New wiki page on delta geometry and auto calibration

I've created a new page about these topics in the Duet3D wiki at at [duet3d.com]. Please let me know of any typos or inaccuracies. The section on geometrical errors is applicable to any delta printer, and I hope to add some images soon to illustrate them. The section on auto calibration is specific to RepRapFirmware.

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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].

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7-factor: as 6-factor but also adjusts the diagonal rod length (M665 L parameter).
...
9-factor: as 8-factor but also adjusts the diagonal rod length (M665 L parameter).

That is twice diagonal rod lenght

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LVD

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7-factor: as 6-factor but also adjusts the diagonal rod length (M665 L parameter).
...
9-factor: as 8-factor but also adjusts the diagonal rod length (M665 L parameter).

That is twice diagonal rod lenght

I don't think so, because 8 factor is 6 factor + bed tilt and does not adjust the diagonal rod length

Edited 1 time(s). Last edit at 01/03/2017 10:24AM 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].

OK got it: 8 factor is +A +B -L parameter; 9 factor is +L again

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LVD
OK got it: 8 factor is +A +B -L parameter; 9 factor is +L again

That's right. What's missing is that you can't currently calibrate for bed tilt without calibrating for tower positions too, and that might be useful to have.

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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].

That's really good David, concise and covers everything I can think of.

A few typos, might be more but its late...

Preferably, use accurately-machined metal corners to connect the rowers to the lower and upper frames, not printed corners.

Three force sensitive resistors (FSRs) mounted in the bed supports. The nozzle itself is used to push the bed and thew FSRs detect the force. The design of the bed supports is critical, because the bed must be constrained not to move sideways yet the weight must be taken by the FSRs; and the FSRs must be protected from the heat of the bed heater. A small piece of electronics is generally used to measure the resistance of the FSRs and provide a trigger signal to the Duet or other electronics.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Thanks DjDemon, I have now correkted those.

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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].