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Inkscape to OpenSCAD

Gear!

Oh yeah! You can totally draw gears in Inkscape… In fact “draw” isn’t even the right term, as you can “render” them using one of Inkscape’s extensions. Here’s a nice post about laser cutting some gears that explains it quite well.

Gear Rendered!

Normally for 3D printing I’d export something like this as a DXF file and extrude it into a 2.5 dimensional object, like I outlined here, but there is another way… by using the Inkscape to OpenSCAD converter! (Here’s a nice blog post about it as well.)

Gear in OpenSCAD

It may not generate code that’s easy to edit, but it’s fast, and seems to do the job, which is often exactly what you want. I’m also quite pleased that Inkscape is becoming such a valuable tool not just for 2D work, but for 3D work as well. I might consider teaching an Inkscape class at Milwaukee Makerspace once we get our classroom up and running.

3D Printed Plastic Gear

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Motorized Camera Slider

Motorized Camera Slider

Still very much in progress, but here’s the first iteration of my motorized camera slider. The slider ends are this part, and the carriage is this part. I had to tweak the heck out of the OpenSCAD file for the carriage to get it to fit right. I also learned about silicone spray to get things sliding more smoothly, and the fact that it’s better to leave bearings a little loose if you don’t have precision alignment.

The “motorized” part is pretty simple…actually too simple, and I need to complex it up a bit. It’s a continuous rotation servo with a spool attached and some string wound onto it. It just slowly pulls the camera across the rods. I need to add some controls to allow for setting the speed, and some gearing might also help things move a little better. I’d also like to investigate using a threaded rod as a screw drive, which could also function as a third support.

Ultimately, I want to have a rig that will move the camera slightly, then trigger the camera to snap a photo, then repeat. I’ve got the code for all this, so right now it’s mainly a matter of the mechanical build (needs improvement) and wiring things up without it being too messy. (The guys at the Federal building told me they get concerned when they see wires and batteries.) A nice case might be in order. I might also look for a smaller ball head, as this one is quite large and heavy, which doesn’t help outside on a windy day. There’s a long list of improvements to this, so expect more posts in the future.

See a video of one of the early tests of this thing.

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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.