MRRF: ARM-Based CNC Controllers

March 17, 2014 by 23 Comments

 

8-bit microcontrollers are the standard for RepRap electronics, but eventually something better must come along. There has been a great deal of progress with ARM-based solutions, and of course a few of these made a showing at the Midwest RepRap Festival.

First up is [Mark Cooper], creator of Smoothieboard, the ultimate RepRap and CNC controller. It’s an ARM Cortex-M3 microcontroller with Ethernet, SD card, and up to five stepper drivers. It had a Kickstarter late last year and has just finished shipping all the rewards to the backers. In our video interview, [Mark] goes over the functions of Smoothieboard and tells us about some upcoming projects: the upcoming Smoothiepanel will feature a graphic LCD, SD card, rotary encoder and buttons, all controlled over USB by the Smoothieboard.

Next up is [Charles] with a whole bunch of CNC capes for the Beaglebone. By far the most impressive board was a huge I/O expander, motor driver, and everything controller for a Beaglebone featuring – get this – three parallel port interfaces. This was a one-off board costing thousands of dollars, but [Charles] did show off a few smaller and more practical boards for Beaglebone CNC control. Here’s a link to [Charles]’ capes.

Videos below.

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MRRF: 3D Printed Resin Molds

March 16, 2014 by 26 Comments

 

Visiting the Midwest RepRap Festival, you will, of course, find a ton of 3D printed baubles and trinkets. A slightly more interesting find at this year’s MRRF was a lot of resin cast parts from [Mark VanDiepenbos]. He’s the guy behind the RotoMAAK, a spinny, ‘this was in the movie Contact‘-like device designed for spin casting with resins. At the festival, he’s showing off his latest project, 3D printed resin molds.

With the right mold, anyone with 2-part resins can replicate dozens of identical parts in an hour. The only problem is you need a mold to cast the parts. You could print a plastic part and make a silicone mold to cast your part. The much more clever solution would be to print the mold directly and fill it with resin.

[Mark] printed the two-part rabbit mold seen above out of ABS, filled it with urethane resin, and chucked it into his RotoMAAK spin casting machine. Six minutes later the part popped right out, and the mold was ready to make another rabbit.

Video below.

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A 3-Axis Paper Cutting Mini Laser

March 16, 2014 by 29 Comments

LaserCutter

Laser are awesome, and so are projects that use lasers. A recent Instructable by [kokpat] gives an overview of how to create a fully functional laser paper cutter using CDROM stepper motors and an Arduino.

What is special about this build, is that it showcases how easy it can be to build a 3-axis mechanical system used for laser cutters, CNC machines, and 3D printers. Using a stepper stage that consist of a motor screw with a nut slider based carriage, the mechanical system can be put together quite easily and cost effectively. Luckily, from an electronics and software perspective, everything is quite standardized with the proliferation of the RepRap and similar machines. Simply pick any three stepper drivers, find the most pertinent firmware, and voilà! You’re done! Well, almost. Don’t forget a 100mW violet laser!

We have seen a ton of really cool laser cutters before, but this has to be one of the cheapest. See the laser cutter in action after the break.

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MRRF: CoreXZ

March 15, 2014 by 13 Comments

It is mid-day Saturday and the Midwest RepRap Festival is in full swing. Saying that there is a lot of 3D printers here is an extreme understatement. There must be at least 100. Out of all these, there are a couple that stand out from the rest due to their non-standard geometry. These are both creations of [Nicholas Seward], called the Wally and Simpson.

Both of these printers were designed to not use linear rails or bearings and be as reprap-able as possible. For example, the Simpson’s only non-printed custom parts are the two wooden base plates and the print bed. The rest of the parts are general hardware and standard 3D printer electronics.

Simpson3

[Nicholas] is showing off something new this weekend (less than 2 weeks new, actually). It is a new printer, currently code named CoreXZ. Unlike his previous designs, the CoreXZ does use linear rails and bearings. The frame is laser cut and is held together with zip ties. This new design uses an h-bot style setup for movements in the X and Z axes. The Y axis is a standard moving bed design with linear rails and bearings.

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Solving Endstop Woes With A Simple Analog Filter

March 7, 2014 by 19 Comments

NoiseEndstop

You know what’s cool? Using your engineering knowledge to solve problems that you have while building something. This is exactly what [Reinis] did when his 3D printer’s endstop wasn’t working.

Many of us automatically go to a microcontroller when we run into a problem with a sensor, but often a simple analog filter will do the trick. The endstop in [Reinis’s] RepRap style 3D printer was giving off an unusual amount of noise when closed. When he hooked the endstop up to his oscilloscope, he was shocked to see how much noise there really was. In comes the low-pass filter. Unhappy with the response time of his low-pass filter, [Reinis] solved the problem using a pullup resistor. Two resistors and a capacitor was all that he needed to fix the problem. A great solution!

How have you used analog filters in your projects? Send us a tip and let us know!

The Stepper Driver Driver

March 2, 2014 by 16 Comments

KONICA MINOLTA DIGITAL CAMERA

The Stepstick and Pololu motor drivers are the heart of just about every Reprap electronics board, but they can go bad. The usual way of testing these things is to rig up a microcontroller on a breadboard, grab some cables, and wire something up. [Ken]’s Easy Stepper Motor Controller is a much simpler solution to the problem of testing these drivers and could, with a bit of practice, be constructed on a single-sided homebrew PCB.

The Easy Stepper Motor Controller is a very simple board with connections to a motor, a power supply, and headers for a single Pololu or Stepstick motor driver. Two buttons and a pot control the rotation of the motor with the help of an ATtiny10, and jumpers for up to 16x microstepping are right there on the board.

There’s a video after the break showing what this stepper motor driver driver can do. It’s not much, but if you’re just testing a driver, it’s all you need.
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OpenKnit, The Open Source Knitting Machine

February 20, 2014 by 57 Comments

For all the hubbub about 3D printers leading a way into a new era of manufacturing, a third industrial revolution, and the beginnings of Star Trek replicators, we really haven’t seen many open source advances in the production of textiles and clothing. You know, the stuff that started the industrial revolution. [Gerard Rubio] is bucking that trend with OpenKnit, an open-source knitting machine that’s able to knit anything from a hat to a sweater using open source hardware and software.

We’ve seen a few builds involving knitting machines, but with few exceptions they’re modifications of extremely vintage Brother machines hacked for automation. OpenKnit is built from the ground up from aluminum extrusion, 3D printed parts, a single servo and stepper motor, and a ton of knitting needles.

The software is based on Knitic, an Arduino-based brain for the old Brother machines. This, combined with an automatic shuttle, allows OpenKnit to knit the sweater seen in the pic above in about an hour.

Since OpenKnit is inspired by the RepRap project, all the files, software, and assembly instructions will be up on Github shortly. there’s also a video available below, and a Flickr gallery right here.

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