[localbroadcast]

Hello! I have been dreaming of building a CNC machine for quite some time now. Today is the day that I actually am going to start putting money on the table and ordering some parts to put this thing together!!

Basically I am building a small machine for metal work. Travel will be about 1.5' x 1.5' x 1'. My goal is to use Servo motors, as long as things don't get too complicated or expensive.

Here's where I am starting out..
I am interested in using mach3 software.
I have found some boards on ebay that seem to be quite well priced, and are labled DDCM3V5.0. They seem to be a board from China, but I am not quite sure what exactly they can do. Do they act as both the breakout board (pc interface) and the servo motor driver in one device? Or would I still need servo driver boards attached to this? Does the encoder feedback from the servo connect to this board somewhere, or would this feedback be a connection on an additional motor driver board?

If these boards are not fit for servo CNC, can anyone suggest a good starting point for a breakout board / driver / servo combo for me to look at ? I really would just like a good recommendation for a cost efficient driver / breakout board combo for servos / encoders etc.

Goal would be 0.001" precision. Speed does not need to be extremely fast, but is a bonus of course. The spindle router will most likely be in the range of 5 - 10 pounds, 10 000 RPM.

Thanks!

[awerby]

It's generally not a good idea to spend your money on electronics before starting to build your machine. That's the last thing you're going to need, and by the time you get to that point you might find out that your goals - and the machine itself - have changed a lot from what you originally intended.

Many people start out thinking they're going to build themselves a machine that's capable of cutting steel and other metals with great speed and precision. But unless you're set up to cast iron on a large scale, that's not likely to happen. The typical CNC machine people here build can cut wood and plastics pretty well, with accuracy of about +/- .01" or so. If the business end of this thing is a typical wood router, like you describe, there's no way it will cut anything harder than aluminum. Spindles designed for metal-working generally go much slower, with lots more torque and less run-out. Mills designed for cutting metals generally are shaped like a "C", with a very heavy casting forming the cantilever that holds the spindle and a moving table. Only the largest of them give you 18" of Y travel, although the X travel is typically longer.

If you want to pursue a new concept in mill construction, that's great. But I'd suggest posting some drawings of what you propose to do, and get some feedback on the idea. There are lots of people here who have tried various different approaches to this, and you can profit from their expensively-acquired wisdom before spending any of your own money. The last thing you need to worry about at this point is what to use to drive the motors you haven't got yet.

[localbroadcast]

It's generally not a good idea to spend your money on electronics before starting to build your machine. That's the last thing you're going to need, and by the time you get to that point you might find out that your goals - and the machine itself - have changed a lot from what you originally intended.

Many people start out thinking they're going to build themselves a machine that's capable of cutting steel and other metals with great speed and precision. But unless you're set up to cast iron on a large scale, that's not likely to happen. The typical CNC machine people here build can cut wood and plastics pretty well, with accuracy of about +/- .01" or so. If the business end of this thing is a typical wood router, like you describe, there's no way it will cut anything harder than aluminum. Spindles designed for metal-working generally go much slower, with lots more torque and less run-out. Mills designed for cutting metals generally are shaped like a "C", with a very heavy casting forming the cantilever that holds the spindle and a moving table. Only the largest of them give you 18" of Y travel, although the X travel is typically longer.

If you want to pursue a new concept in mill construction, that's great. But I'd suggest posting some drawings of what you propose to do, and get some feedback on the idea. There are lots of people here who have tried various different approaches to this, and you can profit from their expensively-acquired wisdom before spending any of your own money. The last thing you need to worry about at this point is what to use to drive the motors you haven't got yet.

Ok.. I have not bought any electronics or any motors or any parts at all at this point. I am still in the research and development phase of things!
I want to mill copper for the most part, with some plastic as well. mainly copper plate up to quarter inch thick, as well as some 3d modelling with plastics and aluminum. You are right I may have to use a spindle with a slower speed and higher torque.

Besides that aspect of things, this post was mainly to find out about that board I posted a picture of and to find out if anyone knows information on it? Does it work as a break out board and a driver built in one? Or does it function solely as the pc interface / breakout board, and I would need servo drivers in addition to this?

[localbroadcast]

no input??

[aarggh]

no input??

From google:

DDSM3V5.0 200KHz 3-Axis CNC USBMACH3 Card Interface Board with Aluminum Shell and Case $90.82 Free Shipping @GoodLuckBuy.com

These boards are just BOB's, that you connect to the driver boards, but considering the fairly crappy Engrish used throughout, I'd assume the same quality control was applied to the manufacturing. I could be wrong though about that, but there's plenty of good quality BOB's available on Ebay.

cheers, Ian

[Poseidon]

I would avoid buying the above mentioned board. I made that mistake in trying to get away from the parallel port on the cheap. Single parallel(DB25) interface boards can be coupled to a UC100 for very basic conversions. If you need a high number of inputs and outputs the UC300 will serve this need nicely as will the Ethernet SmoothStepper.

Positioning feedback can be done via an encoder that loops back to the motor controller, an encoder that loops back to Mach3 or DROs that feed position information to Mach3.

[Jon.N.CNC]

Hello! I have been dreaming of building a CNC machine for quite some time now. Today is the day that I actually am going to start putting money on the table and ordering some parts to put this thing together!!

Basically I am building a small machine for metal work. Travel will be about 1.5' x 1.5' x 1'. My goal is to use Servo motors, as long as things don't get too complicated or expensive.

Here's where I am starting out..
I am interested in using mach3 software.
I have found some boards on ebay that seem to be quite well priced, and are labled DDCM3V5.0. They seem to be a board from China, but I am not quite sure what exactly they can do. Do they act as both the breakout board (pc interface) and the servo motor driver in one device? Or would I still need servo driver boards attached to this? Does the encoder feedback from the servo connect to this board somewhere, or would this feedback be a connection on an additional motor driver board?

If these boards are not fit for servo CNC, can anyone suggest a good starting point for a breakout board / driver / servo combo for me to look at ? I really would just like a good recommendation for a cost efficient driver / breakout board combo for servos / encoders etc.

Goal would be 0.001" precision. Speed does not need to be extremely fast, but is a bonus of course. The spindle router will most likely be in the range of 5 - 10 pounds, 10 000 RPM.

Thanks!

Avoid that board infact avoid 99% of ebay bobs. That one is especially rubbish.

Go for a uc400 and i use hg08 bob's, they are virtually indestructible..

[James Newton]

First off, no matter what you decide PLEASE don't buy the crap from China? It's a nightmare that sucks in so many people...

If you are using an old PC, which I strongly recommend, you don't really need a fancy BOB at all. Just wire the drivers to the parallel port. Opto-isolators cause far more problems than they solve. If you want the convenience of cables, my BOB PCB (see link in signature) provides a really clean, cheap, direct connection to PMinMO standard drivers.