3D Printed Bullet-Jackets

[HollowPoint]

Yes I have seen the SLS metal 3D printer you've mentioned. Unfortunately for me I don't have the tech-saavy to build one for myself and the latest desktop models that are on the market are still out of my budget range.

Just today I came across one of the latest version 3D Printers presently under development. (Sculptify) They have a print nozzle that heats up to 626 degrees F and it prints parts NOT from print filament but, from plastic pellets of may different kinds. This eliminates the cost of having to buy processed filament. You just pour the plastic pellets into a hoper just like you would when making coffee in a coffee maker.

I was thinking if a guy could pour lead-shot into that same hopper, the melting point of pure lead is somewhere around 621 degrees F. We might have another means by which to make our own lead bullets. And, with CAD software we could design the interior of our cast bullets in such a way that their terminal ballistics is optimized while their exterior profiles could remain optimized for maximum efficiency in flight. (Spitzer pointed-Boat Tails) (Just thinking out loud here.)

I think I'll ask one of the Moderators to move this thread to the Cast Boolits section of this forum. I think it's run its course here in the Paper Patching section. It may have been the wrong place to start this post in the first place.

I think this new technology has the potential to change the way we think about cast bullet design. If the price points of the latest crop of 3D SLS Printers comes down enough, we'll even be able to design and print our own lead-free bullets for those who have to deal with Lead-Free Hunting Regulations.

I've been thinking of selling my CNC mill and using those funds to buy a 3D printer that can Print metal. With the money I have left over I can buy a manual vertical mill.

I have a million ideas and not enough time in the day to begin a fraction of a fraction of them all.

HollowPoint

[Blanco]

I was, and still am sure it will work. My only concern was using the correct material or print medium.

There is one called "Laywood." Google it. (LayWood Filament) It's made of wood pulp or wood fiber; as is paper. 3D printers with enough resolution can easily handle this task.

One Hundred microns seems to be the industry standard at the high end of the resolution scale. One Hundred microns equals 0.0000393700787402 of an inch. Even a cast bullet cast in a perfectly built bullet mold with perfectly regulated temperature and the purest lead or lead alloy would be hard pressed to achieve this degree of accuracy so I'm not really sure why there would be any concern over tolerances.

Some of the higher end consumer grade 3D printers can achieve even higher resolution.

In regard to 3D printing lead bullets directly from a modified print head on one of these 3D printers, think about this; some of the print mediums or print filaments that are being used right now, melt at a higher temperature than certain kinds of solder. With filament diameters that are only 1.75mm-.8mm, lead wire of this diameter would be easier to liquify than the lead billets we picture in our minds when we think of melting lead in our pots in order to cast our bullets.

Mark my words; it's only a matter of time before some of us will be telling some of you, "I Told You So."

HollowPoint

Sorry about this in advance.
You have your numbers a bit mixed up here
1 micron (.001mm.) = .00003937 Or in rounded numbers 4 millionths of one thousands of one inch (sub-microscopically small) This is an extremely hard to measure standard. Measuring something this small requires it to be out of human hands. Even breathing on most materials will change measurements at this level.
100 micron(.100mm.) = .003937 Or rounded would be 4 thousands of an inch. This is generally close to most machine shops tolerance. Still very small but very achievable tolerance or accuracy in a machine shop environment.
Big difference between the two

Sorry I saw it and couldn't let it slide.. Worked in very high precision manufacturing before. I don't know of much of anything that is made that needs to be accurate to .001mm and is generally not achievable by most methods.

[HollowPoint]

Blanco: You're absolutely right. In the last couple of days I've gone back and edited that particular post more than once. If you look at the bottom of the page where it gives the reason for the edits it reads the very thing you've mentioned. It may still be incorrect but the point I was trying to make is still valid.

Thanks for pointing that out.

HollowPoint

[Blanco]

Sok
Lot of people have trouble with metric conversions. I kinda cut my teeth in a machine shop working on Japanese CNC equipment. You learn it real quick. To be honest once you figure it out it actually makes much more sense than the English system.

Trivia question ...
The metric system has a base measurement, that all of it it based on.

Do you know what it is?

[.22-10-45]

The number 10

[Fyodor]

I'm a mechanical engineer, and worked with 3D-printers quite a lot.

