print object size bigger then 3d model object size

rlyt123456

Kossel hardware structure with 0.91 or 0.92.x firmware 

If  scale 3d model size form 1 to 0.97 in repetier-host，then print object size equal 3d mdel object size.

How can I fix this ?

Repetier

Delta printers distort objects when length are wrongly calibrated. Here I assume your steps per mm were correct which should be easy math to do so at least for belt driven systems. To be sure you can measure that with pure z moves where the geomatry has no effect. So measure height when at top, go down 100mm and measure again. If it is exactly 100mm the steps per mm are right and diagonal length/radius are wrong causing distortion. 

Try this

http://www.thingiverse.com/thing:745523

for calibrations. Seems suitable for length calibartion.

rlyt123456

Thank you for getting back to me.

Oh, I always only calibrate diagonal length/radius, I will try check steps.

 

When I calibrate diagonal length/radius, I measure  diagonal rod length and fill it to eeprom.

then measure  diagonal radius fill it , 

Next move x, observe nozzle movement locus, increase or decrease measure  diagonal radius to fix x/y movement arc. 

 

Maybe this is problem reason?

Should hold diagonal radius unchang, only change diagonal rod length ?

Repetier

This math is a bit too high for me. What I did was compute diagonal length from calibration and then adjust horizontal radius to have it flat again. Then repeat until it is converged. Now my length are correct (0.4mm difference before).

rlyt123456

Finally, I figure out problem where is.

My carriage width not equal effector width.

My carbon stick width in carriage side bigger then carbon stick width  in effector  side.

Thank you very much.