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Show"N"Tell ( Your Machines) / Re: 5 axis Spinning Lathe: machine and control panel in progress
« on: February 03, 2010, 02:25:50 PM »
Good work, lighting - lots of work for the right spinner. We do all microwave stuff, generally C-band to Ku band with the odd one at nearly 40GHz. All ours are hand spun though.
If it helps, large PNC machines usually have a roller of a known shape which is moved across the static tool, and the path recorded, then the gap set according to the stock material thickness and the path recreated based on this - Thus arbitary shapes can be reproduced easily. There's more to it than that of course, it's very much a learned skill rather than a fixed process.
Errors on parabolic reflectors are usually measured using photogrammetric modelling: lots of dots and a couple of coded targets are photographed from various angles using a very decent digital camera; all the shots are then fed into a laptop and the target dots' position calculated relative to each other and relative to a 3D model of the dish. the software is called Photomodeler ... it's very very clever.
We can hold 0.6mm RMS surface error on a 3 metre dish
If it helps, large PNC machines usually have a roller of a known shape which is moved across the static tool, and the path recorded, then the gap set according to the stock material thickness and the path recreated based on this - Thus arbitary shapes can be reproduced easily. There's more to it than that of course, it's very much a learned skill rather than a fixed process.
Errors on parabolic reflectors are usually measured using photogrammetric modelling: lots of dots and a couple of coded targets are photographed from various angles using a very decent digital camera; all the shots are then fed into a laptop and the target dots' position calculated relative to each other and relative to a 3D model of the dish. the software is called Photomodeler ... it's very very clever.
We can hold 0.6mm RMS surface error on a 3 metre dish
