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View Full Version : Anyone with CNC interested in selling polymer AR 80%'s?


sharxbyte
06-16-2012, 8:16 AM
we've probably all heard about people milling their own receivers out of polymer, as well as the plumb crazy and other commercially available receivers. What I'm wondering about is a polymer 80%.

This SHOULD make it extremely affordable to make more than one project at a time, or just have a few on hand, or be used as a training project when teaching ones children about milling, and firearms/laws. I don't know how much of a market there would be, but I for one would be extremely interested.


Anyone have ideas on a price tag?

feelgood
06-16-2012, 8:34 AM
i've heard about polymer lowers but they are still Untested...I know they are affordable but i think i have to wait a while before purchasing one...that's me i don't know about the others..

Peter.Steele
06-16-2012, 9:41 AM
Thing to remember about the polymer lowers is that they aren't CNC milled out of a block of plastic. They're injection molded, and they use a fairly specialized mix of materials that you can't just walk into Home Depot and buy.

There's several hundred thousand dollars worth of work that goes into injection molding that first AR lower, when you factor in all the tooling and R&D work. There's really little or no up-side to offering them as 80% kits, although I suppose if you're planning your tooling out ahead of time for that possibility, you could do it easily enough.

OrenG
06-16-2012, 10:19 AM
i've heard about polymer lowers but they are still Untested...I know they are affordable but i think i have to wait a while before purchasing one...that's me i don't know about the others..

I wouldn't say that. I don't have access to Plum Crazy's records but I'm pretty sure he's sold quite a few lowers, and out of those I've only seen two different documented incidents where the lower cracked in half.

You could be just as likely to have this happen on an aluminum lower if you are unfortunate to get a kaboom.

In fact in total I've probably seen more aluminum lower kabooms than polymer ones.

sharxbyte
06-17-2012, 1:30 AM
Peter, there are quite a few instances of people milling out of a reasonably hard plastic. I realize that the commercially available ones as of yet are Injection molded, but that's because injection molding is easier/faster to mass produce. CNC also has a lot in start up costs, but if someone is already set up, all they need are the cad files for the lower receiver, and a lot of high grade plastic/polymer.

Thordo
06-17-2012, 6:07 AM
Peter, there are quite a few instances of people milling out of a reasonably hard plastic. I realize that the commercially available ones as of yet are Injection molded, but that's because injection molding is easier/faster to mass produce. CNC also has a lot in start up costs, but if someone is already set up, all they need are the cad files for the lower receiver, and a lot of high grade plastic/polymer.

Been there, done that. Couldn't make it work.

Peter is right. Our UBBT products are not our primary business. We've specialized in high end medical grade plastics and semiconductor machining (PEEK, Noryl, GF polycarbonate, polypropolene) for over 20 years.

Polycarbonate, glass filled polycarbonate, and nylon 6 were the off the shelf plastics I used. PC machined great but was too flexible, GF PC is VERY difficult to machine and is also very brittle when machining thin walls. Nylon 6 is a B#$%ch to machine, dimensionally unstable and leaves a horrible finish .

There aren't any off the shelf plastics that possess the same properties as the resin used to mold the Frontier armory lowers. That blend of nylon co-polymer is ONLY available in in pellet form. You'd have to have it custom molded into ingots to make it machinable. A manufacturer like Westlake Plastics typically require a minimum run of say 500 pounds, take up to 10 months to get, and cost $$$. Not to mention that that blend of nylon co-polymer is VERY difficult to machine and leaves a terrible finish. It may also be proprietary.

The bottom line is that it was not economically feasable to CNC machine polymer lowers and once the LW-15 came out, we stopped development. I'm sure the mold for their lower probably cost $80K minimum.

Thordo

sharxbyte
06-17-2012, 6:49 AM
Been there, done that. Couldn't make it work.

Peter is right. Our UBBT products are not our primary business. We've specialized in high end medical grade plastics and semiconductor machining (PEEK, Noryl, GF polycarbonate, polypropolene) for over 20 years.

Polycarbonate, glass filled polycarbonate, and nylon 6 were the off the shelf plastics I used. PC machined great but was too flexible, GF PC is VERY difficult to machine and is also very brittle when machining thin walls. Nylon 6 is a B#$%ch to machine, dimensionally unstable and leaves a horrible finish .

There aren't any off the shelf plastics that possess the same properties as the resin used to mold the Frontier armory lowers. That blend of nylon co-polymer is ONLY available in in pellet form. You'd have to have it custom molded into ingots to make it machinable. A manufacturer like Westlake Plastics typically require a minimum run of say 500 pounds, take up to 10 months to get, and cost $$$. Not to mention that that blend of nylon co-polymer is VERY difficult to machine and leaves a terrible finish. It may also be proprietary.

The bottom line is that it was not economically feasable to CNC machine polymer lowers and once the LW-15 came out, we stopped development. I'm sure the mold for their lower probably cost $80K minimum.

Thordo


Well, I'm slightly dissapointed in the fact that its not feasible, but I really appreciate your numbers and experience.