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What could you use it for?
- Thread starter gr8scott
- Start date
Unscrewing things with vibration is easy, it requires no finesse at all, just ask anybody wearing glasses 
The trick is to ram a screw into something.
Having said that many plastic and even a few small metal assemblies are currently welded together using ultrasonics
The trick is to ram a screw into something.
Having said that many plastic and even a few small metal assemblies are currently welded together using ultrasonics
Ultrasonic Welding Explanation
This is the much simplified explanation. If you really want to learn all there is on the subject try The Ultrasonics Book
Ultrasonics are high frequency sounds, like the ones bats use for navigation and hunting.
For welding we work on two assumptions:-
1/ If you fire sound into something solid, the item will vibrate. You can test this with the fabled tin and string telephone, if you speak into the tin and touch the string very gently you can feel the string vibrate as you speak.
2/ When two parts are rubbed together hard enough they heat up and ultimately melt. Again easy to test, the easiest is by sawing a length of polypropelene cord across another piece.
In an ultrasonic welder the two parts are subjected to high frequency sound from a piezo generator (from about 7.5KHz for plastic). This causes resonant vibration in the parts, effectively rubbing them together at very high speed. Where they meet (the interface) they become hot enough to melt. Press them together firmly, remove the vibration and the material sets again, giving a bond.
Because it is only the very surface of the part that melts, there is no heat generated in the rest of the component, so there is no damage and the setting time is minimal, because it is conducted away almost instantly.
May be worth noting that ultrasonics are heavily used for a range of other tasks in industry, including inspection of hard to reach places, forming, automatic feeding and non-mechanical pumps
This is the much simplified explanation. If you really want to learn all there is on the subject try The Ultrasonics Book
Ultrasonics are high frequency sounds, like the ones bats use for navigation and hunting.
For welding we work on two assumptions:-
1/ If you fire sound into something solid, the item will vibrate. You can test this with the fabled tin and string telephone, if you speak into the tin and touch the string very gently you can feel the string vibrate as you speak.
2/ When two parts are rubbed together hard enough they heat up and ultimately melt. Again easy to test, the easiest is by sawing a length of polypropelene cord across another piece.
In an ultrasonic welder the two parts are subjected to high frequency sound from a piezo generator (from about 7.5KHz for plastic). This causes resonant vibration in the parts, effectively rubbing them together at very high speed. Where they meet (the interface) they become hot enough to melt. Press them together firmly, remove the vibration and the material sets again, giving a bond.
Because it is only the very surface of the part that melts, there is no heat generated in the rest of the component, so there is no damage and the setting time is minimal, because it is conducted away almost instantly.
May be worth noting that ultrasonics are heavily used for a range of other tasks in industry, including inspection of hard to reach places, forming, automatic feeding and non-mechanical pumps
I can understand loosening an embedded object via ultrasonic vibrations, but to actually unscrew an object from its encasement just seems to far fetched. It would require too much finite control that would contradict the overall ultrasonic vibrations. To unscrew an object, you would need some form of force field, or tractor beam technology. Not just a resonator. By it's very nature, sonic waves are strictly reactive. But to unscrew something it would require active not reactive.
This has a lot to do with the science involved with resonant frequencies and such like, as such is not my particular field.
Ultimately sound is just vibration. Find the right frequency and amplitude for the right part and it will do more or less what you want it to do.
What I would observe from experience is that, with one or two notable exceptions, I had to wire all the nuts and bolts on my Velocette motorcycle shut. Nyloc nuts and loctite were never enough to stop whatever they were holding in place staying put. There was never any great finesse involved.
Ultimately sound is just vibration. Find the right frequency and amplitude for the right part and it will do more or less what you want it to do.
What I would observe from experience is that, with one or two notable exceptions, I had to wire all the nuts and bolts on my Velocette motorcycle shut. Nyloc nuts and loctite were never enough to stop whatever they were holding in place staying put. There was never any great finesse involved.
[Originally posted by ray gower: Ultimately sound is just vibration. Find the right frequency and amplitude for the right part and it will do more or less what you want it to do.]
You know, I thought about this very interesting discussion for a little while today. And you're right ray, frequency and amplitude are the two properties of sound that we know.
But this is a science fiction show, so what if the Time Lords are manipulating properties of sound of which we are not yet aware? What about direction? And I don't just mean in terms of pointing a speaker in a certain direction.
We are used to thinking of a sine wave where the top and bottom are equal distances away from the center line. But what if you could apply direction to the wave? Then you might be able to use the sonic signal to push or even pull, just as you use a real screwdriver to loosen or tighten.
Then you could use it as a real "sonic driver" to apply the force in a specific direction. It wouldn't be hard to assume that "sonic screwdriver" would come to be the common term used for such a device.
Of course, that's still too simple a device to account for all the uses that the sonic screwdriver had.
For instance, if you're going to use it to open locks, as The Doctor often did, you going to have to build into it a computer that can manipulate the signal to push and pull on the right parts of the lock to make it open.
I know that's not scientific, but as we all know, the good Doctor never let the science get in the way of telling a good story.
Great discussion topic though guys. Very thought provoking.
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gr8scott = Speaker - 2nd Foundation
Wow! Another Asimov fan, I thought we had all died off years ago.
You know, I thought about this very interesting discussion for a little while today. And you're right ray, frequency and amplitude are the two properties of sound that we know.
But this is a science fiction show, so what if the Time Lords are manipulating properties of sound of which we are not yet aware? What about direction? And I don't just mean in terms of pointing a speaker in a certain direction.
We are used to thinking of a sine wave where the top and bottom are equal distances away from the center line. But what if you could apply direction to the wave? Then you might be able to use the sonic signal to push or even pull, just as you use a real screwdriver to loosen or tighten.
Then you could use it as a real "sonic driver" to apply the force in a specific direction. It wouldn't be hard to assume that "sonic screwdriver" would come to be the common term used for such a device.
Of course, that's still too simple a device to account for all the uses that the sonic screwdriver had.
For instance, if you're going to use it to open locks, as The Doctor often did, you going to have to build into it a computer that can manipulate the signal to push and pull on the right parts of the lock to make it open.
I know that's not scientific, but as we all know, the good Doctor never let the science get in the way of telling a good story.
Great discussion topic though guys. Very thought provoking.
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gr8scott = Speaker - 2nd Foundation
Wow! Another Asimov fan, I thought we had all died off years ago.