This curiously shaped device prevents hard drops of the Z stage on the MakerGear M2 when the motors are turned off and disengage. It is designed to have enough flexibility to gently slow the Z stage to a halt, but not prevent the Z stage from being pushed all the way to its maximum extent if needed. It slips over the M2's frame base and snaps into place. It is designed to be printed in PETg, which has the right amount of strength and flexibility for the spring's thickness, width, and curvature as designed.

The original version worked but was incorrectly sized, and so has been deprecated and removed. There are now three versions: springcurve2, springcurve3, and springcurve4. Springcurve2 installs with the curve pointing toward the back; in this position the curve must be made narrower and is therefore stiffer. It has not been tested. Springcurve3 is a re-creation of Michael Hunter's Z axis return spring (http://www.thingiverse.com/thing:615104), but with the ability to clip onto the frame base like the other springcurve models. I find that it exceeds the strain limit of the plastic and tends to permanently deform it. Springcurve4 installs with the curve pointing toward the front. It is a direct derivative of the original springcurve model, but correctly sized, and the front of the base conveniently snaps into place. This one has been installed and tested, and is the recommended model to use.

Inspired by Michael Hunter's Z axis return spring (thing 61504).

The model "springcurve4" has been tested and is the recommended model to print and install.

Use PETg filament, which is what this is designed for. ABS probably works about as well. PLA is too rigid/brittle for the application.

Install springcurve4 with the end of the curve facing forward on the M2. The curve should meet the base just forward of the wiring harness. With the motors disengaged, let the Z stage drop from the height of the extruders. The springcurve should stop the base gently. It should be possible to continue to crank the Z stage down with minimal force; this should not cause the springcurve to permanently deform.