3D printing track

This section allows guests to comment or ask questions. Posts from guests require explicit approval (which generally takes a day or so), before they appear, so that we can prevent unwanted spam.
Proto87Stores

3D printing track

Postby Proto87Stores » Sun Feb 02, 2020 3:50 pm

A few things I would suggest are checked out before investing too heavily in printed track.

1 What's the coefficient of expansion? Especially under bright layout lighting being turned on and off?
2 Most of us have gone along with the 50 year experience idea that plastic wheels on metal rail are a constant source of crud. Does that mean that metal wheels on plastic rail will be any different?
3 Friction has been mentioned. How about wear? Metal wheels against plastic rail will last how long? Could plastic check rails wear enough to shrink the P4 check gauge?
4 If the answer to 2 and 3 is to use both plastic wheels AND plastic rail, where do you stop and still use metal? Plastic coupling rods? Plastic coupling rod pins? Plastic axles, plastic axle bearings? Will a pacific pull away a 10 coach train without something bending, buckling or breaking?
5 If 4 os the answer, What's the wear rate of plastic on plastic?
6 What's the life expectancy of 3D resin under "daylight" layout lighting.

Andy

User avatar
Martin Wynne
Posts: 868
Joined: Mon May 14, 2012 4:27 pm

Re: 3D printing track

Postby Martin Wynne » Mon Feb 03, 2020 5:52 am

Proto87Stores wrote:A few things I would suggest are checked out before investing too heavily in printed track.

Hi Andy,

Why always so negative? No-one is "investing heavily" in 3D printed track. What I'm doing is having a dabble with Templot and my 3D printer to see what it can do. No doubt others are doing the same. So far it looks very doable for a shunting layout in 7mm scale. 4mm scale is proving trickier, but I have today achieved a reasonable 4mm scale representation of BS-95R rail.

1 What's the coefficient of expansion?

It will be greater than for metal. But given that any trackwork must be made up from modules no longer than 8" (the size of my printer bed) I doubt there will be any significant problem. We shall see what size expansion gaps need to be programmed in. I can't see anyone wanting to use 3D printing for long lengths of plain track, when flexi-track and/or handuilding is available. What I'm looking at 3D printing for is complex pointwork, designed in Templot.

2 Most of us have gone along with the 50 year experience idea that plastic wheels on metal rail are a constant source of crud. Does that mean that metal wheels on plastic rail will be any different?

If there is any crud it is likely to be on the rails, not metal wheels. It's easier to clean rails than wheels. In P4 crud on wheels reduces the flange depth and leads to derailments -- crud on the rails is unlikely to be so detrimental to running.

3 Friction has been mentioned. How about wear? Metal wheels against plastic rail will last how long? Could plastic check rails wear enough to shrink the P4 check gauge?

It's very prototypical for check rails to wear. If they do they can be replaced. That's prototypical too.

4 If the answer to 2 and 3 is to use both plastic wheels AND plastic rail, where do you stop and still use metal?

Modellers can stop wherever they choose to stop.

6 What's the life expectancy of 3D resin under "daylight" layout lighting.

I know nothing about 3D resin printing. What I'm doing is FDM filament printing with toughened PLA-PLUS bio-polymer. It's biodegradeable -- in about 2 years buried in a compost heap, and about 200 years in air.

Folks talk about "3D printing" as if it's all one and the same thing. The filament printing and resin printing processes have very little in common. I believe some 3D resins are cured using UV light and then have to be protected from further UV in daylight by painting, otherwise they become brittle and crumbly. There are dozens of polymers available for filament printing, some will be more affected by UV than others.

cheers,

Martin.
40 years developing Templot. And counting ...

