Calibration, endstops and bed levelling issues

Hi,

Fisher built and runs. Do 'Home All' and it runs up to the endstops and back down. Instead of stopping 4mm above the print surface per the instructions the nozzle hits the print surface. Then if you try a bed measuring macro and it drags the nozzle across the print surface and spits off the belts. (I didn't try 'Auto Bed Compensation' at the time because if you don't have the browser window wide enough it vanishes.) I have looked at online instructions for the Fisher and the Duet, can't find anything about how to set up the endstops, height, bed leveling etc. The instructions for the Duet are for the Ormerod so don't seem to apply. I can see settings for endstops etc. in the machine settings window. I don't see any instructions on what to do with them. Any instructions appreciated.

Cheers,

Theo

The H parameter in the M665 command in config.g defines how high the firmware thinks the head is when the printer is homed. So try reducing it

Are your microswitches triggering at too low a carriage height?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

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

Yeh, that is weird. As dc42 said, are your endstops triggering low? After bending the levers on the microswitches it reduces my build height by a couple of mm, but I wouldn't have though it would be enough to cause a head crash with the default settings.

Just to clear up the obvious / other things that would otherwise effect your build height:
- are all of your endstop levers bent at the same place and to the same angle?
- are you using the latest SD image for the Fisher (not Omerod etc)?
- are the balls sitting on the top side of the bed and the bed under the pair or contacts at each corner?
- are all the corner contact mounts screwed down fully?
- is your hot end properly mounted in the head? - ie. you haven't somehow mounted it too low in the head

It also surprised me that you say it pops the belt off. I've had the towers appart a few times and I find it pretty fiddly to detach the belts... there's certainly no way they'd manage to pop off on their own.

OK, thanks. I can't edit the configuration file through the web browser? I was going to try lowering the Z value, thanks for the informed opinion.

I was probably too aggressive with bending the microswitches, but they trigger fine. I only downloaded the Fisher SD image yesterday. Print surface is fine and triggers the E-stop fine, so it stops when the head runs into it. Top of heatsink flush with top of fan duct so it seems to be the right height. Belt overlap came out of carriage, which is a good thing in my book.

Quote
Theolodian
OK, thanks. I can't edit the configuration file through the web browser? I was going to try lowering the Z value, thanks for the informed opinion.

Use a text editor (e.g. Notepad++) to edit the copy of config.g on your PC, then upload it using the button on the Settings page of the web interface. Then use the Emergency Stop button to reset the printer so it reads the new file.

Edited 1 time(s). Last edit at 07/31/2015 04:39AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

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

Yeah, was doing that. A bit fiddly really as I had to fire up a laptop to deal with the SD card. Didn't do the Emergency Stop but had powered off the machine and then applied new settings.

Set height to 170. It stopped about 8mm off the surface. Endstop settings are the default M666 X0.35 Y0.29 Z-0.64

Just run Auto Bed Compensation now?

Many thanks.

Quote
Theolodian
Yeah, was doing that. A bit fiddly really as I had to fire up a laptop to deal with the SD card. Didn't do the Emergency Stop but had powered off the machine and then applied new settings.

Set height to 170. It stopped about 8mm off the surface. Endstop settings are the default M666 X0.35 Y0.29 Z-0.64

Just run Auto Bed Compensation now?

Many thanks.

8mm is probably too high because the dive height (H parameter in the M558 command) defaults to 5mm AFAIR. You can safely probe now, but I think you will find it doesn't probe deep enough to trigger the bed switches.

Edited 2 time(s). Last edit at 07/31/2015 04:59AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

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

Part of the mystery solved. The bowden tube was knocking the Y endstop harness off when homing and it kept going with really bad homing values. Endstop harness now taped to panel, but head now at 12mm from surface with height at 175 so still some adjusting to do. For future reference if the head doesn't come back down in the centre of the print surface it isn't homing correctly....

Edited 1 time(s). Last edit at 07/31/2015 05:14AM by Theolodian.

OK, just to keep records in the right place, the issues were the Y endstop harness being knocked off by the Bowden tube and bed.g in the sys folder having a G31 statement with a Z0.1 which was trying to put the nozzle at least a quarter of a mm into the print surface at the start of the print. This wrecked the BuildTak surface and caused the extruder to jam up. A bit of cello tape and changing the Z0.1 to Z-0.2 or (Z-0.3 to be safe) solves it all.