Good afternoon. I have searched for this problem but I was unable to locate anything. I noticed that the Z-probe sets the work offset from the top of the work piece. This seams like a problem to me. Workbee (stock) has a limited working Z height. If a .75" work piece and a probe with a 20 mm height (~ 0.78"), this leaves very little room. Would it be better to set the tool height measured from the spoiler board? This ensures that the bit will not go into the bed (ideally). The software sets very little room for adjustment (software that works with Blackbox). How can I correct the problem? Which G-code commands can I type in to set tool offset from the bed and not the top of the work piece? Rick
Well, you don't have to use a probe to set Z zero height - just jog Z to lower the axis until it just touches the spoilboard then click "set zero". I actually leave a gap of about 0.1mm from the tool to the spoilboard which leaves a thin skin after machining which is easily removed and helps prevent damage to the Spoilboard.
@Richie800 When I used Fusion360 to generate my Gcode - or Sketchucam - I always picked the spoil board as the z- zero in the CAM portion of the software. But, like I said, you have to generate the Gcode with them. I am not familiar with the Openbuilds software since I have always used the other programs to generate the gcode. What are you using to generate your Gcode?
Thank you for the quick reply. I am using Autocad grbl.cps to generate g-code. Slightly off topic, all my generated g-code has Tx M6 and G28 G91 X0 (which moves to the opposite corner relative to home) commands in it. I'm not sure what to do with this other than deleting the lines. I have to read up on this one. By the way OpenbuildsGRBL.cps does not work for me.
Information: Configuration: Open Hardware CNC Router V13 using GRBL Information: Vendor: Openbuilds and the Swarfer Information: Posting intermediate data to 'C:\Users\***********\AppData\Local\HSMWorks\nc\3d Plate.nc' Information: Total number of warnings: 1 Error: Failed to post process. See below for details. ... Loading locale from 'C:\Program Files\HSMXpress\locales\english_us.xml' Code page changed to '1252 (ANSI - Latin I)' Start time: Tuesday, March 24, 2020 1:40:54 PM Code page changed to '20127 (US-ASCII)' Post processor engine: 4.2.1 42270 Configuration path: C:\Program Files\HSMXpress\posts\OpenbuildsGRBL.cps Include paths: C:\Program Files\HSMXpress\posts Configuration modification date: Saturday, September 21, 2019 10:13:34 AM Output path: C:\Users\***********\AppData\Local\HSMWorks\nc\3d Plate.nc Checksum of intermediate NC data: 78b6ca151e252f3b6c901f8b927b7983 Checksum of configuration: 7392f8a6f3f4a8e14340e901912b4f2c Vendor url: Build List | OpenBuilds Legal: Copyright (C) 2012-2019 by Autodesk, Inc. Generated by: HSMXpress 2020 R0.43575 ... Warning: GRBL configured to mm - CAD file sends Inches! - Change units in CAD/CAM software to mm ############################################################################### Error: Fatal Error : units mismatch between CADfile and GRBL setting Error at line: 491 Failed while processing onOpen(). ############################################################################### Error: Failed to invoke 'onOpen' in the post configuration. Error: Failed to invoke function 'onOpen'. Error: Failed to execute configuration. Stop time: Tuesday, March 24, 2020 1:40:54 PM Post processing failed.
Grbl Settings > Direction Invert -> Flip the switch for the axes thats incorrect > Save > Reset when prompted
When you do this and then jog the machine to your X0 Y0 your Z for 1/2" material would read Y.5 correct? If you hit run job wont the Z plunge to Y0 and into the material before starting the job?
you do need to also generate the Gcode with the work offset in the correct position, so the Gcode 'knows' that the bottom of the part is Z0 and thus does all the work above Z0. Having Z0 on the top of the stock is a convention that makes life easier because when you read the Gcode (or have to hand write it) you know that an negative Z movement is cutting and any positive Z movement is not cutting and is usually safe to rapid.
So its not as simple as it sounds in Christian James's post above? I'm not familiar with how to generate the Gcode a work offset.
In your cam software (what are you using?) you set the origin of your workpiece. If you tell it front/left/bottom (ie where the spoilboard is) you cam software and post processor would work out the toolpath to start at a safe distance above the workpiece. The important thing is to set the workpiece ORIGIN in your cam software at the same place as you set the WORKPLACE coordinates system (wcs) ZERO. If you want to check it works as it should go through the process, but don't put the workpiece in place - it should then "cut" some thin air.
I use Vcarve and usually set everything on front, left, work piece zero. In the openbuilds control I would zero everything to the same location. What I'm not understanding is if I set everything to left, front, spoilboard zero do you still jog the machine to the top of the work piece before hitting start? Would the project just start from the last place you jog the router to and work its way to Z zero (the wasteboard)?
You are getting a bit confused about words (jargon). In Vectric, when you start a new job you set where the reference point is going to be. You are setting points on the workpiece (your material) - this often referred to as the ORIGIN. You tell it where X, Y and Z zero is going to be set when you get to your machine. When you are setting up your machine you need to set the WORKPLACE CO-ORDINATES SYSTEM zero. You need to set this in the same place as you told your cam software it was going to be. So if you want to set Z zero on the spoilboard you need to set X and Y zero so that the centre of the bit is exactly on the corner of your workpiece. You need to move a little away from the corner to set Z zero on the spoilboard. Your cam software (eg Vectric) should sort everything out, but personally, after I have set workplace co-ordinates zero I always raise Z slightly above the top of the workpiece. Alex.
Yes, its simple enough. In the V-carve job set-up page, make sure you have set "Z zero position" to "Machine bed". Then, as above (Alex), jog your X and Y axis to front left (if that's where you want to start) and zero these axes. Move a little away from there so you can jog the Z axis down to touch the spoilboard and then zero Z. Then lift Z up a few mm to clear spoilboard. Return the X and Y to front left corner zero position. Start your job. Note: It doesn't really matter where you raise the Z axis to after setting to the spoilboard - the software will either raise it up a bit or lower it down to match the "Safe Z" position in the V carve toolpath tab.
I'm following you all the way until setting zero on the spoilboard. So when this is done I'm telling the controller that the spoilboard is now Z zero. Do you then jog the machine back to the surface of your work piece or like you said slightly above and hit "run"? Isn't the controller going to think its to high and want to return to the safe height (whatever that was set at, mine is at .2) meaning its going to carve into your material before starting the job?
Thank you Christian! I didn't realize that you were setting up the Z zero in vcarve off the spoilboard. This all makes sense now. Thank you to Alex!
