SketchyBot Week 2 Progress Report

This week I continued refining my design, verifying all my measurements, and testing how parts interacted with one another in real life during assembly.

I’m trying to look at my work critically with an eye for how to make the assembly process as simple as possible in future revisions. See what works, and what doesn’t.

I started off the week by switching the spare electronics Sketchbot started with out for some optimized components.

IMG_20180325_122607

New Micro Controller!

IMG_20180325_144206

I’ve switched to some simpler electronics for the project. I’m going to use a Metro Arduino Uno clone because it uses micro USB and has hardly anything I don’t need.

I found this GRBL 1.1 shield on ebay for only $12. It works great and came with three stepper motor drivers (plus heatsinks)!

Printing new parts – 

I finished printing the new Back Cover that I proposed in last week’s blog entry. I may want to backlight this with some RGB LED strip lighting, because I’ve realized how well the striated texture of a 3D printed part can defuse light.

In the future, I believe this could be printed without supports! I was very impressed that such a skinny part didn’t fall off the build plate.

IMG_20180327_001051

I reprinted the front nameplate because I sourced new pancake-style Nema 17 stepper motors didn’t need to intersect with the component anymore! This also means the holes for the stepper motor cables can be hidden from sight, which is awesome.

I also increased the diameter of all the through holes in this part.  I originally was threading holes on the PLA part, but I’m switching over to using heat-press threaded brass inserts.

Testing the nameplate light filter –

IMG_20180325_023301

Testing the nameplate light filter. I decided to split it in half to decrease the amount of supports the letters needed.

For some reason I thought a notch on the left side would be needed, but I was wrong. This left side was reprinted after all these photos were taken.

IMG_20180325_023615

The tolerances of this press-fit were really dailed in! At first I was worried about this, because the light filter CAD model is built through references to the nameplate through converted sketch geometry.

Ordinarily, this wouldn’t have been anything to worry about, but the nameplate utilized splines in the creation of it’s side profile geometry. Splines/bézier curves can be notoriously difficult to work with in certain ways – Solidworks does not handle offsetting splines elegantly!

It was quite a relief to get this part fitted without it breaking halfway into the nameplate. In the future I will want to marry these two pieces together into one dual-extruded object.

Alternatively, instead of dual-extruding a two-tone part, I could slice this part with varying infill density. That way a single extruder could potentially create a built in light filter. All things to try in the future!

IMG_20180325_024127

Here’s the results of the nameplate light filter, photographed in low light. Much better!

All in all, everything has been a huge success! Very few mistakes were made in this stretch of development, which is always nice.This project is moving along quite smoothly 🙂

Leave a Reply

Your email address will not be published.