trustytrev
Posts: 22
Joined: Tue Nov 27, 2018 10:19 pm

Re: 3D printing track

Postby trustytrev » Mon Feb 03, 2020 1:33 pm

Hello,
People with an interest in "Warhammer" stuff seem to be taking full advantage of resin printing technology to quite a serious level.
The detail in "Warhammer" stuff is amazing and the expectations and requirements of its fans are extremely demanding.
If one considers how document printing has evolved in such a short time is their any reason 3D printing machines will not become as ubiquitous in peoples homes and work places? Children take such things for granted now.
trustytrev. :)

User avatar
Jol Wilkinson
Posts: 804
Joined: Mon Jul 21, 2008 7:39 pm

Re: 3D printing track

Postby Jol Wilkinson » Mon Feb 03, 2020 5:24 pm

Apparently SLA resin printing is a rather more "messy" process than the filament technique. The dream of the 3D printer on the desk which produces perfect images of 3D artwork without any "fuss" may be a little way off.

trustytrev
Posts: 22
Joined: Tue Nov 27, 2018 10:19 pm

Re: 3D printing track

Postby trustytrev » Mon Feb 03, 2020 7:29 pm

Hello,
The same was said about people having printer/scanners at home. Then again humans in space seems to have turned predictions on their head.
trustytrev. :)

User avatar
Guy Rixon
Posts: 694
Joined: Sun Mar 27, 2011 6:40 pm

Re: 3D printing track

Postby Guy Rixon » Mon Feb 03, 2020 8:58 pm

Document printing has evolved ... but it took its own sweet time about it. My research group got its first laser printer in 1987, at great cost. 32 years later, I finally managed to buy a home printer that's both affordable and works well, all my previous home printers having been expensive, or skipware, or both. If 3D printing takes as long to evolve a turn-key desktop solution I shan't be around to use it.

Jol is right that resin printers are messy. The resin stinks (allegedly; I don't have a resin printer myself), so has the same domestic problems as casting in resin. The prints have to cured under UV light, which typically means fishing them out of the printer, while they are soft, into a second device. They then have to be washed.

One could imagine a combined printer-curer-washer-dryer device that keeps the smelly and toxic bits away from the user and emits finished prints. AFAIK it doesn't exist yet at a price for hobby users.

Proto87stores

Re: 3D printing track

Postby Proto87stores » Mon Feb 03, 2020 9:47 pm

Today's issue is that messy resin printers have far better resolution than filament printers. And their comparative printing speeds are subject dependent.

Basically a filament printer moves it's head to print only the requested 3d pixels per each slice serially, while a PLD printer photographically prints the whole, full plate size slice, regardless of content, sequentially at a fixed rate.

As to evaluating pertinent unknowns before starting a project, I don't see how that could be considered as a negative attitude. I didn't want to indicate any bias by pointing out that I've been supplying plastic based turnouts for the past almost 20 years. But I have always replaced the plastic crossings, check rails and throw bars with pre-formed metal parts of my own design and manufacture. As result, I have had only satisfied customers and zero requested returns or aged, broken or worn replacements for the whole time. OTOH, I've never taken the risk of supplying those parts in plastic form. But for other suppliers turnouts that have plastic crossings, see various RM WEB topics for problem reports.

Andy

User avatar
Martin Wynne
Posts: 868
Joined: Mon May 14, 2012 4:27 pm

Re: 3D printing track

Postby Martin Wynne » Mon Feb 03, 2020 10:35 pm

Proto87stores wrote:As to evaluating pertinent unknowns before starting a project, I don't see how that could be considered as a negative attitude. I didn't want to indicate any bias by pointing out that I've been supplying plastic based turnouts for the past almost 20 years. But I have always replaced the plastic crossings, check rails and throw bars with pre-formed metal parts of my own design and manufacture. As result, I have had only satisfied customers and zero requested returns or aged, broken or worn replacements for the whole time. OTOH, I've never taken the risk of supplying those parts in plastic form. But for other suppliers turnouts that have plastic crossings, see various RM WEB topics for problem reports.

Hi Andy,

By all means evaluate everything up to the hilt as a manufacturer and trader.

