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Path: utzoo!watmath!watdcsu!herbie
From: herbie@watdcsu.UUCP (Herb Chong [DCS])
Newsgroups: net.audio
Subject: Re: Re: Cassettes / Audio Amatuer
Message-ID: <1259@watdcsu.UUCP>
Date: Wed, 17-Apr-85 09:47:48 EST
Article-I.D.: watdcsu.1259
Posted: Wed Apr 17 09:47:48 1985
Date-Received: Thu, 18-Apr-85 01:44:03 EST
References: <1477@decwrl.UUCP> <451@cybvax0.UUCP> <462@edison.UUCP> <1620@ut-sally.UUCP>
Reply-To: herbie@watdcsu.UUCP (Herb Chong [DCS])
Organization: U of Waterloo
Lines: 32
Summary: 

Someone wrote:
>> > 	I heard a rumor (i.e. take it for what it's worth) that the companies
>> > that use screws to join the shells together do so for product appeal (looks
>> > sturdy) and not for any practical reasons.  
<deleted comments by other people>

the real reasons are that
1)	it is easier to control amount of pressure in precison molded
	cassette halves (TDK quotes 10 microns for each half) by torquing
	the screws instead of sonic welding.  with bubble slipsheets
	the force on the actual tape can be known just from the force
	required to advance the screwdrivers (which are totally automated
	gun-types capable of doing about 2 cassettes per second).

2)	it is practical for repair broken cassettes wich are screwed
	together, but then the optimum pressure is no longer present
	unless you have a screwdriver with a torque gauge and you know
	what it is.  

it is far more expensive to use screws than sonic welding, so no
manufacturer is going to use it unless there is another overwhelming
reason to.  most do because of the requirements to maintain consistent
and standard tape skew between tapes and batches of tapes.

Herb Chong...

I'm user-friendly -- I don't byte, I nybble....

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