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RepRap Report #2

End Stop

Somehow I can’t believe it’s been four months since my last RepRap update! I’ve got a lot to report…

In July I took the RepRaster 5000 to 3D Printing Camp in Madison, and that didn’t work out too well. The first problem was that I couldn’t get the bed up to temperature (and yeah, I print with ABS.) I didn’t notice the ceiling fan directly above me. I moved. I also managed to knock the Z end stop out of place, which made the extruder crash into the bed. No real damage from it, but I decided I needed a new end stop solution. The new one is way more solid. No easy way to bump it out of alignment.

I also took the RepRap to the Milwaukee 3D Printing Meetup. Once again something went goofy, but I did get it working fairly quickly after the first fail. (Just a few weeks ago I took the RepRap to BarCampMilwaukee7 and had no issues at all. Success!)

Power

At some point I got sick of all those damn wires coming from the ATX power supply, so in the process of making them shorter, I hosed something up good and ended up with a power supply that supplied no power. I finally got a smaller (and more powerful!) power supply. I’m not 100% happy about the mains not being totally covered up, so I should make a case for it at some point. It works very well though… much better than the ATX supply did.

Spools

My great spool experiment was a bit of a failure. I mean, at least I don’t use soup cans, and while I still think my idea was good (or at least looked good) trying to wind a coil of filament onto a spool is damn near impossible. Just ask my daughter, who had to hold back from laughing when the power drill kept slapping me in the head with filament. I’ll probably move to one of those adjustable filament holders you can easily get a coil onto. At home I end up just hanging the filament from the ceiling, so that works fine.

QU-BD Extruder

I ended up getting an extruder from the QU-BD Kickstarter campaign, and I haven’t bothered to assemble it yet. My original plan was to donate it to the DIY 3D printer we were going to build at Milwaukee Makerspace. Since we ended up getting a Replicator, we didn’t build a printer. It’s a 1.75mm extruder, and since I use 3mm now, I may end up switching to 1.75mm in the future, so it could come in handy.

Netbook

My best RepRap hack was getting my MacBook out of the picture and making good use of my old Eee PC 701. This was the first netbook ever released, way back in 2007. I’ve struggled with how to make it do something useful, and now it does. I’ve connected an old LCD display I got for free to it, and it sits on the shelf near my workbench. It does one thing… control the RepRap. It’s plenty powerful for that. I do all my modeling and slicing on my MacBook, so the Eee PC just runs Pronterface. And for traveling I can just bring the Eee PC and it doesn’t take up much room.

Mr. Pumpkintatohead

Hey look, it’s Mr. Pumpkintatohead! Nothing amazing, but I’m getting better at using OpenSCAD. I managed to design all the parts (minus the knobs) for my Laser Kaleidoscope in OpenSCAD (no, they are not parametric, but hopefully I’ll get better as time goes by.) I also managed to complete a home repair thanks to OpenSCAD and the RepRap. Hooray!

I’ve still got some challenges. Now that it’s getting colder out, and I’m printing bigger objects, I’ve got some warping issues. As winter comes, this may be my biggest problem. Besides that, things have been working really well. One thing I’ve found is that I’m not happy with my z height. It’s just 75mm, and I’d like to see a bit more. Oh, I also switched from Sprinter to Marlin, so I may be able to get a few more millimeters of height by just updating the firmware. (I was a little conservative at first.) I can probably gain a few more millimeters with a new piece of plywood under the bed. There’s always something to tweak with a RepRap…

I think the biggest change from June to October is that I am now confident enough that I can hit ‘print’ and leave the basement and I’ll come back to a successful print. I used to just stare at the bed as the skirt went down, and that first layer went down… in part because I was fascinated, but also in part because I always assumed something would go wrong. Things tend to go right almost every time now… it’s almost like having 3D printer at home is a normal everyday thing. :)

(You can see some photos of my prints over on Flickr. I’m way behind in taking photos of my prints, but there’s a few interesting ones in there.)

