CNC Forging V.S Casting -Which is the better CNC Technique For Manufacturing Parts

 

The Reason Why Casting Parts Are More Likely To Have Imperfections

The internet is full of discussions over which parts are better. cast or forged, it doesn’t matter if you’re talking about gun parts or car parts, it seems that the overwhelming consensus is forged parts are better. simply put, cast parts are weaker because they have all these voids in them they have no grain structure. there’s no organization, it just looks all haphazard. if you were to look through it with a microscope. you will see that it’s very porous and it kind of looks like a sponge. why does this happen? well, in the casting process and let’s take into consideration that we have the perfect mold. one side is not cooling faster than the other side, the viscosity of the steel that’s being poured is perfect, we’re talking a casting process at its highest possible quality. there are still going to be voided in there. as the steel is cooling from the outside to the inside. things called dendrites are going to form and they look kind of like snowflakes. as they cool down, they will form grains, but the grains are not in any order, there’s some are small, and some are big, or even coarse, fine, etc. they’re creating these voids, and even if we have everything perfect, there are still will be voided. and that’s why casting doesn’t create a very strong product.

 

#Billet

is Casting good for other things? yes, but for gun parts that are under high stress, it’s not the best decision. and that’s where a billet comes into play. we know we have to have something with a good grain structure. how do you get that liquid steel into a billet? it’s pretty easy, instead of pouring it, all they’re doing is they’re cool off that liquid steel, slide it down this chute, so that it’s kind of in the shape of a rectangular tube and as it’s going down, it’ll hit these rollers called a hot roll and the hot roll is squeeze that steel straight through it. it’ll line up all these grains and smash off a lot of the voids.

 

# Forging

if you wanted to take that a step further, you could cold roll it, which would increase the price of the billet, and all that would do is increase the strength of the grain structure and get rid of a lot of more voids. but if you want to stop at the first process, you would have a billet and then from there you have to decide if you want to come in there and mill or cut out the shape that you want or once you have the billet, forge it down into the shape that you need and then mill it. so it’ll do an additional strengthening process when you’re using this method. what’s good about that is it’ll keeping as much of the grain flow together as possible instead of coming in and interrupting the grain structure by cutting it out. That’s the main difference that this separates itself from other methods. take the billet that’s been forged once and then do the forging process all over and then they mill it.

 

In Conclusion

Well, for cast parts if you’re making light production, something that doesn’t have a lot of stress going on it, use a cast part, because you can get it to be very detailed for a very cheap price, it’s very cost-efficient to use casting for those types parts. the billets that are machined or milled out, you can see spikes tactical that’s a great example for air 15 receivers, they got skulls and the airplane, and all they’re doing is they’re taking the billet and they’re milling out what they need and that can get detailed too. but it’s not the strongest. what you want to do is just forge whatever you’re doing so that you can keep the continuous grain structure.