Burmese and Retics both tend to get testy. My daughter's first pet was a Ball we tried to save from a pet store. I put a bunch of Vet money into it but it didn't make it. I've owned large Boas and med retics in the past, helped out in the herp house of a zoo in the Midwest. I quit when it became obvious that I was allergic to the anti-venom. The large king Cobra was just too dangerous to give baths to.
Dave in Fairfax
Pussy.
Huh? How is it used in artillery shells?
Unless it is.
"Near diamond"? To what substance, specifically are you referring?
However microprocessors are solid state devices with no moving parts. That doesn't mean that microscopic machines with moving parts will be equally reliable, nor that they will be useful in the making of woodworking tools.
You have to make a convincing case that such a device will work better than a simple mechanical fence and cost the same or work as well and be cheaper. All I see is arm-waving. How would this fence work? How would it be adjusted?
Well, actually we're well on the way to reading a lot of hype about what such machines will do. They will no doubt be useful tools in their own right, but that doesn't mean that they'll replace all other types of tool.
They are? How do you know this?
Oh? What temperature do they "handle"?
According to the guy that developed them the "incredible power to weight ratio" is simply the result of the small size and the square-cube law. Scale one to the size of an aircraft engine and you lose that advantage.
Which researchers are those? Where do they say this? What happens when the rider steps on the intakes? Or they get full of mud?
Depends on where the computer is stored. You don't usually find computers in open workshops either.
Mouse shit in the intakes to your microturbines would most assuredly be a problem.
So where is the "proof of principle" form of the table saw replacement?
Actually, the two big obstacles have always been cost and runways. Helos address runways but they still need a good deal of space and make a huge amount of noise. While in principle I could keep a helo in my back yard, in practice the neighbors would lynch me in a week. The new designs use ducted fans for vertical takeoff but they don't promise to be any quieter and are unlikely to be very fuel-efficient and you can buy a fighter jet for the projected cost of most of them.
You haven't really described any "capabilities" in the context of actually working wood. You've done a lot of "rah-rah" stuff but you haven't demonstrated how something that is only cheap if it is made small is going rip a piece of 2" lapacho in less than a month.
And there is no indication that the cost of silicon per se is going to go down. Chips get cheaper because you can fit more of them on a wafer, not because the wafer costs less. Your microtools are only going to be cheap if you can fit a lot of them on a wafer.
Ever give a Cobra a bath? You get a horse trough and fill it with tepid water, put the tail of the snake in and draw it under the water. That makes the parasites crawl up the snake towards the nose to stay dry. Snakes like water so it isn't a problem as you work more and more of the snake under water until you pulll the head under. The snake goes ballistic. For some reason it just won't belive that you have its better interests at heart. When you've tgot an annoyed, and now slippery 10' King to deal with, pussy starts to look like a great idea. The guy I was working with told me that the venom isn't too bad, makes you feel kind of spacey and high. I'm an RN, that makes me a control freak (news, huh) spacey and high sounds too much like a loss of control, not even considering the dying part, for me to be interested in trying it out.
Dave in Fairfax
laser spotters, fuses, fin microadjusters, etc. there's lots of electronics that get put into shells. heck, they make artillary launched a-bombs.
a lot of watch faces now are artifical sapphires.
Guidance systems. See
It might be, but the odds are against it. The expense lies in fabricating these things. Our experience with these kinds of materials is that the prices drop sharply as we learn how to make them and the volumes increase. We're still at the beginning of this particular roller coaster ride, but we're already seeing this happen.
Fabricating these devices and materials is closer to making simple semiconductors than anything else. In fact most of the technology for fabricating this stuff is adapted from semiconductor manufacturing. The same kinds of economies of learning and scale apply.
This statement is not, please note, just a matter of looking at price trends. The people working on these advanced materials and MEMS devices generally have a very clear idea of what they need to do to bring the prices down. It's simply a matter of learning and doing it.
The technical name for the most common form of the stuff is "Diamond Like Coating". This refers to materials, usually films, which are composed of diamond without the long range crystaline structure. This is sometimes called 'amorphous diamond'. Some of the coatings have a certain percentage of other forms of carbon mixed in, hence the term 'near diamond'. There are a lot of variations on this general theme and they're being used for a number of things. See
For an explanation of the composition, see:
Their use in woodworking tools is speculative. The reliability of MEMS devices is not. As a rough rule, the devices are somewhere between as reliable as microprocessors (acellerometers for air bags) and about one-tenth as reliable (laboratory structures).
