Doing the RepRap #10

Before you can print from your STL file you need to convert it to gcode. Think of it as Postscript for 3D-printers and 2D routers. The tool of choice for people working with RepRap has been Skeinforge, which has acquired tons of functionality at the expense of usability: It’s ugly as sin and has more features than are properly documented (or documented at all) so I’m happy to see that there are alternative versions cropping up, like SFACT.

Also, putting the printer together I ran into some issues with the otherwise excellent documentation put together by Gary Hodgeson, namely the parts using the LM8UU linear bearings instead of printed bushings. Because I don’t have any spare parts I’m terrified of messing up those I bought from Greg Frost (shipped all the way from Australia) so am anxiously browsing the RepRap wiki and forums in search of instructions. I’ve already managed to put the Y-motor bracket in every position possible, and finally had to email Greg to get a picture of how to do it properly. I’m documenting every step, but so far it’s more of a blooper reel…

I finally found an excellent description of how to fit all the parts together: How to build up a LM8UU Linear Bearing Prusa. It does exactly what it says on the tin, and with the exception that I’m going for a three bearing bottom plate, I ought to be able to finish the build in no time. Now, if I could only settle on which lubricant to use for the rods, I’d be set. “Light machine oil” or “PTFE spray” is the question.


Update from the comments. In the video below I’ve inserted the pins from the wrong side. The black plastic bits should go on the underside of the Polo, so that it’ll sit flush with the mounts. As it stands, the Polos work for me soldered this way as well, but it’s more finicky and there’s a risk that you’ll have too much solder left and won’t be able to push the pins far enough into the mounts.

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Fabbing: Been there, done that, made a copy of the copy.

I’m putting together a project description of a workshop I’d like to run. The people I’ve pitched to are enthusiastic, but putting the course into academic-speak is difficult. It’s about 3D printing and other rapid manufacturing technologies, so I’m trying to get my bearings on the state of the art.

I don’t know how I missed the Rhizome article on the subject, Means of Production: Fabbing and Digital Art, as it’s a good primer on how radpid manufacturing is used in modern art. To sum it up: There isn’t much happening and what is happening is mostly concerned with sculptural works.

(Then again, there are trials with printing living cells, so your kids might soon be able to not only pull the legs off spiders, but design and manufacture better legs as replacement…)

Fabbaloo links to a 2001 presentation by Marshall Burns and James Howison which pretty well sums up what I tried to express in the pirate ebay post, when it comes to how our relationship to the object might change:

As in other cases where revenues are in doubt, designers and manufacturers will have to ask themselves what business they are in. In other words, what is it that people will pay them for, what will be their value proposition? Clearly, it will become harder to get paid for the physical arrangement of atoms in a product because that will be too easy for fabbers to make. Even the creative content (“intellectual property”) of a design fades in monetary value because it is too easily duplicated. Link

But now I do have to stop. I simply must. I must put away the Red Bull cans, and stop clicking and typing. I have to stop, so I can print my bed. I have to print my bed, so that I can lie in it.

→ IconEye, Bruce Sterling: The hypersurface of this decade (Via Fabbaloo)

Cornucopia is a concept design for a personal food factory that brings the versatility of the digital world to the realm of cooking. In essence, it is a three dimensional printer for food, which works by storing, precisely mixing, depositing and cooking layers of ingredients.

→ MIT, Fluid Interfaces Group: Cornucopia, Digital gastronomy (Via Shapeways)

On the moon, a research station is being constructed by robots.On top of a gantry, in place of the usual lifting hoist, an automatic arm extends downwards over the station. At the end of this arm, a nozzle squirts a concrete-like material onto the half-built walls like a mechanical hand icing an implausibly large cake. At the same time, computer-controlled trowels shape and smooth the concrete so that it’s flush with the wall below. The whole assembly moves back and forth to build up internal and external walls in layers. Further robotic arms are positioning services inside the building and lifting lintels onto the walls in order to make the roof. In just 24 hours, the house will be complete.

→ Craft, Lee Hasler: A giant leap for a brickie (pdf)

For some reason I start thinking about the space gel ant colony, where the hapless ants are allowed to burrow in 3D space, and out of a solid material create space. When diving last summer the thought struck me that we lack a model of envisioning architecture as a three dimensional space — not strange since we can’t fly, nor swim through the air — except maybe for the astronauts in space, for whom “up” is an arbitrary concept. (Or the IDF soldiers in Gaza, as BLDGBLOG pointed out recently)

Lets assume that 1) we’re extracting space out of matter, not building spaces, but extruding them out of something; destroying material. 2) And into this shapely void which we have made, we introduce objects that we desire – and we don’t build them, or assemble them, but rather extrude them. Need a table? Extrude it. Need somewhere to place the table? Extrude it.

Human will as a metaphor of a factory; Of a digging, burrowing animal, constantly crawling through strata, leaving tunnels behind, filled with the debris of time, want and need, manifested in ABS plastic.

Morning noise.

In order to keep the neighbourhood pretty and motivate the costly housing, we’ve had peeping toms on both sides the yard the past weeks. They’re painting and hammering and doing stuff that Real Men® do.


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You are a screw; A spirally inclined plane.

The Manual tells us that in the beginning the Builder decreed six fundamental Machines. These are his six aspects, and all we do we must do with the Six. We need no other machines. I believe this with all my heart. I do. And yet sometimes I seem to intuit the existence of a seventh Machine, hovering like a blasphemous ghost just beyond apprehension. There is something wrong with me, and I don’t know what it is.

→ William Shunn: Inclination.

Although we refer to the six simple machines there is really only three – the lever, the wheel & axle, and the inclined plane. The wedge, the pulley, and the screw are modifications of the first three.

→ Balmoral Science Department: Simple Machines.

A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force. A simple machine uses a single applied force to do work against a single load force

→ Wikipedia: Simple machine.