, BoxMaker is an awesome tool, and I look forward to getting the cutting part right next time.