That's a really cool idea for sourcing traction tires for hard-to-find locomotives. I've never printed with TPU before, what are your observations from working with it?

It's just as easy as PLA and I used the same nozzle and bed temps. Also same print speed. I could probably print these without brim supports for less trimming. I have quite a bit of 3rd Rails now and finding tires to fit can be a challenge. Even if these aren't as good as factory ones they're so cheap and easy to make it's an OK trade-off. Long term durability should be interesting. Not sure how they will stand up to oil and grease exposure. Only one way to find out!

If you can whip up Sunset and Weaver tires you may have a lot of new friends Norm! Informative post.

Norm

Very interesting project for 3d printing   Let us know how it works. Hopefully this could also help to reduce the ridiculous prices being charged for traction tires.

Marty

Yeah $10 a set anymore! We'll see how it goes...

It also occurred to me these could be printed in silver TPU for stealth mode tires. Hmm.

@Norm Charbonneau posted:

It also occurred to me these could be printed in silver TPU for stealth mode tires. Hmm.

That would be an interesting visual Norm.

Nice Norm!

Tom

Very cool Norm, finding the skinny tires for some of the Williams, Weaver and early 3rd Rail brass is getting harder, this could be a solution.

This is a very interesting thread. I made measurements for a traction tire and printed a PLA version to see if looked feasible.

The measurements were Outside diameter = 31mm,  width = 2.5mm,  and the thickness = 0.5mm. The picture shows the result.

So far I have never used any filament but PLA, but after reading this thread I have placed an order for some TPU filament.

After I receive the TPU I will post my results on this thread.

I'd love it if more people tried! I got a bit frustrated snapping tires right at the end of long upgrade/mod projects. As said above, many of them are getting hard to find now and it's not unusual breaking precious ones in your stash trying to fit them to something they weren't made for. More experimenters would get more durability data too. I am not aware of any softer durometers available in TPU but it would be neat to try them if they are out there. Printing them in clear, gray or silver would be neat to see.

95A might be a little brittle, that's pretty high on the SHORE HARDNESS SCALE.  I would think that 40A-50A would be the desirable range.

I’d honestly be surprised if regular traction tires are softer than 85A. Besides, I think we should be more concerned about the material’s modulus in traction tire form. The ability to not absorb energy and go plastic on us while under strain is the key to long term durability.

I saw your video on youtube today where you printed these and was going to make a topic and ask you about them! I'm glad I found this thread first.

I have never used anything besides PLA because PLA gets the job done for what I have done. I was curious what nozzle and speeds you're using. Did you have to lower your speeds?

It’s a trade off the softer material will grip better but will wear quicker. My guess is 70-80 shore A is what you want to be, depending.

Other factors would include stretch or modulus of elasticity and uniformity in thickness and width. I think some older traction tires were rubber,I’m guessing they were around 60 duro shore A. Interestingly some older traction tires I’ve seen had a cross pattern.

As a wear test think tubular track with gaps.

I have  been looking at traction tires as sort of a hobby project.

I think you’d want urethane due to wear properties and elasticity. You could get all fancy and cast and mandrel cut.

One thing to consider as the tires stretch the material will get thinner. Somewhere one of the manufactures will have tolerances on existing traction tires. Be interesting to check it out.

Of course I don’t know about 3D printing PU.

You could have different duro’s in different colors or dual duros stacked, if you had the thickness to work with. I sold micro pitch urethane timing belts eons ago. The casting and cut mandrels would be pricy but at ten dollars a set who knows it may be doable.

JM2C

Steven

Bill, like I mentioned above, I used the same settings as PLA. Only thing I might do different is print without a brim so there’s less trimming.

I missed the settings part with PLA @Norm Charbonneau. Now I'm thinking maybe I should pick up a spool of TPU. I'll be watching this post closely!

Great result, Norm!

Just so folks know, TPU is short for thermoplastic urethane. TPU's are a family of block copolymers  which can be tailored for different applications by changing hard segment and soft segment composition and content. Generally, greater hardness results in better wear but less traction and vice-versa. TPU's have good resistance to oil and grease. Because Norm's selection is readily printed by additive fabrication via melt printing in the same range as PLA (polylactic acid) , I assume it is a polyester-based TPU.

Super!

Bob

Thanks Norm... timely thread.  I replaced a tire on one of the Challengers today and saw that the tire had sort of adhered to the driver and that the tire had ripped itself apart.  It was still a whole tire... just all limp/stretchy and such.   It did take a little force (not much but force nonetheless) to remove the the remnants of the tire from the driver.  I'll be keeping an eye on this thread as well.

I’d be interested in hearing about ANY train related 3d printing.

Bill

Looks good Norm.  I am going to try this as well.

Bill

Norm,

Fantastic work! TPU is a fun filament. What brand are you using?

I would also suggest checking out ColorFabb's NGEN_Flex or NinjaFlex TPU. In the realm of TPU, I have had great sucess with NinjaFlex.

Bryce

I am using Novamaker from Amazon: https://www.amazon.com/gp/prod...00?ie=UTF8&psc=1

I should have bought gray for the traction tires. Not sure what else I'll make with the stuff. I'm a bit surprised I haven't seen anyone else try this yet.

