Richard Cann This is Me

 Web References

1. 1. AMCE home

   www.ammagazine.com/amce2000pro - [Cached]

   Published on: 9/6/2000   Last Visited: 9/6/2000

   Richard Cann, Corporate Consultant, RH Lyon Corp
   
   Accelerating Product Development Using Rapid Prototyping Systems

2. 2. Acoustical Society of America - Decibel by Decibel, Reducing the Din to a Very Dull Roar

   www.acoustics.org/swa9602.html - [Cached]

   Published on: 12/6/1999   Last Visited: 9/15/2000

   This makes too much noise, unpleasant noise, announces one RH Lyon engineer, Richard Cann, in the inflections of his native London. He is holding up a weed whacker. From the same bench he picks up a partially dissected leaf blower. This fellow is the most unpleasant. it be now banned in about 150 communities, he continues, contemplating the eviscerated blower as if it were a dead adder. It has to be lightweight to ride on your back, which leaves little room for noise-control materials, says Cann, adding that the gasoline-powered tool--essentially a vacuum cleaner in reverse--blows out a 250-mile-an-hour gale. you have got the wind whooshing through a nozzle, plus a noisy fan, and manufacturers worry their products will not be usable..
   
   Cann, a Cambridge University-educated engineer, has been a part-time RH Lyon noise detective since 1977. He has now turned his attention to a belt sander, which he has under sonic surveillance. The power tool hangs from strings, suspended just above the floor. that be where you might hold it to give it a try at the store, he explains, adding that he also will probe the sander's sounds when it is actually sanding a board. The manufacturer wants to know why it be so noisy, and what changes they should make on their new model. Inside the tool, Cann notes, a high-speed motor drives a belt, which turns a speed-reduction gear. The gear then turns the sanding belt. Because the motor generates heat, the sander's metal casing is slotted for ventilation. An internal fan draws in cooling air and blows it out, while a second fan blows sawdust through a channel inside the sander and out a slot at the back into an attached bag.
   
   All three processes--belt driving, motor cooling, dust extraction--are driven by the same motor ; all make noise.
   ...
   Cann must identify which processes are making which noises, pinpoint objectionable sounds and decide what to do about them. That means sleuthing. For instance, look at this belt that runs inside the sander, Cann suggests. The belt is ridged to engage cogs on the pulley that turns it. Each time a ridge of the belt fits between cogs on the pulley, a little puff of air squishes out, creating a noise. The pulley has ten teeth, so the belt is making ten air puffs every time the motor turns, creating an amazing amount of noise. Meanwhile, the sander's fan blades produce whirs and buzzings. You also get turbulence as the fans move the air--and with the grating of the sander against wood, altogether it sounds like a small jet taking off, says Cann.
   
   One key question is how the sander radiates its sounds. Do all the sounds come from the vibrating of the sander's metal shell? Or do some noises emanate from inside, through the sander's ventilation slots? To find out, Cann has puttied up all the ventilation slots to see if that makes a difference. But, as usual, the test creates its own complexity. We have to test the surface vibration before and after puttying up the vents to be sure that the putty itself is not changing how the shell of the sander vibrates, Cann points out. Our other concern is that, with the vents puttied up, will it melt down? So we have to do our tests quickly..
   
   That is what Cann now does, aiming a microphone at both unputtied and puttied sanders and letting them roar. The sounds turn up as frequency-graph squiggles on a nearby attached computer, with spikes indicating particularly loud noises. That one's about 100 decibels for the user, says Cann, pointing. Because he knows the specifications of the sander's various moving parts, he can mathematically deduce which parts are making which spikes. By comparing the puttied and unputtied sanders, he can determine which sounds waft from the ventilation slots. And by puttying only some slots, he can begin to pinpoint which parts make which noises. Look at the graphs, he says. The air holes are a major part of the sander's problem, and you can not fix it without dealing with that--you can see that with the puttied sander we have reduced the noise by 10 decibels..
   
   It is painstaking work. But backers of an experimental new technology called active noise control (ANC) promise to make silence easy. The idea is to wipe out a noise by generating a diametrically opposed sound : where the unwanted sound's time graph has a peak, the anti-sound has a valley, and vice versa. When the opposed sound waves intersect, they cancel each other out and all is silence.
   ...
   Did you ever try to drive a big luxury auto with the power steering turned off? asks Richard Cann, remembering the project's rigors. It did lead to a conclusive finding : no noise came from below. No shield was in fact necessary.
   
   Sometimes, instead of trying to eliminate noise, the acoustic engineers exploit it. For General Electric, for example, RH Lyon developed a diagnostic system that senses surface vibrations on a diesel locomotive's engine block. The data--properly processed--reveal combustion pressures inside each of the diesel's 16 cylinders.
   ...
   There was a noisy computer hard disk, too--the solution turned out to be drilling holes in the right places, remembers Richard Cann.
   
   Such work can lead to sensitive ears. Cann has discovered that by repositioning a newspaper that he is holding up, he can make his wristwatch seem to tick louder or softer. And not long ago, at lunch in a noisy Cambridge cafe David Bowen suddenly looked distracted. A new roar, muted by distance, had added its note to the din. Abruptly Bowen brightened : Dishwasher! he announced triumphantly.

3. 3. Science News Magazine - Sources - This Week 12/21/96

   www.sciencenews.org/sn_arch/12 - [Cached]

   Published on: 12/21/1996   Last Visited: 8/6/2001

   Richard Cann RH Lyon Corp 691 Concord Avenue Cambridge , MA 02138 E-mail : lyoncorp@lyoncorp.com