Re: 2465 Fan Collet Thingy


Chuck Harris
 

Hi Siggi,

One thing to think of, if the collet is drawn vertically
by the printer, it is certain to break, but if you draw
it horizontally with long strokes, and in halves, it might
be strong enough.

Especially if it is ABS.

No matter what, I would expect that the threaded section
will have to be done manually with a tap and a short chunk
of threaded rod.

Most slicers will allow you to draw your own paths, if you
wish to go to the effort. Done once, it can be replicated
by anyone.

It wouldn't even be all that hard to build a custom printer
that had an X, Y and R axis. Like a 3d printer lathe.

-Chuck Harris

Siggi wrote:

On Sun, Nov 10, 2019 at 12:15 AM Chuck Harris <cfharris@...> wrote:

I am not sure that an all plastic printed solution will
work... tektronix didn't think so, and made a much more
expensive metal/plastic hybrid.
A home-printed plastic fused-filament collet almost certainly won't work,
those things will delaminate at the shade of a hint of a threat of any
stress in my experience. I'd be surprised if Shapeways and other commercial
services couldn't produce a usable part using SLS in nylon-like plastics
<https://www.shapeways.com/materials/versatile-plastic>.
I did machine a batch of these collets from delrin/acetal, and those will
work just fine - delrin will hold the thread just dandy. (I've been
shipping these out for postage, but I'm out of stock now - alas).
The reason Tektronix used an insert is IMHO not for strength, but because
you can't injection-mold threads, and a secondary machining step on this
collet would be awkward.
Injection molding around an insert is however no big deal, and you can
potentially use the same insert in many different injection-molded parts.
Machining the part from raw stock would also have been expensive in the
day, but the inserts would have dropped out of a screw machine by the
hundreds/minute.

Siggi



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