Experimental Plug Track: 3D-printed, CNC-milled, laser-cut

[Martin Wynne]

Just out of interest what are the printing costs please

@Hayfield

Hi John,

Do you mean the cost of getting them printed commercially? Sorry, no idea.

If you mean the cost of making the chairs yourself, the actual resin cost is about 3 chairs for 1p (4mm scale).

But at a bare minimum you will also need:

A well-ventilated workshop area away from your living space. A bathroom + extractor fan or openable window might be suitable.

3D resin printer, around £200. The one I'm using (Elegoo Mars 2P) is currently on Amazon at £230, but there are cheaper models, offers and bundles.

A bottle of "ABS-like" liquid resin, around £35 per kg bottle. (Bundles will likely include the cheaper more brittle resin.)

A bottle of 99% isopropanol (IPA) solvent for washing the chairs. Price varies, the stuff I'm using costs £3.80 per litre.

A sunny day.

The amount of resin needed to make a chair is negligible, more resin will be wasted in the support sprues and washing than ends up in the actual chair. For the last batch of 144 chairs which I made, the software says the total cost of resin including supports was 26p. Say about 48p including washing, IPA and clean-up, which makes the chairs cost 0.33p each or 3 for a penny.

How you factor in the cost of the printer is up to you, but once you have one you will be able to make all sorts of other models and parts, not just chairs. But note that a resin printer is no good for making the filing jigs, for that you need a FDM filament printer (which is no good for making chairs below about Gauge 3).

If you don't have any sunny days in stock you can use a UV lamp instead. Cost is the same as a length of string. Or a dedicated UV curing and washing machine to match the printer costs around £100.

cheers,

Martin.

 

[Hayfield]

Martin

Thank you, I think the biggest problem is not having am outside workshop, secondly my inability of being able to use said machine. like injection moulding it seems the costs of materials are quite inexpensive. So I assume it will not be long until someone like Wayne comes along and offers a service at a reasonable cost

I may have misunderstood a previous post but the longevity of the resin seems questionable if unpainted and left in sunlight

 

[timbersgalore]

Martin

Laser cutters are capable of understanding shapes. What it means is that when presented with a nested set of rectangles they work out what is inside and outside. The result is that the cut planner can works out which bits to cut first. It also means that the laser can provide the Kerf offset. It would be worth checking whether a cutting service is automatically applying it own kerf offset to closed figures. That said it would be usefully to have the timber outline and chair socket layers on there own layers.


Here is a screen shot showing the cut layer from my recent test:-

A little shape manipulation is required to join the spruces to the timbers.


Timbers

 

[Martin Wynne]

secondly my inability of being able to use said machine

I may have misunderstood a previous post but the longevity of the resin seems questionable if unpainted and left in sunlight

@Hayfield

Hi John,

For the Templot chairs you don't need any ability to use the printer -- the files from Templot are ready to use. Just follow the instructions to make a few clicks on the computer and switch the printer on.

For other models, lots of modellers are making their model files available if you don't feel able to use CAD design software yourself, for example on RMweb. And there are huge libraries of other stuff online if you need a Toby jug or a new part for your vacuum cleaner.

Yes, resin-printed items are susceptible to UV light (as are many other plastics). They will harden and crumble over time if left in sunlight. They need to be painted to offer some protection, and preferably kept away from strong sunshine. Wayne probably mentions the need to paint his 3D-printed track bases in the instructions.

cheers,

Martin.

 

[Martin Wynne]

I have descovered it is very straighforward to place my own socket outlines using the track edge and timber centre line. Is everything you mentioned in the live version of 228 or is it unrealeased?

You track sample looks good, is that 7mm scale?

@timbersgalore

Hi Timbers,

Sorry, I can't remember what is in 228a. I think I put the bare minimum for folks to experiment. I'm planning to release an utterly experimental 228b shortly.

Which track sample? This one is 4mm/ft scale (EM):

I have held off playing with 7mm for now because I just know I will get distracted. I expect the results to look good, but the limited FDM build area will be a challenge.

Your GWR chair is now looking much better. Your key might be a bit short -- prototype keys are 6" long, i.e. 2" longer than the chair jaw.

cheers,

Martin.

