The old, and the Oh! so new...

[Mark Adams]

Hi All,

I will be embarking on a bit of a new business venture here quite soon. With the advancement of technology, and after a random comment by Michael Grace, I formulated a plan on my way back from the Assembly;

On the way to me is a 3D printer as well as a 3D scanner. The printer I have coming has the capability of printing in a castable resin. This means that I will be able to go directly from a print, to casting in Bronze, Brass, or Aluminum. The printer is capable of a deposition rate of 25 microns. (0.000984252 of an inch) The scanner has a resolution of 100 microns, or 0.00393701 of an inch. Another HUGE plus is that shrink rate in the metal will be able to be added, thus resulting in a perfectly sized replacement part.


What does this mean to the wooden canoe fraternity? Well, it means this: I will have the ability to provide hardware that has been heretofore unavailable. (as long as there is one to scan) I will be able to have an "inventory" that exists solely in the digital realm, and cast on demand, or to provide that impossible to find hardware that you need 6 of, but you just have one. The castings can be provided rough, and in need of polishing, all the way to nickle plated, and ready to install.
The beauty of the scanner is that details, such as screw holes, will be accurately placed, and will match the original. With the resolution it is capable of, even the smallest detail will be captured. (the feathers on that elusive Morris flagstaff eagle...)

At this point, I have no idea what parts will cost. But, being able to hit "print" and walk away, to return to a castable part will eliminate a huge amount of time (and thus dollars) savings as compared to traditional lost wax casting.

I will be printing and casting both a Courting canoe canopy cleat, as well as a Willits style deck cleat as soon as I have the bugs worked out of the system. (and as soon as I receive both the hardware, and the parts to scan....)

What think you?

 

[Dan Lindberg]

Mark,

Adventuresome.

Who's going to be doing the casting for you? or are you doing to do that also?
And can you also pour cast iron in these molds?

Have you researched the market? there are already companies that make fast prototype parts?

Dan

 

[MackyM]

Great idea! My experience with digitizing has been exact replication.

 

[Mark Adams]

Dan, Rapid prototyping is a bit different. That process is taking a CAD drawing, and printing it to check the design. I will be doing exact duplicating, as Macky has done. The ability to exactly scan a piece in, and then reproduce it exactly is what has me excited.


Also, it won't be able to be used in casting ferrous metals. that is a completely different casting (and molding) process. I wish! Also, I plan on farming the actual casting out. I don't really wish to get a foundry up, and running! Imagine the permitting process...

 

[pklonowski]

How about bronze Fin-necked bolts, which were used for mounting thwarts and seats in early Old Towns? There were 3 or 4 different lengths needed on my 1918/19 HW model. If I have one of the short ones that's still straight, and need bolts of longer lengths, would you be able to make them?

 

[Dave Osborn]

Paul,
If your fin necked bolts are under a cap rail, they will never be seen. Use bronze carriage bolts.
Dave

 

[Dan Lindberg]

Mark,

I'm a little familiar with 3D printing, though my exposure is a bit old - I worked for Stratasys for a year a few years ago.
I believe there are Rapid Prototyping places that provide duplicating as well as prototype checking.
BTW, printed parts are NEVER exactly like originals.

Dan, Rapid prototyping is a bit different. That process is taking a CAD drawing, and printing it to check the design. I will be doing exact duplicating, as Macky has done. The ability to exactly scan a piece in, and then reproduce it exactly is what has me excited.

This why I asked, you were using so many terms I didn't know what you were doing.

"Also, it won't be able to be used in casting ferrous metals. that is a completely different casting (and molding) process.

Printing and "castable resin" don't make any sense. And you will be printing, not casting the part, why do you keep referring to it as a "cast" part?
Are you not putting the material down in thin layers, with a bond/"weld" between layers?

Parts I've had printed were very expensive, in the range of $150-$200 for a small part, roughly 2" x 3/4" dia.

