Choosing a Z probe

The type of Z probe used can have a significant effect on the quality of first layer achieved. For delta printers using an appropriate Z probe is important for accurate auto calibration

There are many types of Z probe available. This table may help you to choose one suitable for your printer.

Type	Size	Weight	Compatible bed surfaces	Precision	Remarks
Duet3D Smart Effector	Medium	Light	Any	Very high	For delta printers only. See https://www.duet3d.com/DuetAddons/DeltaS....
DC42 IR Sensor	Small	Light	Most	Usually high when used with opaque bed surfaces, medium or sometimes low with transparent surfaces	Transparent surfaces (glass, PEI etc.) must be backed with a matt black surface. See https://miscsolutions.wordpress.com/mini....
Hot end mounted piezo	Medium	Light	Any	Very high	See https://www.precisionpiezo.co.uk/shop.
Under-bed FSRs or piezos	Small	Light	Any	High	For FSRs use JohnSL interface board. Mainly used with delta printers. Trigger height may vary a little with probing position.
Inductive	Large	Heavy	Steel, or aluminium without glass on top (thin PEI is OK)	Medium	Most types need 12V or 24V power. Trigger height may vary with supply voltage and temperature.
Capacitive	Very large	Heavy	Any	Low	Trigger height is affected by temperature and humidity
BLTouch	Medium	Medium	Any	Medium	Needs an expansion pin assigned for probe control. Design is closed-source and patented, so not RepRap friendly.
Servo deployed switch	Medium	Medium	Any	Medium	Needs an expansion pin assigned for probe control. see http://reprap.org/wiki/Z_probe#Microswit....

Important note!

If your Z probe is separate from the nozzle (i.e. all the above types except the Smart Effector, piezo mounted in the hot end, or FSRs/piezos under the bed), then if the print head tilts as it moves in the XY plane then the relative heights of the nozzle and the Z probe will vary with the tilt. This will cause apparent variations in the trigger height with XY position. This effect can be minimised by mounting the Z probe as close to the nozzle as possible. The DC42 IR sensor is designed to be small enough to fit below the heatsink of a E3Dv6 hot end.

Tilt is not usually a serious problem with Cartesian and CoreXY printers, but it is hard to eliminate it completely on delta printers. Therefore, nozzle contact probes are recommended for use on delta printers.

More information on Z probes: