Size change?

[AdamF]

Please bear with me, i'm new the the cnc set up/programming world. I have 4x8 table with a gantry from precision plasma llc and electronics from CandCnc. It's running mach3 and sheet cam.

I can import a file to sheetcam, set the sheet size and all the other parameters and everything looks fine. The part I'm wanting to burn fits into the red box in sheetcam and all looks good. But once I start to actually burn said part its huge and cuts right off the edge of the sheet. Last might I tried to burn out a generic logo that was supposed to be 19.5" wide and it would've ended up around 80" if there was enough table.

Like I said before,I'm new at this game so I'm hoping it's something simple that I'm just overlooking.

[tnbndr]

When you do your import of the dxf in the message box that pops up do you have the correct units checked in the scaling section?
Your part may fit in the red box when importing but what is the size of that red box? You can set that in the options menu - job options- material size.

Hope this helps.

[AdamF]

I have the table size set to 48x96 and last night the sheet I was trying to use was set to 40x60. On the screen my 19.5" logo took up about half the width like it should have.

[AdamF]

I just tried to burn out a circle 11.9" in diameter with sheetcam set to a 20"x20" piece of steel. The table burt out a circle that is 29.125" diameter. Something is obviously not right, but what is it? Maybe the problem isn't in sheetcam and is in mach3?

[acourtjester]

In sheetcam you can get a measurement of the size of the part by looking at the bottom of the display and moving the cursor to the part’s top and side. If you start with the part in the lower left corner that will be 0,0 as the cursor moves to the right you will see the number change at the bottom in the X direction and move up for the Y direction.
There are 2 display options, 1 under options, job options the other is under options, machine, work envelope.
If it is wrong then your scaling is off (drawing could be metric and loaded in inch or vice versa)

[AdamF]

Apparently I need to tune the motors. Starting to wish I would have bought a different system.

[WyoGreen]

The prints you received from Precision Plasma should have the settings for your Mach3 motor settings. It sounds like the problems you are having are related to the motor tuning.

Steve

[AdamF]

It was motor tuning, spent all day getting them dialed in. Just looked at the paperwork and there's no settings anywhere.

[acourtjester]

I assume you are using CandCNC mach 3 screen display. If you want to calibrate your axis motors steps per here is a post I sent earlier.

Postby acourtjester » Wed Oct 21, 2015 10:42 am

Setting up the steps per is very easy in Mach 3 you go to the "settings" screen and at the lower left is Axis calibration. Click on it and it takes you to a procedure for calibrating each axis. You select the axis a box shows up you put a distance in and push enter. The axis moves and you measure how much and enter that in the next box. Mach will then calculate the steps per. repeat about 3 time to refine the calculations and move to the next axis DONE. If you are using CandCNC software go to "view" click on load screens this brings up a folder with "Plasma.set" click on that the screen will blacken for a second and then return with the standard Mach screen. This has the "Settings" page so you can do the steps per calibrations. When done go back to view and when the folder comes aback on click on CandCNC's screen set screen blackens again then its back to your original screen.

[AdamF]

There is no plasma set option in my mach. I turned the motors with a tape measure and calculator

[acourtjester]

Ok then try the router set shown in attached image.

set screens.jpg (59.9 KiB) Viewed 2501 times

set screens.jpg (59.9 KiB) Viewed 2501 times

[AdamF]

They're tuned now but I will remember that way if I have to tune again one day. I'm onto the dthc now. As soon as the torch fires z raises up about 1.5".

[sphurley]

You should be tuning without the DTHC first. Only use a feeler guage (torch is powered off) and confirm that you are getting .06 height. Now run the torch on some straight 6" cuts and monitor your voltage. It should be close to what you dialed in from Hypertherm.
Once you are done there you will confirm with Mach 3 off using the Hub program to verify your torch moves the right way in the DTHC (Mach is different) and also you have to match your motor steps from Mach in the Hub settings. .

[WyoGreen]

It seems like I've seen the "no settings on the prints" issue several times lately. Things have changed a lot at Precision Plasma since I bought my system. (my system is not even offered anymore). After a lot of searching, I came up with this PDF document. They could have made life a little easier for their customers and included the information with their gantry, like they did when I bought mine. I guess they wanted to cut down on their paper costs.

Anyway here it is.