The Disc Manufacturing Process

[JHern]

True enough. There are some dudes here in CA making discs out of wood, they are actually really nice and this would be a great way to experiment with the influence of shape on flight, but of course wood will never pass the flex test.

What if there was a tool that could cut, grind, and polish TPU the same way it does for wood? That would be ideal.

Anyways, thermoplastic injection molding seems to be the cheapest process by far, but it is prone to a great deal of sensitivity to plastic properties variations as well as operator dispersion. I wonder what the best way might be to break through this barrier, that's really what is holding the sport back in terms of equpiment.

 

[JR]

That machine should match the speed of injection molding machines too.

I would not wonder if TPU cutting and polishing machines already exist but how fast are they? They cut way harder materials and polish them given time with current CNC machines.

I had higher hopes for MVP using molds and liquid TPU. Theoretically with material that shrinks so little and hopefully the material lasting for a while there should have been no variations in the material. And the molds should determine the shape well because there is no heat applied. But i have not checked the recently linked video only read what they wrote here when they started.

I do not think the sport is being held back technologically it seems to be the other way around. There is need for limiting how far discs fly since so many courses have shrunk to too little demanding with current disc distance increases. The available land is a problem already and there are safety issues already. I do not believe that anyone that likes to play DG would stop just because discs are inconsistent and no sponsor would say no to sponsoring for that reason. I don't see how the equipment is holding back anyone. The largest gains for anyone would come from throwing better rather than switching discs. If added D was a requirement porous durable material flight plates might make the largest dent. And would likely cost a lot. And thorns would still pierce the flight plate easily no matter what kind of protective mesh was used most likely. Since all plastic flight plates get punctured too.

 

[JHern]

I had higher hopes for MVP using molds and liquid TPU. Theoretically with material that shrinks so little and hopefully the material lasting for a while there should have been no variations in the material. And the molds should determine the shape well because there is no heat applied. But i have not checked the recently linked video only read what they wrote here when they started.

That sounds highly promising. I know that thermoset plastics can also be used in some kinds of processes...kind of like an epoxy, in which 2 fluids react to make a tough solid. But I don't know of any particular kinds that would be suitable for discs.

I do not think the sport is being held back technologically...

While the distance potential of sport is not necessarily held back (PDGA rules already limit it), disc design, production, and QC is definitely held back. Consider that a disc design can be mathematically optimized to obtain a desired flight pattern with the least sensitivity to release errors for the best golf results, yet no manufacturer does this or even understands that it could be done. A disc could be mathematically modeled all the way from the formulation of the plastic, injection into the mold, shrinkage, stamping, and it's first throw and flight could be precisely predicted...but they have to entrust it to process engineers and pay them a salary, which is probably the biggest hurdle. Once they get to that point, there will be a noticeable jump in disc quality. No, you won't be able to throw farther, but you will be able to throw better golf scores with equipment that is precision-tuned for each purpose. Think of a perfectly stable disc that holds any line forever, and which is designed so that impacts don't alter the PLH. Or a disc that flexes or turns over slowly and controllably and predictably every time.

Anyways, for the modern manufacturer, the question isn't about whether or not the sport is held back, the question is how to increase market share and make the kinds of products that do exist even better. Innova has a jump on everyone because they've made so many different molds and they've tried so many different designs, they have a large library of empirical knowledge to stand on, and a large sales catalog (i.e., it is an excellent bet that any player can find multiple Innova molds that they like to throw, and which they find useful in their golf game). This gives them a huge leg up on everyone else, and only Discraft has come close to offering such variety. And then they are still doing cool new stuff, like Blizzard plastic, which proves that working on innova-tion can still pay off. New start-ups have to focus on producing only those kinds of discs which are perceived as being the most popular, they don't have the financial resources to buy hundreds of molds and blanket the market. They must pick and choose their way into the market, and it takes a while before they can fill all the slots in a bag with their molds.

 

[JR]

At least blunter primo discs won't deform in the PLH normally. I'm not so sure that design alone can make speed 13 and over discs maintain PLH indefinitely. That would slow down the wear a lot and it might not be financially sensible for any manufacturer to pursue that. Some discs do already hold their lines to the ground.

