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Subject: Re: [Homebrew_PCBs] CNC mill X-Y tracks?

From: "Stefan Trethan" <stefan_trethan@...>
Date: 2005-06-25

On Sat, 25 Jun 2005 03:00:11 +0200, uhmgawa <uhmgawa@...> wrote:

>
> I'd imagine tape reels are a non-issue for the type
> of prototyping under discussion here. As you suggest
> a far more common scenario is dealing with cut tape
> segments. But even here I don't see the advantage
> to gradually pull back the tape as components are
> consumed nor much of an overall advantage to peeling
> off the tape from a strip and feeding from the exposed
> carrier. It is likely for some unused components to
> remain and you'll need to find another home for them
> anyway.
> I've just abandoned the tape carriers all together and
> strip components wholesale from them over a funnel which
> feeds into a small ziplock bag. I can dump whatever I
> need into a tray for placement and the excess goes back
> to the bag via funnel. The bag also offers a much more
> hospitable means to identify component values compared
> with the carrier tape.

I was thinking you cut off the required amount of parts for the number of
boards you intend to make, and put that on the machine. I use the strips
extensively, and like it much more than loose components. The strips can
be written on, and the parts are in little drawers, so i see no need to
further identify them.


>
>> For other components like ICs that you don't have in strips one might
>> mill
>> out small indentations in a plate.
>> of course this would also work for smaller parts.
> These days prototype IC count tends to be far lower
> than days gone by. Such that I don't have much of
> an issue just sitting the packages on a foam slab
> prior to placing. Alternatively if you need to
> prebake the packages before reflow soldering to avoid
> popcorn damage a metal tray works as well.

What would that help? sitting them on foam would require you to build some
kind of machine vision, which is a vast amount more difficult than just
pick here place there.

ST