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Science

Using Microwaves to Drill Through Glass 140

Posted by CowboyNeal from the hot-stuff dept.
Linux_ho writes "UPI is reporting that Israeli researchers have developed a drill that can melt a small hole in glass, ceramics, or concrete with no dust or noise. Nature.com reports that it doesn't work very well with good heat conductors or materials with very high melting points, but the researchers envision a wide variety of manufacturing applications, and possibly some medical uses as well."
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Using Microwaves to Drill Through Glass More

Using Microwaves to Drill Through Glass

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  • And spy movie uses! (Score:5, Funny)

    by ottffssent ( 18387 ) on Friday October 18, 2002 @04:47AM (#4477095)
    Can it be suction-cupped onto a piece of glass to cut a perfect circle out?

  • Military applications (Score:2, Insightful)

    by *Pres* ( 114530 )
    I suppose it also melts through bunkers and armoured vehicles?
    • I suppose it also melts through bunkers and armoured vehicles?

      I agree on the concrete bunkers, but I don't think it would work on armoured vehicles (assuming the armor is some sort of metal), since the article states it only works on non-conductive materials.

      • Re:Military applications (Score:1, Funny)

        by Anonymous Coward
        Yeah, but after experiments with CD's in microwaves, you have to agree that it would look good... whilst being totally ineffective...

      • Re:Military applications (Score:4, Informative)

        by AlecC ( 512609 ) <aleccawley@gmail.com> on Friday October 18, 2002 @05:36AM (#4477216)
        Except that the leatest, greatest armour is ceramic, not steel. But, according to the article, it limited to the 1/4 wave of the microwaves - an inch or so. And it only makes tiny holes. Somehow I doubt that making pinholes in the armour of a tank is going to slow it down much.
        • The articles too slashdotted to tell, But assuming it does it quick enough all you would need is some ammunition the size of a pinhole ;)

          Maybe you could 'cut' with it, like frying ants with a magnafying(too tired to spellcheck) glass? where the area of heat is small but constant, so it could easily slice open some armor.

          Also, breaking an air tight seal in the future might be needed. A small pinhole is all you neeed to pump gas into a tank and make it a death trap.


        • do
          make tiny hole
          move along 1/2 diameter of tiny hole
          until BIG HOLE is cut
        • It's just as well you don't design tanks. With a pinhole through the armor you could deliver anything from blast to nerve gas.

        • Re:Military applications (Score:4, Insightful)

          by Mr.Sharpy ( 472377 ) on Friday October 18, 2002 @01:15PM (#4480406)
          Well I think for anti-tank use, i don't think it would have to make a very big hole, or even a hole at all. All it needs to do is make a small hole of irregular shape, or even just weaken the armour in the impact location. If the armour loses its integrity in one spot, the area around that spot will fail if it is struck.

          If this device could be made small/cheap enough, think of this in the end of a missle or bomb, softening it's target as it approaches. Or more reusable, this along side the targeting laser for laser guided bombs.
          • This is ridiculous. The drilling method they described is very short range (not to mention too slow for a bullet) and thus would be completely ineffective in allowing a missile/RPG to inflict more damage.

            I thing that the best thing this could be used for is some sort of small smart patch that could be thrown/stuck/launched at a tank. It would then stick to the tank. Then by using some simple robotics it would move across the tank and position itself to slowly drill into the engine block (or the magazine for even more fun!)

  • Excellent (Score:5, Funny)

    by Anonymous Coward on Friday October 18, 2002 @04:49AM (#4477100)
    I've always wanted holes in my windows.

  • So... (Score:5, Funny)

    by iomud ( 241310 ) on Friday October 18, 2002 @04:51AM (#4477104) Homepage Journal
    What kind of time are we talking about for the average hotpocket? I'm just thinking about the immediate benefits here.

  • Not quite (Score:4, Insightful)

    by jukal ( 523582 ) on Friday October 18, 2002 @04:52AM (#4477107) Journal
    By heating a target to nearly 2,000 C, the microwaves soften it up enough for a small rod to be pushed through

    So, the article was a bit misleading as the microwaves are not enough to go through.

    • Re:Not quite (Score:2, Interesting)

      by Anonymous Coward
      Using Microwaves to Drill Through Glass
      or
      Using Microwaves to Melt, while a Metal Rod Drills Through Glass

      It's a headline. It's supposed to lie. I mean, all the ones in real news sources do.
    • By heating a target to nearly 2,000 C, the microwaves soften it up enough for a small rod to be pushed through
      So, the article was a bit misleading as the microwaves are not enough to go through.

