What accuracy do I need?

[energyforce]

I am building a plasma / oxytorch combo.
The table can cut however thin metal a plasma cutter can cut --all--the--way--to 7 inch thick steel with the oxytorch.

As for the accuracy of how well I built the table in terms of tolerance, thats my problem but my question is related to the stepper motors.

After movement going through all the driver, stepper motor, reducer, and finally rack and pinion how much should I aim my torch head to move? What I mean is I could aim for .009 or .005 or even .001.

I know too much of a reduction will slow things down too much and just be a waste of torgue but I want to hear what the numbers are that you guys aim for for a machine like this.

Erik

[DanOSB]

how much ipm do you guys suggest too.. the highest ipm the table needs to run is 500?

im currious about that answer too

[jpgdesigns]

The two processes for your machine have a limited accuracy to start with... I am assuming that you are not using "highdef" plasma torch... Most large plasma/oxyfuel machines cut within a 32nd of an inch at best... Naturally I would suggest looking at the size plasma unit you will be using and see the max speed it can cut in the thinest material you would cut alot of... and aim for that speed plus a little for rapid traverses... and also consider that for oxy-fuel cutting that the machine will have to move very slow about 4 to 6 ipm for 7 inch plate...

Sorry for not giving a direct answer. Just consider you application plasma max cutting speed for thinest materal you will cut and the thickest material you will cut with oxyfuel that should answer your question for what you need...

my 2cents
James G.

[energyforce]

Originally Posted by jpgdesigns Most large plasma/oxyfuel machines cut within a 32nd of an inch at best... James G.

Thanks this is the kind of info im looking for. I will look into plasma cutters and find out what their cutting accuracies are. It obviously would be a waste of money and time and machine speed to create a machine that can go beyond the accuracy of the plasma cutter itself.

Erik

[DCparts]

I cut within .005" on production runs, using the Hypertherm HPR130 with the auto gas console http://www.hypertherm.com/mech_systems/hpr130.htm but it is $25,000 - $30,000 plus another $50,000 for the table/control). Most of our cutting is at 150ipm or less, but rapid travel is 1500ipm, it saves alot of time when there is a lot of rapid moves.

On our CNC flame cutter we can cut up to 8" thick. Although it is possible to pearce around 6" with our system, I would recommend predrilling, it will save you a fortune in consumables.