roll your own?

I recall working at a company making high precision 
manufacturing equipment, for semiconductor fabs.  
At one meeting, an engineer announced he wanted to 
design a custom motor, for a particular project.  

I wasn't involved in that, don't know the specs.  But I 
wondered, and still wonder, what would be the requirement 
for a custom design?  From a system perspective, my 
view of 'motor design' is thumbing through vendors' 
manuals.  There are thousands of models available, of 
every form factor and power level.

Why would you need to roll your own? 

--
Rich

On Sunday, June 19, 2022 at 2:06:06 AM UTC+2, RichD wrote:
> I recall working at a company making high precision 
> manufacturing equipment, for semiconductor fabs. 
> At one meeting, an engineer announced he wanted to 
> design a custom motor, for a particular project. 
> 
> I wasn't involved in that, don't know the specs. But I 
> wondered, and still wonder, what would be the requirement 
> for a custom design? From a system perspective, my 
> view of 'motor design' is thumbing through vendors' 
> manuals. There are thousands of models available, of 
> every form factor and power level. 
> 
> Why would you need to roll your own? 

I've contemplated it for a couple of projects. The one that comes to mind was for better electric piano.

Piano keyboards are complicated mechanisms with some 14 to 19 moving parts per key, and keyboard touch is extremely important for concert pianists.

One of the things that mechanism does is to detach the hammer that huts string form the key you press to get it moving before the hammer actually hits the spring,  and the pianist can clearly feel that release as the key goes down. Nobody is conscious of it but the exact moment the hammer hits the string is controlled to within 10msec  at concert level performance. Caroline Palmer wrote her Ph.D. about it

The linear motor that would be narrow enough to fit in the width between the keys, long enough to cover the key travel and powerful enough to generate the forces required wasn't on offer in any of the manuals I looked at. It took me a while to sort out a design that might have worked, and the cost of making 88 of them put me off. One researcher put together a ten key element of a calliope keyboard - where the keys were a bit further apart - based on head positioning motors he'd dug out of obsolete hard disk drives, but it was purely a proof of principle machine.

-- 
Bill Sloman, Sydney

On Sat, 18 Jun 2022 17:05:58 -0700 (PDT), RichD
<r_delaney2001@yahoo.com> wrote:

>I recall working at a company making high precision 
>manufacturing equipment, for semiconductor fabs.  
>At one meeting, an engineer announced he wanted to 
>design a custom motor, for a particular project.  
>
>I wasn't involved in that, don't know the specs.  But I 
>wondered, and still wonder, what would be the requirement 
>for a custom design?  From a system perspective, my 
>view of 'motor design' is thumbing through vendors' 
>manuals.  There are thousands of models available, of 
>every form factor and power level.
>
>Why would you need to roll your own? 

A wafer scanner has high-power lightweight motors that move big things
around with nanometer precision, even in motion. That is a very
special motor.

Some aircraft and spacecraft motors have to run at +- hundreds of
degrees C. Lots of motors, valves, alternators, solenoids, synchros,
torque motors, things like that on airplanes are full custom. It's
even hard to get data sheets.

I've had to get used units by various means and measure them. Some
people even consider the weight to be secret.

ebay sometimes helps, or second-tier suppliers, basically aircraft
junkyards.



-- 

Anybody can count to one.

- Robert Widlar

RichD wrote:
> I recall working at a company making high precision
> manufacturing equipment, for semiconductor fabs.
> At one meeting, an engineer announced he wanted to
> design a custom motor, for a particular project.
> 
> I wasn't involved in that, don't know the specs.  But I
> wondered, and still wonder, what would be the requirement
> for a custom design?  From a system perspective, my
> view of 'motor design' is thumbing through vendors'
> manuals.  There are thousands of models available, of
> every form factor and power level.
> 
> Why would you need to roll your own?
> 
> --
> Rich
> 

1) Can't get one.
1.a) Can only get one through sketchy and unreliable channels.
2) Control of quality parameters is a universally agreed critical
risk item.
3) The motor design team is owed a favor and out of charge numbers.
4) You need to put a motor in yourself:
https://www.youtube.com/watch?v=CuQH6M8s6Cw

--
Les Cargill