Think adaptive optics compared to a conventional telescope mirror. A conventional mirror works because it is both rigid and precisely shaped. An adaptive mirror works in almost exactly the opposite manner. It is flexible and its shape is determined by the network of actuators behind it. The adaptive mirror is constantly deformed to produce the desired results as determined by the sensor system.
Now imagine a fence/table system that works the same way. The sensors feed back information on the straightness of the cut and many other things and the fence and table actuators use that information to guide the wood. (I'm assuming some sort of passive control over feed speed here. The user pushes the wood through, but the system will either indicate when it is being fed too quickly or restrict the feed speed. ) Not only does this give you inherently superior control over the cut, but since it doesn't rely on mass and precision of machining or casting, it has the potential to be significantly cheaper.
Where this particular analogy breaks down is in the way the technology is used and its effect on price. Adaptive optics isn't (yet) used to make astronomical telescopes cheaper and more widely available. Astronomical telescopes of this class are pretty much one-off items, which limits the opportunities for economies of scale and restricts how fast you slide down the learning curve. Instead we use adaptive optics to give the telescopes capabilities (effective apeture, cancelling atmospheric distortion) that we pretty much can't get otherwise. So adaptive optic astronomical telescopes don't get cheap.
Much more than hype. There are a lot of proof of principle devices working in labs, more stuff in advanced development and a few devices in consumer products, in some cases for more than a decade. The acellerometer that is the heart of an air bag sensor is a MEMS device.
Google MEMS and you'll find a lot of hype. But you'll also find a lot of very real devices.
Well, we can start with the basic laws of physics and what happens when you scale structures. Or we can go by why I've been told repeatedly by the researchers and companies working in the field. Or we can go by their demonstrated performance.
You should have read further into the ASME paper you cite. On p 16 there is a chart (table 2) comparing material properties. Conventional alloys for jet turbines top out at about 1000 C. (This is the temperature of the material, not the inlet temperature of the turbine, which can be much higher.) Silicon carbide, which is a long way from the optimum material, can run at 1500 C by the same measure.
A little further along Fig. 23 compares the performance of alloys and MEMS-type materials at various temperatures.
Ultimately the material properties determine the device characteristics (or at least set the outside boundaries). Higher temperature materials allow higher temperature devices and hence more thermodynamic efficiency.
Of course even silicon carbide isn't the ultimate for microturbines. There are a number of materials with better properties we are still learning how to fabricate using MEMS techologies. The paper mentions sapphire as an example.
There are other considerations as well, of course. For instance most turbines have active cooling of some kind. Active cooling for microturbines is aided by the greater heat transfer that results from the higher surface to mass ratio. Bearings are a notorious failure point in gas turbines. Microturbines can use air bearings, which can be made much more reliable. The list goes on.
Even the early, very (and deliberately) crude microturbine described in the paper matches the performance of WWII jet engines.
Well Duh! The whole point is that these turbines are small. That's what gives them their advantages. You use them in groups to get more power, not make them bigger.
The statement appeared in an article in "Science" several years ago about MIT's micro turbine program. The researcher who made it was being facetious, obviously. But the thrust would be there and he was pointing out that microturbines for larger aero vehicles would be used in large numbers.
You forgot the smiley on the that one. :-)
You can tell a really good idea by the enemies it makes
A lot of electronics yes. But how are MEMs used in current production artillery shells? MEMs and electronics are not the same.
Incidentally, in WWII, _tube_ electronics was used in artillery shells. The fact that something is used in artillery shells does not mean that it is inherently durable, it means that by dint of great effort the Army or some arms manufacturer has found a way to make it work acceptably in the application.
And a-bombs do not need any electronic components.
If you look up the chemical composition of sapphire you'll find that it's simply aluminum oxide. Nothing new there at all--synthetic sapphire was used in watch crystals in the '80s.
It is not in any sense "near diamond". If it was you'd be able to sharpen carbide tools with aluminum oxide abrasives.
