Zero tolerance engineering

If you want to say something that doesent fit anywhere else!
MAIN WEBSITE: http://www.wheelchairdriver.com

Zero tolerance engineering

Postby Irving » 14 Aug 2019, 20:31

As an engineer there's something very satisfying watching these exquisite parts being assembled...

https://youtu.be/9NbuvIHiOOk
Puma 40, 75Ah LiFePO4
Spectra Plus
User avatar
Irving
 
Posts: 1286
Joined: 04 Dec 2012, 11:51
Location: NW London

Re: Zero tolerance engineering

Postby stevelawiw » 14 Aug 2019, 22:12

I've never seen anything like that before, I didn't think it would be possible for two pieces to be so accurately machined that when put together you couldn't se a join
stevelawiw
 
Posts: 290
Joined: 21 Jul 2012, 20:55
Location: Isle of Wight, UK

Re: Zero tolerance engineering

Postby Burgerman » 14 Aug 2019, 22:30

You can do that with a hacksaw, file and an old hammer. If like me you cant see properly any more.

How is it possible. How is flex of materials, tool wear, backlash, etc all removed?
User avatar
Burgerman
Site Admin
 
Posts: 45991
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: Zero tolerance engineering

Postby Irving » 14 Aug 2019, 22:39

Burgerman wrote:You can do that with a hacksaw, file and an old hammer. If like me you cant see properly any more.
:lol: :D

How is it possible. How is flex of materials, tool wear, backlash, etc all removed?

I think the last few microns might be done with EDM (spark erosion) as there other videos mentioning that technique. However it's done, it's impressive.
Puma 40, 75Ah LiFePO4
Spectra Plus
User avatar
Irving
 
Posts: 1286
Joined: 04 Dec 2012, 11:51
Location: NW London

Re: Zero tolerance engineering

Postby stevelawiw » 14 Aug 2019, 22:41

I've worked it out 8-) It's all done with CGI :lol:
stevelawiw
 
Posts: 290
Joined: 21 Jul 2012, 20:55
Location: Isle of Wight, UK

Re: Zero tolerance engineering

Postby Burgerman » 15 Aug 2019, 00:29

But you may be right. However its done ZERO tolerance from intended figures are actually impossible. Ignoring all the other issues, even the material temp change when machining cant be that accurately controlled.
User avatar
Burgerman
Site Admin
 
Posts: 45991
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: Zero tolerance engineering

Postby Irving » 15 Aug 2019, 03:40

Burgerman wrote:But you may be right. However its done ZERO tolerance from intended figures are actually impossible. Ignoring all the other issues, even the material temp change when machining cant be that accurately controlled.

Agree, I think thats a marketing thing. If you look at the numbers printed on the pieces the actual tolerance is around 10 - 50um
Puma 40, 75Ah LiFePO4
Spectra Plus
User avatar
Irving
 
Posts: 1286
Joined: 04 Dec 2012, 11:51
Location: NW London

Re: Zero tolerance engineering

Postby LROBBINS » 15 Aug 2019, 08:04

If I didn't screw up the decimal place, 50um is about 2 mils (for those who think in U.S./Imperial measure), and I'll bet Will can keep to that even with conventional equipment. 5 mils is a lot easier. 10um though is another matter and I'll bet they don't have a few pieces that get rejected if force to meet that tolerance.
LROBBINS
 
Posts: 4466
Joined: 27 Aug 2010, 09:36
Location: Siena, Italy

Re: Zero tolerance engineering

Postby Irving » 15 Aug 2019, 08:37

LROBBINS wrote:If I didn't screw up the decimal place, 50um is about 2 mils (for those who think in U.S./Imperial measure), and I'll bet Will can keep to that even with conventional equipment. 5 mils is a lot easier. 10um though is another matter and I'll bet they don't have a few pieces that get rejected if force to meet that tolerance.


All of which may be true, but IMHO, what fascinates is the artistry/fluidity of those test pieces and the invisibility of the joints. The joints are so close and the surface finish so smooth as to be gas tight with no sealing.
Puma 40, 75Ah LiFePO4
Spectra Plus
User avatar
Irving
 
Posts: 1286
Joined: 04 Dec 2012, 11:51
Location: NW London

Re: Zero tolerance engineering

Postby Burgerman » 15 Aug 2019, 08:40

0.01 mm = 10um? I can do that with great care on a single thing by hand on a knackered myford lathe for bearing mounting bore or modelplane engine parts. Its about as accurate as I can get with a decent digital vernier. But I throw away the first 2...
User avatar
Burgerman
Site Admin
 
Posts: 45991
Joined: 27 May 2008, 21:24
Location: United Kingdom

Re: Zero tolerance engineering

Postby Irving » 15 Aug 2019, 09:00

:?
Burgerman wrote:0.01 mm = 10um? I can do that with great care on a single thing by hand on a knackered myford lathe for bearing mounting bore or modelplane engine parts. Its about as accurate as I can get with a decent digital vernier. But I throw away the first 2...

It's been a while since I needed to work to those tolerances - as a rule I try to design them out - and, as you point out, repeatability is key.

On another note I learnt today our newly refurbished mech-eng workshop up at the lab has taken delivery of one of these
PSX_20190815_085748.jpg


Can't wait to get back in the chair and have a play :D
Puma 40, 75Ah LiFePO4
Spectra Plus
User avatar
Irving
 
Posts: 1286
Joined: 04 Dec 2012, 11:51
Location: NW London

Re: Zero tolerance engineering

Postby Burgerman » 15 Aug 2019, 09:31

It's been a while since I needed to work to those tolerances - as a rule I try to design them out - and, as you point out, repeatability is key.


Me too. But before everything went electric I used to make model plane engine bits. So much care needed. And many bits discarded.

I suggest that those parts in the vid are actually pretty accurate. But external faces were likely finishes after the parts were put together so as to hide the join. Air tight ish, as in a small piston or liner in a plane engine, is actually quite easy with a lot of patience. And a drop of oil.
User avatar
Burgerman
Site Admin
 
Posts: 45991
Joined: 27 May 2008, 21:24
Location: United Kingdom


Return to Anything

Who is online

Users browsing this forum: No registered users and 44 guests

 

  eXTReMe Tracker