How do you design your custom / "fake tips" for doing toolchanging with a liquid handler?

Tools
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After 100’s to 1000’s of pickups, we’ve been running into issues, where the tool stopped getting picked up due to the tip breaking (see below)

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and with a thicker design, presumably due to wear (see below)

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This tool in particular weighs 67 g and is used in the following workflow

As an aside, I’ve also noticed that Opentrons tips have a few grooves pointing in, that I imagine helps with this issue. Naturally, the material plays a big role here. We’ve been using typical PLA, but could also print using CF-reinforced PLA (we have a BambuLab X1E) or on a Formlabs resin printer. I’ve also considered trying to use a “real” tip and fastening/gluing it to the tool.

cc @Neil-YL who’s done most of the heavy lifting here.

Related: Search results for 'fake tip' - Accelerated Discovery

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I would go with your latest suggestion (which I have seen working in labs, but can’t guarantee the 1000’s pick ups): cut a regular tip and clue it to the part you want moving.

FDM, in my experience, does not give great results when under shear stress. Can this be what’s happening every time the tip goes down (a small conical expansion that moves through the layers of your print)?

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3

I don’t deal with this firsthand, but my thoughts are:

  1. If you can do 1000s of pickups, thats pretty darn good.
  2. If we’re just sticking with fdm pla parts, i would break it into two parts and print the fake tip separately (and have mounting screws between the fake tip and main body). And if it breaks after 1000 pickups, have a maintenance step to replace the fake tip.
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