RE: [CAD_CAM_EDM_DRO] Need Help with CNC Mill Conversion

Dan:

You are a businessman, I am a retired hobbiest with a strong interest in
programming and a frugal budget. So, what's right for my situation may not
be right for yours. But, here is my recommendation for what I believe is
your situation:

1. Look through the Sherline web site and find vendors of CNC equipment for
their products. Most offer both complete units (Mill & controls) or
"add-ons." Visit their web sites and compare their offerings and prices.
"Reasonable" prices are in the eyes of the beholder so, when "time is money"
enters the picture, paying more than the component cost for a tested system
is viable. I enjoy (or at least tolerate well) building kits, writing
software, and putting it all together. I bought the Sherline 2000 mill and
later bought the Sherline motors & mounting kit, Camtronics driver kit,
TurboCNC (which I'm modifying), ACE Converter and both VectorCAM and
Intellicad. My power supply is a used highly regulated surplus supply bought
from "Western Garbage." It's a hodge-podge that I'll make work. If I were
actually making money from this eqiupment, I'd buy a complete kit and
install it (if I hadn't considered CNC prior to buying the tool) or buy the
complete CNC tool.

2. Consider double ended motors instead of single ended ones. These allow
you to use the equipment manually and automatically. This feature may be of
use to you. Sherline's motors are double ended, which is why I bought them.

3. To answer the questions posed in your note:

You'll need the following items in addition to your CNC ready machine tools:

Stepper motors - one for each axis of motion. I strongly recommend double
ended motors.

Stepper motor driver - one channel for each axis of motion (Examples are
Camtronics or Gecko)

Power supply - Not necessarily regulated, but with sufficient capacity to
properly supply the drivers.

G-Code Interpreter - (Software that actually makes the motors go-round).
Select one that implements as many G-Codes as possible. Examples are
TurboCNC, CNCPro, Master5

DXF->G-Code Translator - (Software converts CAD drawing into machine codes)
Example is ACEConverter from Yeagersoft

CAD program - (Software "drawing" program) Examples are AutoCAD, Intellicad,
VectorCAD-9

Computer - (1 or 2) You'll have to decide if the computer running the
machines should be the same computer that you use for design. Personally,
I'm using separate computers since I already have them. If you're buying
new, I believe that the minimum would be 400 Mhz Pentium MMX, 64 Mbyte
memory. This is definitely OVERKILL for any of the DOS G-Code interpreters
that you may start out with, but is needed for either the CAD program or if
you ever move to a Windows based G-Code interpreter.

Some programs, such as VectorCAD-9 also generate the G-Codes directly,
eliminating the need for the DXF->G-Code translator.

You can buy a decent power supply from several electronics surplus outfits.
Although a regulated supply is not necessary, you will probably wind up
buying a highly regulated supply if you purchased used/surplus equipment. If
you choose to build, you'll probably wind up with a transformer, bridge
rectifier, filter capacitor, and current limiting resistor or inductor (very
small resistor - just to limit inrush current when charging the capacitor on
start-up). You'll also need the meat-and-potatoes parts such as
cabinet/chassis, switch, fuses, etc.

Many of these units use the printer port of the computer. Some use the
serial port of the computer; these usually require some extra box (it's a
"computer" but they won't call it that) to convert the serial output of the
computer into step-direction signals for the drivers. You'll find that, with
the exception of Fenerty's Master5, most windows based software uses an
external box simply because Windows is not a very nice operating environment
for real-time control.

Although you currently do not see the need with your current business, I
would convert all three orthogonal axes to CNC at once. The cost of doing
this vs. doing two axes at once and then adding third axis is not all that
much and you've only got to do the job (and its debugging) one time.

-- Jerry Jankura
Strongsville, Ohio
So many toys, So little time....

| -----Original Message-----
| From: Dan Statman [mailto:dan.statman@...]
| Sent: Wednesday, September 12, 2001 11:51 PM
| To: CAD_CAM_EDM_DRO@yahoogroups.com
| Subject: [CAD_CAM_EDM_DRO] Need Help with CNC Mill Conversion
|
|
| I have a basic Sherline mill with the stepper motor mounts installed from
| the factory. I have been using the mill as a manual mill only,
| and I would like to convert it to CNC.
|
| What I would like from the people on this list is a detailed
| explanation of
| all of the components that I would require for this conversion. Here is
| what I am currently looking at: