Z-Axis_Brake

thingiverse

This thing prevents the bed of a Core_XY 3D-printer from going down after power-off. It's greatly inspired by the Anet A8 Z Axis Brake, created by Gear_Down_For_What, found on Thingiverse at https://www.thingiverse.com/thing:2238760. One motor with one lead screw can easily handle my 330x330mm bed assembly weighing over 4kg, except for the going down issue, which is hardly their fault. It's a familiar problem without a simple solution until I saw Gear_Down_For_What's idea. Great thanks. The usual stepper motors with 5mm axes are built to withstand sideways forces, but I use a motor with a built-in lead screw and I'm not sure about that. (I use this combination because I couldn't find a lead screw with enough accuracy.) So, I thought it safer to exert pressure on two sides and have some control over the braking force too. I don't need a motor coupling, but it would be nice to have some smooth metal to brake on, like in the original design. Something printed just won't cut it. Something like half of a coupling that fits the 8mm lead screw or the 5mm motor axis would work great. With the help of a saw (it's only aluminum), that's easily provided for. Check for sharp edges. In this way, people who use the usual configuration can use it too by placing this below the normal motor coupling in their "motor + coupling + lead screw" setting. If one has a coupling with two 8mm bores and uses a built-in lead screw, they can use that as a dummy without sawing, of course. A M2 bolt gives better control over the braking force than a M3 bolt, though there is just enough room for a M3 bolt if one wants to try that. An earlier lighter design gave way pretty soon, so I hope this sturdier one will keep. Otherwise, it's easy enough to make it still more stiff and exchange the open version. Don't hesitate to ask for it when you see your bed going down after a while. Remember: one would like to use as little pressure as possible to just prevent the bed from going down. Experiment a little with the M2-bolt. There are two variations: an open one in two parts and a closed one. The open one can be mounted and replaced without having to unmount anything else. I used: 2x M3x8 2x M3x12 4x M3 washers and nuts 1x M2x15 1x M2 washer and locking nut 2x M4x4 socket set screws to replace the originals (M4x6) which stuck out 1/2x flexible motor coupler (see text) PLA