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

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
p.s.

This is what happens if you enter a gauge adjustment on the DXF dialog:

chairs228_5.png


The entire jaw, key and rail seat assembly moves sideways on the chair base.

Clearly I overdid it a bit. This is intended for minor tweaks to correct for variations in the rail section and resin shrinkage, not trying to convert 00 to P4! :)

Martin.
 
_______________
message ref: 1839

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
Everything in Templot is already generated "on the fly"

And just to prove it, this is what happens if I get the plug depth wrong:

wrong_plug_depth.png

It certainly makes sturdy track. :)

Time for a boiled egg.

Martin.
 
_______________
message ref: 1852

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
That's better:

better_plug_depth.png

The default plug depth is 3" (scale), but would need to be reduced if using thin 1/32" (0.8mm) plywood timbers in 4mm scale.

The chamfered plug corners for easier fit in FDM-printed sockets were missing on the previous file.

I need to do something about the fillet rads between the rail seat and the side of the jaws. They are no match for Andy's or Richard's. How much difference it makes painted and covered in track grot is moot.

Martin.
 
_______________
message ref: 1853

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
Sizing the chair sockets in the timbers:

This is what appears on the screen, and in 2D DXF files, if you switch on the experimental chairing:

plug_fits.png


The socket size will be adjustable to get the best fit for the chair plugs with your equipment and materials.

The clearance defaults at present are:

X = 0.05mm, so 0.1mm (4 thou) theoretical side-play in the socket. For a solid push fit you might want to tighten it up, for a glued fit you might want to widen it a bit to leave space for the glue.

Y = 0.025mm, so 0.05mm (2 thou) theoretical end-play. It's tighter than the side-play because it affects the gauge accuracy. Ideally you would adjust it to achieve zero end-play. The actual gauge can then be adjusted on the chairs, as I showed earlier.

The socket outline will be in the 2D DXF file for those who want to laser-cut the sockets in plywood timbers.

socket_fits.png


Writing this stuff now in case I forget to mention it later. I forget everything these days.

cheers,

Martin.
 
_______________
message ref: 1854

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
I think it would be a much better investment of your time if you were to create methods that allowed Templot users to add their own chair/clip/spike designs to Templot 2-D designs.
@AndyB

p.s. Andy,

This has actually been in Templot for a few years now. The rail seats act as block markers with the datum location and rail angle on the gauge-face. Just switch off what you don't want, and add your own blocks:

block_markers_dxf.png


cheers,

Martin.
 
_______________
message ref: 1867

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
Today's task was to get the top face of the timbers filled in around the chair sockets. Not as simple as it looks, with chairs of different sizes, positions and angles:

chair_sockets_3d.png


The defaults are currently for chair plugs 3" deep, with blind sockets 3.75" deep in timbers 4.75" thick. All adjustable to whatever you want. I'm in two minds about the default option for blind sockets. I was thinking through holes might make the filament-printed timbers a bit fragile where sockets come close to the edge. For laser cut plywood they will always be through holes of course.

cheers,

Martin.
 
_______________
message ref: 1870

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
p.s. I have changed the default timber thickness to 4.75".

This scales to 1.6mm (1/16") in 4mm/ft scale, corresponding to the standard "thick" timbering used for some commercial tracks.

This means the default socket depth is also changed to 3.75".

For 4mm/ft scale, the remaining 1" thickness in the base of blind sockets scales to 0.33mm (13 thou).

For 3" plugs in 4mm/ft scale, the 0.75" clearance for support trimmings in the bottom of the sockets scales to 0.25mm (10 thou) clearance. Flush cutters will be needed to remove them from the printed supports.

All these settings are adjustable if wanted.

cheers,

Martin.
 
_______________
message ref: 1871

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
Now the option for through sockets:

chair_through_sockets_3d.png



For plain track sleepers, they are going to be a bit flimsy without a solid base in the sockets. Remember in 4mm scale these sleepers are only 3.3mm wide. The sockets are 2mm wide:

chair_through_sockets_3d_plain_track.png


Looking at this, I'm wondering if it is feasible for plywood.

Anyone know the typical minimum width for laser-cut 0.8mm plywood?

I don't want to make the chair plugs smaller because it makes the chairs more fragile to handle.

cheers,

Martin.
 
