Prints off by 10%

[USMCPelto]

When I export the file, the dimensions in Solidworks are 12.75mm, when Sliced, the resulting G-code has 64, 0.2mm layers, or 12.8mm, but when the end product is complete, it measures 14.35mm tall. Any ideas?

[Polygonhell]

When I export the file, the dimensions in Solidworks are 12.75mm, when Sliced, the resulting G-code has 64, 0.2mm layers, or 12.8mm, but when the end product is complete, it measures 14.35mm tall. Any ideas?

How many layers does the slicer tell you it has?
i.e. is it actually supposed to be 12.8 mm tall.

The only firmware configuration that affects height is the steps per mm setting, what sort of pulley do you have and what's the setting in the firmware?

[USMCPelto]

Slicer reads 64 layers, which is exactly what it should be. The object should be 12.75mm, but it rounds to 12.8 would be my guess. As each layer should be .2, it should be 64 layers, and indeed that is what Slicer states. I have some of the newer stepper motors. I followed the instructions on setting those. I was able to print it to the right size if I scaled it in Slicer.

[dsnettleton]

I'm leaning towards steps/mm like Polygonhell, since your height is off. Try homing your axes (G28), then marking the top of your bearing fixtures on the aluminum rails with a pencil. Then lower the printer head by 300mm. Since my printer height is set to 370mm in both my firmware and Repetier-Host, I do this with the GCode "G1 Z70 F1200", where G1 is the instruction, Z70 means set the Z position to 70mm, and F1200 is the feedrate. Measure the distance from the top of your bearing fixture to the pencil mark on your rail. It should be exactly 300mm. If it's more like 330, you're definitely getting a 10% increase on your steps. I believe the new stepper motors are supposed to be 80 steps/mm on the 20-tooth pulleys. Also, don't forget to check your EEPROM settings (Alt+E in Repetier-Host). These might be different from your firmware settings, and usually take precedent.

[Polygonhell]

The other thing to remember here is if you do find the steps/mm are incorrect, currently it has to be fixed in BOTH places, the EEPROM number and the number you set in the firmware have to be the same. This is a "bug" in repetier firmware, it uses the firmware numbers to compute constants for the Delta motion, but uses the EEPROM value when actually moving the motors, if they don't agree you can get massive doming in the motion of the head.

[dsnettleton]

The other thing to remember here is if you do find the steps/mm are incorrect, currently it has to be fixed in BOTH places, the EEPROM number and the number you set in the firmware have to be the same. This is a "bug" in repetier firmware, it uses the firmware numbers to compute constants for the Delta motion, but uses the EEPROM value when actually moving the motors, if they don't agree you can get massive doming in the motion of the head.

I didn't know about the bug, but it's a good practice anyways.