50% price increase on Shapeways FUD

[bbussey]

That is a bit more than a 50% price increase. That should take care of their problems with being swamped with orders. I know that my interest in these models has gone down significantly.

Supposedly if you group a number of models together into a single STL (whether disparate models or multiples of a single model) and maximize the available footprint (roughly 5"Lx7"Wx6"H) it is more economical than previously.  I've been playing with packing the STLs differently to get the pricing and that does seem to be the case.  That helps with people who design their own models, but not so much for those purchasing onesies and twosies from the Shapeways online stores.

I'm less concerned with the FUD pricing than with the stainless steel pricing.  Rendering rolling stock underframes seems to be reasonably priced, because a lot of material isn't involved.  But the locomotive chassis parts are proving to be expensive since they basically fill the entire cavity of the body shell.  It may not even be necessary to fill the entire shell since steel is more dense than zinc.  I have an underframe coming, and the weight of that will determine how to proceed.  I suspect that it won't be necessary to fill the body cavity with stainless steel because the metal has enough weight.  If that turns out to be true, then the cost of a stainless steel locomotive chassis drops significantly.
 

[Dave Schneider]

Thanks for the clarification on the footprint and costs Bryan. It makes sense to have fewer but larger jobs rather than a bunch of little fragile pieces to deal with.

Best wishes, Dave

[Zox]

But the locomotive chassis parts are proving to be expensive since they basically fill the entire cavity of the body shell.

Could you make the expensive stainless-steel portion hollow--with the details on the outside and just a retaining wall/dam on the inside to form the motor cavity--and then pour lead (or other cheap, low-temperature alloy) between the walls?

[Scottl]

That's what I was thinking.  Lead shot and glue came to mind.

[Philip H]

Bryan,
If the frame idea you have works, that would open up a world of low pro frames which means way more space inside for decoders, lighting and the like. 

[bbussey]

Bryan,
If the frame idea you have works, that would open up a world of low pro frames which means way more space inside for decoders, lighting and the like. 

That is true.  But with the lead time on rendering stainless steel parts coupled with the other scheduling issues, it's going to take a few months to figure out if it's viable.

[daniel_leavitt2000]

Ok dumb idea time. Why use the machined steel at all? Can't you use standard material as a master? I think it would be fairly easy to cast a medium hard high temp alloy from a rubber mold or spin casting setup.

[DKS]

Ok dumb idea time. Why use the machined steel at all? Can't you use standard material as a master?

I think the idea is to be able to make these parts without having to machine anything. Not having a mill, lathe or whatever makes it hard to produce masters; Shapeways lets you make complex, precise metal parts using only software. Plus, the cool thing about RP is you can produce parts that would be difficult if not impossible to machine or cast.

[bbussey]

It also allows you to make the chassis without having to worry about milling or drilling mistakes.  While not as tough to do with existing chassis, the degree of difficulty goes up when milling a master from scratch - regardless of whether your making a master to spin cast or for actual use.

I like the idea of rendering motive power chassis for a few reasons in addition to what David wrote.  The Shapeways process leaves a smooth finish on the stainless steel, which is different than the FUD and other materials.  Second, you have the option of rendering initial test parts in one of the cheaper plastics/resins to insure all of the mechanism parts fit properly,  Third, it's harder than zinc and pewter so no worries about frames bending out of shape.  And fourth, you can design a chassis specifically for the motive power you're creating - think steam locomotives in addition to electrics.  And as Philip pointed out - if the steel is indeed heavy, it means that the entire bodyshell cavity doesn't have to be filled, which is not only cheaper but allows other internal details to be modeled.

[Chris333]

So I understand how the resins work, but how do they RP metal, ceramics, and glass?

[DKS]

So I understand how the resins work, but how do they RP metal, ceramics, and glass?

