At 02:44 PM 12/7/2005 +0800, you wrote:
>Lately I have to deal with more and more mechanical
>and process issues even though I am an electronics
>engineer. I have some basic mechanical knowledge but
>not much.
>
>Are there any good tutorials on plastic mould? It
>seems to be very important but quite a difficult topics.
>The mould is always not cheap to make and
>hard to modify, not like electronics circuits. ;-(


I have "Plastic Part Design for Injection Molding", Malloy, along
with a small shelf of books on mold and die design.

Given the costs involved, and the special knowledge, it is probably worth
your while to subcontract the detailed part design to experts-- first in
the mechanical engineering and then the mold design and mold making. There are
many subtleties, and the people who are good at mechanical engineering
and plastic part design are just as smart and knowledgable as those in
electronics or programming. But at a minimum if you are involved in the
design process  you should know a bit about minimum draft
angles, polishing and texturing, constant wall thicknesses. Snap fits are
another complex area for mechanical design, at the best of times.

As with circuits and firmware, you can learn a lot by looking at existing
well-designed parts-- measure the wall thicknesses, try to figure out the
reason for every feature- stiffening ribs, fillets, where is the parting
line? where are the ejector pins? where was the gate? what plastic
was used? crossovers? slides?

>I am also interested in the ABCs of ultrasonic
>welding. It seems to be a cheap process than gluing and
>laser welding but seems very hard to get good quality
>in terms of IP protection (for example IP67: air tight).
>Note this IP is not Intellectual Property but Ingress
>Protection.

Branson has a rather thin book on this. I don't know a lot about the book
or the process, other than having seen it in operation. The horn is custom
to the job and costs a fair chunk of money, IIRC. I'm more familiar with
elastomer seals to achieve seals.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


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