Building a more accurate Ormerod

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Davek0974
Ball-screws would be good and with the right nuts will be zero backlash, but, they are far heavier. They would be ideal if building a serious size machine like a 450mm sq print area or more. I recently built a mini-mill with 16mm ball-screws and a 400mm bed, the accuracy is amazing.

Don't forget lots of machined aluminium parts

What lead are the ballscrews you used? I'm worried that with 5mm lead that when the motor has to slow down and change direction that it is going to be too stressful or cause issues even at lower print speeds. Also what motors did you use?

I was looking at 300 x 200 or 300 x 300 as the heated beds are readily available in this size.

DC42 - In terms of changing motors and the drive method, the one thing I haven't asked is how you set the movement scaling as it will be different to stock.

What sort of price will the new board be?

Jon

Quote
Firefox3D
DC42 - In terms of changing motors and the drive method, the one thing I haven't asked is how you set the movement scaling as it will be different to stock.

What sort of price will the new board be?

(a) easy, use the M92 command in config.g

(b) not finalised, but perhaps around 20% more than the Duet 0.8.5.

PS - if you are going for a heated bed larger than 210x210, then be sure to use 24V power otherwise the heated bed current gets silly.

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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].

Thanks I thought it be down to the M92 command, can you get the printer to echo back what the steps per mm values are I and not near mine at the moment.

Yes I had looked into the 24V heated bed, have enough electrics knowledge to build a separate power supply for it if necessary.

Edited 1 time(s). Last edit at 06/07/2016 12:24PM by Firefox3D.

Quote
Firefox3D
Thanks I thought it be down to the M92 command, can you get the printer to echo back what the steps per mm values are I and not near mine at the moment.

The Ormerod calibration page [reprappro.com] may be useful to you, also the Prusa RepRap calculator linked from that page. [prusaprinters.org]

(from Ormerod calibration page)
To check your settings, send ‘M92’ to the printer. It should respond (in the Pronterface log window, or the ‘Message Log’ tab of the web interface) with the current steps per mm setting for all axes, which will be something like:

For firmware version 0.78c and before, the setting for the X, Y axes show an integer with no decimal places; the exact steps per mm setting is actually 87.489:

Steps/mm: X: 87, Y: 87, Z: 4000, E: 420.000000:420.000000:420.000000:420.000000:420.000000
For firmware version 1.04 and later:

Steps/mm: X: 87.489, Y: 87.489, Z: 4000.0, E: 420.000:420.000:420.000:420.000:420.000
The extruder shows the steps per mm set to 420 steps per mm, for up to 5 extruders.