What machine do you have coming?
Dan

On the way to me is a 3D printer as well as a 3D scanner. The printer I have coming has the capability of printing in a castable resin. This means that I will be able to go directly from a print, to casting in Bronze, Brass, or Aluminum. The printer is capable of a deposition rate of 25 microns. (0.000984252 of an inch) The scanner has a resolution of 100 microns, or 0.00393701 of an inch. Another HUGE plus is that shrink rate in the metal will be able to be added, thus resulting in a perfectly sized replacement part.

......and cast on demand, or to provide that impossible to find hardware that you need 6 of, but you just have one. The castings can be provided rough, and in need of polishing, all the way to nickle plated, and ready to install.
The beauty of the scanner is that details, such as screw holes, will be accurately placed, and will match the original. With the resolution it is capable of, even the smallest detail will be captured. (the feathers on that elusive Morris flagstaff eagle...)

At this point, I have no idea what parts will cost. But, being able to hit "print" and walk away, to return to a castable part will eliminate a huge amount of time (and thus dollars) savings as compared to traditional lost wax casting.

I will be printing and casting both a Courting canoe canopy cleat, as well as a Willits style deck cleat as soon as I have the bugs worked out of the system. (and as soon as I receive both the hardware, and the parts to scan....)

 

[MackyM]

Dan,
I think the casting process is a separate foundry operation. Aluminum, brass, and bronze molding is a fairly simple operation using sand casting. I believe the printed part will be used as the pattern for the mold. I'm sure Mark can clarify all of this.

 

[Mark Adams]

Hi Guys,

Macky has got it. The printer prints in a material that after a cure in a UV oven, can be sprued as part of a foundry cast. The material burns out cleanly, and results in a perfect mold. However, it isn't the sand casting process. in that, the poured material fills a void that has been created in tamped sand. The process I will be using will be either ceramic shell, or ludo. in both of these processes, the "waxes" are coated (ceramic shell) or embedded in (ludo) the material. the whole kit and kaboodle is then placed in a kiln at about 1600 degrees. The "wax" almost instantly evacuates the mold, then it is fired for a while. (time is size dependent) After this is done, the mold is removed, and cools down. Then, the bronze or brass is poured into this mold. THAT cools down, then the mold material is chipped away. This results in a tree of parts.

Dan, you said that printed parts are not the same. Why is this? with 10 micron resolution on the scan, and 25 micron deposition on the print, it will be pretty dang close!

 

[Dan Lindberg]

OK, now I think I understand.

You are not printing the finished part - you are printing a piece to make a mold from, and then you will cast the actual part in the mold.

The printed piece will have lines where the layers are, small but they are there. And if they are polished out, then the dimension changes, and it will be hard to keep this change consistent across the part. (on the plastic parts back when I was at Stratasys, they chemically "polished" the printed parts if you wanted a smooth surface, but they didn't compensate the printed dimension for the material "melted" off.)

But, being they are cast parts, the new part will probably be within the original casting tolerances.

The other differences won't matter to you, as you aren't printing the actual part, the density of a printed part is (usually) different, the material properties will be different (no matter what the printer manufacturer claims) and the printed part is porous.

I did a quick check and metal printing 3D printers have come a long way in the last few years, but at least according to the sites I saw, they are a ways away from home use, with the current machines selling in the $100 to $300K range. And there are companies now that will directly print a metal part for you, but again they will have the layers and will have different material properties.

Looking forward to seeing some of the parts you will make.

Dan

 

[Dan Miller]

But, being they are cast parts, the new part will probably be within the original casting tolerances.

Except without compensation, they will be smaller than the originals - bronze, for example, shrinks 3/16" per foot when cooling.

Not a problem, typically, but can be an issue when close tolerances are required - e.g. reproducing an oarlock horn for an existing oarlock - the shaft will be undersized.

I expect this is a trivial problem to address with CAD. Just increase the size of the 3d scan by X%

 

[Mark Adams]

Yup. One of the very first things I thought of. Both the printer, and scanner software allow for scaling.

 

[Dan Lindberg]

BTW, I wasn't referring to the casting shrinkage, as Mark says above, the software adjusts for that,
I was talking about the difference between the cad model and the actual printed part.
IIRC the printer software adjusts for the shrinkage in the printing process,
but doesn't account for the/any change due to the polishing.

Dan