RE: [CAD_CAM_EDM_DRO] Yes, here in the back of the room. I have a question...

Jasson

Welcome to the CAD_CAM list. You have already taken a BIG step that many
people are afraid to take on the road to your own CNC machine and that is
being willing to step up and say you don't know what you are doing but would
like help. Congratulation on being adventuresome.

To give you the short answer yes you can do it and with the help of the
people here it will not be all that hard. Here is a rundown of the items you
will need:
Computer:
Requirements will vary with the software you choose. Everything from an old
486 to a current Pentium class machine. Generally you only a small amount of
memory (32 will probably be fine for the GUI based Windows or Linux programs
and less for the DOS based stuff) and not a very large HD. Video card for
the controller system does not need to be top of the line stuff either.
Software:
There are 2 parts, the software that drives the motors and the software that
generates the program code for the part. Cost on these is from free to VERY
expensive. My choice for the motor driving part at the moment is EMC which
is a free Linux based controller. I am also playing with a Windows based
controller package that uses an external "black box" called DeskWinNC. So
far so good. It is priced at $200 with the black box. Others that I have no
experience with but seem well received are CNC Pro and Master Control. For
the part design I use Vector which is an integrated CAD/CAM package. There
are also free CAD programs and Yeager Automation (maker of CNC Pro) offers a
.dxf to g-code (part program language) converter for free.
Now working back from the machine:
Motors:
2 ways to go, servos or steppers. Steppers are the more traditional route.
Servos are higher performance and with the introduction of a drive by
GeckoDrive that makes a servo as easy to drive as a stepper it has made
servos a viable option for a home setup. If you go steppers you will want to
look for a 135 - 180 in/oz NEMA 23 motor.
Mounts:
Again will depend upon the motors you get. If it is steppers Dan at
Camtronics was offering a nice mount kit for NEMA 23 motors to Sherlines
Drivers:
If you choose servos there is only one real choice for the money and that is
the Gecko G310 or G320. If you go with steppers it depends upon your goal.
If it is to get up and running fast buy a set of Gecko G201 or G210 drivers.
They are commercial pre-built and perform great for a very reasonable price.
If you are willing to build a kit or if you want to design your own driver
that will work also, but the CNC will then become a little more of the
project than the production of the parts. A kit is a nice compromise. Dan at
Camtronics offers a nice 2 amp bipolar chopper drive kit for about $160. It
will do a good job on the Sherline. My advise is stick with bipolar chopper
units. Yes a unipolar will work, but it is dated technology.
Power supply:
Just a linear supply. You can easily roll your own with a transformer,
bridge rectifier, capacitor, and a bleed resistor. Voltage and amperage will
be dictated by the drive and motors you choose.

That is about it. I am sure others will offer various options for each item
and there are lots of right choices. My opinions are based upon having used
the products and turning to the vendors for support. All the brands I
mentioned are active on this list and are top knock in helping a new CNC
hobbyist. I have done a Sherline conversion and then moved on to bigger
machines. I will warn you that this stuff is addictive. Once you get started
you will want a bigger machine, but the Sherline is a great starting point.
I sort of miss mine.

Tim
[Denver, CO]

> -----Original Message-----
> I am not sure if I am ready for this or not, so here goes.
>
> I found this group through the Sherline group down the hall. I am a
> true hobbist beginner at machining. I am 31 and have no machining
> experience. I have a standard #2000 mill, and have made a few things
> so far. I do a fair amount of woodworking, and thought I would enjoy
> working with metal. The main reason I got the mill was to mill on
> paintball gun bodies and make small parts. I have done a few for
> myself and friends.
>
> I have quickly learned that having CNC capacity would be better for
> the end result I am looking for, BUT I know very little about
> machining and even less about CNC. I am no dummy, but act like one
> most of the time. I would like to know what I would need to look
> into to get started. Drives? Computer requirements? Software? I
> don't expect you to get me going tomorrow, just point me in the right
> direction. I know that would save me a lot of time, and also let me
> know if I can handle it or not.
>
> I am sure questions like these come by all the time, but I went
> through several posts and could not find any.
>
> Thanks for your help,
>
> Jasson Thomley
>
>
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