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Speed up G30 for travel speed?

Posted by PDBeal 
Speed up G30 for travel speed?
July 24, 2016 04:03PM
So I've built another CoreXY with the Duet 0.8.5 board, one to the point it does 360 height with the Z axis on a single motor belt system. Because of this, my Z axis lives at the bottom of it's travel. In my homez.g file, all I do is move X and Y to the center of the bed and issue a G30. Is there anyway to speed up the travel with G30? Is this related to the M558 P1 X0 Y0 Z1 H3 F200 T5000 line for the IR probe?

Edited 1 time(s). Last edit at 07/24/2016 04:03PM by PDBeal.
Re: Speed up G30 for travel speed?
July 24, 2016 05:10PM
Yes, the F200 parameter specifies the Z probing speed. You can increase it, but probing accuracy may suffer. If you use a Z probe with an analog output such as my differential IR probe, then the probing speed is reduced by a factor of 3 when approaching the target height, which allows you to use a higher initial probing speed.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Speed up G30 for travel speed?
July 24, 2016 06:40PM
Would increasing the T parameter not make the bed rise faster at the start? I guess alternatively, I could just add a G1 Z-200 F3600 to get the bed half way there, and then issue the G30.
Re: Speed up G30 for travel speed?
July 24, 2016 07:17PM
Quote
PDBeal
Would increasing the T parameter not make the bed rise faster at the start? I guess alternatively, I could just add a G1 Z-200 F3600 to get the bed half way there, and then issue the G30.

How do you know where the bed is, so that it is safe to use G1 Z-200 F3600 first? The point about G30 is that you can use it when you have no idea how far the print head is from the bed.

If you have already homed the Z axis approximately in some other way (e.g. using a microswitch), then you can do G1 Z5 F5000 to put the head 5mm above the bed, and then do G30 from there.

If you are using the Z probe as your primary Z homing device, then you can do it in two stages. First send e.g. M558 F1000 followed by G30 to home quickly, then back off a few mm, then send M558 F200, and do G30 again to home more accurately. This can be done in the homez.g file and in the Z homing section of homeall.g.

The T parameter sets the travel speed when probing multiple points in response to a G32 command, so it won't help here..



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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