OK, let's run that pop fly out.
1) There are several aspects to making a MP. There's the internal chamber which is generally a molded or cast form with minimal finishing just to clean it up. Nowadays there are people machining the chamber with CNC machines, which can make some shapes that casting can't, but can't make some shapes that casting can. There's the facing, which can be done by machine start to finish, can be roughed out with a machine and finished by hand, or can be done by hand start to finish. And there's some fine tuning of baffle and that area right in front of the tip rail, which is probably always done by hand or left off altogether.
2) Let's take these one by one.
- If the chamber's CNC machined, there might still be need of some handwork to create some shapes that casting/molding would do but CNC can't.
- If the chamber's cast/molded, there should be some handwork to clean it up; whether it goes beyond that to create shapes that casting/molding can't is the choice of the manufacturer.
- I can't see that there's any advantage to making the entire facing by hand, but if you're not prepared for the investment in machinery and setup to make accurate machine cut facings, you'll want to do the facing finishing by hand. Advantage is that it can be really accurate; disadvantage is that such accuracy is 100% human dependent and the best human is far less consistent than a good machine.
- Tip rail and baffle fine tuning - if your machine made parts are accurate enough, fine tuning these shouldn't be needed - unless you need to make shapes that the machine can't. But it may not be possible to get "accurate enough" unless you invest cost-prohibitively.
3) The ability to make by machine mouthpieces accurate enough and consistent enough to equal or exceed the results of human fine finishing is not a technical challenge. It's a financial challenge. I guarantee, as a mechanical engineer of almost 40 years' experience wtih mass production manufactured products, that the equipment I've worked with in my career can far exceed the tolerances of any manual process. The question is, are you prepared to invest? You've got to sell a pant load of mouthpieces to pay for the equipment. And that means only a few designs. And even then there's going to be SOME hand work. Ever try to deburr a machined part without hand work? Even with free cutting brass it'd damn near impossible never to have burrs that need manual removing.
4) If you want something different than the mainstream, you're back to hand work to get it. You're going to have to accept less consistency and accuracy than the best machine made product, in return for getting a design that the mass production houses can't afford to make. And that's what the huge number of mouthpiece makers currently entering the market are offering.
5) Keep in mind that those great players of the past typically played machine made models of modest price that may or may not have been fiddled with. Look at the setups and it's just the same names over and over and over again: Link, Brilhart, Berg, Meyer, Gregory, and a couple others.
If the complaint is that people are using 3-d printing to make good accurate products that work well, that's just a modern day version of forming the chamber shape by casting (technology of 1500) or CNC machining (technology of 1990). Unless you mine the copper and tin and zinc yourself, smelt it, cast it, and do every bit of work using hand tools only (OK, a spring pole lathe is acceptable) then you're relying on machine technology. How do you think the files you use to clean up castings are made? On a big honkin' automatic machine. Where do you think your brass bar stock comes from? Ever seen inside a modern rolling mill? Your hard rubber blanks are molded in an injection molding machine which at this point in time is festooned with computerized controls to give you a more consistent product by far than what Otto Link bought back in 1940 from his molding house that used cam operated machines with big Bourdon tube pressure gauges.
If the complaint is that people are using 3-d printers to make inaccurate products that don't work, I suspect that'll fix itself because the products will suck.