      That's +5 insightful? The headline didn't say "Using ONLY microwaves to drill through glass". Of COURSE it requires a small rod or some physical means to remove the molten material from the intended hole area. So, for a minute you thought someone had come up with a way to form a Green-Lantern-like drill bit energy field out of microwaves that physically cut into the material and spiralled it away from the target? No, sorry to disappoint you. The process is still very accurately described by the phrase "Using microwaves to drill through glass".
      • First, just because the headline exempted the word "only" doesn't mean it was misleading.

        Second, you make it sound as if vaporizization is only in the realm of science fiction. Lasers by themselves are used to cut materials. It's not such a stretch to imagine that (even unorganized) microwaves could do the same.

  • Max Depth? (Score:5, Interesting)

    by BoBaBrain ( 215786 ) on Friday October 18, 2002 @04:57AM (#4477119)
    The article mentions that it can only drill to a depth equal to a quarter of its wavelength. Why is this?

    Surely it could also drill at depths of .75, 1.25, 1.75 etc.

    • Re:Max Depth? (Score:5, Insightful)

      by AlecC ( 512609 ) <aleccawley@gmail.com> on Friday October 18, 2002 @05:42AM (#4477230)
      As I read the article, below 1/4 wave, the drill bit behaved more like a hosepipe - microwave frequency oscillations in the conducting drill bit produce an intense microwave field just beyoind the point of the bit - probably using the Near Field bits of Maxwell's equations, which I never did understand. Above 1/4 wavelength, the drill bit functions as a tradition aeriel, radiating the energy sideways from the drill bit. It is not that some sort of effect doesn't exist at the end of the bit, it is that far to much energy escapes sideways to make it worthwhile.
      • What about using more than one antenna to emitt the microwaves in such a way that they either cancel each other out everywhere but at the target, or amplify at the target point. Would that allow you to move the drill bit further away from the material? Would it be possible to move the drilling point just by changing way the microwaves interact?

    • Re:Max Depth? (Score:5, Informative)

      by Ilari ( 27923 ) on Friday October 18, 2002 @06:05AM (#4477269)
      From the article: "The device is limited to a penetration depth of a quarter of the wavelength of the microwaves used -- in this case, about an inch. If the drill bit is any longer, the microwaves are no longer beamed forward but instead radiate in every direction like an antenna."

      If I understand correctly the drill works as a highly directive antenna - beaming microwaves towards the material to be melted. The drill needs to be short to achieve good directivity.

      Different frequenciens have different penetration depths - that is, how deep the electric field or radiation energy can penetrate into the material which is being "drilled". The penetration depth also depends on the conductivity of the material, so different materials can have very different penetration depths for the same frequency.

      I think the depth of "a quarter of its wavelength" is just a very approximate rule given to journalists. It is more of a comparison rule: the penetration depth is comparable to a quarter of the wavelength. (Although I'm not sure why, the penetration depth is proportional to the square root of the wavelength, if I remember correctly.)

      After they have reached the penetration depth, they need to move the antenna/drill forward. So of course they can drill deeper holes than that, but not at a time.

      What kind of an "antenna" are they using? To achieve good directivity, they would need to use "traveling wave antennas" (or whatever they are called in english), I'd imagine. Does anybody know any details of this?

      • Re:Max Depth? (Score:5, Interesting)

        by AlecC ( 512609 ) <aleccawley@gmail.com> on Friday October 18, 2002 @06:50AM (#4477370)
        The antenne *is* the drill bit - and the quarter wave rule is to stop it acting as a real antenna and broadcasting microwaves all round the room. Below 1/4 wavelength, some undecribed mechanism creates intense heating just below the drill bit, which is where you want to drill. They can't move the drill forward without moving the (presumably non-conducting) chuck, or all their micropwave energy will radiate sideways, gently heating that which they do not want to heat and failing to heat that which they want to drill.
        • The antenne *is* the drill bit - and the quarter wave rule is to stop it acting as a real antenna and broadcasting microwaves all round the room. Below 1/4 wavelength, some undecribed mechanism creates intense heating just below the drill bit, which is where you want to drill.

          That's what I said: the drill is a highly directional antenna. The undescribed mechanism is the radiation energy absorbed by the material which is being drilled. (Energy equals heat, among some other things.)

          They can't move the drill forward without moving the (presumably non-conducting) chuck, or all their micropwave energy will radiate sideways, gently heating that which they do not want to heat and failing to heat that which they want to drill.

