The Zortrax M200® performs auto-sensing of bed height by means of direct electrical contact between the nozzle and plated contacts on the bed surface, and an initial height offset supplied by software. This is a simple and inexpensive system, but corrosion, plate damage, plastic on the nozzle, and other factors can cause variations in initial layer height, which in turn can affect print quality, adhesion, and ease of raft removal. The small connector on the bed is easily damaged, and the plating on the bed contacts wears over time,. In extreme cases, contact or wiring failures can cause "crashing" of the nozzle into the bed, damaging the bed, nozzle, or both. And of course, the software-specified initial layer height necessitates use of a mechanical shim in order to increase the distance when printing with PLA and many other materials.
The Z-Sense Bed Height Control installs in minutes with no permanent modifications to the printer and eliminates all of these problems. It eliminates initial layer height variation, bed wear, nozzle damage, and the need to use a shim, while permitting printing on any build surface - glass, BuildTak™, PEI, tape, whatever you like.
The disadvantage of Z-Sense is that since it does not do automatic bed sensing, it should be recalibrated each time the nozzle, hot end, or build plate thickness is changed. Calibration, however, is quick and easy.