From: "Martti Koskimo" 
To: 
Reply-To: "Martti Koskimo" 



Drag polishing is polishing with full size tool where the tool is prevented
from rotating
or rotated reverse direction compared to table rotating. There is very
short stroke( say 20 mm in 500 mm surface)

This technique is used especially in figuring corrector plates and very
fast paraboloids.
The tool has leaf or other pitch pattern depending on what kind of figure is desired.

If the tool is allowed to rotate then there is the tendency to generate
figure to spherical direction
or as mentioned Zoned  multi radius surface.

All the times I have used Drag polishing I could not wholly prevent  slight zones.
This is not the fault of the Drag polishing principle itself.

For normal Paraboloids ( F4 or longer) I suppose that Drag polishing has only a very
minor or no use value at all.

Martti Koskimo


----- Original Message -----
To: "Martti Koskimo" 
Sent: Saturday, January 18, 2003 12:56 PM Subject: Re: ATM Mirror making
machine question


> Martti,
>
> >Computer modeling shows that you need CNC machine to effectively figure
on
> fast revolving table.(Drag polishing is an exception)
>
> What is drag polishing?

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