I know it sounds dumb, but this is in reference to a problem brought in this post Test Job Stalls This solution is where I'm now stumped: "Z switch is supposed to be at the top else you wont be able to use the machine properly with Fusion's G53 moves, no proper homing, no WCS, etc Homes to top. SoftLimits stops it before it gets to the bottom. Long before the carriage hits the bottom, the router/endmill crash will already have happened" Makes perfect sense, so as I had already Inverted the X axis, (and rewired the end switch to the other side but at least now it copies my 3D printers) I thought inverting the Z would be fine but perhaps I have to change it somewhere else in the firmware or Rewire? The image attached shows where I made the changes (be advised this is not a screen shot from my setting its just an image I found of the same section) I ran ghost job and noted that the Spindle was going up when it was supposed to be going down. So what did I do wrong, Thanks
positive Z motion, whether jogged or programmed MUST be UP, negative is down into the cut. Z home is UP at the top of travel. This is an industry standard and none of the Gcode generators will understand having it the other way round unless you are a pretty good programmer and can program your own postprocessor. The Z down soft limit will only prevent a crash if you are very careful to set it up for every tool length, ie each time you change tools you measure where Zmin travel is and change the soft limit to match it. even so, you can still crash into the material. if that is happening, you are doing something else wrong (-:
"Check $3 first, make sure it Jogs" Lost me there.... if I go into the serial console and type $3 or 3 I just get errors - I don't know grbl so I'm relying on the Gui so all jogging is done there. As David the swarfer indicated X+ does go up and X- goes down successfully if I dont invert X So if I don't Invert X I can operate it, I ran the Surfacing wizard yesterday just fine. My concern is what was referred to in previous posts about "Fusion's G53 moves" I don't want run into this problem later, I know with my 3d printers if the motor direction was reversed I could flip the plug on the Arduino to solve the problem, but I'm reluctant to do that here as I don't know what negative effects I'll create. If I just go with my 3d printer experience it seems as though I need Invert X and Reverse the wiring.... But I'd perfer a seasoned pro answer then just my guess.
You really HAVE TO read the Grbl wiki without it you will have no understanding of how to setup Grbl - head over to gnea/grbl and read every page. It will take you an hour, but empower you for life! $3 is also available on the Grbl Settings tab in Control Reading the Commands page will teach you how $$ and $x commands work. Reading the Configuration page will explain all the options and how they tie together The Frequently Asked Questions page has a lengthy detailed section about Homing and how the coordinates are set (the section is titled something along the line of "why is everything negative after homing" but do read it all, its worth it to make you feel empowered
Ok I have been seriously over thinking this..... I just spent time re-reading and checking videos and just like this video OpenBuilds LEAD Machine Electronics and Software (Using BlackBox) I have the limit switch at the bottom so it activates when the Z axis is in the Positive or Up travel, I was just want so concerned I didn't trigger a future problem I started chasing my own tail. But yes I will look into the grbl Docs as it can't hurt to know it for future reference. Thanks for the help.
The default settings of the Openbuilds post for Fusion360 will work just fine since they cause Z to be raised to (home minus 10mm) at begin and end of job. This avoids hitting the home switch, though you can probably fine tune the -10mm to -1 or -2mm, just enough to reliably avoid hitting the switch. Why raise like this? The code generator has to assume that 'just move to start of job' will hit something, a clamp, the material, or the vice. an unsafe move. "Raise Z as high as it will go" ensures the maximum space between the end of the tool and the work/vice/clamps before it moves to the cut start position. A safe move. Same at the end, raise Z for safety, then move to either 'work 0,0' or 'machine 0,0' (you can select which in the post options).