          Yes, you're right about that. I first thought that the mechanism of drilling is as follows: heat the material with microwaves and when the material is sufficiently hot/soft, push the drill/antenna as deep as you can and repeat. The problem is that the "hole" made is just wide enough for the antenna, so they can't push the drill/antenna any further. So they can't make holes any deeper than the given a quarter of wavelength rule.


      • wavelength = 0.1016m
        c = 300x10^6 m/s
        freq = c/wavelength

        freq = ~ 2.95 GHz

        Allowing for journalistic approximation, they could be simply aiming a 2.4GHz microwave oven magnetron at rocks.

  • CPU key fobs (Score:5, Interesting)

    by Perdo ( 151843 ) on Friday October 18, 2002 @04:57AM (#4477120) Homepage Journal
    I doubt that steel conducts the heat away too fast. I'd wager that the steel conducts the RF radiation itself. Just like this device has an antenna, steel would be an antenna too. Not exactly impedance matched, but certainly enough to prevent the steel from being heated except across the entire piece.

  • In other news... (Score:5, Funny)

    by Anonymous Coward on Friday October 18, 2002 @04:57AM (#4477123)
    ...Burglars and Bankrobbers Corp. raised it forcasts for the financial year 2003 after a R&D breaktrough.

  • Not a big deal (Score:5, Interesting)

    by Sinbit ( 546592 ) on Friday October 18, 2002 @05:00AM (#4477129) Homepage
    I was doing the same thing over 10 years ago for my Master's thesis with a pulsed CO2 laser with ~500W time averaged output. What is the advantage of using a microwave beam over a CO2 laser?

    • Re:Not a big deal (Score:2, Informative)

      by Anonymous Coward
      According to the nature article- cost.

      And that drives everything

    • Re:Not a big deal (Score:4, Interesting)

      by geordieboy ( 515166 ) on Friday October 18, 2002 @06:00AM (#4477261)
      It's probably a lot cheaper - the article says
      that this microwave device is not more expensive
      than a mechanical drill. How much does a 500W laser cost?

      • Re:Not a big deal (Score:4, Funny)

        by JUSTONEMORELATTE ( 584508 ) on Friday October 18, 2002 @07:17AM (#4477452) Homepage
        How much does a 500W laser cost?

        I have no idea:

        All Categories
        0 items found for 500w laser

        Try these search alternatives
        • Search: Title and description
        • Search again using fewer or different keywords.
      • The cheapest lasers cost about $1/watt currently (semiconductor lasers); but normally you're talking $10s or $100s of dollars per watt.

        Semiconductor lasers could be made to work, but they're awkward, you'd need a large array of them and you'd need focusing lenses, and a lot of mucking about and aligning.

      • Forget the cost of the 500W laser. Have you priced a live shark lately?
      • Looking at commercial CO2 cutting lasers, even a secondhand one will rush you between £40,000 and £110,000 (with control systems).

        Having said that, most of these lasers are > 1KW, so it may be that you could pick up (or build) a straight 500W CO2 laser for around £1000 (no control systems etc.)
      • oops! looked at a few hobby type sites - a 20W CO2 laser can be built for roughly £70. This site: a funky CO2 laser [subterrain.net] has some nice pix.
        • You can build the laser HEAD for roughly $100, if you get a really good deal on the lenses. After that you need to rent a tank of CO2 laser mixed gas (~$150), buy a power supply (or build one, in which case the price depends on what components you have on hand). You also need a pump that can draw a very high vaccuum to pull the gas out of the tube (I got mine free from a petroleum lab; they were getting rid of it because the manometer containes a LOT of mercury). Buying one would be expensive.You're also going to need a good quality HeNe laser (and associated power supply) to align the thing so it'll lase when you're done. Water pumps and a radiator for the cooling system will also be needed. I think you could build a 25W continuous 100W pulsed laser for less than $1000 if you shopped around, had some components on hand, got lucky finding others, and have LOTS of experience with high voltage (the power supply to run one of these things will definately kill you if you screw up). Not a small project, but doable.

    • Re:Not a big deal (Score:4, Informative)

      by crywolf ( 445243 ) on Friday October 18, 2002 @06:20AM (#4477297) Homepage
      If I'm understanding correctly, the microwave beam has a very limited range. This would make it much harder to accidentally hurt someone with it. You can hurt someone on the other side of a large room, or possibly in the next room over, with an industrial laser.
    • You should sue for patent infringement and cash in, duh!
    • Val Kilmer did it way before that.

