3d printing chairs and sleepers for bullhead track

[rdr]

Well we have entered the 21st century with a bang when it comes to modelling all aspects of model railways, the 3d resin printer has got a firm hold of small scale (pun intended) production in model railways. Whether or not your computer literate the 3d resin printer can be a help over a wide range of items in the modelling world, from aspect lights to zebra crossings. 

 

My interest in 3d printing comes from a P4 background and track production, which most modellers never have to consider, you're the lucky ones. C&L, Exactoscale, produce great track parts that look fantastic and do the job perfectly, so why am i looking to produce track parts with a 3d printer. Well it's the old factor of cost, and on a moderate sized layout the cost of producing your own P4 track is quite high. I have about 22 metres of scenic track and a further 24 metres of fiddle yard track.

 

To produce track parts you need a rendering of the type of chairs you require in a format the printer likes to see, now this is where the computer rears it's ugly head, and is the main stumbling block for the average modeller. There are several chairs required for track production, from running chairs for plain track to specialised chairs for pointwork, and several models of each type of chair depending on the region you want to model in. I've gone for possibly the most common chair for bullhead track the BR S1 chair.

 

Next is the printer itself, which can be a minefield for some but a walk in the park for others. There is definitly a steep learning curve with these printers, as they are a combination of mechanical controlled movement with the alchemy of resins, and fluid motion. There are also several ways to print on a 3d printer and each have their own unique inherant problems, which can be very frustrating for the beginner. If you print a model and use a raft that supports the model away from the print plate, then you bypass most of the problems with alignment of the plate. But if your plan is to print directly to the build plate then alignment of the plate is essential and must be accurate, or you will have problems. I am producing a mod for this printer to get over the problems associated with printing directly to the build plate.

 

Getting on to the printing, here's a sample of what can be made. 

 

PS. sorry for the poor quality of the photo, it's taken from my phone.

 

 

 

Edited June 23, 2020 by rdr

[Mark]

I had a go at this several months ago. Works quite well and ideal for special chairs in point work. I still have some more tweaks to make but other projects got in the way!

 

Mark

[rdr]

Hi Mark, i've kept the option of chairs alone as well, there's always a place where one or two need to be juggled and when used on points. I'm going to mix a bit of flex in the resin to get over the brittleness, have you tried this ?

 

Edited June 24, 2020 by rdr

[Mark]

Not yet. I had a problem with my printer shortly after the prints were done and by the time it had been sorted I was working on other things. 
 

I intended to do a mixture of integral chairs and individual chairs, especially for point work where fitting flared wing rails would be almost impossible. I have wondered if I could include some check rails in the prints but I will need to spend some time on cadds first to generate those and they will need to be tested to be sure they don’t wear over time.

 

Mark

[rdr]

One thing i noticed when i first started printing multiple items on the plate, if you space them out about 5mm apart the resin clears a lot better. What printer do you have ?

[Mark]

17 hours ago, rdr said:

One thing i noticed when i first started printing multiple items on the plate, if you space them out about 5mm apart the resin clears a lot better. What printer do you have ?

I am using the Anycubic Photon S. The problem I had came to light after I did a software and firmware update. The new software allowed the position of supports to be edited but required the firmware on the machine to be updated. It worked fine initially but on the third iteration of chairs, the printer refused to read the file. I got in touch with Anycubic and they sent a replacement mother board. However that didn’t work either. I then discovered that the new software doesn’t seem to recognise the machine print area so if the cadds geometry goes slightly outside the print area everything on the stick got blocked. I need to modify the third iteration file by removing some parts from the original geometry and then do it again. At the moment I am focussing on other things so I probably won’t go back to track work until the Autumn.

 

Mark

[rdr]

i bought the standard Photon, as i'm making a mod for it to take out all the levelling issues. I was thinking of upgrading the firmware to use the new file system, but a lot of owners are having issues with the new firmware.

[makeitminiature]

These are brilliant. Well done Sir!

I had been thinking about doing something similar for my Bexhill West project. 
I’ve been constructing the buildings quite closely to scale and it’s nearly time to think about trackwork. 
I’ve been using my project to introduce others to CAD work through my YouTube channel ‘Bexhill West’ and am always trying to think of aspects of the project I can apply to CAD to. 
I wonder if you might be able to let me know where you found the drawings for the rail chairs please? I’m very happy to draw my own in CAD, but have no idea where to find a drawing of the original. 

