CNC Build Ditches Rods For Hardboard

This is a redesigned x-axis for [Peter Jansen’s] selective laser sintering rig. We looked in on his SLS project last month and since then he’s been refining the design. The new component uses a rack and pinion system, relying on some Kapton tape to reduce friction for a nice smooth slide. One stepper motor powers the laser-cut gear box with four gears interfacing the sled to the frame for stable and accurate motion. Now he’s just got to work out the math/physics that go into finding the optimal gear ratios as this prototype is just a rough guess. If you’ve got the skills to work it out please lend [Peter] a hand as we’re quite excited with where this is going.

3D Printing With Chemicals

From the horse’s mouth,

“In this lithography experiment light creates free radicals from phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide which induce polymerization of 1,6-hexanediol diacrylate.”

Or for those without a Chemical Engineering degree, light from a (high resolution) projector interacts with a special liquid, producing a hard polymer on the surface. A platform within the liquid is lowered, taking the layer of polymer with it. Shine the projector again to produce another layer: lather, rinse, repeat. Long story short, an atypical 3D printer using light on a very small scale.

You get the chemicals and lab equipment, we’ll get the laptop and projector, and for goodness sake [Jimmie] stop bumping the table.

[Thanks Tomas]

Selective Laser Sintering Rig On The Cheap

[Peter’s] been hard at work designing an affordable Selective Laser Sintering (SLS) 3D printing platform. We first saw his work on this back in April when he was working mostly with acrylic. Now he’s moved on to a design that relies on hardboard which has resulted in a build that comes it at around $20 including the motors.

The design uses a dual z-axis table for the feed stage and the build stage. That is to say, as the powder is fused together by the laser the platform it is on is lowered. Next to this platform, the feed platform is raised, allowing the power to be swept onto the build stage. This setup is moving in the right direction, but we’re still waiting to see what works when it comes to adding the laser and sourcing the powder.

Machining A Horizontal Stirling Engine

Satisfy your need to view some quality machining by looking through this Stirling engine worklog. We’ve seen these engines used a few other times in creating electricity from solar energy, powering a car, and even built from aluminum cans. [David Morrow] built this rendition to push the limits of his machining skills. We’d say he succeeded. The finished piece should run with the help of a heat source such as a candle. There’s no video of this engine, but we’ve embedded a clip of a similar device after the break in order to give you an idea of how this would work.

Continue reading “Machining A Horizontal Stirling Engine”

3D Printed MakerBot

[Webca] has made a 3D printed MakerBot with his MakerBot. Using five pounds of plastic, the design replaces all of the plywood used to create a regular MakerBot. This complements the existing designs for the 3D printed extruders, dinos, and other parts already on Thingiverse. An interesting mile marker in the history of 3D printing. We might make one after we make a Mendel and tons of Hack a Day Badges. We also look forward to improvements people will contribute to the design such as using less plastic or a parameterized design to make a really big (or small) MakerBot.

PartKAM Produces CAM Related Files Online

PartKAM is a Flash-based CAM production package created by [Jack Qiao]. There are a ton of computer aided manufacturing suites out there, this one is simple and requires nothing more than having your browser open. We played with it for a few moments and found it useful but still a bit buggy. Most notably, it lacks a ‘undo’ option. That being said, you can export as SVG or gCode for use when you just need to hammer out a few parts with that CNC mill you threw together.