Printerposition

The files for this print are available here.

I’ve recently been experiment with breaking the build adhesion by co-processing motors into my print. Last week’s experiment was a test to see what kinds of things I needed to think about, and this week I’ve delved a bit further into the process. Instead of just getting the print to break the build adhesion, I was able to get the print to successfully drive off the build plate. By integrating the servo motors into the part as I did last week, and using cam-like wheels for my drive system, I plugged my two servos (which can be found here) into an Arduino to drive them off the build plate at the end of the print, like so:

I incorporated two servo motors into the print to get it to drive off the build plate.
I incorporated two servo motors into the print to get it to drive off the build plate.

Although this looks for the most part simple if you’ve kept up to date on my blog, I ran into a few problems along the way. Here’s what happened to my print in its first iteration:

In this print, the printer head was offset when it rubbed up against the servo motor.
In this print, the printer head was offset when it rubbed up against the servo motor.

As you can see, the printer got offset by about a quarter inch after the co-processing, because it dragged along the top of the servo motor, offsetting the printer’s stepper motors. Basically, what this means is that the space I left for my servo motor was too small. However, after a few changes to my CAD file I got it to work.

One of the things you’ll notice is the funky shape of the wheels, and the part in general. The part was designed, like last week, to have very minimal contact with the build plate. Each of the wheels is tangent to the build plate, which is where it prints from. The wheels are cam shaped so that they can act as a lever arm, like in last week’s print. This allows them to pry the middle section of the print off the build plate, and also generates a funky walking motion.

A shot of the cam-shaped wheels on the coprocessed build plate walker.
A shot of the cam-shaped wheels on the coprocessed build plate walker.

You’ll notice in the video that I put some blue tape on top of the servo motors; as you may or may not know, painters tape is a great surface for PLA to adhere to, and most people, myself included, lay a strip of tape down on their print bed to improve adhesion. Turns out that this also works well for co-processing! I laid a strip of blue tape down over the two servos and it printed over them really well.

Placing tape on coprocessed components allows the printing to start over your coprocessed parts better.
Placing tape on coprocessed components allows the printing to start over your coprocessed parts better.

After the servo motors were placed in, and the print finished, all I did was plug the arduino into my computer to run the motors. So nothing fancy there. But you could imagine in future iterations having a sensor determine when the printer is finished printing, so that it could walk off the build plate all by itself!

Check out the video about this here:

Happy printing!

-Alex

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