Reply with QuoteWhen it bogs down and/or emits smoke?Originally Posted by jschoch
underpowered spindle
how do you know when your spindle is underpowered?
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Re: underpowered spindle
When it bogs down and/or emits smoke?
Re: underpowered spindle
so if the magic smoke does not escape it is sound?
How do you differentiate bad bearings from boggin down?
Re: underpowered spindle
Bad bearings make noise, bogging down means it slows down or stops while cutting.
Gerry
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Re: underpowered spindle
I took my 500w brushless spindle apart and discovered quite a lot of dust inside. I also noticed that I can push/pry the shaft down with a nominal amount of force. The shaft is 12mm at the core and 10mm for the bearings (CX WHIST 6800Z) I'm assuming there is some intentional pre-loading but this seemed like way to much movement axially. I had a thin washer and put it in the rear bearing housing to see if taking the slop/spring out could be done. It spun up but it also heated up quickly (as expected). I'm wondering if I should attempt to make an additional spacer to take the axial slop out? I think this is creating quite a lot of chatter but i'm not sure. I notice chatter on ramps quite loud. adaptive cuts seems to run ok.
Also regarding bad bearings, they were not super super smooth but the motor is nearly silent running at 12k rpm. How much can I tell from running the bearings with no load?
Re: underpowered spindle
Those small brushless spindles are pretty nice, but they have a few problems:
- The original bearings are junk;
- The bearing preload is not adjusted at the factory;
- The drive (DDBLDV 1.0) is very easy to burn out, so don't try any large diameter tools or deep cuts with that spindle.
If your bearings are silent at 12K, they are probably OK. The "not super smooth" feeling could be just the motor cogging.
How hot do the bearings get? The correct amount of preload should make them somewhat warm. The axial slop definitely must be eliminated.
Re: underpowered spindle
All you have is a regular 500w Dc motor, this was not designed to be used as a spindle, they just mount a ER collet on the shaft and call it a spindle, the bearings are not even correct for a spindle as they are just regular deep grove ball bearings which you can not successfully preload them, these motors need axial movement so as they heat up they have some clearance expansion room in the bearing housing to move in, so you won't be able to eliminate all of the axial play you have
As for being under powered, you have to limit the size of cut you make, they are not very good if you want to do a lot of profile cutting, are ok for engraving, they are only 12,000 RPM which also limits how fast you can cut with it ( Feed Rate )
Best would be to make a real spindle if you want quality parts, and then use this motor to drive the spindle
Mactec54
Re: underpowered spindle
Thanks for the feedback. I feared the deep groove bearings were the problem.
any suggestions on parts to make the spindle with? I has no lathe
If i can't make a spindle without a lathe I'm thinking I should get a 800w with angular contact bearings to save on weight. I don't think I need much more HP or weight but I may be wrong. Searching .8kw spindles seems to show some with deep groove and some with angular contact. Wondering how to avoid another bad choice in spindle.