Uh, do you understand what is meant by 'proof of principle'? Hint: It is not a prototype.
I'll disagree on both counts. The cost of some of the designs in volume production would have been less than an luxury automobile. And the runway issue was addressed by a variety of the designs in different ways.
Well no. A major component of the noise from a helicopter is the interference in the air flow between the main and tail rotors. If you've ever heard a NOTAR chopper you'll see they are significantly quieter. For a discussion of noise levels and reduction in helicopters, see:
Whether they're quiet enough to make good neighbors is another issue. It's worth noting that one popular method of operation would have the aircar drive on the street several blocks to a 'parking lot' and take off from there.
The ones that are furthest along promise both reasonable fuel efficiency and a cost less than a high-end sports car. And this is only the first generation.
How about something that can take the place of a tablesaw, bandsaw and probably several other tools, cost much less than good quality tools and do much more accurate work? Will that do for a description of capabilities.
Now if you want to know exactly how these tools will be designed, you'll have to find someone with a clearer crystal ball than mine. Given what I have seen already, and the way the industry works, I can tell you that something with those capabilities and using these kinds of principles could be available in a few decades. Trying to predict exactly what it will look like or how the details of how it will work will lead to something like that 'RAND corp. design of a personal computer' that's making the rounds of the web. We just don't know enough yet.
You're confusing the sensors and actuators (which are small) with the complete tool (which isn't) and the cutting element -- which will be sized appropriately for the tool.
Untrue, as it happens. The price of silicon is on a long-term downward trend. In 1959 metallic silicon cost a little over $1 per pound. By
1998 or so it was down to around 60 cents a pound and headed lower.(The highly refined silicon used in making semiconductors is currently running about $30 a pound. However that's pretty much irrelevant to this discussion because of device differences and what drives prices in that market. A couple years ago that same silicon was selling for about $30 a pound.)
Well, no. Assuming by 'wafer' you mean the wafer of unprocessed silicon, the cost per square inch drops significantly with every increase in wafer size. That's why the industry has gone to bigger and bigger wafers. The price drop is particularly noticable in raw wafers.
We're talking about components like actuators and sensors here, not complete tools. And of course you're going to fit a lot of them onto a wafer. But like current MEMS devices they will be diced and packaged before use. You don't have to put the whole tool on a single wafer.
Given the way semiconductor fabrication works -- and given the differences between MEMS devices and things like microprocessors or DRAMs -- the prices of these devices will be extremely low in volume production. And of course it's unlikely that most of the sensors and actuators will be designed specifically for woodworking tools. They'll be adapted from devices used in higher production devices.
I also don't think you grasp what I mean by 'cheap'. The active elements in these devices are going to cost on the order of what a transistor costs in a modern microprocessor -- for exactly the same reasons. Each tool will contain a lot of them, but the the resulting cost will still be very low.
You can tell a really good idea by the enemies it makes
They have synthetic dimond sharpening wheels on the market for industrial applications. According to my cousin (the owner of a carbide sharpening service), they're not very commonly used because of pressure from the natural diamond suppliers- I guess anyone purchasing synthetic diamond is somehow "blacklisted" and no longer allowed to purchase the natural product, which is still better for some things. Please bear in mind that this is all second-hand from a conversation several months ago, so there are bound to be a couple inaccuracies, but the basic idea is still correct.
Aut inveniam viam aut faciam
I don't know about the "blacklisted" part; but the current synthetics differ only in that they're available without the natural impurities/flaws.
I'm eagerly looking foreward to low-cost router bits and saw blades for wood with diamond cutting edges and I don't really care if they /look/ beautiful or not.
Just imagine a plane or chisel with a razor sharp diamond edge!
I can see where MEMS might be useful for the gyros, but how is it used in the fin actuators?
The price per square inch doesn't drop appreciably, the price per part drops as more can be fitted into a square inch. You need a certain amount of surface area to cut wood. That means that any macroscopic woodworking tool based on this technology is going to be expensive.
And low cost then relies on high density.
Well that's fine for optics, but we aren't talking about optics. Now tell us what, specifically, your tool would do better than existing tools and how, specifically, it would accomplish it.
Adaptive optics is a useful technology because for many purposes a correction has to be made for variations in air density. It is not a cheaper way to make telescopes and in the absence of air it is not a better way either.
