[#14] Prototype Stereotype | Reprogramming a 3D Printer to perform 2D Embroidery

When: 20 June 2019, 10am
Members present: All

The Main Body Mk I

Our Main Body Mk II printed out overnight all right! It was pretty successful for a (technically) first print. We tried it out and it worked just as planned. The grooves were perfect for the protruding screws. Note that the cuboid cavity on the piece on the extreme right of the above set of images was to give allowance for the protruding screws of the 3D printer part that we would be securing it to. More adjustments would need to be made to get it perfect. But for a first prototype, it is indeed a good start!

Video to show how the two halves of the Main Body Mk I fit together with the Needle-Tubing Connector Mk IV.

Movement of the Needle-Tubing Connector Mk IV in the Main Body Mk I, when applied a linear force using our hands. This mimics the actual movement of the Linear Actuator, which would ideally be attached at a separate location.

Overall, here’re our criticisms for the Main Body Mk I:

The Good

The Bad

Connector is able to slide inside cavity relatively smoothly
The two halves are able to be closed completely; cavities for tubing and needle are sufficient)

Tubing cavity is too narrow; enlarge to smoothen the needle movement
Rectangular cavity for connector needs to be slightly deeper to reduce friction
Attachment points (the ‘mickey mouse ears’!) were out of alignment to the piece that we would secure to
Two attachment points are insufficient to support the Main Body, we should add at least 2 more attachment points
The holes for the screws to secure the two halves together were not the right size
The protruding screws prevented the attachment of the Main Body to the 3D printer; may require a countersink design
PTFE Lube should be added to the inner cavity to reduce friction further
Need to add the screw points for the attachment of the Yarn + Needle Feeder

We began modeling Mk II given these comments.

Countersink Testing

We also tried out printing a countersink mock-up, so we can figure out how to eventually add this into our final Main Body design. The first one did not have clear screw tunnel clearance, but the second one that was printed was a perfect fit for the screw.

Countersink test prototypes!

How the countersink works with the 40mm depth screw.

The Main Body Mk II

Our main consideration was how to get the back of the Main Body aligned with the screws of the piece we planned to attach it to. After A LOT OF TRIAL AND ERROR (including poking holes in a cardboard piece with a pencil, printing the flat design slice out on a piece of A4 paper, and of course, concerned looks from Qi Jie), we finally figured it out and sent the two halves of the Main Body Mk II for printing in the form of our two files BAOZHA and BAOZHA2. We’re leaving them to print overnight.

Fusion 360 previews of the Main Body Mk II piece.

Needle & Yarn Feeder Mk II

It printed out well, but some of our measurements were incorrect.

Here’s the review of the Yarn & Needle Feeder Mk II:

The Good	The Bad
Let us estimate the required screw points for the next prototype Quick adaptor connector piece could fit well	Needle guiding tube is too tall; the needle is unable to reach the end of the tube when we need the needle to be able to stab through Wool yarn feeding tube is too narrow; the threader got stuck at the fork Screw points for attachment are missing

Needle & Yarn Feeder Mk III

Working on the bad points from Mk II, we pretty quickly managed to model a new and improved Needle & Yarn Feeder Mk III. Most notably, it has a shorter needle guide tube that is short enough for the needle to poke out beyond the bottom of the feeder base, and the three holes near the top for attachment to the back of the Main Body.

Needle & Yarn Feeder Mk III

22 June Edit: Here’s the video of the test we did the next day, on 21 June. 🙂

Blog UPGRADE!

We made some new updates to the blog!

Every post has a FEATURED IMAGE which appears in the sidebar
Bold, italic, and linked text are now styled!!!
Finally changed the faded grey colour of the blog title
New page: Prototyping Log
- An overall summary of all the different prototype attempts we’ve made over the project for easy viewing
- Includes remarks and points for improvement from each prototype to the next
New page: Final Process
- A step-by-step ‘manual’ of how we actually built our final product
Updated the Introduction
Added a more useful Landing Page (first page when you enter the blog) for easier navigation
- Includes a calendar for easier navigation