Re: [CAD_CAM_EDM_DRO] purpose of the group

Hi Peter,

I do understand your point. There is a but!!!!!!!!!!!!

The machine I run was designed for manual operation with power feed in one axis. It was probably a very good design for its day but now it is old with a little wear. The point I am making is that the machine slides were never meant for fast repetitive movement, so at the speeds and feeds that some are putting their machines through I am surprised they last more than a week. True CNC machines designed for production are manufactured with low friction and low wear slides.

If I managed to get 60ipm out of the servo system that I'm putting together I'll be happy and this would only be used to move the tool while it is not cutting. I only mentioned the real metal by way of explaining that most of what I cut is steel in different degrees of hardness, so the cutting feeds and speeds are quite low. It would be silly of me to set up a system that is capable of dealing with Aluminium at the speeds and feeds necessary for production times when I cut this metal so rarely.

I would think that most hobby machinists, that use hobby type machines, would have some difficulty reaching the speeds and feeds of production machinery if only because of the rigidity of their set-ups. The point I am making is that the quest for speed results in exceeding the set-ups and machines that will wear out quickly.

Then I have seen the quest for bigger, faster and just more of it defy reason so many times with men wanting 800mhz puters for word-processing. Its a man thing :-)

Regards,

Terry




In a message dated 07/07/2000 11:56:24 AM Hawaiian Standard Time,
wotisname@... writes:

<< The quest for greater speed is something that I don't follow. If I get
60ipm on my Bridgeport type machine I'll be happy, I only cut real metal.

Regards,

Terry

>>

Terry,

Guess my machines up to now have been on the sloppy side. I used to do bi
directional surfacing, cut to the left, then to the right etc. I get all
kinds of patterns and strange bumps, I would guess from the backlash in the
axis drives, the gibs, and from flexing in the machine. Once you decide to
spend the time and cut all in one direction, you can literally double your
machine time. The faster your G0 speed, the better. Because my operation
straddles the line between a hobby and a commercial venture, I often machine
many medium size lots. 500 is a common lot size, I often do 2500 part lots.
If you can shave even 2 seconds off every part you make, it really adds up.

At 60 ipm, a move a quarter of the way across the bridgeport's table may
take close to 10 seconds. Do that 1000 times and.......


Peter Tsukamoto
THRD, Inc.



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