Answered Z steps per unit

Has anyone else seen an issue with "DEFAULT_AXIS_STEPS_PER_UNIT" being insufficient for Z? Upon receiving the R1 which was a "Manufacturer Refurbished" unit, I was able to print small objects ok, but they did not come out to correct height. I zeroed the extruder, measured distance between the bars and the bed, and issued a raise Z 100mm. Upon remeasuring I was significantly below 100mm. I discovered here that there was an occasional issue with the 5/16th firmware being loaded on an 8mm machine. That proved to be the case. Loading the correct firmware solved most of the issue but printing a 1X1X1 cube left the height still slightly under so I again checked the raise 100mm height. I was 9-10mm below 100. I started playing with the "DEFAULT_AXIS_STEPS_PER_UNIT" and increasing Z until about 2610 I was seeing an actual 100mm rise in the unit. I have left it at this setting and I am getting decent quality prints. The only other issue I found was that the fan on the ramps was unplugged causing problems on large prints.

The threaded rods and the flat rods are all lubricated sufficiently, all screw/bolts are tight, all belts are tight, I see no evidence of binding, everything moves smoothly. So really I am just looking for some opinions as to, has anyone else needed to change the setting, why would it be off on mine, or does is not really if 100mm does not raise 100mm?

Thanks for your time.
Nick

 

Thanks Mark, at least I'm not alone with this problem but apparently still pretty rare.