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(Additional) Nerdy Derby Cars

Great White

There’s a great post over on the Milwaukee Makerspace site about Milwaukee’s First Nerdy Derby, including some sweet video, but I’m mainly going to talk about my own cars here. :)

I spent a lot of time before BarCampMilwaukee7 getting ready for the event, but I also found a bit of time to fabricate a bunch of parts for people to build cars with, so I was down to the wire when it was time for me to make more cars. I already had Poundin’ Sand, my fully laser-cut car, but I wasn’t content to just have one car. (I had heard Jim R. from the Makerspace had five cars. He didn’t race that many, as I think one or two of them exploded during testing.)

My second car was titled “Great White” and was a 3D print of Mr. Jaws. I ended up kicking out some quick axle mounts in OpenSCAD and just hot gluing them to the bottom of Mr. Jaws. They probably weren’t on straight, but I didn’t take the time to care. In the category of 3D printed cars… I still came in second! Ed managed to build an amazing 3D printed car, and the worst (best?) part is, he pretty much had the same idea as I did, but he managed to succeed. (Print time and print failure were the two biggest concerns for both of us.) I ended up using stock wheels instead of the 3D printed wheels I made a few weeks earlier, which seems silly as I could have gone for a full-on 3D printed car… oh well.

RasterMobile!

My third car was the RasterMobile! which actually consisted of a block of wood from a real Pinewood Derby kit, turned sideways, with two holes drilled all the way through, and 5/16″ threaded rod with inline skate wheels attached. I had skate bearings that seemed to turn well, I had some weight and mass, and it was painted black with RasterWeb! stickers on it. What could go wrong!?

So how did my cars do? I didn’t expect much out of Great White, as it was really light, and the wheels were probably not completely straight. It rolled down the track, so that’s all I can report on that one. I still think it looked cool and was a neat idea. The RasterMobile! didn’t do as well as I expected. I thought it would fly down the track, and I suppose it did, but the mass of it probably slowed things down too much at the bottom. I did get a some satisfaction that Gary saw the skate wheels, ran to his car and ripped apart his inline skates just to try to beat me with my own idea. :) Oh, the RasterMobile! also had an accident where it jumped out of its lane, so that certainly didn’t help things.

So which car did the best? Surprisingly it was Poundin’ Sand that performed the best out of my three cars. I wasn’t sure the laser-cut wheels would be up to the task, and I questioned whether not gluing the 3 layers that comprised each wheel together was a good idea or not, but it did alright!

Poundin' Sand

There’s been talk of doing another race in the future, so I may not be done building tiny cars…

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Mold Making

I’ve been digging into OpenSCAD lately and managed to come across this Flickr photo with the most minimal of explanation of how to do a reverse object in OpenSCAD, but it was all I needed…

Space Invader SVG

I started with the SVG file of the classic Space Invader character, sized to the width and height I wanted, and then exported it from Inkscape as a DXF file.

Space Invader STL

Once we’ve got the DXF we can pull that into OpenSCAD and extrude it into a 2.5 dimensional object. (It might be 3 dimensional, but I’m not going to argue 2.5D versus 3D right now.) 


linear_extrude(height = 10, center = false) import("spaceinvader.dxf");

After we compile the code we can then export our object as an STL file. We can then pull that STL file into OpenSCAD again for the next step…

Space Invader STL (reversed) 


difference() {
	translate([40,42,2.5]){
		cube([90,70,14.5], center=true);
	}
	# import("spaceinvader.stl", center=true);
}

You’ll need to tweak those numbers of course, and as for the # at the start of the import line, that’s to show us the object even when we can’t see it, as it were… sort of. It’s an OpenSCAD trick I learned from Mark Finn at BarCampMilwaukee.

So now that we’ve got the object dropped into a block (at the proper height) we can then export it as an STL file, which could be cut on a CNC machine, or 3D printed.

Space Invader G-code

I’ve not yet attempted to 3D print this, and I’ve had not much luck in printing things that are water-tight. I might try getting some silicone to coat the piece which would make it water-tight, and food-safe.

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BarCampMilwaukee7

BarCampMilwaukee7

Whew! It’s BarCampMilwaukee time! This weekend, October 6th and 7th, 2012 is BarCampMilwaukee7… that’s the seventh BarCamp here in Milwaukee, for those of you keeping track.

