Z-Axis and Ball Screws

[Swede]

Gas springs (like auto hatchback springs) come in a huge variety of sizes and forces and make a nice, neat countering force for a vertical axis. Even if the Z axis is not backdriving power-off, a countering force will make the Z quicker with less wear/tear on the motor and screw, and it will allow you to use a somewhat smaller Z motor as well.

But a brake system is excellent too, probably the best overall answer.

[samualt]

Anyone have some pictures of a brake for the Z-axis. Or does that have to be built into the motor? I haven't been able to find a picture, much less where to buy one. I probably don't need it but I might as well learn about them.

Thanks for any info...............Sam


Here is a picture of my new baby. Just got it on Ebay (.80" width, 9" travel, 5 TPI.)
Ain't she a beauty! If I had cigars I'd pass them out!

[HuFlungDung]

Samualt,

You are using servos, aren't you? I would not worry about it. The servo can easily hold it tight, without even getting warmed up.

Little do some users know, but when climb milling, the cutter is attempting to "backdrive" the ballscrew all the time. The servo acts more like a "metering device" because the cutter is actually driving the work ( in heavier cuts). In a carpenter's terms, climb milling is most definitely like "ripping from the wrong side" of your tablesaw.

[lsfoils]

Hi Samualt,

A little late but here is a screen shot of the design I'm going with. I am running the Z nut @ 1:1 with the stepper and so I won't get any help holding the assembly in place when the power is off. I plan to counter some of the weight but I don't want to take any chances. My boss' Multicam has a brake. It has slipped 2 times now and his Italian spindle did things he didn't like. Anyway, I'm going to use a cheap 110 volt solenoid and when the router comes on the solenoid will retract the spring loaded brake shoe. I found a solenoid in the C and H catalog that says continuous duty for around $6.00. Half amp draw shouldn't give me any trouble. Holler if you have any ideas or questions.

-Doug