Anyone able to actually print 230mm wide on U2?

[gr5 2,168]

The print head will hit an endblock - that's usually what stops the head from moving farther. The print head is made from black plastic and has a very flat surface. The endblock that is attached to the belt and holds the rod that the head travels on - that is *also* very flat. Those two surfaces touch when you are at the extremes.

You can get a little bit more than 230mm out of the X axis if you play with the limit switch - you can loosen the screws and move it slightly or you can just bend the end of it with some pliers. If you push it too far then the head can't reach the limit switch.

 

[gr5 2,168]

I did a quick experiment with Cura. I loaded an stl file that was 10mm on a side and pushed that cube around on the bed until it turned gray.

Cura shows a gray/blue checkboard pattern with 10mm squares to simulate the glass bed (the actual glass is wider so it simulates the printable area). Then it also shows 4 gray areas which are "keep out" areas or zones where you can't print. Whenever my object to print got too close to one of those keep-out gray ares the part went gray. Those of course represent the clips that hold the glass.

Then I tried something else - I tried to scale the box up in only X and used the "to max" feature after making it long in the x direction and the max print space I could do in X was 228 so cura wants 1mm on either side for some reason (even though the nozzle width of .4mm should buy you an extra .2mm on each end).

So I would think I can go to 230.4 but I could only go up to 228mm.

The fix is obviously to go to 232mm in machine settings. But then it prints 1mm to the right - to fix that you can do this:

G1 X0 (move to the left most position)

G92 X-1 (tell the printer that this is at postion -1

Make sure you do that after all the moves to X=0 in the gcode - if any other moves in the code go to X<1mm then they should all be fixed but I don't think that's an issue - there should only be one or two moves to X=0 and only at the very start. I'm not sure if G92 can even work with negative numbers. It will probably work.

It seems like Cura shouldn't steal those last 2mm from me. In fact it is stealing 2.4mm from me. I shouldn't have to hack the gcode to get it back. Maybe I'm missing something.

 

[randyinla 14]

I love that autocorrect, "print head will heat an endblock" (assume you meant meet or hit?)

I understand how the end blocks / switches work and how playing with the switch position can yield a teensy bit of room (or take it away if misaligned). Even if I were to do that (and I probably won't) I would still have to update Cura to 231mm or 232mm.

This dancing around a few mm's in Cura to print out a 225mm wide piece just reminds me of an underlying angst; that I would LOVE to expand my U2 in both the X & Y by maybe 4" each .

 

[randyinla 14]

Great investigating work! I am sitting here, trapped at work, living vicariously through your experiment

Ok. So setting Cura to 232mm width means the center is 1mm to the right. How is that a bad thing? When my piece printed, I believe it looked like I still had maybe 1cm of glass space to the right, so there is enough flooring for the plastic to adhere to. And my gantry never hit the side wall (granted, I had to bend the metal fan housing a tad). Would I really have to tweak/adjust the G1/G92 hacks?

 

[gr5 2,168]

I'm sure it *did* hit the right side - the print head hit the right side block. I'm sure of this because you said your right wall was 15% as thin. I've had the same thing happen - you can press the head against the right block and move a little farther with the stepper and the belt will stretch a bit but it won't move the head any farther.

This happened to you because you lied about the width (232mm) and so it put the center of the part at 116mm (instead of 115mm) and printed the part 1mm to the right of where it should have and went just a tiny bit to far on the right edge when it printed to approximately X position 231mm.

So telling Cura the machine width was 232 may have fixed it so it printed but it printed 1mm to the right of desired position.

YOu could subtract 1mm from *every* X coordinate in the gcode file with a new plugin. Or fix it with the G92 command.

 

[eldrick 65]

Here was my testing last year:

http://umforum.ultimaker.com/index.php?/topic/5447-um2-does-not-meet-its-build-volume-specs/

Some of the issues about the clips have been fixed in newer versions of Cura, but the basic issue remains, that it does not meet its specs. At least not without loose definitions and some after-sale tweaking.

 

[randyinla 14]

If it hit the right block, wouldn't that cause the stepper to skip, which in turn would cause higher layers to be shifted?

I simply have to try the piece again and be more aware of what's happening during the print. I should also try to drag the piece a little more to the left rather than click "center object on platform".

 

[gr5 2,168]

If it hit the right block, wouldn't that cause the stepper to skip, which in turn would cause higher layers to be shifted?

 

That's what I thought but I printed something that *did* hit the block and only tried to move 1mm farther and the belt stretched a bit but the motor didn't skip. Fortunately for me it was printing the skirt and so it only tried once on the whole print. If you go a little more (maybe 2mm instead of 1mm) it will eventually skip as you say and the rest of that layer and all layers above will have moved a bit.