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.

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. Continue reading “Step-a-sketch”

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.

CNC Project Roundup

We asked for CNC projects, and wow did you guys deliver!

First up is [J-J Shortcut’s] MDF based CNC. He’s made three thus far, with the most recent costing about 180 euro and taking 2 months to build.

[Qwindelzorf] has also constructed a multitude of CNC machines including this industrial size router and this smaller miller.

Finally, [Mick’s] large steel CNC which just made its first cut only a week ago!

Keep up the great work guys, CNC machines are not easy to build and your accomplishments are ones for the record books.

Industrial CNC Controller Retrofit

[Jerry] had a beefy CNC lathe whose controller wouldn’t respond. He cracked open the case and found a large scorch mark surrounding one of the servo controllers. Rather than just replace the IC and still be stuck with a 23-year-old controller he decided to retrofit the machine with modern controls.

The journey from a brick of steel to an incredible machine is fascinating. Using a combination of commercially available boards like the ModIO controller and custom-built circuits, he cleaned up control signals and give life to the lights on the original faceplate. The machine is now working beautifully with a new monitor, automatic oiling, and wireless connectivity.

Punching Out Parts

If you’re more of a code monkey than artist, it may be tough to transform your ideas into the 3D models necessary for fabbing. The folks working on openSCAD apparently feel our pain.

openSCAD uses a language somewhat reminiscent of C for creating models. A preview of the model is rendered alongside your code. Fully cross-platform, it runs on Linux, OS X, and Windows. Much like SketchUp, openSCAD can also extrude 2D outlines into models. This feature comes in very useful if one already has a set of technical drawings for a part. With no price tag, it’s pretty affordable during this costly season.

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.

Continue reading “Sarrus Linkage 3d Printer”