Adapting an USB Vinyl Cutter with sc-99 or sx-74 ?

[JuanPabloCuervo]

some USB Vinyl cutters can controll pressure in grams upto 500g.
also have a resolution of 0.001" or 0.0254mm step.
= more than "20 grooves per milimeter."

the cutting shape can be drawm in software.!!

it would have steady groove separations, not variable volume grooves but...

http://en.wikipedia.org/wiki/Gramophone_record#Structure

[JayDC]

some USB Vinyl cutters can controll pressure in grams upto 500g.
also software has a resolution of 0.001" or 0.0254mm step.
= more than "20 grooves per milimeter."

the cutting shape can be drawm in software.!!

it would have steady groove separations, not efficient variable volume grooves but...

I had a similar idea a while ago, the problems come in when you try to generate an image. I never got that far.

I wanted to use a laser, and a galvometric scanning head. I used to have access to equipment like that coz of my old job.

Another problem is that the shape of a groove is that of a V which would be very hard to recreate as an image.

[subkontrabob]

I wanted to use a laser, and a galvometric scanning head. I used to have access to equipment like that coz of my old job.

L33TN355!

on topic:

couldn't you just bypass the drive electronics for the stepper motor (I guess it's a stepper?) and control it directly for pitch control? If it can manage the weight of a cutterhead, this would be a nice overhead slide. Or maybe it would move too jerky?

hold on, there are big versions of these things:

http://www.bestblanks.com/RolandGX300.html

and the best part: it's made by Roland! The same company that makes musical instruments.

http://en.wikipedia.org/wiki/Roland_Corporation

[opcode66]

I already started a VinylPlotter application before I got my lathe. The idea is to take a wave file and plot what the corresponding groove would be in. Ligher shades of gray mean deeper cut. Black means no cut. So, a groove looks black on the sides and it has a gradient to a white line in the middle. So, depth is plotted as a grayscale. The grooves are plotted laterally as normal. Do this for the enitre wave file and you have one long representation of the groove in 2D. Use graphics engine to take that groove and make it follow a basic spiral (lpi). Then run an algorithm so pack the grooves together from inside to outside while maintinaing minimum groove spacing (land). Now add lead-in and lead-out grooves and locked groove. Send this final image to the printer driver of a very accurate Laser Etching machine with a polycarbonate blank on the cutting bed. You should have a playable record when finished.

The major issue here is the pixel resolution of the device. With a Laser etcher you can get pretty accurate. But, you would have to have one that could make such small cuts that when the .7 Mil playback stylus rides the cut groove it can't tell the difference between the stepped cut of the laser an a smooth cut of a stylus. The gooves when looked at under magnification would not appear smooth like a cut groove but would be graduated or stepped. (just like a digitized wave). Therein lies the problem.

[subkontrabob]

I already started a VinylPlotter application before I got my lathe.

The major issue here is the pixel resolution of the device. With a Laser etcher you can get pretty accurate. But, you would have to have one that could make such small cuts that when the .7 Mil playback stylus rides the cut groove it can't tell the difference between the stepped cut of the laser an a smooth cut of a stylus. The gooves when looked at under magnification would not appear smooth like a cut groove but would be graduated or stepped. (just like a digitized wave). Therein lies the problem.

I don't mean to be rude, but it's kind of obvious that this kind of approach won't work. I don't have "official" numbers, but my old book mentions 65 micrometers ~ 2,5 mils as a maximum value for groove excursion. With 0,0005" precision that would yield 20 dB signal to noise ratio, and still leave you with the "analog quantization noise".

Kudos for trying it out!!

I think the guys were talking about mounting such a thing on top of a turntable and installing a cutterhead instead of the plotter mechanism...

[opcode66]

Precision of 0.0005" is totally doable. Yes there would be some background noise. Sooner or later there will be more accurate laser etchers. The idea is technically viable. The technology isn't quite there to make it work. But soon.

Remember, they had patents on variable groove systems in the 20's or 30's (can't remember exactly). Well before the technology was there to do it...

I just thought you guys might like to see another concept for cutting. FYI, there is a guy overseas already doing something like this. They built a laser cutterhead that goes on a standard overhead mechanism. Different approach but essentially the same concept, cutting with a laser.

[subkontrabob]

Precision of 0.0005" is totally doable. Yes there would be some background noise. Sooner or later there will be more accurate laser etchers. The idea is technically viable.

The technology isn't quite there to make it work. But soon.

