I was curious if there is a resin that Formlabs makes that would work for toy or model production. I have experience with the regular grey resin, and have made prototypes that i then mold and cast in a Smooth On resin. Its works fine and I planned to keep working that way, but it would be great to cut down some of the production process if there was a resin that might be more durable. The grey resin can be brittle in comparison to a cast resin.
What sort of material properties are you looking for? Both Tough and Durable Resins have a bit more give than the Standard Resins and have higher impact strength.
Ted,
I know what you mean. I just started using the dental model resin as a standard. Holds details and it doesn’t warp! The grey resin tended to warp after 2 weeks. I also use the smooth-on products for casting. I previously worked at Mcfarlane Toys for 11.5 years and currently working at another toy company in North Jersey. I also freelance after work hours.
Richard
Ro-Man Studios
A resin that could handle light sanding and painting, and would not be brittle if printed fairly small. The grey resin worked well as a prototype, and to make a mold from. I noticed there is a Pro grey resin and wasn’t really sure what was the defining difference between the tough and durable.
Have you been able to try either the Tough or Durable Resins? Both of those sound like they would work, and the main difference for your purposes will be greater flexibility and impact strength for Durable Resin as compared to Tough Resin.
The difference between Grey Pro and Standard Grey is tricky to communicate through mechanical specifications. Grey Pro is resistant to deformation in applications where a consistent load is applied.
I’ve been using grey for over a year for stuff like this without too many complaints.
Though I have found that I need to thicken up some of the finer parts.
The grey resin is fine for a prototype, but its brittle. I have made a series of figures and can share my process. I make the print, then make a mold and pour resin casts. Im just looking to cut out my molding and casting phase on some smaller production work. The Durable resin looks to be the answer. Ill try it. It looks to have a slight flex to it as well.
Hi. I also make train models and I’m looking to possibly change standard gray. Did you have a chance to try durable resin? I’m thinking about also trying dental model. I’v read here that it gives best details but don’t know how it will hold up in time.
Depending on the thickness of your parts, Durable can have more than a little flex. You can also see significant warping even if you post-cure (which is necessary when using Durable) on the supports.
The new Grey Pro resin is less brittle than Standard Grey - you might give that a try. It will require an LT tank.
I have been interested for quite some time in plating with someone like Repliform. I would imagine if you send them a decent number of parts the cost would be pretty reasonable.
I do a fair amount of model design from plans and photos building train parts as well as scale figures that have been scanned. Some of this work, is used as a master that has molds and castings, others are used for the actual models. CAD work in Sketchup and Fusion 360. I use standard gray, and it holds the detail very well. Most of the work I do scales at 1/4 scale so it can be enlarged or reduced some.
If you would like other examples please let me know
Tough resin is going to be the closest analog to the urethanes you are using right now.
Durable in thin parts is going to be way too bendy… more like an injected vinyl.
AND Durable has very poor memory… you bend it and it stays bent.
Does anyone have suggestion for a resin to model train railings like the one in the picture? When converted to 1:87 size (H0 scale) the diameter is about 0.3mm (0.012 in) and gray just breaks to easily when handling the model. Details aren’t such an issue here because it is just a round wire. I’ve tried to make the railings out of thin wire but I can’t bend it good enough to look ok on a model. Maybe someone knows a wire bending machine that could handle such delicate wire?
0.3mm is probably too thin for any resin. Can you print a negative and bend the wire around it?
I was thinking about doing that but some would be really complex to bend. This one on the picture is simple one. I’d reeealy like to print them instead 
Model the railings so that they are flattened- and sticking out of a flat plane like an embossed relief detail.
Print the flat plate with the embossed railing detail. Or in short sections that you can isolate as planar. Like the railings you have outlined have bends in them, but would lie flat on a plane with those bends intact.
Make silicone mold from the print.
Use odorless white urethane resin to cast the railings. You can heat the urethane castings and bend them to the contour you need, and then cool them to set them in place…and the Urethane parts will be somewhat bendable, and resistant to breakage.
You can make them even more robust by dropping fine wires or fibers into the cavities of the mold and casting the resin to embed them like reinforcements.
Another trick is to use any very thin extruded thermoplastic that is resilient enough- you can spot heat a thin rod of styrene, or polypropylene, and bend them then immerse them in cool water to set the bend.
For example-if you have access to a filament printer- find a printer with e .3mm nozzle and have it extrude straight lines of plastic that you can then use the above trick to form.
Or- switch to a larger scale of train model.
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HO scale is too small to see the details.
Thank you for all the suggestions. It seems mold is the only way to go. Ideally I’d do it with wire bending tool but it needs to be some kind of CNC bending machine so it looks identical from one part to another. Can’t find one though.
CNC bending machine might be a bit overkill unless you’re doing thousands of those.
Could possibly print/build a multi-piece progressive die/guide to do the bending consistently? .3mm wire isn’t exactly going to take a lot of force.
Well I’m not gonna do thousands of those but I do plan to make a bunch. Train modelers are known for requesting absolute perfection in models so I try to make it looking the best I can. Since I know some electronics I was thinking about making a bending machine myself with few servos and arduino to make my life easier, but I need to think and plan a lot for it to happen. I was thinking also about progressive die and made some test pieces but it just didn’t look good. Formlabs - make something that can print 0.3mm wire 
Why not go with photo-etched?
Check out:
https://www.etchworks.eu/