Printegrating Factors

This week I printed my first test run of a fully integrated, coprocessed system. I combined my light sensor idea from last week’s post and my build plate walker test from two weeks ago to create a full system that could be coprocessed and then walk off the build plate.

Sequence 04
The print job walking off the build plate…almost

There were two primary issues with this print job. The first had to do with the part design itself: because the parts were very minimally contacting the build plate, the entire print job was very precarious, and I had to restart it multiple times because one piece or another fell over mid print.

The front and side views of my CAD model, note the minimal build plate contact.
The front and side views of my CAD model, note the minimal build plate contact.

You’ll notice the wheel shape and overall attachement method for the servo motor is very much the same as my first test of it, which you can see here. The wheel and servo horn were designed to constrain the servo horn while still making it easy to coprocess, and increase the leverage of the motor to pull the part of the build plate.

Once the print did adhere to the build plate adequately, it was time to coprocess my part. I added a Sparkfun Protosnap arduino mini board, a light sensor, two continuous rotation servo motors, and an AAA battery case to the print job and turned it on during my coprocessing step. Prior to the print, I had printed a test piece that was similar to the final model without its the top, and as you can see, the parts fit well, but some of the wiring was a bit tight:

A test piece I printed to make sure the parts fit in well.
A test piece I printed to make sure the parts fit in well.

This was the likely cause of my second issue. After I coprocessed the components, the printer had a difficult time sticking to the tops of my coprocessed parts, especially the servo motors. Because some of the wires were sticking out of the job, the very hot extruder head likely hit and melted some of them, and possibly shorted some of the connections.

The part printing slightly after the coprocessing step. As you can see, there were some adhesion and offset issues.
The part printing slightly after the coprocessing step. As you can see, there were some adhesion and offset issues.

As you can see as the print continued, the adhesion issues were mostly resolved. Note the chimney-like channel printing above the light sensor. Once this channel gets closed off, my arduino code would wait for a given amount of time, and then activate the motors. This code structure was almost identical to the code from my initial test of this part of the system in last week’s post.

After some adhesion and offset issues, the print was able to get mostly back to normal.
After some adhesion and offset issues, the print was able to get mostly back to normal.

With potentially shorted wires, minimal build adhesion, and a live system inside my print, once the light sensor was covered by the printer, something went wrong, and the part immediately pulled itself off of the build plate and messed up the rest of the print.

My print rolling off the build plate...too early.
My print rolling off the build plate a little bit too early.

So I didn’t get exactly the results I wanted. But I did learn a lot about coprocessing an integrated system, and going forward I will be cleaning up the wiring in my prints to make sure they don’t interfere with the extruder head. I will also be testing other sensing methods that may be more reliable than the light sensor. Please let me know if you have any ideas!

If you’re interested in more of the issues I ran into while coprocessing, please check out my video here:

Happy printing!

Alex

Advertisements

2 thoughts on “Printegrating Factors

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s