The process is sort of like making pottery. They start by printing the object with powdered material deposited together with a bonding agent that's just strong enough to hold the powder in shape. At this point, it's called "green" which is very delicate and will crumble easily, so it's not a process that's suitable for delicate designs. The green parts are then fired in an oven to harden them. For stainless, the steel powder is mixed with brass powder, and the firing melts the brass to fuse the metal. Stainless parts are also tumbled to polish the surface.

They also offer sterling silver as an option, although for this they print a wax master, and then use traditional lost wax casting to produce the finished parts. This is their highest-resolution process, incidentally, as the wax master is supposedly finer than FUD. It's also twice as expensive as stainless steel.

Could you make the expensive stainless-steel portion hollow--with the details on the outside and just a retaining wall/dam on the inside to form the motor cavity--and then pour lead (or other cheap, low-temperature alloy) between the walls?

I would have two concerns about this. First, the hollow parts will be more delicate and prone to damage in the green state. And second, it may be cheaper from a materials standpoint, but the labor of filling in the parts adds to the cost, at which point it may likely be a wash (assuming they were being produced for resale).

[Catt]

So, if I wanted to make a BQ23-7 cab for my Atlas B23-7s, how would one do that?

If you do these count me in for a few of them too,if for no other reason than they are so funky looking. ;D

[bbussey]

I just checked the specs.  The weight of Shapeways stainless steel is 8,070 kg/cc.  Zinc is 7,135 kg/cc.  So a chassis rendered in this stainless steel / bronze hybrid material is 13% heavier than the zinc equivalent, which means a frame designed with 13% less stainless steel provides that percentage of additional free space as well as 13% off the cost.

SolidWorks allows for the measuring of mass of an object.  So using the New Haven EP-4 Streamliner chassis as an example - the Kato GG-1 chassis is similar in dimensions.  If I weigh an empty GG-1 chassis, I will know how much material I can remove from the EP-4 chassis to match, thus lowering the cost in the process.

UPDATE:  Zamac zinc has a density of 6,600, which translates out to 23%.  That should allow enough removal of stainless steel for additional electronics and cab interiors, while lowering the price a significant amount.

[daniel_leavitt2000]

OK, I so the RP chassis is more acurate than a machined chassis, but what about casting the master steel chassis parts with less expensive metals? You would have all the benifits of a persision engineered RP design with a much lower cost.

Another question. Can they RP tooling if they are already doing steel? It would be awsome to print an FUD prototype, then quickly order RP steel tooling basted on the design if it comes out as intended.

[bbussey]

UPDATE II:  I have an EP-3 frame I milled from a GG-1 frame, so I weighed it.  The mass of the zinc composite that Kato uses is ~6,288 kg/cc, or 53,864 mg.  Since I designed the milling guide in SolidWorks, I have the solid model of the EP-3 frame.  The mass of the digital model in Shapeways stainless steel is 8,060 kg/cc, or 68,756 mg.  That's a whopping 28% of frame that can be trimmed from both the mass and the cost.

OK, I so the RP chassis is more acurate than a machined chassis, but what about casting the master steel chassis parts with less expensive metals? You would have all the benifits of a persision engineered RP design with a much lower cost.

What metal are you going to cast it out of that is as hard and inflexible as stainless steel?  And by definition of the process of casting it won't be as precise, especially spin casting which is more suited to smaller parts.

Another question. Can they RP tooling if they are already doing steel? It would be awsome to print an FUD prototype, then quickly order RP steel tooling basted on the design if it comes out as intended.

Probably, as long as it fit within the Shapeways building footprint.  It might even cost less than machining the steel tooling.  But I'd rather design the solid positives and leave the cavity arrangement to my tooling contractor, rather than have to worry about making sure my multi-part molds have the proper injection/ejection points, are properly polished and fit their mold base.  Also, remember that the tolerances for the stainless process are not as fine as those for FUD, so fine detail is an issue.  The stainless process is better suited for underframes and chassis rather than carbody detail.

HOWEVER, that might work with simplified two-part tooling that could be injection-molded here in the States.  Food for thought, as long as the surfaces of the tool that would form the plastic parts can be polished smooth.