    • Re:Not a big deal (Score:5, Interesting)

      by Idarubicin ( 579475 ) on Friday October 18, 2002 @08:51AM (#4477995) Journal
      What is the advantage of using a microwave beam over a CO2 laser?

      There are a number of advantages. First is price--you can use off-the-shelf microwave oven pieces for most of a microwave drill. Granted, carbon dioxide cutting lasers are also available essentially off the shelf from a limited number of suppliers, but they tend to run in the tens of thousands of dollars.

      Durability. Laser tubes don't tend to be happy about being moved about a lot. They contain optics that are very sensitive to misalignment.

      Size. Microwave sources for this application would be quite a bit smaller than a carbon dioxide laser, especially when you add in all the ancillary equipment in my next point. In addition, combining size and durability makes a much more portable tool.

      Limited complexity. No delicate optics. No vacuum system. No water cooling system. No mixed lasing gas to deal with.

      Safety. Lasers can remain well collimated for significant distances--you can make holes in your coworkers from across the room if you're not careful. A microwave drill as described isn't acutely dangerous beyond an inch or two from the end of the drill bit. (There might be heating effects beyond that distance, but reflex action--Ow! It's hot! I'm moving my hand now!--would likely be sufficient to protect you. You need the same level of common sense that it takes to operate a band saw--don't put your fingers near the business end!)

      So, that's why microwaves would be advantageous. That said, CO2 lasers can perform extremely well, as long as you don't have to move them to the field. Manufacturers already exist for the lasers, and it's a proven technology.

      • That could be a factor, surely there would be some savings in energy usage if they were.

        Cutting transparent glass with a laser has to be hella ineficient.
        • At room temperature, most materials that we think of as "glass" are relatively poor absorbers of microwaves. However, if there is a concentrated pulse of microwaves delivered to a small region (sufficient to heat that part to ~500 degrees Celsius) then that region of glass will become much more strongly absorbing--once melting has started in a region, it will continue from there.

          I don't know if room temperature absorption might be increased by selecting a different wavelength from that used in microwave ovens. I suspect that there would be incremental improvements only, but I invite experts to comment.

          If you want to cut glass with a laser, use one that operates up in the infrared. Ordinary glass cuts off transmission at wavelengths longer than about 2 microns (2000 nm). Quartz optics can still be used up to ~2500 nm. There are many commercially available lasers that operate in this regime. Industrial carbon dioxide cutting lasers emit at ~10.6 microns--special (expensive, delicate, finicky) optics have to be used to even let the laser beam out of the lasing cavity.

          My big concern for cutting glass with lasers would be the danger posed by specular reflections from the material being handled.

  • Ummm "Pipe" making ! (Score:2, Funny)

    by Anonymous Coward
    What a great way to make holes in complicated glass pieces. I see a brave new future for the science of "pipe" making.

    Stoners of the world unite ! Yay for those ingenious asians

  • Build your own (Score:4, Funny)

    by dubstop ( 136484 ) on Friday October 18, 2002 @05:09AM (#4477151)
    If you want to know how to build something similar yourself, Kent Fukuzura [thetoque.com] has some easy to follow instructions.

  • Jewlery stores (Score:4, Funny)

    by hatchet ( 528688 ) on Friday October 18, 2002 @05:26AM (#4477192) Homepage
    I guess jewlery stores will now use transparent aluminium [sci-fighter.com] instead.

  • IP Violation! (Score:3, Funny)

    by Da Fokka ( 94074 ) on Friday October 18, 2002 @06:09AM (#4477278) Homepage
    That device is very similar to my 'Death Ray TM'

  • Nice invention (Score:2, Funny)

    by Kj0n ( 245572 )

    This sounds like a nice invention for burglars. Now they no longer have to make noise when trying to break the window.

    Next week on /.: invention of a burglar alarm that can detect microwaves.

  • Apple's Cube (Score:3, Funny)

    by terraformer ( 617565 ) <tpb@pervici.com> on Friday October 18, 2002 @06:35AM (#4477329) Journal
    This probably would have solved the cracking problem in Apples now defunct cube...

  • See what happens deep inside Israeli underground.. (Score:5, Funny)

    by gorehog ( 534288 ) on Friday October 18, 2002 @06:49AM (#4477368)
    ...top secret weapons labratories?

    Physicist #1: Oh man, this Dr. Brown's Cel-Ray bottle would make a killer bong!

    Physicist #2: Ah, they shatter on the drill press, I tried it last week.

    Physicist #3: (eyes red and bleary)Hey, what's wrong with the microwave? I wanna make this popcorn.

