Archive of the former Yahoo!Groups mailing list: MOTM

The 2 main problems with going all SMT, all assembled route for MOTM:

a) you HAVE to use specific reel sizes for SMT "loaders" if you want the machine to place the
parts. The problem is: these reels hold ∗5000∗ caps/resistors or ∗2500∗ diodes/transistors/etc.

Look at any kit BOM. Look are the number of ∗different∗ resistor values. See the problem?

The 5% resistors are cheap, a reel is like $22. However, caps are like $280 a reel! So, I'd have
to spend several $$$$ of dollars buying 40-60 reels of stuff. AND THEN.....about 10% of the
caps/resistors are hand placed anyway, because of the precision 0.1% stuff (a reel of these are
like $13000!!!!)

b) the solder paste is applied through a precision laser-cut stainless steel screen. This screen
is unique to each board. These screens are about $500 EACH (1 per module). AND....let's say I
build 150 EGs. Then I run out. I have to run at ∗least∗ 100 more (and pay for ALL 100 in 30 days,
even if it takes 4 months to sell them all). You can't call up and get 20 more of a SMT run: it's
in batches of ∗100 at a time∗. The screens have to be cleaned and set up in the machine (called
"registration"). The fee for that: $375. Oh...then, the operator has to unload the parts reels
for the prior job, and load in MY reels (in the ∗correct order∗). This charged $5/reel. So, a SMT
run for 1 board, before you place 1 part on it, can be easily a $800 "set up charge". Running
10,000 motherboards? big deal! Running 100 MOTM....$8/board for 'nothing'.

Well, the conclusion is: there is not much I can do except plow ahead.

Paul S.
2 oxen and 100 acres to plow