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From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: sci.electronics.design
Subject: Re: 3D Printers
Date: Sun, 19 Oct 2025 23:59:16 -0700
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On 10/19/2025 10:50 PM, DJ Delorie wrote:
> Don Y <blockedofcourse@foo.invalid> writes:
>> Doesn't work when you want 100K of them.  Waiting to see if a hard-tooled
>> part will work can be costly.
> 
> Prusa prints a lot of the parts that are used to make Prusa printers, on
> Prusa printers, so sometimes it does work even when you need 100k of
> them.  It depends on how quickly you need those 100k, how often you plan
> on iterating the design, and what the capabilities of the final part
> are. how expensive the tooling is, etc.

My goal is to leverage the same tooling for multiple parts.  As stated
elsewhere, the boxes look largely the same -- "nondescript black boxes"
(because they aren't deployed in locations where they would be visible).

An *embossed* label (so it can be read tactilely) is applied to each
that indicates what's inside, serial number, model number, etc.

Printing 100K would require one every ~12 minutes, 24/7/365.  How
reliably do you think printers could do that?  What *cost* for each
item vs. injection molding them?

The value of being able to iterate the design BEFORE prototyping
(i.e., printing models) is to be able to sort out how to adjust
the designs to minimize the number of different "parts".  Easier to
change the layout of a PCB inside an enclosure to ensure a connector
aligns with a cutout in a preexisting case than to have to create
another type of case, another mold, another part number to inventory,
etc.

(Hard) tooling for small parts is about $25K so it adds 25p to the
cost of each part for the first year's production.  You can probably get
500K parts out of a set of tooling before it needs retouching.  So,
the tooling cost after the first year drops to nothing.

> Heck, I once printed an M14 nut for my electric motorcycle conversion
> because I didn't happen to have enough on hand and I needed to mount the
> battery box for testing.  Then I forgot about it for a couple of months,
> during which I got the bike up to a few live tests.  It worked *well
> enough* for its purpose (although I did swap it for a metal one when I
> realized, duh ;)
> 
> But, of course, we each have our own needs...

I am using business "needs" to make my decision; G-jobs just being diversions
that a printer might facilitate because the business needs represent more
*needs* for the technology; I can live without a custom designed, printed
orange picker -- as we've done for the past 20 years.  Making time to
tinker with such things would come at the expense of business not getting done.

But, fabricating and tweeking models for a bunch of similar (but different)
designs with any degree of accuracy and repeatability is hard without a
technology that can do the work for you.  (Let's move this opening 0.030"
to the left; no, don't ENLARGE the existing opening, MOVE it!)