here is a sad cautionary tale about the quality of honda's current
engines. i was shocked a while ago to learn that they'd stooped to cast
cranks, but it seems that's just one part of a much more general decline
in manufacturing standards:
porosity? inclusions? these are absolutely fundamental problems.
No more problems than trying to load that page.
Don't be a fuddy-duddy, soon we'll all be using 3D printers to build
new Hondas at home.
Aren't there high-tech "casting" processes needed for new
higher-strength, directional yada yada materials?
On Sun, 24 Feb 2013 17:36:44 -0500, "Elmo P. Shagnasty"
I am running an antique desktop here, but it's still pretty sad that
only a 3gz processor and 512mb of RAM won't load a BBS page.
It would probably load better on Chrome than IE8, but even so, I have
better security running IE8.
buy a "chrome book" from amazon. cheap as all-get-out, no micro$oft
tax, fast, secure. in combination with google docs, it'll handle pretty
much anything you're likely to encounter at home.
no you don't. while m$ have done a lot to "improve" their security,
there are still some serious fundamental problems that m$ simply can't
fix unless they break all their legacy apps. and that's not going to
much like "nanotechnology" [which used to be called chemistry] and
"biotech" [which used to be called pharmaceuticals], "3d printers" are
/WAY/ over-hyped. you simply can't get the mechanical properties out of
that process like you can with conventional production methods. it's
good for prototyping shapes which can then be used for traditional
castings, or shapes that don't get much physical load, but that's about
it. it certainly won't be producing high strength componentry any time
for metallics, casting is basically the reserve of complex shapes at
reasonable price. if absolute mechanical performance is what you need,
then you have to forge. cnc machining /can/ be better than casting,
provided the shape isn't too complex, but it's not as good as forging.
there is another intermediate called "thixoforming" which offers many
advantages of casting and some of forging, but the cost of tooling is
high and often people just cnc instead.
for composites, there are the reinforced thermoplasitcs [like the tanks
on your aluminum radiator] or the reinforced cross-linked polymers like
the fenders on an old crx. for the latter, you're stuck with either
hand lay-up or a kind of "shot-crete" approach, but both require
considerable effort and therefore expense.
neither are 3-d printing, which is analogous to sticking sand particles
together one by one. as i say, i'd use it for creating the molds from
which castings can be made, but i wouldn't be making aircraft landing
gear from it any time soon.
I thought Honda was using some zippy process to put silicon surfaces
on aluminum block walls for the S2000 engines, but first the aluminum
had to be cast in a certain way to get the silicon there to be
So I wouldn't jump to any conclusions on all this without some more
they're cast for a different reason - high temperature creep resistance.
you wouldn't want to use a single crystal crankshaft.
single crystals are used at very high temperatures because
poly-crystalline metals creep at grain boundaries. the smaller the
grains [forging], the more grain boundary, so the more the creep at
these highly elevated temperatures. single crystals eliminate grain
so, having figured that out, you can reduce creep further - of the three
crystal axes, one has a lower creep rate than the other two, so blades
are grown not just as single crystals, but specifically oriented single
i think the s2000 has steel liners. but some of hondas other engines
have carbon fiber composite liners so maybe it's that. i'm pretty sure
they don't use relieved silicon.
the "relieved silicon" process is something the germans have been doing
for a long time. some people swear by it. others at it. but
basically, you have a high silicon aluminum casting alloy, and when
you're done machining and heat treating, you etch the aluminum away from
the cylinder walls leaving silicon crystals at the surface. silicon is
hard and provides the wear resistant working surface.
but it's hard to machine and temperamental in other ways, so as always,
there are pluses and minuses that need to be balanced.
i know, people are trying to promote the heck out of it, [and themselves
at the same time of course], but the fact remains that it's basically
just a toy. 2500 hrs to "print" a car is about 1000x too long, and it's
still just for the polymeric stuff, no metallics or high strength
maybe i didn't explain this adequately, but one of the important
features of many metals and polymeric materials is "directionality"
[otherwise known as anisotropy]. this directionality is very important
to strength and fatigue resistance. high strength components such as
chassis members benefit considerably. 3d printing, pretty much by
definition, can't and doesn't have any directionality, so it can't
provide this important benefit.
but then again, the proponents of 3d printing aren't materials experts
or even engineers most of the time, so they don't know what they don't know.
Cast cranks have been around for decades and used by every manufacturer.
Most people are not modifying a stock Honda engine to build a race car
as shown in your referenced link. Grandma doesn't care if her crank is
cast or forged when she drives to the grocery store. This is another
"sky is falling" non-story. The solution for your "problem" is simple:
if you don't like Honda, don't buy Honda.
rtfa. the cautionary tale is about head porosity and inclusions, not
the crank. /i/ mentioned cast cranks because they're inherently
inferior in fatigue and the quality of the bearings surfaces possible.
both impact durability, especially when asking the engine to perform.
that means this engine is inferior in multiple departments, not just one.
how does this affect my grandmother? poorer bearings have more friction
which consumes more gas. poorer fatigue strength means it has to be
heavier, >30% heavier. more rotating mass means more gas consumed. so
yes, it most definitely impacts my grandmother.
the point is, since apparently it needs to be spelled out to you, that
honda quality has dropped to the point that they're not a viable option
any more - so i and many others /won't/ be buying them.
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