4 replies to this topic

[dr thrust]

hmm, got a slight problem my old ball mill sounds like a cement batching plant, so i need the tone the noise down a bit, are there any issues with the milling apparatus being enclosed in a box? the box is foam lined loose fitting with no fixings to the base and will have a hinged lid, also i mill out side and the jar is empty in the vid to show its full noise potential! noisey thing

[pudi.dk]

I'm currently digging a hole in the ground outside to put the mill in.

Both to reduce sound, and to prepare for possible explosion when milling BP.

[cooperman435]

Chris I have almost exactly the same setup but am planning a new ballmill that is itself housed inside a sealed box with sound deadening and doors.

[pyrotrev]

With my "other job" being an acoustic/audio engineer I'll try to offer some help. Rule #1, if you can reduce the noise generation, you're quids in - so line your milling jar with rubber. Rule #2, most noise problems are increased by conduction to other objects that resonate/radiate the noise - so either sit your mill on something SOLID like a solid concrete/stone floor/earth or support it on some rubber blocks to isolate it from the substrate. Enclosing it in a box is a good idea, but you'll have to take heat buildup into account, not just from the motor, but a certain amount from the mill as well, after all we are milling explosives that can be initiated by heat. The box should be isolated from the mechanism (=not touching in any way) sealed with a dense foam gasket as far as possible, and ideally lined with an acoustically absorbent foam (do a search for Pyrosorb S). To get the necesary ventilation your best bet is forced air cooling through as small an orifice as possible, if there's a noise issue with this, forcing the output air path through zig-zagged bits of acoustic foam will give some useful reduction as well. Otherwise just make the box big to maximise heat transfer through the walls , and DO put a thermometer/thermal trip in to monitor the temperature. All this is assuming that you've got sufficient safety distances anyway, Pudi's idea of digging it in would be a good idea unless you've got a LOT of space and or no neighbours - if you think I'm being fussy get an old mill jar, drill a Visco sized hole in the side, fill with good BP meal and milling media, take to a safe place, insert (long) fuse, light and leg it whilst a mate films it!

[dr thrust]

thanks for the input chaps just didn't want to make something that could be potentially dangerous, ill take on board everything you've told me, the rubber mat liner is a great idea,( the simplest ones always are!) and ill check for heat build up in the box and vent accordingly,

the foam lining in the box was free we've renovating a pub at the moment and all the floors in the apartments above the pub are having "sound block " chipboard with a foam/ rubber Matt/ foam sandwich glued to the bottom and i thought there must be a use for this? (skip rat chris)