opulo-inc/lumenpnp

Strip Feeder Standardization

lucian151 opened this issue · 0 comments

lucian151 commented

Version Number

v3.1.0

Bugfix or Enhancement

Enhancement

Description

Over the past few weeks I've spent some time working on improving the strip feeders used by the LumenPnP with the following goals:

  • Strip feeders should become standardized in form and attachment methods
  • Strip feeders should be able to mount anywhere on a staging plate in both 0ª and 90º orientation
  • Strip feeders for 8mm - 16mm tape should be 45mm wide with as many tape channels that can fit in this width
  • Strip feeders for 24mm tape and beyond should be as skinny as possible with only a single tape channel per print
  • Strip feeder for 32mm tape must support lateral translation for mounting
    • This feeder should be adjustable in how it mounts to avoid wasting space on the staging plate
  • An adjustable strip feeder design should also be created to support 44mm, 56mm, and any additional non-standard widths of tape

Issues

There were a few big challenge with mounting to the staging plate -

  • There are many places on the LumenPnP where a M3 button head screw can get in the way of installing a strip feeder
  • The EIA-481-F standard's max tape depth specifications do not leave much room for fasteners at the base of each strip feeder

Solutions

The solution to EIA compliance while respecting pre-existing M3 button head screws is to use a Small Ultra Low-Profile Hex Socket Cap Screw such as CSHELHF-ST3B-M3-10 from Misumi. This is in consideration of the following constraints:

  • Every mounting hole in a strip feeder must be at least ⌀6mm ID to give clearance for a possible collision with any pre-installed M3 button head screw
  • Given the above, fasteners used for attaching strip feeders must somehow be larger than ⌀6mm OD to function

The CSHELHF-ST3B-M3-10 is great for this application because it allows us to use a ⌀6mm ID hole with a ⌀8mm x 1mm ↧ counterbore. This low-profile bolt will allow us to stay adherent to the EIA standard.

image

Alternatively, a Metric Steel Pan Head Slotted Screws such as 90383A104 from McMaster-Carr would potentially work as well.

pan head slotted screw

After considering the above constraints and findings we are left with the following design for the LumenPnP strip feeders:
strip-feeder-standardization