Re: [CAD_CAM_EDM_DRO] Basic questions

On 01/02/2012 02:23 PM, Gordon Anderson wrote:

> 1.) How do I hold material on the table? I will be cutting thin wood, liteply and balsa wood. I will be cutting through the wood to cut out parts. My question is how do people hold the material in place and what do you put under the part you are cutting to make sure you do not cut into the bed of the machine.

For light and thin stock, double sided "turner's" or "carpet" tape is
often used, with vacuum being another good choice for non-tabbed parts
which are big enough that the forces make sense. If the parts are
tabbed (have small, short sections not cut by the machine to hold the
parts in place), mechanical hold downs are more common into the spoil board.

A spoil board is a sacrificial piece of stock which is locked to the
table on which workpieces are placed, I have seen stuff as thin as paper
used and as thick as 3/4" MDF, on a Bridgeport, I have seen brass and
mild steel used for such a purpose. For your purposes, Masonite is
probably a good choice as it is flat, hard and cheap. Cutting 1/32 into
1/8" spoil boards and regularly replacing them does no harm. You will
need a big cutter to surface the board after each change, basically take
a skim cut over the entire surface to ensure it is flat.

> 2.) I have old drawings with patterns for formers (mostly from model airplanes) that I would like to convert to gcode files to enable cutting the parts. Is this possible? If so where can I learn more about the process. I hope I can scan them in and then convert them to gcodes.

You may find that scanning them in is a bad idea since dimensional data
will not be used. You will probably need to use a good vector graphics
program to trace the scan and adjust the dimensional data after
scanning. It may be just as easy to scan a bitmap and use it as a
template to draw the parts.

Dave 8{)

--
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media, which holds forth the proposition that it is entirely possible to
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