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 | Intended for delta printers only, but has been used on at least one CoreXY printer. See https://www.duet3d.com/DuetAddons/DeltaS.... | |
| DC42 IR Sensor | Small | Light | Most | Usually high when used with opaque bed surfaces, medium or 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 or medium | 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. Closed-source and patented, unlike many of the alternatives. | |
| 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:
- How to Test and calibrate a Z probe
- Information on Connecting a Z probe
6 Comments
The test and calibrate a Z probe link goes to the editing page.
Vance Howard - Reply
Thanks, I’ve corrected it.
David Crocker -
Hi, is the “dc42 IR sensor“ in the “configurator.reprapfirmware.org/Endstops” a “simple modulated IR Probe”? Should I post this in the forum?
Lucas Bahle - Reply
See the wiki page on connecting and configuring a. Z probe.
David Crocker -
Same question as Lucas Bahle. I went through the wiki page as suggested, but could not find a hint on what exactly to chose in the RRF Config Tool. Are there any clear and non hidden words?
I have a dc42 IR sensor wired, and now I am on page four of the RRF Config Tool (https://configurator.reprapfirmware.org/...). Now what is the correct choice there for the dc42 IR sensor? “Unmodulated or Smart IR Probe”? Or “Simple Modulated IR Probe”?
thx,
Stefan
Stefan Zurhorst - Reply