Appreciation of Engineering Tolerances

[Cav]

This is an Engineer's wet dream... [video]https://youtu.be/ULEJatGhcks[/video]

[Kwacky]

That's amazing. I presume it's all cut by computer?

[Cav]

Yeah but that will only get you to within about 30 microns, a great deal of time was taken to do these and you're talking less than 1000th of a micron to achieve this

[Kwacky]

so how do they get it so precise then?

[Cav]

A large part will be high precision toolsetting (setting the tool length and diameter of a ball-nose cutter) and a lot of in-cycle gauging.

In-cycle gauging is used to prevent the removal of the part from the machine as you will never return it to the exact same position. It isn't typically used this way, but it can be used to measure the part after each cut, accurate to within 2 microns typically. A scanning probe was probably used to record form in a layer-by-layer strategy and then somehow used to adapt the program parameters OR the tool offsets.

I'm guessing it's a combination of these and probably more - it's not something I can do that's for sure !!

[Cav]

Something else they can do is calibrate the machine bed and all it's axis (pretty sure this would be with a 5-axis machine). This would require high end software and strain gauge equipment used in conjunction with a high precision datum ball.

Essentially, they would calibrate it for the working volume of the parts in question and ignore any errors outside of this envelope.

[Deegee]

That is some very special engineering ability being demonstrated there, they can't leave those parts together for long, the clearances are so low that they can fuse together overnight, becoming one solid piece of metal, I've only ever seen that level of accuracy in Slip Gauges before, which are expensive to buy and generally only found in tool rooms and standards rooms in engineering companies.

P.S. Thanks for posting Cav, I love that!

[Cav]

Exactly, DeeGee. Kept together they would fuse, however, kept apart and they will degrade. To keep any life in these parts they will have to be carefully stored and handled infrequently to avoid any oxide or nitride layers forming and changing the profile and/or dimensions.

Extremely satisfying to watch!

[D41]

Seemless. I had no idea that tolerances that fine were possible.

[kiwikrasher]

I used to overhaul Skyhawk hydraulic pumps which had a metal to metal dynamic seal between the valve plate and piston barrel that handled up to 4500 psi (test pressure, operating pressure was 3000 psi) I had to lap them to 3 helium light bands which is about 0.9 microns. I thought that was high tolerance but that vid is next level!!

[Cav]

What do you estimate those tolerances as, Kiwi?

My gut it saying about 0.1 of a micron (100 nano meters for everyone else)

I also don't know how they would lap the curved surfaces but it looks way too good to possibly have been machined.

SO MANY QUESTIONS!!

[kiwikrasher]

What do you estimate those tolerances as, Kiwi?

My gut it saying about 0.1 of a micron (100 nano meters for everyone else)

I also don't know how they would lap the curved surfaces but it looks way too good to possibly have been machined.

SO MANY QUESTIONS!!

I wouldn’t have a clue to be honest. I even did some googling to find an answer and had not luck

[Monty]

Loved that Cav, it's almost down to atoms!

[Rossgo]

I want one. That is extremely satisfying

Sent from my SM-G935F using Tapatalk

[D41]

I used to overhaul Skyhawk hydraulic pumps

Skyhawk is a bad-ass jet!
"Hey..Viper is up here...oh sh!t!!"