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Topic: Centre of the bed
slimshader
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slimshader
Centre of the bed
on: June 24, 2012, 18:21

Hi all,


made a bit more progress today and have updated the firmware to the one from https://github.com/emaker/Sprinter. The only change I could see that I needed to make for my particular machine was the Bed thermister setting, which was defaulted to 2 and should be 1.


So, I started commissioning again, marvelling at my now lovely smooth movement in the correct direction for a change and have hit a bit of a snag – well maybe.


After homing X and Y, I hit the centre button, and expected the nozzle to sit in the exact middle of the bed – it doesn't – looking from the front of the printer, it sits to the left and behind of where centre of the plate is. Is that normal?


I am using the Huxley-PLA-05-03 profile with Skeinforge, and have checked the multiply settings – they are set as 70/70 for X/Y. Changing these to any value made no difference to the behaviour of the Home button at all, even after a save and reboot of the printer.


In my particular case, a manual G1 X87 Y87 does an *actual* centre of the head on the platform.


Any idea why this is, and if its not normal, how I can change it?


Thanks!

British ex-pat working and living in Russia as an IT Manager for Mars Information Services for the last four years.
kyle_c
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Re: Centre of the bed
on: June 27, 2012, 06:01

I think that those settings in the Multiply module only control what point the model is centered over in the generated gcode file. The buttons in the host software probably don't know anything about your Skeinforge settings.
slimshader
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slimshader
Re: Centre of the bed
on: June 27, 2012, 08:53

OK, so is the above behaviour normally when an STL sn't loaded? My thought is that is it doesn't know where the centre of the bed is, it may try to print off the bed area.

British ex-pat working and living in Russia as an IT Manager for Mars Information Services for the last four years.
richgain
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Re: Centre of the bed
on: June 27, 2012, 16:41

Home X and Y and then command each axis in turn to move 50mm and check accurately whether it does move exactly that amount.

If not your steps / mm settings in configuration.h may be wrong.

Settings will look something like this:

//// Calibration variables

// X, Y, Z, E steps per unit – Metric Prusa Mendel with Wade extruder:

float axis_steps_per_unit[] = {91.4286, 91.4286,4000,866.66};

richgain

Doctor working in clinical terminology by day – 3D designer and builder by night.
slimshader
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slimshader
Re: Centre of the bed
on: June 27, 2012, 18:12

Quote from richgain on June 27, 2012, 16:41

//// Calibration variables

// X, Y, Z, E steps per unit – Metric Prusa Mendel with Wade extruder:

float axis_steps_per_unit[] = {91.4286, 91.4286,4000,866.66};

richgain


Cool, thanks richgain! I hoped it would be something easily configurable like that. I won't get a chance to try until the weekend, but it sounds promising.


Can you please advise if that's the settings for your Huxley? Mine are currently the stock ones from the github, which are:


{80, 80, 4571.429, 880}


I appreciate that each machine will be different, but I would expect two Huxley's to be closer than that!

British ex-pat working and living in Russia as an IT Manager for Mars Information Services for the last four years.
richgain
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Re: Centre of the bed
on: June 27, 2012, 19:10

Quote from slimshader on June 27, 2012, 18:12

Can you please advise if that's the settings for your Huxley? Mine are currently the stock ones from the github, which are:

{80, 80, 4571.429, 880}


No, those are in the reprappro firmware I downloaded. The sprinter and eMaker Marlin are the same though, so I'm quite surprised yours is only 80. That probably explains your problem though.


Doctor working in clinical terminology by day – 3D designer and builder by night.
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