Norm,

  Before I jump fully into making traction tires, I have a few questions.  As a test, I found a tire for a toy car on thingverse and was able to scale it down to the diameter that was needed and printed it with PLA.

1.  how elastic is the filament when you go to put it on over the wheel?

2.  Any thoughts on durability?

3.  I was able to get the outside diameter and width pretty close but how did you adjust the thickness of the tire?

4.  Is it a plastic you can use for models of structures such as accessories and scenery around the railroad?

thanks,

Marty

There’s only three dimensions needed for a tire, OD, ID and width. Tweaking the ID can give a proper fit, OD can be adjusted for grab. Width has to close otherwise the tire won’t seat well. These tweaks are trivial for a printer. So far, the material mechanical properties of TPU seem very close to regular traction tires. Please keep in mind I am not running a full suite of static deflection and dynamic characterization on the these parts, only trying to see what I can get away with at this point. If these tires are only half as good as regular ones, the cost to make them is somewhere around 35 cents apiece.

Norm, thanks for the feedback.  Ordered a small spool of TPU and give it a try.

Marty

Has anyone tried this using a flexible resin?  There are resins available with a Shore rating of 80A.  I would think that a resin printer would give one greater dimensional control.

Jan

@Norm Charbonneau posted:

I am using Novamaker from Amazon: https://www.amazon.com/gp/prod...00?ie=UTF8&psc=1

I should have bought gray for the traction tires. Not sure what else I'll make with the stuff. I'm a bit surprised I haven't seen anyone else try this yet.

Norm,  I'll give it a go.  What other Shore rating would you like to see tested (90A, 98A)?   Any other specification variables (other than color)?

Bryce pointed out that he liked the NinjaFlex. Maybe try the 85A in Silver? I wish I was a little more imaginative when I picked my color!

I ordered a sample

This is available for My FormLabs 3

Flexible 80A

Hard Flexible Prototypes

Flexible 80A Resin is the most stiff soft-touch material in our library of Flexible and Elastic Resins, with an 80A Shore durometer to simulate the flexibility of rubber or TPU. Balancing softness with strength, Flexible 80A Resin can withstand bending, flexing, and compression, even through repeated cycles.

Handles, grips, and overmolds

Cushioning, damping, and shock absorption

Seals, gaskets, and masks

Cartilage, tendon, and ligament anatomy

Durometer

Soft

80

Hard

Springback

Slow

35

Fast

Ultimate Tensile Strength

Low

75

High

@Norm Charbonneau posted:

Bryce pointed out that he liked the NinjaFlex. Maybe try the 85A in Silver? I wish I was a little more imaginative when I picked my color!

LOL!  Those are 'designer' tires Norm.     Ordered - NinjaFlex 85A TPU in Steel (Gray)

Alan!!!!  Crank out some clear tires!

It probably wouldn't be a bad idea to send each other a few sets for individual testing.  Maybe I'll send a set to Gunrunner after I adulterate them on my Atlas track

Anyone else notice this?  A quick inspection of a dozen or so Locos showed a few dried out and cracked tires... but, the number of soft, spongy, swollen tires really surprised me.  The newer, say post 2016 were the spongy & swollen and pre 2016 were the dried & cracked.  Looks like someone changed suppliers?

Clever idea!  What else could we use for traction tires?  or temporary traction tires?

rubber has a short lifespan, especially when it is repeatedly stretched and compressed.

Recall all the "blackened" damaged rubber hold-downs on the Post-war flat cars.

Maybe resin "rubber" has a longer life as is stated in FormLabs description as

"Flexible 80A Resin can withstand bending, flexing, and compression, even through repeated cycles."

I have no idea how accurate that is as applied to engine drive wheel tires!

Sample rubber-like resin that I got from FormLabs. See the flexibility like silicone.

It's a model of a heart vein I think.

to make the tires I need the flexible resin material and the two dimensions shown above the Radius to the outside and the tire thickness and width

I make a few TPU resin tires today.  Took some tweaking of the printer for the TPU to work but got some pretty good results.   If you plan to print it you do not need any supports. I used Lionel`s dimensions and got pretty close to what was needed.  I will probably have to make additional adjustments to get a better fit, but it works.  I found the printed tires incredibly strong.  They were hard to cut with a razor knife.  They were able to stretch quite a bit to get them into the groove.  They were harder than the original tires. The TPU had a rating of 95.  Have not had an opportunity to run them on an engine.  But at least I know that there is an alternative if tires need to be replaced.

Marty

Marty

when you mentioned razor knife I though since I am printing why not add a slight Tread Pattern.?

would a tread design give better traction than a flat surface?

@AlanRail posted:

Marty

when you mentioned razor knife I though since I am printing why not add a slight Tread Pattern.?

would a tread design give better traction than a flat surface?

K-Line used to think so, I don't know if it helped or not.

When I first started this project, I found some toy car tires on thingiverse  which had a little bit of Tread on them.  They were printed out using TPA and with modifications the tread did print.  Have not tried printing them with TPU, that may be tomorrow's experiment.

Marty