a question on xy scaling

[stonewater]

I have a reprap full gaphic smart controller I am installing it on my robo. there is a case for it on thingiverse. the x and y dimensions according to the edit function in mattercontrol are x dim of 98 mm y dim of 91.8 mm the print came out x dim 96.8 y dim 90.89. its JUST to small for the LCD to fit in the case is there a way to correct for xy scaling errors on my max?

here is the STL

Tom C

[JFettig]

Diagonal rod length needs to be decreased

[stonewater]

thanks I will step it down.

Tom C

[jetpad]

I'm having a similar issue. Were you able to fix your problem with that adjustment? Since your part is distorted by a different amount in the X and Y, I would think that adjusting the single diagonal rod length value wouldn't let you scale on the X and Y axis separately while keeping Z the same.

[0110-m-p]

X and Y should scale differently because the rod angle rate of change is different when moving in X vs. moving in Y. I don't know what the ratio would be (probably depends on rod length), but Y moves directly toward and away from the Z-tower, while X moves are at an angle from all towers. So it would make sense that if the rod length variable of the delta equations changes, then the X and Y distance moved would be different since the math to calculate that distance is different.

If you'd like to read more about delta printer kinematics...

https://groups.google.com/forum/#!topic ... 6ATBdT43eU" onclick="window.open(this.href);return false;

EDIT: One thing to note though...If your print is dimensionally accurate in one direction but not in the other two (say X is off, but both Y and Z are accurate), then it probably isn't rod length since changing rod length will also make the parts bigger or smaller. More likely that the machine isn't square in some way.