3D Metal Printing

[nicksc]

Hi everyone, I want to thank all the people who have helped me to make my pursute in 3d sculpting successful.

My next step is to print my LionDoorKnock in a stainless steel infused bronze. However for a 18"H X 13"W X 4"D (image shelllion.jpg ) part is going to cost over $5,500.00,

That just doesn't seem right. Does anyone have any ideas who can give me a fair price on 3D printing done in metal, or any other suggestion for making my part real.

One of the main reasons I am learning to sculpt in 3D is to print my product. However I'm discourage if it's going to be that expensive.

[Psmith]

I would think, being a blacksmith and thinking economically, the way to complete this project and get the product to market would be to design molds, (with 3D software), for casting in the metals you speak of.

You could have the molds printed in plastic, (cheap), refine them as needed, (or print molds for making molds capable of holding molten metal - also printed in plastic) - then, for far less than the prototype, printed in metal, build a small foundry to mass produce the knocker.

Just a thought.

Greg Smith

[nicksc]

Psmith, If I can,I'd rather print it, you get great detail with the printer. However I may have to cast it like your suggesting If I can't find a resalable alternative.

If it could be printed in a ridged and durable material other then steel, that may work also. It just has to work like a knocker, I could apply a faux finish to make it look like one.

[polyxo]

I'd guess you'll not find a metal-printing process which will be considerably cheaper.

It's being done with machines which cost hundredthousands of Dollars. So if you block it for a day or so with such a large model I wouldn't

be surprised about the costs!

What one could try however: Print cheap Plaster Models with a Zcorp-Printer or similar and use them as as a Template for Sand Casting.

[nicksc]

polyxo your probably right. that would be an alternative. I'm looking into that very thing. However keep the comments coming. I really like having the opportunity to bounce ideas around at this forum. Has been very helpful.

[spacepainter]

Are you sure you made it as thin as possible?

Otherwise wait until you can have it printed in wax ( coming soon) and then have it produced by lost wax method.

[patternmaker]

Haven't had time to check into the forum in a while - this is in my field, so I thought I'd reply. First, that is really big for a doorknocker! Is it 18 inches or 18 centimeters tall? $5500 doesn't sound bad for a metal printing 18" tall. Who did you find with a machine that big? Anyway, sand casting is the cheapest way to do this only if your time is cheap or free, and you know what you are doing and can make what the foundry needs to do the job. You could get this printed in some kind of plastic and hand work the result so it would be usable. FDM would be cheap enough, maybe at that size, but you will need to put in a lot of work smoothing it out, not just knocking down ridges, but actually filling in negatives, too. Other 3D printing methods will cost more and still require hand work. Sand patterns need to be quite smooth, and definitely well drafted (tapered in the direction the mold separates), preferably at least 5 degrees for something like this. Z corp models would need to be used to make more durable models by making molds and new plastic positives, usually cast polyurethane, because they are too fragile to use in a foundry. If you really want to go this route, aim for a uniform wall section of about 3/16", no less than 1/8", and no more than 1/4". That rule of thumb applies whether it is 3" tall or 30" tall. Have it made in silicon bronze, preferably everdur, which welds easily, since the casting will almost certainly need weld repair. Realize that the casting will be about 1-1/2% smaller than your pattern. If you make just what you've shown, it would be called a "loose" pattern, and many foundries will not use those. They may also not like you to ask for just one, but if they are hard up for work, which many are these days, they may do it for a few hundred dollars. The resulting casting will likely be fairly rough textured and will need a lot of hand work to get it smooth, but if you don't mind the texture, maybe you could use it to your advantage. Shadows in deep areas will be darker and make the sculpture look even deeper than it really is. As to waxes and investment castings - the process is much more expensive, but art foundries are more used to stuff like this than sand foundries, so they would help you more with it. Probably charge you several thousand, though, even after you have made a "perfect" original for them to use. Commercial industrial investment casting foundries will want nothing to do with this type of thing. If you just want this to be functional for your own use, you might want to just get it printed as cheaply as possible, smooth it out yourself, make a rubber mold from it (Smooth-on makes fairly cheap materials), then cast a bronze-filled epoxy or urethane into the mold. I've seen a number of sculptures done that way, and they look OK.

Anyway, nice job modeling! Sorry if I don't reply to this thread in a timely way after this - really very busy right now, just saw this on my lunch break and thought I'd make a few points. Best of luck!

[nicksc]

patternmaker, Thank you so much for the info. You said, "As to waxes and investment castings - the process is much more expensive, but art foundries are more used to stuff like this than sand foundries, so they would help you more with it. Probably charge you several thousand, though, even after you have made a "perfect" original for them to use." this sounds very promising. That cost doesn't scare me, it is what it is, you pay for custom. also I don't think I would have to think about drafting with this method. Do you think this would be my best alternative?

