Sunday, September 26, 2010
Dem Bones
In which your narrator creates a way to separate parts from an undifferentiated OBJ file scan of the bones in a human hand.
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Friday, September 17, 2010
Dealing with detaching rafts
In which your narrator seems to have come up with a way to prevent raft peel for ABS on an acrylic print table.
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Thursday, September 16, 2010
Mendel Drawing
The artist Lauren van Niekerk spend a while in the Bath RepRap Lab recently. One of the things she did was this pen-and-ink drawing of Mendel, which she has given to the project. A 400 dpi scan of it is in the repository here.
Feel free to download it, print it on art paper in your A3 printer, frame it, and hang it on your wall...
Labels: art
Saturday, September 11, 2010
RepRap repraps RepRap electronics
Several people are starting to work on having RepRap make electronics. This includes, of course, making its own circuitry. For example, I'm pleased to say that this blog post itself is rather eclipsed by Johnny Russell's beautifully neat Arduino Mega Shield made in a RepRap here.
I have been integrating PCB production into the RepRap software to try to make it as straightforward as possible. I've used the results to make these:
which you can see fully-assembled at the top of this post. They (together with an Arduino Mega) are a full set or RepRap electronics that you can make in the machine itself. It's all described here.
The software is, needless to say, rather experimental. It is described here. When it's been tested a bit more, we'll do another release with it in. In the meantime, it's all in the latest code in the RepRap Subversion Repository.
Monday, September 06, 2010
Wondering what the fuss is about
Thursday, September 02, 2010
A Smarter Approach to Infill
As is often the case, I had my Mendel running a week or two ago, and I was sat mesmerised for far too long watching it work. Fortunately, whilst this was happening I had an idea I thought was worth sharing.
Our Mendel happened to be printing a particularly complex part, I think it was one of the extruder driven gear. I made the casual observation that on the lower fine layers, it does a pretty good job. But once you get into the middle layers, it needs to do quite a lot more in air movements compared to the fine layers, as the extruder cannot get to where it needs to be smoothly because of the low density of the infill. The issue with this is that with present extruder designs, and even with reversing, we still get some ooze that makes a bit of a mess. Annoyingly, the reversing and inair movements start at the outline of parts, and the ooze typically spills over a tiny amount, making the part surface a little blobby. It also makes sense that this problem is particularly true for intricate areas of the part, such as the gear teeth.
Thus, It would be very beneficial to vary the increase the infill density within the intricate regions of parts. Not only would this help with ooze, but intricate areas would automatically strengthened with more material. I also suspect that if this was implemented we could also reduce the infill percentage in simpler areas to speed up build time.
Fortunately, we already a gauge of part complexity, and that is the length of each individual road within the infill(L) and the distance between infill roads(D) could be made proportional to this length.
Labels: infill
