When we talk about the accuracy of FDM 3D printer, there should be mechanical accuracy, layer thickness accuracy and print accuracy. The one we care the most is the print accuracy, but most of the manufacturer just intend to declare the layer thickness accuracy or mechanical position accuracy instead of print accuracy, it could be the wrong direction to the customers.
As we all know, FDM technology is an additive manufacturing method that creates parts additively with a filament, which is deposited layer by layer according to the digital files. Meaning the layer thickness accuracy has the effect on the dimension accuracy of the prints and is part of the print accuracy. The layer thickness accuracy is around 0.1mm~0.3mm per layer, which is affected by mechanical accuracy also.
The mechanical accuracy is the position accuracy of X, Y, Z axis, which is around 0.01mm in XY axis and 0.0025mm in Z axis. There are lots of impacts on the mechanical accuracy, like stepper motor, motor driver chip, synchronous wheel, the belts, polished rod and so on. Each part independently affects the accuracy and there will be the stacking effects when we combine them together.
So it is better we can take into consideration of the layer thickness accuracy, the mechanical accuracy and the shrinkage of filament when we measure the actual print accuracy, or we should call it theorical accuracy value.
The same, this is also the case with our printers. Although the layer thickness can be controlled at 0.1mm, if the software of the machine does not cooperate well, it will also happen that 10mm objects will be printed to 9mm. For the mechanical positioning accuracy, the nozzle out of the silk is 0.4mm, has far exceeded the mechanical positioning accuracy, and the mechanical positioning accuracy is not the same level. The final or see the overall performance of the machine, that is, molding accuracy. But to tell the truth, this level of machine, do not and the traditional processing industry to compare, or you will be disappointed.