How do I know?

[hawkermetalwork]

this is going to be a trainwreck, i'm warning you guys now. I'm not an engineer, (just an architect & welder) so I've decided to ask for some help. I've been looking at torchmate machines for a while now, but $8000 is a big chunk for me. I've seen all these home built projects and I'm eager to start one myself. I'm hoping to build a 4'X8' table, and the table and gantry aren't an issue, and now that I see some pictures, the bearing system isn't bad either. The questions I do have relate to the motor drive mechanism and computer control.

I've seen gear drives, belt drives and screw drives. which one is best, and which one is easiest? Once i match up a motor to the drive, how does the computer know how fast, and the distance of travel for the torch head? Or is that something that's programmed in once everything is built and the limits are established?

I run autocad all day at work. at home I run a mac. would I have to run another computer with the machine, and a the program and all?

Where would I be able to find all the parts, motors, computer parts and all for it?

any help you guys could give me would be much appreciated, I've read through some other posts and everyone seems very helpful.

[DSL PWR]

I feel for a large table machine gear rack is the way to go.

As far as the control goes do some searches on "Mach 3".

[massajamesb]

Originally Posted by hawkermetalwork I've seen gear drives, belt drives and screw drives. which one is best, and which one is easiest? .

I have tried chain drive and rack and gear drive, and I would have to say that I did like the chain drive, but I feel that the gear drive was a better option for me. I like the smoothness of gear drive, coupled with the timing belt/pulley gear reduction. I am only running 28 volts and still have great accuracy, torque, and speed.

Originally Posted by hawkermetalwork Once i match up a motor to the drive, how does the computer know how fast, and the distance of travel for the torch head? .

Easy. You have to set the "steps per inch" in the controller software.
Most modern stepper motors have 200 "steps" in one revolution of the motor shaft. You will have to do a little math to find out how many revolutions the motor makes to move one inch. This will involve compensating for any gear reduction, drive gear pitch and size, microstepping, etc.
You will then tell your software controller how fast you want it to move, either in a setup table, or in your G code.

Originally Posted by hawkermetalwork I run autocad all day at work. at home I run a mac. would I have to run another computer with the machine, and a the program and all?.

The only controller programs I am familiar with run under Windows or Linux.

Originally Posted by hawkermetalwork Where would I be able to find all the parts, motors, computer parts and all for it?.

Motors- www.kelinginc.net www.homeshopcnc.com
Drivers- www.kelinginc.net www.geckodrive.com

gear rack and spur gear-www.mcmaster.com

various parts, motors, pulleys, belts, etc.-
http://www.stores.ebay.com/HUBBARD-C...Q3amesstQQtZkm

complete electronics packages and systems- www.candcnc.com

CAM software- www.sheetcam.com

controller software-
Turbocnc- www.dakeng.com
Quickstep- http://www.cpwojcik.home.att.net/Qst...step_CNCx.html
Mach- www.artofcnc.com

Hope all that helps!

[hawkermetalwork]

holy lots of information. thanks, i'll have to spend some time going over everything

[massajamesb]

Originally Posted by hawkermetalwork holy lots of information. thanks, i'll have to spend some time going over everything

LOL, you asked.

[Weldtutor]

Originally Posted by hawkermetalwork how does the computer know how fast, and the distance of travel for the torch head?

Hi, & welcome to CNC Zone!

A little more information to add to Massajamesb's great answer.

Regarding your question quoted above, the computer uses a control program to read a machine code language, which is based on the CAD drawing of the part to be cut.

Sequence would sort of be:
1 draw the part in CAD program.

2 Convert the DXF drawing to machine code using a CAM program.

3 Control prog. reads code & sends signals to motors, torch switch, relays or other mechanical devices.


It's the code then, that tells the torch where to go, at what speed, & what to do.