[Elecraft] Surface Mount tech et. al.

[Tim, N9PUZ]

On Tue, 07 Jan 2003 16:44:14 -0500, Morrow, Michael A. wrote:

>I would really *like* to see the introduction of kits with many
>surface mount parts AS LONG AS THOSE PARTS ARE PRE-ASSEMBLED on=
 the
>PCB.  SM parts are not designed for Human installation except in=
 the
>most limited and (to me) trying of circumstances.
>Pre-assembled SM parts would make the kit parts inventory=
 process
>easier, reduce the amount of time spent in the (to me)=
 mind-numbing
>process of sticking fixed-value resistors and capacitors on a=
 PCB
>for hours at a time, reduce the opportunity for builder error,=
 and
>result in a product that would likely be more reliable.

The problem for the manufacturer is if you machine place a few or=
 even one 
SMT part on the board you incur nearly the same cost as if the=
 whole board 
was surface mount. You need the board to make a pass through the=
 silk 
screener, pick 'n place, and reflow oven to do one part. The only=
 time that 
varies is at the pick 'n place machine. Most manufacturers that=
 can do SMT 
work have fast enough equipment that there probably isn't a big=
 time 
difference in placing 1 part or 100.

Another issue for SMT is with small runs of boards. The=
 programming, 
component loading, screen cleaning, and oven profile changes all=
 take time 
for which the customer is charged. Most contract manufacturers=
 need to run a 
lot of an identical board to be able to offer a price that would=
 make the kit 
price reasonable.

Tim,  N9PUZ
http://www.qsl.net/n9puz