 

[Steve_Cornford]

Yes socket outiles are available in 228a (the current released version) :-
First you need to switch on the experimental chairing
Real > Chairing/3D > Experimental chairing.

Then you can:-
Output > Export a file (PDF, PNG, EMF, DXF, STL.....
Click on the [Create DXF/STL] button in the Export CAD file box.
Leave it as 2-D DXF , click on [timbers only] button
change some other parameters you might want for instance the [chair socket fit] button brings up:-

This screen capture shows the defaults.
I used the "socket side clearance" & set it to minus 0.25 to reduce the standard socket width of 2mm to 1.5mm.
(but in reality as the laser cutting service had a kerf of 0.2mm, this actually made the true (as cut) socket width 1.7mm.

Then when you click on the green [export DXF/STL file] box/button in bottom left, the resultant .DXF file has a layer named TIMBOUTL which contains the lines for both timbers and sockets.

I then just opened the .DXF file directly with Inkscape (because thats what I had available), added a new layer called SOCKOUTL and then selected all the sockets in the layer TIMBOUTL and MOVED them to the layer SOCKOUTL.

Steve

 

[Steve_Cornford]

ps the "chair plug clearance (all round)" option only works for 3D exports in version 228a

pps not a complaint or bug... just an explanantion of why i used "socket side clearance" in 2D export.
Steve

 

[Derek]

Martin/ John

Amazon has a deal on at the moment for the Elegoo Mars 2P and a wash/ cure unit. I forget the exact price but it's a lot cheaper than buying both separately. I've no idea whether the 'cure/ wash cabinet' is better than a UV lamp and cleaning materials.

Derek

 

[Martin Wynne]

@timbersgalore @Steve_Cornford

Hi Timbers,

I have moved your post to a new separate topic because what you are doing is not Plug Track -- the new topic is here:

https://85a.uk/templot/club/index.php?threads/laser-cutting-from-dxf-file-export.273/

I desperately want this topic to be about Plug Track only -- folks are so quick to get the wrong end of the stick that it's a constant battle of wits to keep topics on course and prevent confusion. Otherwise it takes hours of my time to unsort the confusion and explain everything, over and over again.

In Plug Track the chairs are slid onto the prepared rail first, one at a time, and the chaired rail is then pressed vertically into the timbering base. If you fit the chairs into the timbers first, the rail must then slide endways through the chairs. Which is doable for simple formations, but impossible for any rails which contain a set bend or knuckle bend or bent check flare, or are otherwise obstructed by other rails already in place.

I can see that I'm going to have make a rubber stamp with this explanation, because time and again folks are going to assume that the rails slide into the timbering base, as in pointwork kits. I shall be explaining the difference over and over again until the end of time, just as I have been doing for 15 years now with 00-SF on RMweb.

Steve's idea for sockets in the trackbed is that you use separate locator plugs to locate and fix the timbers to the trackbed:

These are then removed when the glue has set, and the chaired rail is then pressed into the timbers. This avoids the need for any sprues or webbing between the timbers to align them.

I'm still in two minds about this, because the gauging and rail alignment is set by the chairs and timbers, so the sockets in the trackbed will need to be cut with the same precision as the sockets in the timbers. I can imagine therefore that it will need 2 sublayers to work -- the usual soft cork or balsa trackbed, and then a solid layer of the same material as the timbers, containing the additional sockets. With the risk of warping and distortion as yet untried.

p.s. the excessive bottom taper on the locator plugs in the above screenshot has been removed in 228b.

cheers,

Martin.

 

[Martin Wynne]

The chairs I produce ( using an Elegoo Mars 2 pro, arriving in next 3 hours) will have longer pegs so that they go through the timbers and into the trackbed layer.

@Steve_Cornford

Hi Steve,

If you do that it will not be Plug Track because you will be sliding the rail through the chairs afterwards -- see my previous post.

As you previously explained it, you wanted to use separate removable locator plugs to fix the timbers to the trackbed. Before adding the chaired rail.

Presumably the printer has now arrived -- if you chose it based on my comments I hope you are pleased with it. It's a marvellous piece of kit.

cheers,

Martin.

