Alternate Poorest Man Feeder design for 8 mm tape

This redesign of the Poorest Man Feeder:

• includes an integrated spool holder (and a version without a spool holder)
• sits lower on the 2020 extrusion than the original, giving nozzles more clearance
• provides a slot along the side for the cover tape to be inserted directly into the peel mechanism (without having to be fed)
• exposes the jumper on the feeder PCB, allowing the peel motor for each feeder to be enabled/disabled without disassembly
• uses only parts included with the original Poorest Man Feeder

Each feeder is 18 mm wide, and can be used with 8 mm tape of either 2 mm or 4 mm pitch. The non-printed parts and original design can be found at https://www.microsmt.com.cn/products/poorest-man-feeder-parts-for-openpnp ("PM8*2mm").

A case for the 0816 controller is available at https://www.printables.com/model/634012-case-for-0816-feeder-controller .

Printing

Supports are needed for the 3D-printed parts, but I recommend blocking supports along the tape path, and for all the screw holes. Recommended settings (including painted support blockers) are included in the .3mf file.

Assembly

• The “peel_guide” part needs to be glued onto the metal part close to where the cover tape is peeled—it makes the peeling much more reliable. Superglue works fine, and allows the glued part to be removed with acetone.
• I recommend installing the peel motor with the gearbox in the pictured orientation. I found that in the other orientation, the force from the rest of the peel mechanism causes the gears in the gearbox to start skipping after a while. But I've had no problems with this in the orientation shown.
• The motor and microswitch wires are roughly 10 cm long.

Firmware

I tweaked the original 0816 firmware to change the default angles, and to allow retractions even after advancing by only 2 mm (out of 4 mm). This allows M601 N* to be used directly after M600 N* F2. The new defaults correspond to M620 N* A120 B100 C75 F2. These values need to be tuned slightly for each individual feeder.

The modified firmware is available at https://github.com/dna-topoisomerase/0816feeder . See https://docs.mgrl.de/maschine:pickandplace:feeder:0816feeder:mcodes for more detail about controller commands.