 

[isobar1]

Has anyone tried using a 3D printer to make a few discs and see how they work? I know they aren't cheap, however I believe for someone looking to develop a disc, it would be cheaper to run a few samples in a 3D printer and see how they feel. I don't know exactly what plastic resin most printers use though, it might be too hard to use for discs.

 

[JR]

The material cost is that of a few bought discs so for prototyping the cost is not prohibitive if you can get your mitts on a printer and have the schematics in a format that the printer understands. I'd imagine the end result would be hard and slick. You could make a mold too and pour liquid polyurethane into it but at least some of those are super carcinogenic and allergenic so all manner of protective gear is a must not just recommended.

 

[JHern]

Has anyone tried using a 3D printer to make a few discs and see how they work? I know they aren't cheap, however I believe for someone looking to develop a disc, it would be cheaper to run a few samples in a 3D printer and see how they feel. I don't know exactly what plastic resin most printers use though, it might be too hard to use for discs.

This is an excellent suggestion. While the plastic that is used in the 3D printer might not be ideal for throwing, it would at least allow you to assess the aerodynamical properties and how they trade off with mold shape, which is ultimately what we're after. In other words, the 3D printed disc could be put directly into a small wind tunnel (a research grade tunnel that goes to 80 MPH could be built for ~$10K), and the aerodynamical forces and moments could be measured directly. The wind tunnel measurements will then allow you to assess the flight characteristics precisely using the kind of simulations that myself and others already do.

In fact, we wouldn't even need a 3D printer, a high precision robotic (CNC) lathe would be just fine, since we're producing axisymmetric discs. Just input the CAD profile of the disc, set the tolerance, and let the machine go to work. Just found one for sale on ebay for $2K...
http://www.ebay.com/itm/Amera-Seiki-TC-2L-CNC-Lathe-/111006515789?pt=BI_Lathes&hash=item19d881024d

Note that, to cut the proper mold, you would need to get a consistent blend of plastic, measure its shrinkage characteristics precisely, and then reverse engineer the mold shape that would produce the desired disc shape using plastic shrinkage calculation software (e.g., finite element analysis).

So for less money that the cost of producing one $20K steel mold, you could buy all the equipment you would ever need to be able to reverse engineer disc designs, and obtain the best possible designs. You could even use mathematical analysis to optimize mold shapes for various characteristics:
1) A desired rim depth and width, such that the grip is comfortable for the thrower.
2) A mold shape whose flight characteristics are least affected by plastic variation, yielding the maximum intrinsic consistency.
3) Etc., the list of possibilities are endless.

Of course, you would also need to hire somebody who understands all of this, which would cost a bit more. But maybe some of us would be willing to do it for a small fee on a limited basis, to make it more affordable, like a consultancy type of arrangement.

 

[JR]

Some years ago i saw people write here that some companies have gotten mold made from steel for 5K and aluminum way less 2-3K range. And aluminum molds last max 5000 discs. I have no idea about steel longevity.

 

[JHern]

Some years ago i saw people write here that some companies have gotten mold made from steel for 5K and aluminum way less 2-3K range. And aluminum molds last max 5000 discs. I have no idea about steel longevity.

It depends on where you make it, whether you use union shops, etc.. My cousin is a union machinist, been working in that field for decades, and says a good quality mold will run more than $10K. Either way, it's in the same ballpark as the cost of the CNC lathe+wind tunnel that would permit the disc manufacturer to make the best discs possible...

...a consultancy disc design shop could be setup to handle the entire process, from designing the mold, securing the plastic supply, to getting the mold machined. Of course, at that point, they might as well pick up a couple of plastic injection molding machines and make discs themselves.

 

[scoopa]

I know first hand that 3D printers have been used to make test discs. The only negative stated was they were fragile, no full rips(too much grip pressure), and field throws only for the softer landings.

 

[JR]

Disc golf manufacturing+quality? Not 10K+ then Not surprising considering the variances in discs even after material variations have been factored into the equation.

 

[Wayne Smith1]

The manufacturing process of certain discs are good. This way many golfers and buyers will be amazed on how the materials are being made. Such good videos!