 

[Steve_Cornford]

Hi Martin,
You are right, I forgot to mention that first I would use locator pegs when glueing the timbers to the trackbed.
As an experiment I plan to make the locator pegs with the baseplate on the top, then having applied glue to timbers and positioned them on the trackbed pop the whole assembly, baseboard, tracbed, timbers and locator pegs into a large vacuum clothes bag and attach a vacuum cleaner to let atmospheric pressure apply an even pressure to the whole face of the timbers.
I have used the vacuum bag trick when laminating several layers of thin plywood before to achieve very even gluing particularly on curved surfaces.
But once this is done and the locator pegs removed I assumed that it would not hurt to use longer pegs on the actual chairs for a stronger fix, however this would use more resin.
So after removing locator pegs I would thread the rail into the chairs, then plug the chairs into the sockets.

Yes box has arrived labelled Mars 2 Pro.
I did base my choice on your comments and on some other comments, especially from people who have had other makes but have added the Mars to their stable.
So thank you for all the usefull advice and tips on its use that you have detailed in your Messin with Resin topic
Just waiting for some other bits to arrive before i dare unbox it & get going.
In the meantime am learning more Templot skills and playing with some of Waynes kits.
Steve

 

[Martin Wynne]

But once this is done and the locator pegs removed I assumed that it would not hurt to use longer plugs on the actual chairs for a stronger fix, however this would use more resin.

@Steve_Cornford

Hi Steve,

Having longer plugs on the chairs will make them easier to handle when threading them onto the rail. You would also be able to use a more pronounced bottom taper on the plugs, which makes it easier to align them all over the sockets before pressing the rail home.

The short default plug depth in 228a was to allow for the option of blind sockets in the FDM timbers (which strengthens the timber and removes the need for the side flanges):

from: https://85a.uk/templot/club/index.p...d-printing-and-2d-laser-cutting.229/post-1870

In 4mm scale some users will also want to use thin 1/32" (0.8mm) timbers matching Brook Smith riveted ply (and SMP Scaleway flexi-track). Which by itself allows for almost no bottom taper on the plugs, but if done in ply rather than FDM and combined with your socketed sub-bed it would do.

It would also be possible to combine 3D-printed timbers (with through sockets) with laser-cut sockets in a sub-bed. This would allow bunched timbers to be resin printed without side flanges or webs. Saving on the cost of the laser-cutting if you already have a resin printer.

So many options and settings!

cheers,

Martin.

 

[Martin Wynne]

I have just completed another iteration of the GWR 95 chair.

View attachment 2164

@timbersgalore

Hi Timbers,

The GWR S1 chair (for BS-95R rail) is 8" wide*, and sleepers are 10" wide. Your chair appears to be occupying the full width of the sleeper, so either the chair is too wide, or the sleepers are too narrow? Is this the result of the laser kerf on the cut sleepers?

If they were REA S1 chairs (3-screw) it would look like a length of plain track laid with all S1J joint chairs, which would be extremely unusual but just about feasible. But as far as I know the GWR didn't use any joint chairs.

*the GWR 00-Ordinary chair (for their 00 rail) is 7.1/2" wide, so the effect would be even more noticeable.

The grain effect on your sleepers is excellent, although suggests very old sleepers more likely to be seen on branch lines and yards rather than on a main running line.

cheers,

Martin.

 

[Paul Boyd]

This is all now all getting very confusing. I was following this thread for interest to see what could come out of Templot but it seems now to be covering lots of different methods and opinons of building 3D printed track.

Although I don't have a 3D printer, nor the space to put one, that doesn't preclude me from getting chairs printed!

 

[Martin Wynne]

This is all now all getting very confusing.

@Paul Boyd

Hi Paul,

I agree. Which is why I have hived off the stuff about DXF for laser cutters into a separate topic, and moved some posts about track-building methods into the methods and materials section.

This topic is about the Templot program and its Plug Track output, to create 3D-printed track without requiring any CAD design skills.

The unpainted result looks like this (this is 4mm/ft EM gauge):

The default option from Templot will be to export 3 STL files for the 3D printing.

To make Plug Track for a section of a track plan which I am calling a "timbering brick" (in my case roughly 8" square). It can't normally be a whole template because of size restrictions on FDM (filament) printers, but it may contain sections from more than one template. The bricks will clip together like Lego to create the full track plan (which is why I call them "bricks").