Fine, you have sensors that feed back the information. Now what makes the adjustment with sufficient force to overcome the forces exerted by the hand of the operator pushing the piece through? Can you make that actuator entirely from your hotshot technology? How much will that much silicon cost? How durable will it be? A little piece of silicon properly supported can be pretty durable, a big piece is quite fragile.
Now, you claim that it "doesn't rely on mass and precision of machining". Instead it relies the technology you are advocating being able to provide high forces for practically no cost. It does not appear to be the nature of this technology that it will be able to do that.
I see. So Celestron doesn't enough benefit in this for small telescopes to put it in their mass-production consumer telecopes? Or maybe it's because there's no way to reduce the cost significantly?
Nope, hype.
None of which are tools that are anything like what is needed for woodworking. Yes, some woodworking tools might have some MEMs components someday for some purpose. But using MEMS instead of electromagnetic or hydraulic actuators to move fences and the like is a huge stretch.
None of which do anything like what you are claiming the technology can do.
Define "tough". I'm pretty sure that I can, using tools commonly available in a woodworking shop, break any MEMS device you want to provide me.
I see. So they provide the same 1980 pounds of thrust as the Junkers Jumo
004? I don't think so. They may match the _efficiency_ or the thrust to weight ratio, but that does not mean that they could be substituted unless they can match the thrust for a reasonable cost. And that does not seem likely to happen based on anything that you have described except some pie in the sky hype about how the price will come down because electronics prices came down.So how many do you need to power a 747? And what would the engine look like?
How large would these numbers be, how many square inches of silicon would be required to make the devices, and how much would that silicon, just the raw silicon in the appropriate grade cost? And what would happen if one of these hypothetical engines ate a seagull?
I note that you have not addressed this one. Tiny devices get clogged up with tiny amounts of dirt.
Because there wasn't one. You're advocating a technology that you clearly do not really understand. Learn some engineering and you'll see what's wrong with your claims. It's just not going to scale the way you think it will.
I'm not sure that diamond, synthetic or natural, is the right material for that application. Although hard, diamond is also prone to fracture when subjected to impulse-like blows by fracturing along the crystal bond-lines. I imagine a router bit or sawblade with diamond would basically grind or pulverize the diamond as opposed to cutting the material you want to cut.
If the principle is that the device can be used to replace a table saw then the "proof of principle" is a device that replaces a table saw. I don't care about "proof of principle" that some kind of device can be made--you claim that that device can do something, but you don't have any backup for that claim at all, just brainless advocacy. I suspect that if the engineers and scientists who are working on this are reading this thread they are cringing and what you are claiming because they know that they can't deliver it and it won't be remembered that it was _you_ making the claims and not _them_ later.
You can buy new airplanes now for less than the price of some luxury automobiles. Most people can't afford to drive a Ferrari though.
Addressed by what designs other than helicopters that actually flew well enough for anybody but an experienced test pilot to survive the experience?
Have you ever had one crank up in your back yard at 2 AM? "significantly quieter" and "quiet" are not the same.
Yeah, yeah, rah rah rah. Now, have you ever stood next to anything with a high powered ducted fan as it spun up to full power? Try it sometime and then tell me how quiet it is.
So we're back to runways, or at least helipads. Now, in my neighborhood, whose house would we tear down to make this "parking lot"?
Uh huh. If you've been around aviation long enough you'll have seen all kinds of "promises" that were never delivered. And nothing that uses lift fans is ever going to match the fuel economy of a Honda Civic.
Believe it when you see it. So far it's just more pie in the sky.
How about if we make it concave and convex and work either sex and play with itself in between.
Now, what device that has been made or even designed has these capabilities that you claim will be made available by this technology?
In other words you don't have a clue whether your precious little MEMS can actually do what you're claiming or how they might be used to do it if they can. All you have is bad science fiction.
What "industry"? The MEMs industry hasn't been around long enough for you say anything about how it works. If you mean the electronics industry, don't assume that MEMS is like electronics.
Or not, as the case may be. Personally I'd say that "not" is the way to bet. At least not based on the technology you are hyping. Some other technology might come along that allows it of course.