First thing: Do NEVER believe in the accuracy they give in the ads. This is for the drive positioning only. And it's not absolute, but more about repetition. All they say is that the drive will position within this accuracy again, when moved to the same position. Usually the actual tolerance in the finished part is about 2 to 5 thenths of a millimeter... 200 to 500 microns. And it's not isotropic, which means the accuracy in X and Y direction are not necessarily the same. It might even be a different scale (!) in both directions. Z-axis (heigth) is even worse. And up to now all we talked was accuracy of positioning. When it comes to physical resolution, it's becoming really ugly. For example, if you want a round hole with a diameter of 0.3mm, you need to design a square hole of 0.5mm. That's because of not perfectly even feed rate, and "drag" when the print head goes around a corner. Imagine trying to pull a rubber band over the floor, laying a "perfect" rectangle, while alway keeping it under tension. Simply doesn't work. Wall thinknesses of 0.3mm are the lowest achievable, and these might collable when built too high. Another big problem with 3D printed parts is delamination. The printer puts layers above layers, that actually are surprisingly sturdy, individually. But they don't stick all that good on each other, and can be separated with a box knife, depending on part geometry. That's because the fresh hot melt doesn't have enough energy to liquify the cold layer below, so it's just a light tak that holds the layers together. It's much better within one layer, because hot melt touches still warm and soft material which bonds far better.

I don't say it won't work. But it's unlikely it'll work with a 1k$ fun printer without many and many frustrating drawbacks.

A material that might be usefull is tribo-filament by igus (a company that specialized in plastic lubeless friction bearings). It's a high tech tribologically optimized 3D printer filament with very low friction coefficient. I have never used it, but saw it on a trade fair. igus is a very customer friendly company, and usually do send free samples without questinos being asked. When I needed one small item for some non-company stuff and asked for a quote, I got the part free of charge instead. They even have an own section for free sample ordering on their website. Just ask, maybe you'll get some tribo-filament for testing for free.

[Blanco]

The number 10

Partially correct...Think bigger
The answer is, The diameter of the Earth

[Fyodor]

@ Blanco:
Why that?

The base unit of the metric length is the meter. The meter is defined as the distance that lights travels in vacuum during 1/299,792,458th of a second.

[Blanco]

I think the answer to that is that you are correct Fyodor. At some point it had to be standardized to a repeatable measurement for the labratory. Consider that the metric measuring system started back in the time of Napoleon

[MOcaster]

I think the answer to that is that you are correct Fyodor. At some point it had to be standardized to a repeatable measurement for the labratory. Consider that the metric measuring system started back in the time of Napoleon

If I remember correctly, it is something like 1/nth (millionth, maybe) of the length of the line of longitude that passes through Paris. Or something like that. It involves fractions, longitude, and a European city.

[Fyodor]

Originally it should have been the 10 Millionth part of the distance between the equator and the north pole on see level through the meridian that passes through Paris. Another idea was to use the length of pendulum that swings with the frequency of 1 Hertz. But because all that changes over time, is highly dependable on the definitions (what is see level, for example), or is not identical on all places in the world (length of pendulum depends on local gravity), these definitions have been abondoned 1799 (!), when it was decided to use the "Urmeter", a physical representation of what was believed to be the 10 Millionth part of Paris Meridian quadrant before. From that on the meter was defined as the length of the "Urmeter". The definition changed to the recent time based definition in 1960.

But actually this is not really topic of this thread...

[garym1a2]

I think 3D printing still has a ways to go, while they claim you can print almost anything the speed I see is very slow compared to normal Injection molding or casting. If you could print a bullet jacket but it took minutes to do one what's the benifit? I can powder paint near 1k per hour will my small oven.

[HollowPoint]

I think that the problem here is that the 3D Printing of Cast Bullet Jackets seems to be visualized as being done one at a time. Even with the smallest work-envelope the smallest 3D printer could print at least one hundred or more in one printing session.

Another thing is, I'm afraid that by posting this subject matter I may have come off as a self-appointed evangelist for this new technology and therefore, I'd have to defend my ideas or opinions regarding it.

3D printing bullet jackets is just another option and nothing more. If it doesn't suit your fancy, I have no problem with that. If it's something you find interesting, that's good; maybe you'll give it a try at some point. Like conventional Paper-Patching, it certainly isn't for everyone.

Debating the feasibility of doing such a thing really holds no value if you consider that it's already been done by someone somewhere.

Do you realize that some of the very same Pro's and Con's and "Probly-won't-Work-For-Such-and-Such-a Reason" were debated when conventional Paper-Patching was introduced? This same dynamic happens nearly every time a new idea comes along; especially when it involves a subject with deep traditional roots like bullet casting and paper-patching.

HollowPoint