Messages

411

General Mach Discussion / Re: Pockets Made Easy

« on: April 17, 2011, 04:20:21 PM »

Also...As much as I love SheetCAM for plasma work, it can not do rest machining.  If that feature is a must have, keep that in mind.

412

General Mach Discussion / Re: Pockets Made Easy

« on: April 17, 2011, 10:35:31 AM »

I think what your after is called rest machining.  That's something that has to be figured out by your CAM software.  What happens is that you start with a large bit and work your way down.  The first passes will be with the large bit to quickly remove material.  The next size smaller will go in and machine the parts that the larger bit could not get to.  If you go even one step smaller, it will machine details that the previous pit could not get to. 

All of that is calculated in CAM.  It's not just a matter or dropping an M6 tool change command in the code.  What are you using for CAM?  I know some of the lower cost CAM programs aren't capable of this.

413

General Mach Discussion / Re: Crop circles in Cut2d

« on: April 16, 2011, 11:41:37 AM »

That second screen shot doesn't look the General Config screen I have.  You should see a option for setting the IJ Mode.  If you've set IJ Mode properly in Mach and it is still in absolute IJ mode, which is usually the cause of crop circles, then look at the header in your code and make sure there is NOT a G90.1 anywhere in the code.  While you're there, add a G91.1 to the program header.  This will force Incremental IJ Mode regardless of how it is set in Mach general config.

The above post is referring to absolute/incremental positioning, not arc IJ mode.  They are two separate things.  The problem you describe is usually caused by improperly set arc IJ mode.  G90/G91 switch distance mode.  G90.1/G91.1 switch IJ Mode.

G90.1 = Absolute IJ Mode
G91.1 = Incremental IJ Mode

  

414

General Mach Discussion / Re: Shopbot with Mach3 Proxmity switch hookup

« on: April 14, 2011, 08:15:47 AM »

Their "mini" switches are around $14 which is quite reasonable, but they are large in size at about 1" x 2".  I have some of these here but can't use them because of the size. 

http://www.automationdirect.com/adc/Shopping/Catalog/Sensors_-z-_Encoders/Double-Insulated_%28PBT%29_Limit_Switches/Stainless_Steel_Rod_Actuator/AAP2T71Z11

415

General Mach Discussion / Re: Cambam / gMax

« on: April 12, 2011, 10:41:03 PM »

Rhino has very good DXF output.  That's what I've been using for years to draw.  I do as others have stated. Place a bitmap in the background and draw over it.  I've never had a problem importing the exported DXF's into either AutoCAD or SheetCAM.  I have an older version of Artcam Pro.  Very cool program for dimensional signs and artistic machining but not so great for precision machining.

416

General Mach Discussion / Re: plasma probing routine

« on: April 09, 2011, 02:13:30 PM »

I've had crashes, but always as a result of a mistake in the program (IE: Not retracting to safe Z before a rapid)

My point was that we cut 16ga and 12ga all day long and 12ga hardly warps at all.  16ga is marginal...1/4" warpage at the most.  I'm not using special steel.  Just plain old run of the mill HR.  In 10 years of doing this, I've never needed a safe Z of more than 1/2".  The best way to speed things up is to not retract to 5" for every rapid, but rather figure out why there is so much warpage that 5" is required.  Even at rapid speeds, that's a lot time when you're doing it on every arc start.

417

General Mach Discussion / Re: plasma probing routine

« on: April 09, 2011, 09:17:33 AM »

You retract to 3 inches and the torch is crashing on rapids because of warpage?  We cut 20ga, 16ga and 12ga all day long.  I have safe Z set at .5".  That means that when the torch shuts off, it retracts to .5" and moves to the next start point, probes and starts the next cut.  These Z moves are relative to the work piece as the THC keeps the torch at set height above the work.  I use G31 for probing, not G28.  I'm not sure why you are needing to command a rapid down to .5" before beginning the probe...or more to the point, why you have the need to raise the Z so high for rapids.  You should be able to retract to safe Z (.5" or less), move to the next cut and call a G31 to probe for the next pierce height. 

You shouldn't be getting that much warpage on 16ga and hardly any at all on 12ga.  What are you're cut speeds and plasma power settings?

"Stay at your safe +5 inch height then do a rapid probe down to find the surface then raise .5 inch above that point and reprobe in slow mode for a more accurate height setting."

Maybe I don't understand the problem.  Why would you need to retract to 5" for rapid moves.  Moving up and down 5" at each cut would take forever on multiple nested cuts.  Even on 24ga steel, I've not seen more than about 1" of warpage and that's rare.  There is only one part we've done where the Z range was about 4".  On this part, I had to bump safe Z up to 4.5".  This was not because of warpage, it was due to the shape of the base material being cut.  even then, if the Z was at the 4.5" rapid height and the cut was at 0", the G31 just probed down to the material.  No need to command a rapid down before beginning the probe routine.

418

General Mach Discussion / Re: DC Motor as Rotational axis

« on: March 28, 2011, 11:14:21 PM »

If you need infinite positioning, then you need a motor controller.  If you just need 0, 90, 180 and 270 degrees, you can use 4 limit switches.  Turn on the motor with a relay and watch for the correct switch to trip.

419

General Mach Discussion / Re: Zeroing with movement?

« on: March 24, 2011, 09:04:37 AM »

I have a zero all button.  There is a system function you can select from the drop down on the button dialog called "Zero All Axes".  It's not a VB script button.

420

General Mach Discussion / Re: Looking for a stepper drive.....

« on: March 13, 2011, 12:36:54 PM »

Thanks Hood... I also found this one at AD (STP-DRV-4850).  Looks like it can accept analog for speed control but still requires TTL input on the direction pin, which I can probably work with. 

As a side note...Yikes...Omega is awfully proud of their products.