RepRap acrylic extrusion using hotbed

[Nophead] started the year off by successfully extruding acrylic using a RepRap machine. The problem when working with this material is that when the hot ooze hits the cold air the printed material tends to warp, badly. [Nophead] raised the ambient air temperature around the part being extruded by replacing the bed of the RepRap machine with a heated aluminum plate.

We took at look at his build details for the hotbed. The plate itself is aluminum that he had milled by a machinist friend of his. It looks like the heat is produced by a network of power resistors bolted and soldered to the bottom of the plate. The original idea was to produce a controllable SMT soldering platform. Unfortunately this heating method doesn’t have the power needed to raise the temp quickly but that failure turned out to be a RepRap success.

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Step-a-sketch

[Chris] is getting his feet wet with Computer Numerical Control starting with an Etch-a-Sketch interface. This is a great way to start out because the really tough parts of the project are already inside of the toy. He’s replaced the two white knobs with stepper motors and connected them through a mosfet network to a PIC 16f84a. The PIC then gets its commands from a computer via the parallel port.

A video of the CNC machine can be seen after the break. He needs to add a frame to increase the precision of the images drawn but this first attempt is pretty good. We prefer to have the computer in charge of the design because controlling an Etch-a-Sketch with a mouse doesn’t make our drawings any better. Read the rest of this entry »

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More CNC goodness

[Jerry] retrofitted a Supermax Mill that he purchased from a friend. The main problem consisted of the original controller failing so he used some Pixie boards and a PC to get the system back up and running.

But thats not all. [Jerry] also retrofitted his Monarch lathe (yes, not a CNC, but are you really going to complain) by replacing the original Ward-Leanard motor generator with a 2 kW brushless AC servo.

The Harford HackerSpace group claims their CNC can kick any other CNC’s butt! Currently it lifts up to 65 pounds, but is still accurate enough to make ninja throwing stars. The only problem left is naming their CNC, any suggestions?

[Ciric] has finished up the hardware side of his CNC project. However the software is still being worked on, but because it is his own stepper control board it might take a while. The good news is the controller and software are planned to be released free.

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Sarrus linkage 3d printer

[fdavies] has been working on his own 3d printer. He is using printed parts, but unlike the RepRap he’s purposed Sarrus linkages in his design. If it works, this should remove the need for precision rods in building these types of CNC based machines. He’s also recovered DC motors and optical encoders from some inkjek printers. Given that many retailers require you to take junky inkjets home when you purchase a computer we’re betting you’ll find friends happy to part with their unused hardware. We’re impressed with the motion of the prototype seen after the break. Let’s hope this leads to the next generation of affordable 3d printers.

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CNC circuit board fabrication

[Jonathan Ward's] pcb mill is as impressive as it is inexpensive. Twenty-six plywood parts, labeled A-Z, are used to assemble the machine along with the customary precision rods, stepper motors, and router assembly. His bill of materials prices the unit at $458.18, a small price to pay in order to forgo a multi-step etching process.

His test board shows some fairly fine pitch that could turn out most home-project circuit boards. We’ve contacted [Jonathan] regarding the specifics of milling the plywood parts out of a 2 foot by 4 foot sheet of plywood. Watch for an update with any information he’s willing to share. We hope he’ll make the milling files for the plywood parts available so that you can build a copy of the device for your own use.

[Thanks Charles]

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DIYLILCNC: do-it-yourself CNC mill

The DIY LIL CNC project is the newest member of the homebrew fabrication scene. This is a three-axis CNC mill that can be built by anyone with basic shop skills and about $700 in their pocket. Many of the materials can be acquired from the likes of Home Depot: the basic framework is assembled from Masonite, while other cost-cutting measures include the use of skate bearings and a common Dremel tool for powering the cutting bit. About half of the cost is for the HobbyCNC driver and stepper motor package that runs the show.

The instructions for the DIY LIL CNC are distributed under a Creative Commons license, allowing for modification and distribution with few restrictions. They’re well-written and quite thorough, including all patterns and a complete bill of materials with suppliers, part numbers and costs. As documented, the ’bot can produce parts up to 12 x 14 x 2 inches, but the project’s creators offer some suggestions on adapting the design for larger work. It’s not self-replicating like the RepRap aims for; you’ll need access to a laser cutter for some of the parts. If you can clear that hurdle, this looks like a great introduction to CNC production.

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Machining Gets Wet and Wild

[Tyler] has had his electrochemical machining hack up for a while now. His final version uses a pump to move electrolyte out through the etching head and onto the workpiece. This keeps fresh electrolyte in the etching region and clears out the insoluble material. We see how this could be attached to a CNC system and used to etch PCBs without the use of a special inkjet printer, toner transfer, or laser etching machine.

[thanks Ian]

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Clock knock block full of puns

This Clock Knock Block has a bit of everything; milling, Arduino, sensing, solenoids, and plenty of dirty puns. Just knock on the box or on the table right next to it and the time of day will be played back to you in a series of crisp, clean knocks. A big part of the fun here is that the box is a musical instrument.

If you take a look inside you’ll find an Arduino, a piezo sensor, a solenoid, and a nine-volt battery. The piezo sensor detects your knocking as an input. It can even listen to and repeat back a series of your knocks. The Arduino actuates the solenoid, which strikes the wooden enclosure, producing the knocking sound.

We’ve embedded a video of this useless machine after the break (that’s where all the puns are). One note for your own build; this box is made out of mahogany and because it is used as a resonance chamber, this may not work as well if it isn’t milled from a piece of quality lumber. Read the rest of this entry »

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RepRap milling machine

[Chris] liked Cartesian RepRap idea so much that he decided to design his master’s diploma project around it. Though it uses most of the same parts as the RepRap (even the PCBs), [Chris] has adapted it so it does milling rather than 3D printing. Most of the parts (such as the stepper motors) were harvested from old inkjet printers and typewriters. The thee-axis CNC machine can already etch and carve styrofoam at an impressively high resolution. To deal with all of the debris that comes with milling, a vacuum attachment (shown attached) was created. [Chris] is considering adapting it so it can work with wood and aluminum as well. Best of all, it uses standard G-code files, just like the RepRap. A publication by [Chris] on the project is also available through his website. No plans to release a kit have been announced yet, but we’ll wait and see. If any commenter knows of an open source CNC milling machine available as a kit, feel free to post a link to it below.

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Six legged crawler

This hexapod was sent to us on the tipline from [Jamie]. If you want to take the six-legged robot a bit farther than our earlier posts, here and here, this is the hexapod for you. The structural pieces were modeled, and cut out of 3mm thick plywood using CNC. He used TO-220 transistor nylon isolation mounts for the bearings, and bolts and locknuts at each joints. The main body houses eight servos, six for the legs and two for a camera head pan and tilt. There are another six servos, one for each leg, to lift the feet. The whole thing is controlled by an Atmel AT90S8515 clocked at 8 Mhz. The code was compiled using WinAVR free GCC GNU-C. He uses a PlayStation controller to help debug the walk cycles, and change parameters as needed. Watch a video after the jump.

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