Re: greetings from new member

I can save you a lot of pain. The floppy drive motors are way to weak. You
will need stepper motors with a torque of at leats 60 oz inches. That
coupled to a fine 20 threads per inch lead screw will give you plenty of
power.
If you are planning to use a those polished rods with bearing for the X axis
then I would suggest that you check the deflection under a load. You will
find that surprisingly little force cause deflections of .005-.010.
I have built about tenty different cnc machoines so I think I can speak with
some authority. My first CB drill machine used kitchen cabinet ball bearing
draw slides. It worked fine for light duty work. See my web page at
www.seanet.com/~dmauch for other tips and solutions.
Dan
-----Original Message-----
From: David Forsyth <david@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Wednesday, May 12, 1999 3:07 AM
Subject: [CAD_CAM_EDM_DRO] greetings from new member


From: "David Forsyth" <david@...>

Hi all

Not sure if this will get through......

I've just joined since I'm busy building a 3axis minimill.
I'm using 2 ex-dotmatrix printer mechanisms for the XY slideways,
giving about 8 inches travel each way. I will have to build an
overhead gantry for the Z axis. Not sure what to do for slideways
there as yet, poking around for another dead printer.....

Drives will be (at this stage) 200step/rev motors from floppy drives,
driving 1mm pitch leadscrews (read as threaded rod from local
hardware store :-)
This gives a theoretical resolution of 0.005mm per step. Of course
this is ondone a bit by the 'leadscrews', but I'll see how it goes.

Z spindle will be either my old Dremel or a flexishaft driven by a
sewing machine motor, possibly with puta controlled speed.

The purpose of this machine is to produce, using CNC, various small
parts in plastic/aluminium/brass for model trains, and to drill PC
boards. Some parts will be molds for casting resin, some original
items. I'm also considering injection molding.

My big interest is really in programming this thing. Yeah, I
downloaded DanCAM, and will be making my interface complatible with
that software, but I'd really like to write my own stuff.

Web searches have turned up plenty of products, but no theory on
generating toolpaths, no sample sourcecode, nothing of interest to a
rabid programmer >-:

btw, my main CAD program is TurboCAD 5 (3d) , which I'm slowly
getting to grips with after using TurboCAD 3.2 for MSDOS for years.


steam and wind
--
David Forsyth DaForce A-T Iwr.Ru.Ac.Za
Keeper of the listserver for South African Railways fans _|_ His
Part time gricer, kiter, photographer, father etc etc | Way
http://www.ru.ac.za/departments/iwr/staff/daf/index.html | Up

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