Re: [rp-ml] AM and non-metal parts

This is already starting to get pretty ridiculous and I think those that actually DO manufacturing for a living would strongly disagree with those of you who think AM is ready for "prime time" and ready to fully compete with more traditional methods of manufacture. This rather alarming lack of insight into the everyday problems confronting manufacturers of real parts could have a lot to do with RP's slow acceptance among the traditional manufacturing community.

First of all, NO consumer is going to accept products that don't have a smooth, accurate, staircase-free, and "nice" looking finish - you can argue with them till you're blue in the face that it really doesn't matter but the simple fact is - they just won't buy it. It is still the case today that ANY functional, durable, and salable item (with the exception of purely static and/or structural items) will have a medium to high level of metal content and very good surface finish. ANYTHING with moving parts that is meant to last for more than 1-2 years, will contain considerable amounts (by weight at least) of metal. Besides bearings, you need motors, conductors, bushings, gears, pulleys, shafts, pistons, supporting frames and strong cases, etc., if anything is going to be able to "do anything" for very long besides - maybe - sit on your desk (to show to students). Do you want your car to be made from 100% plastic, including the engine, body, wheels, and
 transmission? And for all the wonders of composites (including for airplane fuselages) , I don't think Boeing is going to be putting composite engines in its planes, anytime soon. People deeply involved with the field of RP also should make a habit of getting out more and actually talking with those whose daily lives involve the (traditional) manufacturing of real products that must actually perform a function and be able to satisfy consumer and industry demands (as opposed to decorating a desk or impressing oneself). I am getting the impression that many involved with the field of AM are happy just talking among themselves. AM parts have a LONG way to go before they can compete, in any significant way (except in biological fabrication), with more traditionallymanufactured parts. That is one reason I will be sticking with the term RM instead of AM. I guess it goes without saying that I still REALLY like my stuff made from metal, so hold the corn-starch,
 please :-).

G. Sachs

P.S. By the way I was talking a few months ago with a fellow who swore he would never again buy a Ford vehicle because the last one he owned came with, the latest and greatest in, plastic intake manifolds! He said he had to replace three of them within a few years because they had the annoying habit of MELTING! So much for the wonders of plastic and the latest and greatest in manufacturing techniques. Sometimes 'new' is not always better - and that goes for manufacturing methods as well.

________________________________
From: Adrian Bowyer <A.Bowyer@bath.ac.uk>
To: G. Sachs <sachsg@sbcglobal.net>
Cc: rp-ml@rapid.lpt.fi
Sent: Tue, January 12, 2010 3:43:45 PM
Subject: Re: [rp-ml] free STL Files and other (free) things we wish for in the new year

The volume (not the mass) of steel and polymer used annually in the world is roughly the same. There are more metals and metal alloys than steel, of course. But there are also many more things made out of neither (when you add the building industry in). So I think it's highly likely that, as Marshal says, "Most products are not made from metal alloys."

As I look at the objects around me in my lab (which you'd expect to require more precision than average) the only parts of any of them that need machining accuracy are bearing surfaces, and locating holes and projections. The rest (the vast majority of their surface area) could be +/- 1mm or more and still function just as well. So it certainly is the case that, "many parts of most products do not need machined accuracy."

Best wishes

Adrian

Dr Adrian Bowyer
http://people.bath.ac.uk/ensab
http://reprap.org

G. Sachs wrote:
> Marshal Burns: "Most products are not made from metal alloys and many parts of most products do not need machined accuracy."
>
> Marshall, I was a big fan of yours in the early days of RP (and still have your book), but this just isn't right and I'm surprised that anyone involved with manufacturing (AM or otherwise) would make such a claim. More on this later however (as I have no time right now).
>
> G. Sachs
> Paradyme Systems
>
> ------------------------------------------------------------------------
> *From:* Marshall Burns <ListMail2@fabbers.com>
> *To:* RP-ML <rp-ml@rapid.lpt.fi>
> *Sent:* Fri, January 8, 2010 11:17:56 PM
> *Subject:* RE: [rp-ml] free STL Files and other (free) things we wish for in the new year
>
> Most products are not made from metal alloys and many parts of most products do not need machined accuracy.
>
>
>
>
>
> ------------------------------------------------------------------------
>
> *From:* owner-rp-ml@rapid.lpt.fi [mailto:owner-rp-ml@rapid.lpt.fi] *On Behalf Of *Tam
> *Sent:* Friday, January 08, 2010 18:06
> *To:* Elaine Hunt
> *Cc:* RP-ML
> *Subject:* Re: [rp-ml] free STL Files and other (free) things we wish for in the new year
>
>
> Elaine,
>
>
> Additive Rp has never attained the form (machined accuracy) or physical properties of industrial parts machined accurately from metal alloys.
>
>
> Happy New Year,
>
>
> Tom Richards, Metallurgist
>

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