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Printing on a Cupcake with sailfish

Posted: Mon Jan 27, 2014 10:08 pm
by lasda
I've got most of this working except the Z axis motion is a fraction of what it needs to be to work well. The printing is coming out on top of itself, smashed into itself and looks terrible. Everything else seems about right.

in Tools > Firmware > X3G, I've picked Cupcake with Pololu XYZ and MK5/6 extruder with Gen 4 extruder controller. The numbers for the X, Y, Z and A match what I use in my machines profile for Replicatorg.

I even tried to let Replictorg process the Simplify3D gcode file into an X3G file and same result, so something in Simplify3D / gcode seems to be not right.

What am I doing wrong?

Re: Printing on a Cupcake with sailfish

Posted: Wed Jan 29, 2014 5:03 pm
by lasda
I checked carefully everything again and this is what I know:

If I compile and print with Replicatorg, everything works fine. The Z axis turns about 1/8 of a turn for .12mm layer height.

If I compile and print with Simplify3D using the same firmware settings, the Z axis turns only a tiny fraction of a turn -- no where near a .12mm raise in height.

I've looked at the gcode from both and they are changing Z appropriate amounts. I've tried to run the gcode from Simplify3D directly and it seems to behave better in the Z axis, but very little plastic is coming out of the extruder.

Comparing the two gcode files -- the one from Replicatorg has much larger extrusion values, which explains why very little plastic is extruding with the Simplify3D file.

I'm still confused.

Re: Printing on a Cupcake with sailfish

Posted: Wed Jan 29, 2014 6:09 pm
by lasda
I figured out the extruder flow -- it needs to be absolute extrusion distance and was defaulted to relative.

I can now use Simplify3D to make a gcode file that Replicatorg and execute on the printer. I can't use the x3g file though -- not enough z axis action...

Re: Printing on a Cupcake with sailfish

Posted: Thu Jan 30, 2014 10:17 pm
by dnewman
lasda wrote:I figured out the extruder flow -- it needs to be absolute extrusion distance and was defaulted to relative.

I can now use Simplify3D to make a gcode file that Replicatorg and execute on the printer. I can't use the x3g file though -- not enough z axis action...
This suggests that somehow GPX is using the wrong steps/mm for the Z axis. GPX has built in values and for the "Cupcake with Pololu XYZ and MK5/6 extruder with Gen 4 extruder controller", I think it tries to use

static Machine cupcake_P4 = {
{9600, 500, 94.13970462, ENDSTOP_IS_MIN}, // x axis
{9600, 500, 94.13970462, ENDSTOP_IS_MIN}, // y axis
{450, 450, 2560, ENDSTOP_IS_MIN}, // z axis
{7200, 50.235478806907409, 400, 1}, // a extruder
{7200, 50.235478806907409, 400, 0}, // b extruder
1.75, // nominal filament diameter
0.85, // nominal packing density
0.4, // nozzle diameter
1, // extruder count
20, // timeout
3,
};

which suggests the (insane) 2560 steps/mm for the Z axis. But if somehow GPX is being told a different Cupcake config, then GPX would use the wrong conversion from mm to steps thus accounting for seeing a "squashed" Z dimension (too few steps executed for each mm of Z travel). And, being squashed in Z but with correct E values would cause over extrusion -- too much plastic.

Re: Printing on a Cupcake with sailfish

Posted: Tue Feb 04, 2014 8:14 pm
by lasda
Sir, good to see you here too. Can you explain the 2560 number to me? I have the old style threaded rods with 1.25mm pitch and a motor driver v3.3 board. If I run the math, I get 1600 steps in one rotation divided by 1.25 mm to get 1280 steps per mm...

Note: changing to 1280 should make my squished problem worse AND 2560 is what has always been in my machine file for Replicatorg.

Re: Printing on a Cupcake with sailfish

Posted: Tue Feb 04, 2014 10:56 pm
by dnewman
I do not know what the correct steps/mm are for your bot. That profile I showed is simply the profile you seem to need based upon (1) what you wrote your electronics are, (2) what I believe RepG has for those electronics, and (3) what I see in the latest GPX sources that would seem to match.

Dan

Re: Printing on a Cupcake with sailfish

Posted: Sat Jun 14, 2014 12:03 pm
by slamzee
Hello -

I just bought this for my Cupcake also. I have a new printer coming, but thought I would get familiar with this on the Cupcake.

Can you tell me how you set up the homing? I am use to centering the extruder about .2 mm above the platform and hitting print. But so far this software wants to push the bed out of bounds, and the extruder below the platform. I have the platform dimensions right, and the steps seem to be correct when using the jog controls everything moves the right distances.

Any help would be appreciated. Thanks!