My best wishes,

James

[rdr]

sorry for not getting back any sooner, i must have missed the notification on your post.

I had to do a combination of pictures and drawings, to get it somewhere near correct, probably not spot on yet.

I have a very basic cad drawing of a three bolt chair, which i shall try to locate and put up here.

Found it, if i could just figure out how to get it into my attachments. If you want a copy message me your details and i'll send it.

 

Edited January 16, 2021 by rdr

[njee20]

Looking good! I’ve been flirting with how to do this - I’m printing in N gauge, and I worry the chairs will just be too fragile. I’m going to print bases and use Finetrax chairs, like a DIY pegged turnout. Think it’ll work...

 

just going to have to split the turnout bases into lots of parts! Bigger printer needed!

[rdr]

you could use printouts of the points you need and lay single sleepers to suit. With just standard resins chairs are very brittle, but it's not a problem to add a flex resin in a percentage to cure this (pardon the pun)

Edited January 16, 2021 by rdr

[njee20]

Yes, I’m a big fan of Siraya Tech Tenacious for adding flex. If I’m going to lay individual sleepers I may as well use PCB. 

 

You can take a DXF from Templot, extrude the whole design and print, they just need breaking up. I think it’ll be quicker, and certainly my printing is better than my soldering!

[rdr]

and printing looks better

[njee20]

Less jarring alongside chaired plain track certainly. 

[martin_wynne]

On 16/01/2021 at 22:41, njee20 said:

You can take a DXF from Templot, extrude the whole design and print, they just need breaking up. I think it’ll be quicker, and certainly my printing is better than my soldering!

 

Hi,

 

I've made a bit of progress with the direct 3D printing from Templot.

 

No CAD design skills needed, Templot exports the STL file ready for use on the printer. For any turnout size, curved to any radius, and any scale or gauge.

 

The idea is to print the chairs and timbers separately. So that the chairs can slide onto the rail one at a time, and then plug vertically into the timbers:

 

 

 

 

 

Just like normal track building -- but no templates, solder, butanone, jigs or gauges needed! And it's free!

 

 

 

 

 

A Templot update with some initial experimental options will be released in the next few days. It should be possible to create plain track at least.

 

More info: https://85a.uk/templot/club/index.php?threads/3d-printed-track-from-templot.218/post-1873

 

cheers,

 

Martin.

[njee20]

Very interesting! I’ve been doing the DXF/extrude thing, for use with Wayne Kinney’s Finetrax chairs, as I don’t trust printed chairs (in N); I’ve only got as far as checking it’ll work, which it appears it will!

 

I’ve a larger printer coming, which will minimise the number of splits needed, which will be good. 

Edited July 6, 2021 by njee20

[AndyID]

 

More on this topic subject here

 

The DXF files are available at Templot (Messin' With Resin). They are drawn full-size (inch).

 

 

[Mark]

On 06/07/2021 at 06:20, martin_wynne said:

 

Hi,

 

I've made a bit of progress with the direct 3D printing from Templot.

 

No CAD design skills needed, Templot exports the STL file ready for use on the printer. For any turnout size, curved to any radius, and any scale or gauge.

 

The idea is to print the chairs and timbers separately. So that the chairs can slide onto the rail one at a time, and then plug vertically into the timbers:

 

 

 

 

 

Just like normal track building -- but no templates, solder, butanone, jigs or gauges needed! And it's free!

 

 

 

 

 

A Templot update with some initial experimental options will be released in the next few days. It should be possible to create plain track at least.

 

More info: https://85a.uk/templot/club/index.php?threads/3d-printed-track-from-templot.218/post-1873

 

cheers,

 

Martin.

That looks like a very helpful development. Will it include special chairs used on turnouts and compounds like the slab base chairs used for common and k crossings?

 

Mark Humphrys

[martin_wynne]

On 08/07/2021 at 14:46, Mark said:

That looks like a very helpful development. Will it include special chairs used on turnouts and compounds like the slab base chairs used for common and k crossings?

 

Mark Humphrys

 

Hi Mark,

 

Yes, eventually. I will just write that word again -- eventually.

