Comparing the Quality of 3D Printed Gears

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I’m building a RepRap Prusa Mendel 3D printer for producing enclosures for these projects.  I got the printed parts from Hawkins Electronics, and am waiting for the final batch of vitamins to come in before I can complete assembly.

A while back, I posted an Instructable about panelizing PCBs at Seeed for a contest Instructables was having.  I didn’t win, but my Instructable was featured, and so as a prize I received a free 3D printed part of my choice, evidently made from Autodesk 123D.  Since the quality of the 3D printed gears seem to make the most difference in RepRap performance, I ordered an instance of the large extruder gear from the “Greg’s Wade reloaded” extruder I was using.   It arrived the other day, and I promised the guys at Hawkins I’d post a comparison.  Let me say up front that while the Hawkins gear fares rather poorly in the comparison, it was produced on settings that were a compromise for between speed, material use, and quality, and was not intended to compete.

Here we have the Hawkins gear on the left, and the Autodesk one on the right.  They are both made of PLA (as far as I can tell).  The main difference is in the infill – the Autodesk gear seems to have 100% infill, while the Hawkins gear has something less.  The Autodesk gear is therefore more solid, and its teeth are well formed.

Here you can see a closeup of the Hawkins gear.  Note the evident partial infill, which extends even to the teeth of the gear.  It is not visible from this side, but there is a small area with two or three teeth that are a bit deformed.  I attribute this mainly to the reduced infill.  It is not enough to affect its operation as far as I can tell, but it may cause an increased chance of binding as the parts deteriorate over time.  Note also the snazzy yellow color, which I prefer.

Here you can see in more detail the Autodesk gear.  In addition to the complete infill, it appears to be of slightly higher resolution.  The gear teeth are noticeably smoother and more uniform than the Hawkins gear.  It also has a bit more heft, due no doubt again to the infill.

I hope to post more on the RepRap as the machine comes together.  What could be more fitting for a robotics company than a robot that makes other robots?

New Store

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We have set up a new store, which should make processing orders and maybe easier.  The first two users to go through the process and provide useful feedback about how well it works will get one free PCB (i.e., a refund of $5, once everything is processed successfully).

SARduino644 v1.0 Prototypes

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We finally received the SARduino644 v1.0 boards.  There’s more info on the SARduino644  v1.0 page.  In short, we fixed most of the errata from v0.1, added the auto-reset circuit to the FTDI header, a bunch of power and ground rails to the prototyping area, and we separated the prototyping area from the MCU pins, so that there would be more flexibility.

In the tests, everything worked great.  The auto-reset works like a charm, already worlds better than pressing the reset button and hoping for the best.  We have extra PCBs from the prototyping run, so if you’re interested, drop us a line, and we’d be happy to send you one (or more!) anywhere in the world for $5.

SARduino 0.1 Prototypes

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SARduino test boards, with Bus Pirate to program the bootloaders

The SARduino boards (v0.1) arrived, so we put together the test boards, programmed the bootloaders (standard Arduino and Sanguino, respectively), and soldered up the indicator LED (pin D13 on Arduino, pin D0 on Sanguino), to test out the bootloader and enough variations on the “Blink” sketch to satisfy us that they worked properly.

We built the SARduino to be a development board (for the ATmega8, ATmega168, and ATmega328 that folks are accustomed to using in Arduino-based projects, and the ATmega644 and the ATmega1284 for things that require a little more oomph) that we are willing to commit to an embedded project, unlike, say, our BoArduino or Arduino proper.  It is meant to be cheap and flexible enough that we can implement a moderately complex target circuit right on the board (or, if necessary, on a perfboard shield).  We’ve included some SMD breakout areas (SOIC-16, SOT-23-6, SC-70-6), to help make using those things more convenient.

The prototype has really shown us all the things we’d like to improve, and they’re listed in the Errata of the 328 and 644 versions.  We’ll continue working on it, and expect to release an improved version in the near future.  In the meantime, we have a few spare prototype PCBs, drop us a line if you’re interested in one, we’ll mail it to you (anywhere in the world) for $5.

Introducing Space Age Robotics

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Our first boards came in (more on that later), so now we have a compelling reason to set up a site about them, and for future projects.  So, here it is, Space Age Robotics, because that’s the best name we could come up with.