PCB Prototype Drill Bits

I could have gotten SO MUCH done this weekend if they'd arrived last Tuesday like they said they were going to. Pretty tiny! 0.2-0.6mm with 1/8" shanks. I'm mostly going to be using the 0.6mm and 0.3mm, but I'm worried about breaking the 0.3mm bit. These will get chucked up in my dremel since they're 1/8" shank. Also, MADE IN JAPAN!!!! Cool!

0.2mm

0.6mm

Minarelli Fan Mold Making + Preliminary Casting

Here's the top mold... Stay tuned for the bottom mold and preliminary cast. Released the model GREAT. Super stoked.

Printed mold enclosure + integrated mold registration keys. These were printed in two parts in ABS plastic.

This is the negative that will be cast. The division line is on the top flat surface of the fan. Interesting thing about 3D printing, is instead of having to embed the part in clay, you can just print each negative, resulting in a much easier process, and less clean up.

The ring of clay on the bottom will seal the fan negative to the glass.

Mold of top of fan.

Casting the bottom half of the mold.

First fan cast. Takes 10 minutes instead of 3.5 hours + assembly. Mild flashing to clean up and heat treat afterwards, but definitely an improvement!!!

Puch/Sachs/Batavus Encapsulated Hall Sensor for Under Flywheel + Home Etched Boards

This is a rough mockup of what I'm thinking I'll do for a hall mounting solution for a CEV stator/flywheel. The design utilizes the mounting point for the mechanical points which are no longer needed.


The working part will be cast out of urethane with an encapsulated hall sensor within several millimeters of the magnets in the flywheel.

Top view of encapsulation showing footprint of 3D printed dummy/mold negative.

Sensor lead will protrude through the nub and out the stator through an existing hole. (3D printed dummy/mold negative)

Casting is perfectly sized to lock an M3 nut through old points threaded hole. Uses pivot point of the points to fix orientation.

Hall sensor -> 3.5mm audio 3 pole used for the trinket ignition from this post: http://deadped.blogspot.com/2014/03/trinket-arduino-dynamic-timing-video.html

Casting was a success!

The main thing I've been working on though is perfecting a process to etch my own double sided boards at home. I've had pretty good results and been able to use .12" traces, get them to effectively transfer and be continuous once etched. Right now I'm waiting on PCB drills so I can connect traces when they change sides. The bits I had didn't last very long, so I've got a set of carbide PCB bits on the way. Home etching for 32TQFP packages is doable! Biggest thing I had to do was increase the pad sizes for through hole transfers. Because of that, I'm likely going to have to eliminate the ISP header traces from the production boards.