RE: [CAD_CAM_EDM_DRO] questions before building

You can get Acme threaded rod a lot cheaper than you think. Even with
low end nuts and flanges the cost is still good. Much more efficient
than hardware store threaded rod.

http://www.mscdirect.com/PDF.process?pdf=3579&Keyword=Y

Regards,
JJ

Be Kind, Be Careful, Be Yourself

> -----Original Message-----
> From: andrew_k_jones2000 [mailto:andrew_k_jones2000@...]
> Sent: Thursday, November 07, 2002 1:05 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] questions before building
>
>
> Hello List,
>
> I have a couple of general questions that I could not find answers to
> in the FAQ. I have searched in the archives a bit, but the amount of
> posts is making my particular questions hard to find since they
> contain some very common keywords. If anyone can suggest threads
> where some or all of the questions are dealt with, I would be very
> appreciative. I could read these threads and come back with more
> refined questions.
>
> Over the last year I have been collecting surplus hardware to build a
> CNC router. I now have 4 Nema 23 steppers with optical encoders, 4
> CMD260 micro stepping drives, a parallel port interface board (EMC
> compatible), and other bits and bobs of thrust bearings, drive
> couplers, etc.
>
> The material intended for milling and routing is Perspex, plastics,
> aluminium sheeting, wood, and general soft metals (just hobby
> stuff). I am thinking about driving the axis with threaded rod, and
> using brass bushings on solid rod as the axis guides (e.g. like many
> have already done). The design will be a gantry style, with 90cm x-
> axis, 70 cm y-axis, and 10 cm z-axis.
>
> Initially I was going to use a hobby rotary tool for the spindle
> motor, but have decided to first look at something more powerful to
> base the z-axis design around. I figure it would be easier to alter
> a set-up made for a cutout tool to accept a small hobby rotary tool
> than visa versa. I also thought that if I am making this thing, I
> might as well not limit myself from the start. I can always go
> backward to the rotary tool I already own.
>
> My questions are these.
>
> Motor suggestion/recommendations, things I should consider:
>
> I am interested in finding a motor that is... in order of importance:
> able to cut the above materials, quiet-ish, light; accept variety of
> tools (cutting, routing, drills). I am not expecting to find the
> optimum for all these categories in one tool, but some balance. With
> thread-rod, I don't expect the feed rate to be blistering, but I
> would like to not worry about going slower to accommodate the motor,
> and I may upgrade the drive system at some point.
>
> Adaptability of the motor in holding tools:
>
> I am also wondering about the tool holding ability of these motors
> (cut out / router). Can one use a variety of tool shaft sizes, or
> are they limited to a standard diameter, and thus maybe rule out
> small drill bits and accessories (pcb drilling, etching)? I am
> planning to have the ability to attach my rotary tool for smaller
> jobs, so it crucial. But I might pick one motor over another if it
> has more versatility in what it could hold.
>
> X-axis coupling
>
> I am planning to have two x-axis drives. Is coupling these
> electronically (splitting the x-axis step and direction to two motor
> drivers) a good route to go? Should I mechanically link the axis
> drives with a belt? And if so, should I leave the second stepper
> inline? I do have optical encoders on the steppers, and though it
> might be possible to have each x-axis stepper act independently, but
> always carry out the same command. I could then use the feedback of
> the encoders to make sure that x-axis and the "4th-axis" steps were
> successful. I am definitely attracted to the just coupling
> electronically, and counting on relatively few miss steps... not sure
> if this is reasonable.
>
> Thank for any help or advice you can give
>
> Andy
>
>
>
>
> Addresses:
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> OFF Topic POSTS: General Machining
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http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there,
for OT subjects, that are not allowed on the CCED list.

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bill
List Mom
List Owner



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