Printable area

I have discovered that I can only print about 180mm x 180mm on my 200x200 print bed and it looks like 100mm high. How big are you guys getting?
I just printed out something measuring 175 x 160 and I had to adjust the start point to fit it in. Shouldn't I be able to get the full 200x200?

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Richmond, New Zealand
Thingiverse ~ YouTube

Im guessing this may be to do with your extruder motor colliding with the x ends or something similar.
Really the whole design is very much subject to simple modification, and is hardly optimised for print area, the general community, i think, is more interested in print quality.
If you want to maximise your print area it shouldn't be too difficult to modify the machine. Moving the bushings on the y axis, changing the orientation of the extruder or using longer rods to 'stretch' the printer. It all works

Yes the x-axis is limited by the print head motor and I can fix that by rotating the printer head to the outer holes, it should then fit around the fan and I guess that's what the spare holes are for in the carriage.
The y-axis is getting better as I fine tune the position of the microswitch.
But even with these things maxed out, pronterface (and the composer in slic3r) both show 200mm square beds but the printer only prints to about the 180mm mark.
I will try changing the setup to 210x210 and see if it stretches the actual area to 190x190 or something. I have checked the x and y distances and they are measuring correctly, ie 100mm drawn prints 100mm on the bed.

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Richmond, New Zealand
Thingiverse ~ YouTube

Proterface and Slic3r are just display and sanity settings.

There are also max x,y,z setting in most firmwares, these are the more important settings

Ah that might explain the missing 20mm, I'll delve deeper.
Update: Yes you are correct, it is set to 180mm x 180mm in the firmware, must fix that then.

Edited 1 time(s). Last edit at 08/23/2012 05:51AM by Wired1.

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Richmond, New Zealand
Thingiverse ~ YouTube

Fixed the firmware and it now prints 200 on Y and 190 on X. Once I rotate the extruder it will print 200 on X as well.
Got side-tracked trying to get the SD card reader working with Printrboard and Marlin, what a pain in the butt. The y-axis end switch shares a pin with the SD support so you can't run one with the other. I'm building a second prusa at the moment with all the upgrade parts I can source but I'll have to get a friendlier electronics pack for that one.

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Richmond, New Zealand
Thingiverse ~ YouTube

That might be a firmware bug. I haven't used AVRs but on other chips I have used the SS pin is optional when using SPI so you can have it as GPIO and still use SPI.

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[www.hydraraptor.blogspot.com]

I need to read all the Marlin libraries and see where the cockup is. It is a known fault I see from searching this forum. Seems you can get around it by not using the y-axis limit switch but that kinda makes it a pain to set up - you would have to manually position the start point. I am not sure if using sprinter firmware works with SD support but if it does it would be a clear sign it was just a firmware glitch. Other than the SD problem it is a nice one-board solution.

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Richmond, New Zealand
Thingiverse ~ YouTube

The SS pin is the fan on Melzi. I have the fan working with an SD card with Marlin. It is different Atmega though.

I did have a problem: when I first defined the FAN pin it caused the bed temperature to read from the same analogue port as the extruder thermistor. I fixed it by un-defining FAST_PWM_FAN see:[github.com]

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[www.hydraraptor.blogspot.com]