1. a file for FDM filament printing of the timbering base.

2. a file to create a corresponding set of plug-in chairs on a resin printer.

3. optionally a file to create rail filing and bending jigs for the required switches and crossing angles, on an FDM printer.

Resin and FDM printers are now getting quite popular among modellers, but for those without them the files could be sent to commercial 3D printing services (or to friends).

But I want to include other options for those who want them if I can. It should get a lot less confusing when I can remove the word "experimental" from the topic title and describe what actually is, rather than several ideas that I'm trying and what might be one day.

If anyone finds it too confusing the best advice would be to ignore this topic until that happy day arrives. But don't hold your breath.

cheers,

Martin.

 

[Martin Wynne]

I forgot to post this.

These stabilising webbing links between adjacent templates in a brick are called "splints":

They are added manually by drawing line shapes in the background shapes. You can have as many as you like. The default size is 9" wide by 1.5" thick (scale), but can be set to whatever you want. At that thickness (0.5mm in 4mm scale) they match the timber flanges and can be hidden under the ballast. If made thicker they would need to be cut out after track-laying.

I tried to generate them automatically, but a usable algorithm proved too difficult. It needs a human eye to position them sensibly, and some experience with the printer and polymer in use.

In 3-D files all background line shapes are treated as brick splints -- they go in the BKSPLINT layer, and can be turned off there if not wanted.

Remember to save the BGS3 file! (Also for the chair support slabs, which work similarly for all background rectangle shapes.)

In 2-D files background line shapes are drawn as plain lines, in the SBGSHAPE layer (or DBGSHAPE layer if dotted lines), and can be turned off there if not wanted (no change for 20 years in that). Likewise background rectangle shapes in the same 2-D layer.

cheers,

Martin.

 

[Martin Wynne]

Just to add that if you export the above without the timbers, you could print this:

In other words a 3D template into which resin-printed timbers, or laser-cut timbers, could be located. It could be removed from the underside of the finished pointwork in the same way as a paper template. Or if thin enough it could be left in the ballast.

If laser-cut instead, it would have to be done from a 3-D DXF, not 2-D.

If you increase the timber flange width to 12", and don't mind using more polymer, you don't need the timber web links and get this:

I'm minded to call this option a timbering "fret" and put it all in a single layer, but I'm desperate not to keep confusing people by adding more and more options.

cheers,

Martin.

 

[Martin Wynne]

I'm minded to call this option a timbering "fret" and put it all in a single layer, but I'm desperate not to keep confusing people by adding more and more options.

Given such a timbering fret, there might be a third way to create the timbers for it:

https://85a.uk/templot/club/index.php?threads/cnc-miller-instead-of-laser-cutter.276/

Well, yes, it's yet another option setting, and I did say we mustn't ...

Martin.

 

[Martin Wynne]

Just a reminder that nothing in the experimental 3-D chairing is yet working as finally intended. I released it in version 228a only to allow folks to see what I'm doing and tinker about with it, not to use it for real for any actual modelling purpose. Please do not post bug reports related to anything in the 3-D chairing -- until it is finished everything in it is a bug.

See these posts:

https://85a.uk/templot/club/index.p...ck-file-exports-for-3d-printing.229/post-1831

https://85a.uk/templot/club/index.p...ck-file-exports-for-3d-printing.229/post-1838

To use 228a as a normal Templot program update, please leave this setting on the default no chairing:

If you then find anything going wrong, it is a genuine bug, so please report it in the usual way. Thanks.

Please be aware that the above setting is template-specific, so if you have turned it on for any template you will need to turn it off on each one separately, or click the modify group to match function above.

cheers,

Martin.

 

[Steve_Cornford]

Dear Martin,
Please don't regret releasing 228a into the wild.
I for one have loved tinkering with it, and in doing so proved to myself that it is practical to laser cut sockets in 1.6mm ply with a width of 1.7mm, and the process has encouraged me to learn more and more about using Templot (without experimental chairing switched on).

Also more about resin printing and laser cutting, and dare I say it, even CNC milling.

I know you are just at the start of a long journey, and that maybe there will be the odd diversion up a "disused" branch line on the way, but it has really been stimulating to spectate on your journey, so thank you for sharing your progress with us.

Steve