Also this "If you just want this to be functional for your own use, you might want to just get it printed as cheaply as possible, smooth it out yourself, make a rubber mold from it (Smooth-on makes fairly cheap materials), then cast a bronze-filled epoxy or urethane into the mold. I've seen a number of sculptures done that way, and they look OK." This sounds like a good option also. would you sell this as a product? If it can handle all the knocking that it would go through, I don't see way this wouldn't work. Also sounds like it would be at a resalable cost alternative for the client.

Thanks

[patternmaker]

If you want a real metal piece, that is probably the easiest route. Search for foundries that do sculpture or art casting. Your original does not need to be wax, in fact, it is better if it isn't. The foundry will want to make a rubber mold from your original because the first casting often does not work, so you'd lose everything if you used your only wax. You probably only need to have the face side for this. The art foundries typically would paint wax into an open rubber mold of a shape like yours and build up its thickness that way. Sometimes they do the equivalent of ceramic slip casting: fill the mold with wax, wait for a surface skin to form, dump out the excess when it is thick enough. Industrial foundries will demand a complete mold (front and back) and usually inject wax into it, much like plastic injection, so that method would be too expensive for you to use.

You mentioned "client" in your last entry. If this is for someone else, you had better make sure they are ok with the plastic substitute method I described. If they think you are giving them bronze and they get bronze-filled plastic...! anyway, you could make it work, but should probably reinforce the knocker handle with an internal metal piece, and put another piece of metal where the handle will hit. Just put the metal pieces in the rubber mold before filling it with the fake bronze (sometimes called "cold-cast bronze"). The main "head" part should be cast as a solid flat-backed chunk - no hollowing. You may also want to cast in some threaded inserts for mounting screws.

I do not sell materials myself. Look at http://www.smooth-on.com/. You could make this yourself at home with these materials and mass produce it that way if you wanted to. Only one warning: test the materials to make sure they don't interact badly before making a mold of your original. Sometimes the materials can refuse to harden, or etch your surfaces, or refuse to come apart after casting!

[nicksc]

patternmaker, I want to assure you that I wouldn't sell plastic as bronze that would be unethical. What I meant to convey is, the plastic bronze could be a good alternative for someone who likes the design but can't afford the real thing. Also placing a metal ring in the knocker is a idea I was thinking, if it would need it. I will call the manufacture to find out. Also there is no client yet

The best suggestion of all the forums is the one you suggested, the lost wax method. Using this method will allow me to keep all the original detail and create a work of art. Iv'e watched the process on youtube. I think, "if it is going to be expensive anyway", using an ancient process would be more appealing then printing it. Moreover the print process leaves lines. The print process Would have to be far less expensive for me to want to use it now. Why would you want to pay 10 grand for a CNC printed stainless infused bronze part with lines in it. When you could pay less for a part that is smooth and beautiful created by a process that is thousands of years old. This way has far more romance.

Could other materials like brass or pewter be use in this method also?

[patternmaker]

The metal printing process still has a way to go before it can compare to real molten metal casting. Along with layer lines that may need to be blended, I have seen bad adhesion between layers. That was a few years ago, but due to an improperly adjusted machine, I think, not the basic concept of the process. The end product is not really solid metal like a casting. It is a fused together powder, though it may be getting pretty close to a solid material these days. Investment casting (lost wax) will get you the best quality surface for sure, though, as I said, it is not cheap. Sand casting can be the cheapest way, but only if you are able to make the original pattern correctly for the foundry, and the surface will not be as good as an investment casting.

As far as other materials go, not all investment casting foundries will do brass. It requires more careful melting control because it can easily overheat and burn off zinc, which changes the composition and can create lots of problems. It oxidizes more readily than most bronzes and so, is "dirty", and can get surface defects easily when casting. A foundry that knows how can do it, though. A major negative for brass is that it is very hard to weld (because of the zinc content). Pewter is a very low melting temperature alloy. You can pour it into a silicone mold, so it would be a waste of money to investment cast it. The metal itself is fairly expensive, though. Real pewter contains a lot of tin, which, contrary to what you might think from the old phrase "tin can" (actually "tinned can"), is one of the most expensive non-precious metals. Smelters often keep their tin ingots in a safe!

There are a variety of bronzes, though most art foundries use silicon bronze, mostly because it is easy to weld and fairly easy to cast.

Hope this has been helpful.

[nicksc]

patternmaker, I want to thank you for all the great and accurate advice you are giving. I will be successful because of your input.

I am trying to find a service for printing my wax door knocker parts. I can piece the parts together, if there isn't a machine big enough to print it whole. If I had to, I can definitely learn to create my own mold. I am talking with a broker, I told him I will give him the wax parts he needs to make the parts out of bronze. He said if I could give him the wax parts it would be much cheaper. Moreover I would rather be the one to control the quality of the wax parts. I should have a price in a week.

[nicksc]

Lost cast bronze Door knocker foundry cost is around $450.00 not including the wax sculpt. Seems reasonable to me so far. Waiting for the wax print cost.