Was that "RAND corp" which is think tank or was that Remington-Rand the computer manufacturer? In any case, at least they knew how a computer worked. You don't have a clue how the devices you are hyping would actually work.
Modern computers are small and inexpensive because the components from which they are made are very small and there are only a few of them. Now how are you going to cut wood with that few pieces that small? Hmm? Or are you claiming that all of a sudden massive lumps of semiconductor-grade silicon are going to become dirt cheap because they're being used to make MEMs instead of microprocessors?
Can you quote a single researcher who has actually developed such a device who is making such claims?
I'm not confusing anything. You're claiming that this technology is going to be cheap and it's going to be made entirely out of MEMs. If that's the case then the active components have to be very small or it's not going to be cheap.
Now, how much power can a MEMs actuator that can be made with less than, say $200 worth of silicon produce?
I see. So it's come down 40 percent in 40 years. Woo-poo. Now, is that semiconductor-grade or is that just raw silicon out of the mine?
Fine. So it goes down another 40% in 40 years. That's not going to make any damned difference at all in the price of your gadgets.
your own argument.
Uh huh. So how much is the drop per square inch? And is that a drop in the cost of the wafer or of the processing?
Define "a lot". And tell us how that translates to something large enough to cut wood being cheap.
So what good are little bitty things going to do in cutting wood? We're not talking about making furniture for ants here.
Not devices big enough to do what you are claiming.
Huh. So how will having 40 million tiny machines on a lump of silicon a half inch square do anything useful in the way of cutting wood?
I know "sensors and actuators". And we're back to "what are you going to actuate with the minuscule amount of force that such a small device can produce that is going to be useful in woodworking?
Really, before you make these wild claims you should try to at least _think_ about how what you claim will be accomplished will actually be accomplished.
To cut wood you need something big enough to make the cut you need, able to exert enough force to shear the wood fibers, and able to actually shove a big lump of wood around when it is being operated on by the cutter. You're not going to do that with any tiny little machine that can be made on a P4 sized wafer. You might be able to put the control system on something that small, but it's still going to need actuators that can provide the necessary forces and you haven't demonstrated that your MEMs based control system would be superior in any way to a purely electronic control system. So how are you going to make these actuators?
Yes, they do. They have synthetic diamond available for many purposes. So what? I never denied that synthetic diamond was available. But it's not as far as I know used in industrial coatings. Grinding wheels are another story. And that does not alter the fact that synthetic sapphire is not "near diamond" in any sense.
I think your cousin got his paranoia button pushed reading some of the thrillers that feature the diamond industry (11 Harrowhouse for one). I can't imagine how the natural diamond suppliers would find out about someone buying synthetic diamonds without assistance. The original buyers are not necessarily the ones using the stuff in tools, so the list would grow almost exponentially. Are they going to black list every small maker who uses a bit of the material? The blacklist can do no harm to the small maker who uses only synthetics, anyway.
From all the stories, natural diamonds are damned near a drug on the market, with supplies far in excess of desires (outside of industry, there is no NEED for diamonds). If blacklisting is a marketing technique they employ, sooner or later someone is going to grow a substitute that is a shade better than real diamonds for some industrial purposes, and the current big boys will be on the outside looking in. Which would be nice, as over the years, the reputation they developed in S. Africa was not one a good business would want.
Too, it's easy enough, if blacklisting is true, to use a substitute to buy the natural diamonds.
But a bit of googling turns up the fact that suppliers of synthetic industrial diamonds also sell DeBeers industrial diamonds.
Charlie Self "Ambition is a poor excuse for not having sense enough to be lazy." Edgar Bergen, (Charlie McCarthy)
It's going to be a throwaway though. Once you knock a chip out of it, whcih isn't difficult--diamond is hard but it's also brittle--what do you sharpen it with?
>
A diamond file? [-8
Now that would be a thing of beauty...
Aut inveniam viam aut faciam
It's a beautiful idea anyways. And it might work with a hand chisel that isn't hammered on. As far as router blades and saw blades go, I'd suspect you're right in some ways, wrong in others. A diamond point may be pulverized, but I have some serious doubts that it would be ground down by wood. And as far as I know, tile cutting uses diamond blades, though these are more of a thin grinder than a saw blade as used in woodworking.
Aut inveniam viam aut faciam
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