But this is a hobby topic on a hobby forum. I'm not planning to manufacture or sell anything to anybody, and I don't imagine anyone else here is either. My experiments are for fun. If anything comes of them and a new 3D printing function gets incorporated into Templot, it will be free for anyone to use or not as they please, and it will also be available as free open-source code. If the results don't work out too well, no-one will have lost anything.

cheers,

Martin.
40 years developing Templot. And counting ...

billbedford
Posts: 709
Joined: Tue Oct 02, 2012 2:40 pm

Re: 3D printing track

Postby billbedford » Wed Feb 05, 2020 12:47 pm

Guy Rixon wrote:Document printing has evolved ... but it took its own sweet time about it. My research group got its first laser printer in 1987, at great cost. 32 years later, I finally managed to buy a home printer that's both affordable and works well, all my previous home printers having been expensive, or skipware, or both. If 3D printing takes as long to evolve a turn-key desktop solution I shan't be around to use it.


It is the time after the patents run out that is important. Only after that point does the majority of product innovation kick in. Given that the most important patents ran out in the last 10-15 years it may be another 10-15 before the printers reach some sort of mass-market stability. However, it seems that many of the 3D printer manufacturers have begun to realise that their products are never going to have the mass-market appeal of even laser 2D printers and have started to target various industrial sectors.

Jol is right that resin printers are messy. The resin stinks (allegedly; I don't have a resin printer myself), so has the same domestic problems as casting in resin. The prints have to cured under UV light, which typically means fishing them out of the printer, while they are soft, into a second device. They then have to be washed.


That is all sort of true, sometimes. Some resin smell, some don't. Some people are more sensitive to the smell than others. The standard washing solution is IPA, which smells and is inflammable, but you can use DPM (dipropylene glycol methyl ether) which has little odour, and is not inflammable, or even neat washing-up liquid on some resins.

All these resin printers use a UV source to cure each layer of resin. The pieces can be given a secondary curing to cross-link molecules and enhance the characteristics of the resin. I don't usually do this as while extra curing makes the resin 'stronger' it also makes it more brittle, and I think that the flexibility of, especially small parts, is needed while the model is being handled. However, any model left out in ambient light will slowly cure over time. This curing can be prevented simply by painting the model and possibly using a UV resistant varnish.


One could imagine a combined printer-curer-washer-dryer device that keeps the smelly and toxic bits away from the user and emits finished prints. AFAIK it doesn't exist yet at a price for hobby users.


All the printer use an aluminium build plate that lifts out of the resin when the printing is finished, so there is no need to 'fish' for anything.

The usual sequence is print -> wash -> dry -> cure and, with the right equipment, it can all be done without touching the print. At some stage, the supports have to be removed and this can be done either before or after curing.

I have to say that, even after 3 years and now having two prosumer printers I'm still learning what this technology is capable of.
Bill Bedford
Mousa Models
http://www.mousa.biz

trustytrev
Posts: 22
Joined: Tue Nov 27, 2018 10:19 pm

Re: 3D printing track

Postby trustytrev » Wed Feb 05, 2020 8:36 pm

Hello,
One could apply the "messy" tag to just about everything related to model railways really.
Soldering,painting, wiring or even building. Some people are "messier" than others even when it comes to having a tidy up.
trustytrev. :)

User avatar
Jol Wilkinson
Posts: 804
Joined: Mon Jul 21, 2008 7:39 pm

Re: 3D printing track

Postby Jol Wilkinson » Thu Feb 06, 2020 9:07 am

I think Bill's last sentence probably gives a fair indication of where we are with 3D printing. It is probably comparable to the early days ofetched kits.

However, some people don't seem to recognise (or are willing to ) that we are still fairly well down the development/learning curve and that the process isn't always going to provide the best solution to creating accurate detailed models and parts. At least not at a low cost - which is important to a lot of railway modellers.


Return to “Guest Book”

Who is online

Users browsing this forum: No registered users and 2 guests