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Kevin O'Brien wrote:
On 2005-11-14 12:45:14 -0500, Evan Carew said:
Interesting posts. I wonder if you would agree with me that the
kit/small GA builders have wrung most of the fat out of the building
process
I'm not sure that's the case, because we're in the midst of several real
industrial revolutions -- materials, automation, organizational. These
add up to the possibility that we will see, someday soon, airplanes
assembled on a line-production rather than a bespoke basis.
Possibly, that is if you can afford the initial cost of 3D CAD &
fixturing at your local manufacturing house. I currently make water
treatment eq & typically spend ~ $8K / smallish device with moderate
complexity to have the CAD work done. This would translate to a typical
wing or fuse model in fiberglass with the moving parts ( metal models of
the same structures would no doubt cost more). These same parts I have
made up on CAD then cost me ~ $1.2K / unit with ~ $300 in materials
costs to be made on CNC machines. I typically have 10 made at a time.
The manufacturing house I use (one that typically makes transmissions
for GM) tells me that if I go to 100 or more parts at a time, the price
per part will come down to ~ $400.
If you've ever tried to fit a factory airframe part (that cost an arm
and a leg) to a Beech, you know what I mean.
and that any further gains are in incremental productivity / materials
handling procedures? If so, I wonder what you think could be realized
in savings over the current processes?
I know that everyone who's seen the Eclipse plant (including Dale
Klapmeier) has been agog.
Yeah, I've heard. Unfortunately, that tech isn't exactly what the
average kit / small GA aircraft manufacturer can afford to include into
their process. My understanding is that all of their FSW ops are under
CNC control with special fixturing.
[snip]
To return to your question -- I do not think productivity in this
industry is anywhere near where it could be, but the economics haven't
been compelling enough to make anyone chase higher productivity, with
the couple of exceptions noted.
Sometimes people have mistaken getting wrapped around the axle of CAD,
for increasing productivity. Two projects that were going to
revolutionize the sport via CAD were the Prescott Pusher, and the
DreamWings Valkyrie. Worth a search through the back threads of this
group. I presume the CAD files of those two ghastly projects are still
sitting in somebody's closet... for the sake of pilots yet unborn I pray
that the guy's mother throws them out next time she cleans.
Yeah well, organization doesn't always translate into producability. On
that note, I seem to get a lot of feedback from this group about along
exactly those lines. Either the respondents to this thread get hung up
on the idea of design & cost, or are stuck on the idea of producing a
final product. I can't seem to get anyone to twig to the idea that doing
research into processes capable of reducing the labor involved in small
parts count (lightly funded) ops has real merit for this interest group.
Specifically, summarizing final findings down to a collection of process
documents, associated costs, and estimates on final product impact.
IF you take a look at the Eclipse site's tech section, its all about
process. Every assembly is made so it fits in its assigned place
precisely (CAD == known tolerances) and every assembly has an exactly
known final assembly cost (manufacturing studies), and the sheet metal
is but welded with an exotic process adapted to thin metal aluminum
(process innovation). I have to do that for my business in the water
quality eq biz, why don't we do it in this biz? If there was someone who
was, they'd eat everybody else's lunch... oh wait, isn't that Eclipse?
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