Z Axis Belt Drive Brake



  • I'm thinking about using a cam brake system from a radio controlled car as an anti drop brake for the z-axis. Sprung loaded on and solenoid off. Anyone tried this, or got other ideas aside from not using belts for z-axis?



  • A worm gear drive will prevent bed drop and increase resolution over driving the belt directly with the motor.

    If you want to be able to resume a print after power fail, will your cam-brake keep the bed in the exact same Z position when the power fails?



  • Hi, While i have never tested a belt driven Z axis with a direct brake i did have some very good success with balancing the Z-Axis using a long expander rope. Basically i attached it at the Z carriage, and ran it up and down the entire Z axis a few times using pulleys. With the increased length compared to the Z axis travel, the force is fairly linear, and you can easily calibrate it to be "load neutral".

    Cheers!



  • @mrehorstdmd As it is there is a belt reduction drive running the main axis drive belt which increases the steps per mm to more than the typical 4 start TR8 (without using 0.9 steppers) with negligable backlash.

    I'll have another look at worm drives another time but recovery after power cut is not a significant concern for me. When I begin to get concerned by that I'll look at UPS. Thankfully power dips/spikes/cuts are rare here and I don't run long unattended builds.

    All that said while advocating the use of worm drives based on power cut recovery doesn't excite my interest it is more appealing from a risk assessment perspective the probability of the worm drive system failing to stop an axis in power cut is far lower than a cam operated brake and diagnostic coverage is naturally a part of standard running.


 

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