Mbot Cube part fit tests failed but FlashForge is ok

I found one serious problem when printing with mbot cube. The inner hole will become smaller than expected. I use latest mprint version and default options for PLA.

To test that, I use http://www.thingiverse.com/thing:52946, and print the test_print.stl. The cylinder is ok, but the hole is 0.5mm smaller, so the cylinder can’t insert into the hole. I also printed the plug_test2.stl, still can’t fit.

Then I tried to print using Makerbot Desktop and print on another FlashForge Creator Pro machine, everything is fine, the cylinder can fit the hole. Then even I use the same x3g file to print on cube, it didn’t fit.

To find why, I use Slic3r 1.2.7 to print lots of tests and found setting the extrusion multiply to 0.9, the parts fit. So I guess mbot cube’s extruder is not perfect calibrated, so it extrudes more plastic than expected and makes the extrusion width wider than expected.

Another parameter will affect the result is the nozzle size. I know nozzle size is 0.4mm, but is that the exactly measured value? I can’t measure the nozzle size because it is too small.

So to solve the problem, I can use Slic3r and set the multiply to 0.9, so it will extrude 90% of the plastic. But Mprint will not be fixed.

I know there is a json file contains the steps_per_mm for each axis, so if I adjust the A to be smaller or larger, I think it will extrude different volume of plastic. Don’t know if this is good to fix.

If you want to talk to me more or discuss using Chinese, please contact QQ: 38288890 or reply here.

Anyone here to give me answer?

Onething to mention, after changing the extrusion multiplier, actually there are less plastic to extrude, this leads the top fill not solid. So this is really bad.

Hi derekhe,你反馈的这个问题,我们以前有发现过,打印后的模型尺寸会存在一定偏差,大概在0.2~0.4mm,视模型结构而定。减少喷头挤料并不是解决问题的办法,因为同时会带来其他问题,我们会尽快找到解决办法,下周给您回复。

好的哈,但是同样的模型(包括那个小的圆柱的和那个S形状的)用FlashForge Creator Pro又是好的,所以我想可能是哪些地方还需要改进。



对,最新版的MakerBot Desktop


我用同样makerbot生成的同样的gcode,用gpx -m mg18生成s3g,在我们打印机上也有问题。