Park Feature?

[CKerv]

I want to set up multiple boards on the bed and set separate temporary "zeros" for each of them.  I would like to be able to jump back and forth from each work piece, but I don't want to have to manually zero each piece.  I thought "Park 1" and "Park 2" would provide this feature, but that doesn't work because once you get to the Park position, and then zero, the Park position moves.

Any advice is appreciated! 

[dave benson]

Hi CKurv

Without knowing why you want to do this, it's a little hard to help.
You could look into nesting or using the G54\55 ect work offsets.
Dave

[CKerv]

I'm doing epoxy inlay projects, which require multiple cycles of engraving, filling with epoxy, engraving, filling with epoxy.

[EddyCurrent]

Offsets; https://www.cnccookbook.com/g54-g92-g52-work-offsets-cnc-g-code/

[Garyhlucas]

Most CNCs have fixture offsets and default to G54. They then provide G55 - G59 typically. In MDI call G54. Jog to where you want X Y Z zero and set all axis to zero. Call g55, move to home position and again zero the axis. You can also specify those locations numerically.

[Arie kabaalstra]

if you want to move your machine to a specific point, regardless of the coordinate system currently in use, Make your movements in G53 (machine coordinates), in some CNC Controls (I don't know which one you are running) you can set two fixed positions, G28 and G30..

On my machine, G30 is the home position, i always "park"my machine there when shutting down, and G28 is with the head almost all the way up, and the table forward for easy setup and/or exchange of parts.

[lloydsp]

Arie,
That's a good reminder.  Mine's all 'cnc-d', so that stuff happens automatically (normally).  But occasionally (rarely), I must manually command the machine to this-or-that position.  Remembering the codes is important.  Otherwise, one must look them up every time such an event occurs.

Lloyd

[Bob La Londe]

I started to reply to this earlier, but found editing the voice to text results on my cell phone to be to arduous.  Arie is exactly right.  G53 is sort of the magic bullet.  I would add one caveat that can be annoying if you are standing there waiting.  It uses the last mode and feed rate on most controllers.  Adding a G0 on the same line or previous line or using a F(max) parameter (LinuxCNC and Mach 3 differ over this), can alleviate any issue.  Before I discovered this I found myself watching it make my safe park/tool-change move at F1.2 once or twice. 

The other thing to bear in mind is that you actually need to have a home position.  Using homing switches to home your machine on powerup is always a good way to start out, but on some (Mach3 atleast) controls you can also just manually home your machine to a location you like and set that as home.  I have used this method on dead reckoning machines that had no homing or limit switches in the past. 

I use G53 in tool-change "T(x)M6" and program-end "M30 (M1130)" macros on Mach3 and I set the post processor to output G53 moves as needed for LinuxCNC since I do not know how to write macros for LinuxCNC.