SHEETCAM Z PROBLEM CODE
Sheetcam (with THC POST) compiles code that uses all positive Z moves.
When using plasma, homing at the top of Z can be confusing, as I mentioned in above post. G28.1 looks like its meant to be used for homing. Someone else more familiar than me might like to comment. All Z moves will now be positive after homing at the material height, cutting height will now be +1.5 mm and not -123mm ( or whatever), pierce height will be +3mm and so on. I would suggest to ignore homing Z at the top of travel for now, and fit a means to touch the material and then home Z. A floating head with a switch will do this for you, and the code to read it is in sheetcam.ĬNC convention tell us to home our Z at the top, but not Sheetcam with THC. So when using sheetcam you should have a means of determining a home Z at material height. The THC code in sheetcam homes Z at the material height, AND NOT AT THE TOP OF Z TRAVEL. Sheetcam with THC attempts to do this for you. It is easier for a human to think "If I can home my Z at the material height, I can have a good datum and all my calculations will be done in a positive direction, from this height" This can be awkward as a person has to think "upside down" or "backwards" The trouble is both you and the z axis cannot always know where the material is exactly, especially with plasma, as the material warps. With normal cnc conventions on a gantry table, Z is homed at top of travel, and all Z moves are in negative direction. It might be helpful if you read my post about switch hysteresis. S500 = means spindle speed of 500, although you will not have a spindle the plasma may be using the spindle function for torch height or some other feature. The message regarding Mach 4 is nothing to worry about, there are a few things that have that as at one time there was going to be a Mach4 but the features were then integrated into Mach3 instead.į1 = feed of 1 unit per minute (in your case anyway) When you homed the Z DRO (in machine coords) would now read 150 instead of zero and as you jogged down to the plate it would go towards zero. Example is if you home fully up and the distance down to your plate is 150mm then you would set the Home Off value to 150. You could probably keep your home switch where it is and set a Home Off value for that axis as the travel your axis has. I am not sure how the normal procedure is for Plasma as I have never had or used one but it does seem from what you are saying all Z moves are positive. It seems that you will either have to alter the post processor or the code it produces or as you say swap the limit so that home is at the lowest position. And without code snippet.īTW, What exactly is mentioned with those three lines of code: (I selected mm for my units, NOT inch)
SHEETCAM Z PROBLEM INSTALL
I have idea install another limit switch and to home down to find zero position. Sometimes it works, but sometimes, when I load another G code file, I get Soft limits warning when I start cutting, and question to proceed or not.Īctually, don't knew where to look to find problem source. I've been advised to insert snippet code: G31 Z -100 F500 and to set Soft max to 60 mm, Soft min to -50 mm and Home offset to 60 mm and Auto zero checked. I see in generated G code the first instruction is to go UP 50 mm (my safe Z position).
When I start the cut, Z axis goes up, touch the limit switch and this is the end! I home my Z axis torch carriage at the top position. I use plasma table with THC300, and SheetCam postprocessor Plasma THC300 - G31 - corner slowdown.post.