just in case anyone needed convincing

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.

Reply to
jim beam
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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?

J.

Reply to
JRStern

if you had problems loading that page, you need a new provider, a new computer, or both.

Reply to
Elmo P. Shagnasty

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 soon.

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.

Reply to
jim beam

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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 zippified.

So I wouldn't jump to any conclusions on all this without some more info.

J.

Reply to
JRStern

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.

J.

Reply to
JRStern

huh. Old computer here, 2.8 Core 2 Duo. No problems whatsoever.

Reply to
Elmo P. Shagnasty

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 happen.

Reply to
jim beam

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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 boundaries.

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 crystals.

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.

Reply to
jim beam

the guy in the article should have gone with honda's h-series or even b-series. much better quality, better supported, and with the right set-up, much better output.

Reply to
jim beam

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.

Reply to
Joe Bidet

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.

Reply to
jim beam

Well, then look at this link:

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Reply to
cameo

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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 components.

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.

Reply to
jim beam

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