On 6/24/2021 3:42 AM, Clive Arthur wrote:
> On 23/06/2021 22:44, Don Y wrote:
>> Anyone done this? I think it might be less hassle than having
>> small quantities (~60 prototypes -- too few to justify a casting)
> This was done for a project I did the electronics for over 15 years ago. We
> had a machine shop, but it was deemed cheaper to get these made externally by
> laser sintering.
Hmmm... interesting. Most places that I've worked (or with which I've worked)
that have had any sort of "additional facilities" (shake-n-bake, wave,
pick-n-place, PCB fab, machine shop, etc.) have pushed to use THOSE facilities,
wherever possible. Odd that your firm would have taken the opposite approach
(presumably, you had the skillsets in-house as well as the kit?).
But, I wasn't always aware of burdened rates for these sorts of facilities
so couldn't attest to their ACTUAL "economy".
> They were small helical impellers for a multi position flowmeter and were about
> 2" long, 0.5" diameter in Titanium. Very good quality but I don't remember who
> or where. I guess it's more common nowadays.
So, they were machinable parts (else doing it yourself wouldn't have been an
option). Did anything "special" have to be done to accomodate the outsourcing?
Did you just turn over CAD files and a purchase order?
> I think the product ended up using plastic impellers. Still not cheap as these
> are machined from something high temperature, stable and resistant to chemical
> attack. Don't know what.
Yeah, I got a tour of a ball bearing factory when I was a kid. At one point,
a display of products they'd made "locally" -- of course, the exotic stuff
is all anyone really has an interest in). I asked the CEO about a *glass*
bearing -- which seemed odd (until you realize most bearings don't carry any
He sent an underling off to find the engineer who'd designed the bearing
to explain it's purpose and design criteria to me. IIRC, it was used *in*
a corrosive stream for the shaft of a large pump (the balls were an inch in
diameter with an outer of ~6 inches)
Amusing to see what you can do when you feel like spending money!
(also saw some stainless steel bearings with ~36" inners -- in a pile
marked "scrap"... THAT had to be painful!)