I wasn't saying it's technically not viable, only that with that kind of resolution the result will not be satisfactory. Of course you could push this further to a point where it will work. I'm better at ranting and nagging, I know.....

Again: Kudos for doing it, I have way too little expertise to even think about doing something like that.

FYI, there is a guy overseas already doing something like this. They built a laser cutterhead that goes on a standard overhead mechanism. Different approach but essentially the same concept, cutting with a laser.

Getting carried away again: could you build a laser cutterhead that would just evaporate the material on the disc?

[JayDC]

Precision of 0.0005" is totally doable. Yes there would be some background noise. Sooner or later there will be more accurate laser etchers. The idea is technically viable.

The technology isn't quite there to make it work. But soon.

I wasn't saying it's technically not viable, only that with that kind of resolution the result will not be satisfactory. Of course you could push this further to a point where it will work. I'm better at ranting and nagging, I know.....

Again: Kudos for doing it, I have way too little expertise to even think about doing something like that.

FYI, there is a guy overseas already doing something like this. They built a laser cutterhead that goes on a standard overhead mechanism. Different approach but essentially the same concept, cutting with a laser.

Getting carried away again: could you build a laser cutterhead that would just evaporate the material on the disc?

yes lasers will not make chip, and will start fires.. this is why the image must be scanned like an entertainment laser projector works. A laser on an overhead will not work, never will..

A laser used in this way would only replace the stylus, not the recording head. Lasers themselves can only make a straight line, so therefor you would have to vibrate the laser in the same way you would a stylus.

since the laser will not have a point. it cannot cut the V..

[subkontrabob]

A laser used in this way would only replace the stylus, not the recording head. Lasers themselves can only make a straight line, so therefor you would have to vibrate the laser in the same way you would a stylus.

let me guess, you have also seen the ELP laser turntable??

since the laser will not have a point. it cannot cut the V..

I'm thinking tiny mirrors.......

but I guess the energy needed to evaporate things will be prohibitive

as I said, getting carried away offtopic, sorry guys......

......must sleep........too many voices in my head......

[opcode66]

There is a video on youtube of them cutting a record with a laser attached to an overhead mechanism.

You can happily etch plastic without a fire. That is one of their primary uses. Look at the ads for any laser etcher. You can cut plastic. There is an exhaust system with a vent pipe for the gases that are produced when cutting any material including plastic.

And, yes, the material does in fact vaporize. Read about laser etchers. They are very cool! It is similar to tatoo removal in the sense that it is a high power laser that works in pulses and is not constantly on. Each pulse vaporizes the material and represents a pixel cut. You have absolute control over position and depth of each pixel cut. They even have smoothing algorithms so a groove cut in such a fashion would not be so blocky.

You don't cut the V shape with the entire beam. You make extremely small point cuts that together form a V.

My solution would use a laser etcher as is. The other guys I mentioned overseas are trying to do this in an entirely different fashion. Their system would have this exact problem that the groove cut has no V shape. My system does not work like that.

You can find the video on youtube. They make a locked groove cut and play it back. Doesn't sound great but it works.

http://www.youtube.com/watch?v=amTZB0UUngs

[JayDC]

I'm thinking tiny mirrors.......

exactly.. on what are called galvos, this is how a laser projector works, and it could provide exactly what you need, especially with a gradient style image that opicode pointed out.. Would only take about 3 seconds to "burn" a record, and it would not even need to spin.

I could built it tomorrow if someone gave me 1000 to buy galvos, just need the image..




as far as a laser pick up, thats a different thing all together.. That works by the laser bouncing off the groove and a optical sensor picking up the light and translating it to electrical pulses.

[subkontrabob]

I'm thinking tiny mirrors.......

exactly.. on what are called galvos, this is how a laser projector works, and it could provide exactly what you need, especially with a gradient style image that opicode pointed out.. Would only take about 3 seconds to "burn" a record, and it would not even need to spin.

I could built it tomorrow if someone gave me 1000 to buy galvos, just need the image..

I see, very interesting!

but isn't there an inherent problem with using one stationary galvo? suppose it is attached above the middle of the disc, it couldn't create the outside facing wall of the groove, or am I mistaken?

My thought was an overhead mechanism with a small galvo, with a prism and two lasers, one on each side. You could rock the prism laterally to get the lateral signal......