I’ve got a few things I’ll highlight, the first of which is the Raspberry Pi Roundtable, where people who have Pis, or want to use a Pi for a project can get together and talk about them. Having a super-cheap Linux-powered computer opens up some new possibilities, so we’ll talk about what those are.

The session I’ve got planned is titled Money. Maker. Business. and I’ll talk about how I started up my making business. At Milwaukee Makerspace (and other hackerspaces) members often talk about potential business ideas, so my talk will outline the process I went through, including touching on my Maker Business posts.

Thirdly, we’ll be doing our own Midwest version of the Nerdy Derby race. If you haven’t made a car yet, make one now! If you can’t make one now, Milwaukee Makerspace will be providing miscellaneous parts during BarCamp so you can try to build one. And it’s not just all speed and aerodynamics, and there will be style points awarded as well. (We might even call them “Moxie” points as an homage to the Power Racing Series.)

(And yeah, I’m sure I’ll also bring the RepRaster 5000 and enjoy some 3D printing hijinx as well.)

So yeah, barcampmilwaukee.org has all the details. I hope you’ve already registered, because if not, we may not be able to feed you. Come anyway! We’ll figure something out, there are restaurants nearby, it’ll all work out, somehow, as it always does. :)

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Laser Kaleidoscope

Laser Kaleidoscope

We managed to get Milwaukee Makerspace invited to another gallery night, and this time we’re taking part in Bay View Gallery Night at Alterra, so I figured I needed a new project. And hey, what’s better than a deadline to get a project done? (It’s like college all over again… in a good way!)

Interociter

When I was at Maker Faire Detroit back in July I saw this laser spinner thingy called “The Interociter” and decided I had to have one. And by “have one” I mean “make one”… so I did.

(There’s some debate over whether it should be called a “Laser Kaleidoscope” or “Laser Spirograph” or “Laser Spinner Thingy” and while I do like “Laser Spinner Thingy” I also get sick of people thinking all my projects are Spirograph-inspired, so I went with Laser Kaleidoscope. Deal with it.)

Laser Kaleidoscope

Laser Kaleidoscope

So where were we? Oh yes, the project! It’s really simple: a laser is pointed at a mirror, and that reflects the laser onto another mirror, and that one reflects it onto another mirror, and then it shows up on the wall. You can make the motors spin by turning them on with a pushbutton, and then adjust the speed by turning the knobs. There are 3 motors (an earlier prototype had 4) and by setting them all to different speeds, you can get some crazy patterns going.

So how does it work? The laser hits the first spinning mirror, and creates what appears to be a circle. It’s really a single dot, but it’s spinning around so fast it looks like a circle. Add a second (and third) mirror, and since they all wobble just a little bit, you get much more than a simple circle.

Here’s a shopping list:

I say “shopping list” because those are the parts I (mostly) bought… Of these parts I’ll note that with the laser I leaned towards the “safe” side, but it can be difficult to see in well-lit rooms, so I may upgrade to this one at some point. The round craft mirrors came in a variety pack with different sizes. I may experiment with larger mirrors in the future.

Laser Kaleidoscope

Laser Kaleidoscope

There are a bunch more parts involved, one being the piece of wood everything is attached to, and the other parts were all designed and 3D printed by me. (OK, I had a little help with the knobs.)

The printed parts are:

  • (1) Laser mount
  • (3) Motor mounts
  • (3) Mirror mounts
  • (3) Knobs

(I also considered printing some small U-shaped things to hold the wires in place, but haven’t bothered with that yet.)

And yeah, this is why I have a 3D printer. The ability to digitally design something, rapidly create it, tweak it a bit and print a new one… that’s what I love.

My original plan was to make up a nice laser-cut case for this (I thought that would be appropriate) but with the lasers down for repair, I didn’t get that done in time. That’s actually fine, as I’ll probably end up redesigning things a bit before I’m totally done with it. So far though, I’m happy with the progress.

The video was quick & dirty, and really doesn’t do it justice, which is why you’ll need to come see it in person I guess. I figured I couldn’t write this post without including some sort of proof that it actually works. :)

Lasers! They’re awesome!