    Physicist #1 & #2 (in harmony):Microwave?
  • Pizza pops.
  • ...the price of tinfoil hats has doubled overnight in response to the news. A foil hat manufacturer, when asked, was quoted as saying "Well, we had to double the price. People gotta protect themselves from those orbiting mind-control lasers, alien mind probes, and now they gotta worry about Israeli scientists drilling holes in their heads!"

  • How many microwaves did they use? (Score:2, Funny)

    by Anonymous Coward
    I'm assuming the microwaves don't work any more after they use them to drill the whole?

  • Medical uses? Bah! (Score:4, Funny)

    by Vortran ( 253538 ) <aol_is_satan@hotmail.com> on Friday October 18, 2002 @08:00AM (#4477637) Homepage
    Think "Return of the Pink Panther in the 21st Century..."

    What else is a silent, dustless, precision glass cutter good for?

    Vortran out

    P.S. - This is a joke. Please do not feel compelled to point out that the thing probably fills up a whole lab and has all the portability of a pile of bricks.
    • What else is a silent, dustless, precision glass cutter good for?

      An easily escaped, slow-starting, elaborate death-machine for the next Bond film?

      "Vell, vell, Meester Bont! Vonce dis meecrovawe emitter has reached your krotch, it vill begin to heatink it unt den ve vill be pushink a rod into it. Dis process vill be takink about tventy minutes to begin. Ve vill be leavink you to your fate now."

  • Totally impractical... (Score:3, Funny)

    by NewbieV ( 568310 ) <victor DOT abrah ... AT gmail DOT com> on Friday October 18, 2002 @08:05AM (#4477663)
    ...until you can mount one of these on a shark's head... that would be frickin' cool!

    And then you could sell it here [villainsupply.com]...

  • umm.... (Score:3, Interesting)

    by Borealis ( 84417 ) on Friday October 18, 2002 @08:46AM (#4477939) Homepage
    I could be wrong here, but wouldn't an ultraviolet laser be far more effective? Glass is not transparent to the UV spectrum so shouldn't it be able to "drill" right through it?
  • Weren't they doing this back in the 80's on a much bigger scale as a possible "star wars" weapon?

  • Great! (Score:2)

    by Polo ( 30659 )
    Since no man is truly complete without a portable power drill, I eagerly await a consumer version of this drill. ;)
  • I wonder how it would work against a semi-perfect mirror? I've always wondered how a laser or something that would rely on waves would work against a reflective surface.. Can anyone give me a clue?

  • Security issues (Score:3, Interesting)

    by macdaddy ( 38372 ) on Friday October 18, 2002 @12:11PM (#4479792) Homepage Journal
    This makes me wonder about security issues. Imagine if something powerful enough to direct these microwaves at glass from a distance. Lets also say the glass is bullet proof glass. Could that shatter the glass? Perhaps it doesn't destroy the glass but compromises its integrity to the point where teflon-coated bullets can penetrate it. Interesting....

  • Easier ways. (Score:1, Interesting)

    by Anonymous Coward
    With high voltage current you can melt holes in glass... Even a small TV induction coil will do.
    Put the HV wires on either side, if it doesn't start arcing through it then increase the voltage... The problem is that the glass at the hole heats up and the expansion often breaks the rest of the sheet.
  • From the article:

    it doesn't work very well with good heat conductors or materials with very high melting points, but the researchers envision a wide variety of manufacturing applications, and possibly some medical uses as well

    Right. I know human tissue doesn't conduct heat well, but does anybody know its melting point?

  • Sapphire's melting point, for instance, is too high. And steel conducts heat too well for a hot spot to develop.


    Somehow that gave me a mental image of a woman and a man being attacked by Time with more down-to-earth method instead of using parapsychological powers. (I wonder if anyone recognizes the reference ;)

  • I didn't have anything in it, and accidentally hit the cook button instead of the minute timer button. 20 Minutes later, POOF! The whole thing caught on fire. Turns out that the mixing belt failed, so it was all focused on the door. The engineer said, "Lucky you didn't loose the whole house! I've seen them burn straight through glass light bulbs...."

    Pictures and story here [darkphibre.com].

  • water cooled heatsink applications (Score:3, Interesting)

    by t0qer ( 230538 ) on Friday October 18, 2002 @05:11PM (#4482099) Homepage Journal
    I think this would rock for building a CPU heat exchanger. With hundreds of small tiny water filled holes it would wisk the heat away nicely.
  • the security people at the airport know how to identify the #$@%&* things!!!!
  • In other news the next Star Wars will reference upgraded combat technology.

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