[JayDC]

well a laser scanning head is made pretty much the same way a stereo cutting head is configured..

you need 2 galvos 45 degrees from each other to get a complete image



then using a laser diode, you can "dim" the laser very fast.

if you made the image so the the V is darker the deeper it is, then it would work..

it would REALLY work.. and the V would be smooth.. The laser and scanner head would need to be about 3 feet above the disc.

The laser system is easy for me, I ran and maintained lasers for 5 years at a huge nightclub. We had a couple 10 watt AR/KR white light water cooled ones, and a few air cooled diode projectors.

I would start testing with a 1/2 watt 650nm red laser, these seems to burn dark colored objects very well.

If you had the image, and we used pangolins LD2000 entertainment laser controller software, and we'd be burning test disks with in a week.

The barrier is making an image from audio..

[opcode66]

The barrier is making an image from audio..

I can help in that department. I did actually do some dev work on this application. It is a real exe on my computer. I think there are other ways to do it with lasers than just using a laser etcher/engraver. The digital file would be essentially the same.

[JayDC]

yes.. basically you would project the entire image onto a blank and expose it for a moment. Good galvo's can do 60K points per second. So scanning the beam, and using the lasers dimmer function can easily do gradients.

So yeah, it would basically draw many lines, but so fast that it looks like a solid image. And since on a good diode laser, the dimming function is analog, it would make a super smooth gradient.

Finding the correct laser power and wavelength is going to take a bit of thought.. Too much power, and it will vaporize the blank, to little and no groves.

I think a deep red 650-700nm from 1/2 watt to 1 watt would be enough to burn a piece of black poly. Just gotta be careful of the mirror finish, since that could deflect the laser, and put your eye out..

wear eye condoms..

[subkontrabob]

ok some more simple math to spoil the fun:

- suppose the galvo is 3 feet (=36 inches) above the disk
- disk radius is 6 inches

to get the angle that the galvo has to move in order to project the beam to the edge of the disk we use good ole Pyhtagoras: sin alpha = a/c

where a = opposite side of the angle = disk radius ; c = Hypotenuse = laser beam to the edge of the disk

plug the values in:

sin alpha = 6/36,5 = 0.164 -> alpha = 9.4°

So with 9.4 degrees of movement, the galvo covers the entire disk. Let's calculate how much accuracy we need, for simplicity we choose a 100 LPI groove as an example. Accuracy needed to move in 100 LPI increments: 9.4/600 = 0.015° This is the accuracy needed in order to cut a simple groove without modulation. If you want to modulate this groove with LP quality (60 dB dynamic range) signal, you would need a 1000 times higher resolution: 0.000015°

Can a regular galvo deliver that?

[subkontrabob]

http://www.youtube.com/watch?v=amTZB0UUngs

My gosh, I know that dude personally!!!

Have to hit up Jari to see this.......

[opcode66]

I still think that a laser engraver/etcher is the way to go.

http://www.epiloglaser.com/co2_laser_systems.htm

If you put a little money into it, you can get a very accurate one. It takes a grayscale image and etches it into whatever object is on the cutting bed.

[JayDC]

the reason it sounds bad, is coz its not a good method.

a co2 laser is not at all what you want to use.. You want to use a Diode Pumped Solid State Laser with analog dimming.

a co2 laser is like any tube laser, and you would need extra galvo's or a pcaom to dim it out, and if you do that, then you have a waste beam to worry about. No dimming, no gradient, and a huge loss of power.

To use a laser to make records effectively, one needs to get away from traditional ways records are made. You should not even have to spin the blank to cut the program material on the record. and the laser should also not need to move.

There would be no lathe in this situation, or a lathe like machine.

[JayDC]

you would waste so much power with a co2 tube laser. In order to dim a tube laser, you need more galvos, or an A.O.M.. analog optical modulator.. You would then have waste beam, and you would lose 55% or more of the power of the laser.

A better choice is a Diode Pumped Solid State Laser with analog dimming. The advantage here is first Analog dimming is faster then an A.O.M, and the total output power of a dpss laser is not effected by analog dimming.

Using a PCAOM or an AOM will never allow you to use the full power of the laser, by design. The scan rates of those devices are slower then the analog dimming circuits on more modern dpss laser systems.

The advantage of using a tube laser is the divergence, tube laser tend not to get fatter over distance. Cheap dpss laser have very poor divergence, and sometimes oval dot, and not a circular dot. This can be corrected with lenses, at a less power loss then using an aom.

Very good dpss laser systems can dim at over 125Khz, and galvos are available up to about 80Kpps, although 60Kpps is the norm now.