 

Because there is still a long way to go. But we are not without progress, this is the middle bit of a curved B-6 turnout in P4, with equalized timbers:

 

 

Filament printed timbers with blind sockets, resin-printed S1 chairs. Exactoscale steel bullhead. The gauge came out at 18.79-18.82mm, so just needs a small tweak on the gauge-adjustment function. Would have been easily close enough in 00 or EM.

 

More info as I progress it at: https://85a.uk/templot/club/index.php?threads/3d-printed-track-from-templot.218/post-1873

 

The process needs a name. I'm minded to call it 3D Plug-Track.

 

cheers,

 

Martin.

Edited July 9, 2021 by martin_wynne

[Mark]

7 minutes ago, martin_wynne said:

 

Hi Mark,

 

Yes, eventually. I will just write that word again -- eventually.

 

Because there is still a long way to go. But we are not without progress, this is the middle bit of a curved B-6 turnout in P4, with equalized timbers:

 

 

Filament printed timbers with blind sockets, resin-printed S1 chairs. Exactoscale steel bullhead. The gauge came out at 18.79-18.82mm, so just needs a small tweak on the gauge-adjustment function. Would have been easily close enough in 00 or EM.

 

More info as I progress it at: https://85a.uk/templot/club/index.php?threads/3d-printed-track-from-templot.218/post-1873

 

The process needs a name. I'm minded to call it 3D Clip-Track.

 

cheers,

 

Martin.

Thanks Martin. I will keep my eyes on it.

 

Regards

 

Mark Humphrys

[martin_wynne]

@Mark

 

In daylight, and with a scoosh of grey primer to show the chair detail:

 

It's good to see that the chair screws do actually have square tops! (P4) This is the first time I've properly seen the chairs. The translucent resin is all but impossible to photograph. Notice that the key positions are randomised.

 

Martin.

[Fen End Pit]

Quote

3 hours ago, martin_wynne said:

@Mark

 

Notice that the key positions are randomised.

 

Martin.

 

Quote

 

Very impressive,

Couple of suggestions :- could the sleeper 'sprue' be made slightly thinner than the sleepers to aid cutting?

Also ultimately the ability to specify key direction would be ideal so you could knock the keys in with the primary direction of travel on the line or have them alternate for single lines.

Are you finding any problems with the brittleness of the resin?

 

David

[martin_wynne]

12 minutes ago, Fen End Pit said:

 

Very impressive,

Couple of suggestions :- could the sleeper 'sprue' be made slightly thinner than the sleepers to aid cutting?

Also ultimately the ability to specify key direction would be ideal so you could knock the keys in with the primary direction of travel on the line or have them alternate for single lines.

Are you finding any problems with the brittleness of the resin?

 

David

@Fen End Pit

 

Thanks David.

 

The sprue can be set to any thickness you wish, just like most of the other settings. For resin printing of the bases you would probably set it to about half the timber thickness. However, for FDM (filament) printing, there is good reason to make it the same thickness as the timbers. It allows for "combing", meaning that the nozzle can reach all parts of the print without ever needing to cross empty space, either between the timbers or across the sockets. When it crosses empty space it tends to leave a "string" of polymer oozing from the nozzle. Which then gets incorporated into the next layer. There are "retraction" functions intended to deal with such stringing, but in my experience they don't work on small details, or actually make matters worse. Combing is a much better solution. Trimming the full-depth sprues is a far easier task than cleaning up a part suffering from a lot of stringing. Just a tap with a sharp wood chisel does it.

 

Yes the key direction can be specified, and also the degree of randomising or none. Of course, that only really makes sense if you print the chairs integrally with the timbers. If you print them separately you can mix up the ordinary S1 chairs to whatever arrangement you want.

 

The resin I'm using for the chairs is called "ABS-like" and is tougher than the standard resin (and a bit more expensive). There is an occasional broken corner on a chair, but that's prototypical! For the base it is a toughened PLA polymer called "PLA Plus". It's not the least bit brittle and is very tough.

 

Please bear in mind that this is all still very experimental. Nothing is set in stone.

 

cheers,

 

Martin.

[Nimbus]

By now, I'd be really excited if this was for flat-bottom rail !

 

The Nim.

[billbedford]

BR1 chairs?