3D Printed Roma: Negative Pressure Canister Cannon Tested at Maker Faire

Thanks for taking one for the team, Tug!

Jeff,, man thanks for sharing the files. I agree with Rob in that this could revolutionize the hobby for those that use big gun style cannons, including the 1/96 Battlestations format.

Ignoring the cost of the printer, could you estimate the cost of your cannon, both with and without rotation?

Also, what kind of printer did you use? I'm considering investing in one, and am open to suggestions for 3D printing newbie.

Thanks!

 

It's not expensive materials wise. There's probably around $30 in printing filament, $15 in aluminum, a $16 QEV, etc. Call it $75 all in.

I use a Flashforge Creator Pro printer, which is a makerbot V2 clone. It is a great printer, and can be bought on Amazon for around $1200. I also hear good things about the printrbot metal simple, which can be had for around half that cost.

 

Here's why I've been pushing this technology for Big Gun: The last time I bought a Big Gun cannon, it was $275. I bought three ($825), and I had to wait 4 months to get them. You can buy a perfectly decent 3D printer for that amount of money, and then for $75 each, make your own cannons. Your own superstructures and "cosmetic" pieces, such as lifeboats, searchlights, radar units, direction finders, etc., too. The day is coming when 3D printers will be as ubiquitous as inkjet printers, and that means that competition will drive the quality of the printed objects up, and drive the cost of printers, parts and materials down.

If I'm right about all of this, our ships - regardless of scale or format - will look better and better, as replacing shot-up or shot-off cosmetic parts becomes trivial - while at the same time, an increasing number of enthusiasts will take up the hobby. When that happens, numbers will improve for vendors such as Strike Models who supply parts and materials that can't be printed by an ordinary home-level printer, if at all.

Jeff's design leads logically to development of rotating cannons in ever decreasing sizes. Wouldn't it be a kick to see something like an Atlanta-class cruiser with all twins rotating and functional?

I know there are valid concerns about this technology, even beyond the dependability and safety issues, but I figure if enough of us, like Tugboat, are willing to take a few rounds to the nuts in pursuit of excellence, we're going to see some amazing inventions in the near future that will rock our world.

What really has me excited is that the tricky and labor-intensive requirements for producing detailed superstructure parts and cannon are being challenged by this technology, and easy and cost-effective manufacturing is being handed back to the individual captains. It's how this hobby began, after all, and what makes it so enjoyable for those of us who have the skills, machine tools and workshops to make it happen. Imagine the possibilities or fabricating virtually anything you need, right on your desk in your home, while you sleep.

Rob

 

Love it might I suggest using NijaFlex filament for turrets and supper structure. I haven't tried it myself but the concept of being " bluetproof " catches my eye

 

Nice. Ninjaflex is a flexible polyurethane. Print a drive belt and quiet the noisy gears!
Website

 

don't recommend printing a belt. just buy a precast one.

 

I recommended you print a belt, I wouldn't.

 

Jeff, not to worry. Take a look at these pics:



And Bismark:



See the rough paint / armor surface? Your print job simulates it perfectly.

 

Does the negative pressure cannon require a different CO2 system than the "standard" system that supports Indiana cannon?

 

The cannons have held up well since most of the "loaded" parts are aluminum or brass. The 3-d printed parts are just the magazine, which doesn't see to much force. The superstructure is still in fine shape even though it has been shot at frequently by one of our captains running an Iowa that has strong guns. A couple of the secondaries have some embedded ammo, but otherwise she has held up much better that a balsa or foam superstructure.

 

bmark brings up a good point. Normal negative-pressure cannons require a different plumbing system in order to safe your cannons without accidentally firing them. This requires a bleed line and a couple of check valves for each cannon. I didn't see provision for that in your cannons. How does your safety switch disarm your cannons?

 

Very nice looking boat love it and I am looking forward to the big Reaville

 

Can these be done by someone with very little cad experience? Also, are these something you would produce for sale?

 

Howdy. I have a fair amount of 3d printing experience, as well as printing with some alternate materials and nylon mixes. Has anyone considered making the pressure parts, such as the barrel out of these materials? They are harder to print, generally require a special bed, and a heated chamber... but they are much stronger than ABS, I don't believe there would be any problems with a properly designed and printed nylon barrel, but wanted to find out if anyone has tried them.

 

We've shied away from printing critical pieces that must take a beating. It's certainly possible to print something like a barrel, with the bend already in it, but it would take a huge amount of testing before I would consider it ready for combat. It's hard to beat stainless steel.

 

I understand your concerns, but remember, they used to say the same thing about aluminum and airplanes! While I wouldn't be comfortable making a 3d printed pressure vessel to hold the full 880psi unregulated pressure of CO2 from the bottle (although I bet I could), the full 145+-5 psi put out in full by the regulator should be easily handled. Many are already using plastic tubing to go from the magazine to the stainless. At these pressures and with the thinness of the stainless you are using, it's not hard to beat stainless steel in cost or pressure with a composite or a nylon. The barrel can even have a more authentic look, thicker at the breach and thinner at the muzzle. I have built an abs pressure vessel that held way more pressure than I will admit for testing, and Nylon is better in every way, except for cost and ease of use. You can even print a real rifled gun barrel that is good for multiple shots. As I am told Kittens get sad if no pic is included:

 

In my experience 3-D printing is most useful when it is used to make the "bulk" of the thing you're making and using conventional parts where precision or strength are needed. I will always use a stainless steel bearing for rotation over something 3-D printed for example. Same with pressure vessels and barrels. It's easier to braze some copper or aluminum parts together than try to engineer strength into something 3-D printed... At least with today's home level printers.

Having said that, some key patents are expiring that may make metal printers more affordable and accessible. I wouldn't be surprised to see within the next five years and explosion in 3-d printed metal parts. I recently designed a metal canister style negative pressure gun and had it quoted at Shapeways. They have a nice metal printing process where they print in stainless steel powder and then infuse with bronze to make it 100% solid. It was too expensive, however and the gun would have been around $500 for one using that process. Hopefully the cost drops quickly as is typical with most new technologies.