My interpretation of the IFMAR 91 car

[XLR8]

From what I've seen, the breakage problem was associated with Shapeways' US parts. NIX91 "Racer" parts are also available from i.Materialise in both SLS and something they call MJF (HP Multi Jet Fusion). Anyone here have experience with parts from i.Materialise?

[RC10th]

Niki has tested MJF parts which are much stronger. They are only avilable in one color, grey. The parts are black inside though if I remember correctly.

[XLR8]

Yeah, that's what I've seen as well (you have a good memory). I think the grey color can be corrected with some careful application of off-white epoxy enamel paint (or any other color). In fact, maybe the paint would smooth the surface a little and make the parts appear more like those that have been molded. ...not that it matters that much to me since I'm looking to build a runner.
Another benefit; Unlike Shapeways, perhaps i.Materialise have only one facility so the parts Niki has tested would be the same for everyone. Apparently, Niki has only experienced one failure with Shapeways parts but those came from their European office.

[fredswain]

I believe that one day 3D printing will achieve the same material strength as injection molding. We just aren't there yet.

Justin looked into what it would take to have chassis made. The blanks are custom made for us by the same company that made the originals and are then sent off to a different place to be cutout since the original place doesn't do that anymore. The cost for a chassis and top deck appears to be right at or near the $300 mark. Definitely not cheap but they don't do this type of stuff anymore and it's all special order. We certainly aren't going to purchase these on our own dime and then hope to recoup that money later. They don't want to do only one either. They'd prefer to do a minimum of 12 to make it worth their effort. That's a $3600 up front financial commitment. That's why we aren't doing it. We'd need to find a dozen people willing to pay that up front and then wait however long it takes to get them, which could be several weeks to a couple of months. There is another alternative that I've worked with in the past but they've seemed to lose interest in doing rc chassis anymore as well and was the source of the NIX chassis, which is why you don't see anymore of those being made. If people want an authentic car, it's going to be over $500 to complete one and even then, we aren't making ours to be a durable driver as it wouldn't be authentic in looks anymore. The best option for anyone wanting a car that resembles the 91 car is to buy the NIX parts and make their own chassis.

[jeepnut24]

I believe that one day 3D printing will achieve the same material strength as injection molding. We just aren't there yet.

We 3d print titanium and other plastic parts at work that get shot into space. So the strength is there, just not at the consumer level yet. Not sure if the metal sintering will make to to the consumer level... but we can hope.

[fredswain]

I don't think it's a matter of if but when it'll happen.

[XLR8]

Thanks for the information Fred. I would speculate that market saturation has been achieved for this item. Nearly everyone willing to spend 500 or more for an RC car that resembles something that ran 27 years ago currently has one. I'll just go the NIX91/aluminum chassis route and call it good. My focus right now centers around minimizing wasted dollars on poorly made 3d printed parts. I reckon you've never tried i.Materialize before or you would have mentioned it so maybe I'll play the guinea pig. If it goes badly, you guys will be the first to know.

[mk-Zero]

I believe that one day 3D printing will achieve the same material strength as injection molding. We just aren't there yet.

We 3d print titanium and other plastic parts at work that get shot into space. So the strength is there, just not at the consumer level yet. Not sure if the metal sintering will make to to the consumer level... but we can hope.

Shapeways offers DMLS parts in stainless, I'm running RC10 outdrives right now that I had made that way... And I use it all the time at work too. For work, I've had parts DMLS'd in CoCr too, its got some nice properties.

On the topic of MJF parts, I've printed some and run them on my Ten4, I've yet to break them. Those same parts printed using the "regular" nylon SLS process break somewhat regularly. The nice thing about the MJF parts is that the mechanical properties are less sensitive to print direction, i.e. they are more isotropic. The surface is also a bit nicer, they have more of an "orange peel" texture than the gritty sand-cast type surfaces you get with SLS parts. Only available in gray and black so far as I know, so that's a bit of a bummer. When I release the Ten4.1 I'll probably offer the high stress parts (mainly c-hubs and steering blocks) in MJF for people that want to run their cars, everything else can be SLS. For people that want a shelf queen they can have everything in SLS if the white is important to them.

[fredswain]

I have used i.materialize in the past but haven't tried their newer materials.

I don't want to give the impression to anyone that we don't want anyone to have a nice version of this car. Not at all. I just want to be clear what the goals for the project were and the sheer cost of making one. It's a labor of love for us and cost and durability weren't priorities. Neither of us is in any position to try to sell these aside from merely making printed parts available. In the end, like the Nix, it's still an interpretation of the original. We believe it's more accurate but I guarantee when I see it next to a real one I'll see things that are off. I'll revise it again and maybe someone else will come along with another version that's even better. It's just a fun project.

[fredswain]

I looked at the specs of the MJF on i.materialize. Shapeways offers the same MJF printed material now. They call it professional plastic. It costs almost twice as much as the standard SLS parts. I compared the i.materialize price to the shapeways price and the i.materialize prices are the same as the SLS, making this material a nice alternative through them. It's too expensive from Shapeways. It also looks like it would take a few days longer to ship from Shapeways. I'm definitely going to try a couple of MJF parts from them.

[mk-Zero]

Shapeways must have jacked up their prices on MJF then, when I had those parts printed (maybe like a year ago...) they were the same price as SLS.

[XLR8]

Thanks for feedback everyone. I've ordered the race set in MJF from i.Materialise. Estimated ship date is the 13th however they ship from Belgium so maybe I will receive them by Christmas.... 2019.

[fredswain]

I've dealt extensively with injection molding companies at work in the past both in the US and in China. There are good ones there and bad ones here. It's not all only American good only Chinese bad. That generalization does not hold true. The key with doing business anywhere is to find a place that you trust, that does the quality of work that you expect. There's a Chinese manufacturer that I've used that I trust. On average they are about 20% the cost of the American company that we've dealt with and I've honestly seen no quality difference between them. For the fun of it I decided to send off the cad model for the front arm for this car since people sometimes wonder why they can't just have new ones molded. I knew good and well that it was going to be too expensive to be valid but I wanted to get that quote to share it so everyone understands the costs associated with molding parts. Admittedly, there could be a little cost savings by using family molds for trees where multiple parts are made at the same time. That's why they do that. The point was to just show how expensive this is. You'd need to sell 9500 pairs of arms to break even on the initial expense. Once you've topped that number, each arm only costs $0.19 each to make, assuming you order at least 2000 of them. I've removed the company name and contact information. If people wanted different colors, it's another batch of at least 2000. Hopefully this makes everyone appreciate the great financial risk that companies go through in order to get them that new model, and then to change that model every year or two.

[GoMachV]

That’s about 1/4 of a recent verbal quote I received when describing a part to the people that made my molds.

Little trivia- while I own my molds, I’ve never seen them. The company offers a million pull warranty when you store them there- at no cost. If I remove them the warranty is gone. These were made in the early 90’s so that’s a pretty stellar warranty imo haha

[XLR8]

... and there aren't 9500 customers out there to buy these.
I've had similar experiences with molders. For instance, we've sourced a part that was fairly complicated to mold from a company near Detroit (the material was polysulfone). The tooling cost for 2 cavity mold was $35,000. A few years later, we moved assembly for that product to our plant in Brisbane so it made sense to move parts suppliers to that corner of the world as well. The tool for the same molded part from Asian source was $5,900.
The problem with many off-shore suppliers is reliability. They are keen to please at first and then, once everyone is comfortable, the shenanigans begin and you suddenly have product recalls to deal with.