acoustic metrology

Another Monday on the job.
You perform a "ring" test on a 14 inch vitreous grinding wheel prior to mounting
on cylindrical grinder. Then there is an incident----the wheel fragments with workpiece damage
and personal injury.

Shift supervisor questions you regarding wheel mounting protocol.

Does an undocumented ring test count as metrology?

here is german firm RTEAkustik approach to a acoustic testing----2 minute clip

http://www.youtube.com/watch?v=GR0gZoAYvVc&feature=channel&list=UL


jh

Does an undocumented ring test count as metrology?

Click to expand...

At least, here it is part of the required safety check.
Ring test (already done at the manufacturer, must be repeated at customer site), and let it run for 5 minutes (may vary from the type of binding). Rubber bound wheels (IIRC) have to be disposed of after 5 years.


Nick

Gentlemen

thank you for response. This incident is somewhat based upon a Cincinnati Milacron safety program of about 40 years ago.
This course also included slow motion video-vhs-of 30 hp centerless grinding wheel exploding. The 14,000 lb stripped down grinder actually jumped off the shop floor. deadly wheel fragments filled the air.
I have not been able to find this footage since I viewed it in 1994. I called the Milacron company and the libraries of Cincinnati township and university--no luck.

Documentation would include a signed notebook form stating operator completed ring test prior to mounting. Better yet, a printout of spectral pattern
of acoustic recorder taped in grinder day book.

I worked 35 years as surgeon-- a great deal of maxillo-facial trauma.
two grinding wheel cases are worth noting. both from same small town. in each event, an electric motor was used to drive a sandstone axe grinding wheel
intended for hand or foot power. the wheels exploded. I examined one man and sent him to Seattle by helicopter--he had exposed brain. He survived.
in the second case, the victim lost both frontal lobes and was pronounced dead in the aero-vac helicopter.

jh

I just imagine a crank-shaft-grinding wheel exploding. Not one of those lousy ones you see at YT, but one for production. Wheels of more than 1.5 m in diameter!
There are standards by the BG (our OSHA) that define the cages around the wheels depending on the diameters and speeds.


Nick