Um. You're both right.
Injection molding plastic has the advantage of the parts costing pennies a piece, after paying for the very expensive mold(s). The mold would be made on a CNC machine. The life of the mold would depend on the material. More difficult material to mill would last longer. And once the first mold is programmed into the machine, many molds can be run off with just the expense of material and time. They would need enough molds to run multiple pieces at a time, or the worker is waiting for that one mold to cool most of the time.
Plastic surfaces would be finished when they come off the mold, and not machined. So the mold has to be perfect. Surface finish with plastic is best straight off the mold. Any sanding or abrasive polishing will always result in oxidizing. The only way to restore the surface glaze is heat or solvent. The nylon (fiberglass reinforced) that they like for grip frames is not weldable because it turns to clear liquid when melted, so I don't think it can be re-glazed with heat.
Trim the flash off the edges and where the pieces of the mold meet. Some notches and holes are made after the piece is molded, like the notch for the safety on grip frames that are available in pro and safety version.
Molding plastic is not particularly hard on molds like stamping steel. Molds should last pretty long.
Is the manufacturer screwing the customer when they sell them something made out of plastic because it costs pennies a piece to mold? Not if the customer considers how much it would cost to make that plastic piece themselves.
Investment casting is similar to sand casting. A molded wax positive is packed in sand, then melts away when the metal is poured in, leaving a copy in metal. The biggest advantage is reduction of material cost, because you are not standing knee deep in shavings to whittle a piece out of a solid bar of material. Cast metal pieces do require machining, because the surfaces are not perfect (look at the surface of a aluminum intake manifold, steel exhaust manifold, or cast steel spindle, where the non-critical surface has been left natural), and the metal at the surface is not as good and consistent as the material beneath the surface. But this knocks it down to the last couple steps of machining, and eliminates a huge amout of labor time.
The frames and a lot of the inner pieces of the P Series pistols is that famous investment casting. Lots of machined surfaces.
CNC is labor intensive and slow. Anything that is not close to the shape of standard bar is going to end up cutting a lot of wasted material, paid for, and on the floor in little chips and shavings.
But CNC is going to be used to make the molds and do the finish work on the metal molded pieces.
Something I remember reading about Glock is that the designer/company owner was a curtain rod manufacturer, and used his expertise in stamped metal parts in the design. A lot of those internal parts that are cast in the Ruger P Series, are stamped in the Glocks. The rails on the Sigs, at least the kits, are also stamped.
I like plastic for control surfaces and places that get handled. I'm less a fan for structural pieces made of plastic.
I deal with a lot of 25+ year old plastic that has dry rotted, sun rotted, and become brittle. It gets to a point that it just starts turning to powder in your hands. And then you need a new replacement. It is not good for something to be handed down to children and grand children. There won't be new grip frames for discontinued 2000, 2010, and 2020 Rugers available in 2050. There aren't new frames for P95s, P97s, and P345s available now. And that nylon can't be repaired by welding.
I am also seeing the weight reduction as counterproductive to use, because the weight of a steel or aluminum frame acts to reduce recoil. That was a big deal when the Glock was introduced. We were even trying to reduce recoil on 9mms with spring kits, and the Glocks were slighted for not having enough mass to be easy to shoot. Of course, everything at that time was a full sized duty pistol. In the years since, the concern has become more for small size to hide, and light weight so that it does not fall or tire the carrier.
Meanwhile, for shooting competitions, they sell weights and thumb braces for Glocks, to make them easier to operate.
Injection molding plastic has the advantage of the parts costing pennies a piece, after paying for the very expensive mold(s). The mold would be made on a CNC machine. The life of the mold would depend on the material. More difficult material to mill would last longer. And once the first mold is programmed into the machine, many molds can be run off with just the expense of material and time. They would need enough molds to run multiple pieces at a time, or the worker is waiting for that one mold to cool most of the time.
Plastic surfaces would be finished when they come off the mold, and not machined. So the mold has to be perfect. Surface finish with plastic is best straight off the mold. Any sanding or abrasive polishing will always result in oxidizing. The only way to restore the surface glaze is heat or solvent. The nylon (fiberglass reinforced) that they like for grip frames is not weldable because it turns to clear liquid when melted, so I don't think it can be re-glazed with heat.
Trim the flash off the edges and where the pieces of the mold meet. Some notches and holes are made after the piece is molded, like the notch for the safety on grip frames that are available in pro and safety version.
Molding plastic is not particularly hard on molds like stamping steel. Molds should last pretty long.
Is the manufacturer screwing the customer when they sell them something made out of plastic because it costs pennies a piece to mold? Not if the customer considers how much it would cost to make that plastic piece themselves.
Investment casting is similar to sand casting. A molded wax positive is packed in sand, then melts away when the metal is poured in, leaving a copy in metal. The biggest advantage is reduction of material cost, because you are not standing knee deep in shavings to whittle a piece out of a solid bar of material. Cast metal pieces do require machining, because the surfaces are not perfect (look at the surface of a aluminum intake manifold, steel exhaust manifold, or cast steel spindle, where the non-critical surface has been left natural), and the metal at the surface is not as good and consistent as the material beneath the surface. But this knocks it down to the last couple steps of machining, and eliminates a huge amout of labor time.
The frames and a lot of the inner pieces of the P Series pistols is that famous investment casting. Lots of machined surfaces.
CNC is labor intensive and slow. Anything that is not close to the shape of standard bar is going to end up cutting a lot of wasted material, paid for, and on the floor in little chips and shavings.
But CNC is going to be used to make the molds and do the finish work on the metal molded pieces.
Something I remember reading about Glock is that the designer/company owner was a curtain rod manufacturer, and used his expertise in stamped metal parts in the design. A lot of those internal parts that are cast in the Ruger P Series, are stamped in the Glocks. The rails on the Sigs, at least the kits, are also stamped.
I like plastic for control surfaces and places that get handled. I'm less a fan for structural pieces made of plastic.
I deal with a lot of 25+ year old plastic that has dry rotted, sun rotted, and become brittle. It gets to a point that it just starts turning to powder in your hands. And then you need a new replacement. It is not good for something to be handed down to children and grand children. There won't be new grip frames for discontinued 2000, 2010, and 2020 Rugers available in 2050. There aren't new frames for P95s, P97s, and P345s available now. And that nylon can't be repaired by welding.
I am also seeing the weight reduction as counterproductive to use, because the weight of a steel or aluminum frame acts to reduce recoil. That was a big deal when the Glock was introduced. We were even trying to reduce recoil on 9mms with spring kits, and the Glocks were slighted for not having enough mass to be easy to shoot. Of course, everything at that time was a full sized duty pistol. In the years since, the concern has become more for small size to hide, and light weight so that it does not fall or tire the carrier.
Meanwhile, for shooting competitions, they sell weights and thumb braces for Glocks, to make them easier to operate.