_______________
message ref: 1872

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
This is as far as I shall go with the chairing in 228a, otherwise it will never get released and we shall be back to the 227a situation. Further progress with the chairing will have to wait until later. I still have some work on the short-angle diamonds to finish for 228a.

chairing1.png


As you can see, there are no special chairs at all yet, just ordinary S1 chairs. So in 228a it will still be firmly labelled EXPERIMENTAL. But there should be enough for anyone who wants to have a play with 3D printing from Templot to do so, as a proof of concept.

It should be possible to produce usable plain track at least, using C&L/EMGS or SMP code 75 bullhead rail (vertical), or your own custom rail section, or equivalent rail sections in other scales. The options will be:

1. single file chairs and timbers, for one-piece resin printing (if your machine is large enough), for end-threading of rails. In the larger scales (Gauge 1, P-32, etc.) it might be possible to use filament printing instead. For resin printing you could also print the rails as above, for battery/radio control/live steam/clockwork operation. That's difficult with filament printing without support under the rail.

2. print chairs only, with or without plugs*, in resin. For sliding onto rail.

3. print timbers only, with or without plug sockets, for filament printing or resin.

4. export 2D DXF, with or without plug socket holes, for laser cutting of timbers.

In any gauge or scale or radius or sleeper size/spacing.

*if you print chairs without plugs, the support structure will be up to you.

Templot will produce the STL file directly, but it is likely to need a round trip via this free web site (or others similar) to keep your slicer software happy:

https://www.formware.co/onlinestlrepair

I have added a button on the DXF dialog for fast access to the above site.

In an ideal world I would get the Templot STL to a state where no online fix is needed, but don't hold your breath. :)

cheers,

Martin.
 
_______________
message ref: 1873

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
A wet weekend means I've made a bit of progress with the 3D exports: :)

dxf_export_dialog_228a.png


It's now possible to set and use a custom rail section. The custom data for the rail, and any plug/socket fit adjustments, can now be saved and reloaded from a data file (.CRX).

This will be in 228a shortly, so that anyone with access to a 3D printer can create plain track, and tinker a bit with pointwork (the special chairs are not yet ready).

Just a reminder, 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 trackbuilding -- but no templates, solder, butanone or gauges needed! For any turnout size, any curved radius, and any scale or gauge:

sockets_3d.png


s1_chair_on_support.png

cheers,

Martin.
 
_______________
message ref: 1896

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
I've mentioned that the 3D export from Templot can also include 3D-printed non-metallic rails. For battery operation with remote control.

No filing, cutting or bending of rail. No track wiring. Just print some track, stick it down and run trains over it. :)

Here's a fascinating video (first 15 minutes) from 2006 showing an 0 gauge model of Bodmin using the Red Arrow infra-red control system. The track is actually metal, but it didn't need to be, there is no wiring to it. The railway is fully signalled and operated with a lever frame and block instruments.

Food for thought?


cheers,

Martin.
 
_______________
message ref: 1900

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
_______________
message ref: 1911

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
In daylight, and with a scoosh of grey primer:

bibo_sockets_daylight1.jpg


bibo_sockets_daylight_grey1.jpg


It's good to see that the chair screws do actually have square tops! This is the first time I've properly seen the chair detail. :)

bibo_sockets_daylight_grey2.jpg


But the grey is showing that not all the chairs are fully seated home. I'm going to add a small chamfer round the top of the sockets to help with that. But it's also important that the chair plugs are trimmed flush with the supports and are not bottoming in the sockets. Ideally the timbers would be a bit thicker to allow deeper blind sockets. These are 1.6mm thick timbers to match "thick" flexi track. The alternative option of through-hole sockets avoids that problem, but makes the filament printing more troublesome, especially for plain track sleepers.

cheers,

Martin.
 
_______________
message ref: 1913

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
But the grey is showing that not all the chairs are fully seated home. I'm going to add a small chamfer round the top of the sockets to help with that.

Now added:

chamfer_sockets.png


Chamfer 3/8" wide and 5/8" deep (scale).

Martin.
 
_______________
message ref: 1914

Hayfield

Member
Location
Essex
These chairs and timbers are stunning, I am very impressed especially with the detail of the chairs, would it be an answer if either the holes were a tad bigger or the chair plugs a tad smaller, as it may just be that the hole and or plug sizes may vary ever so slightly in the printing process ?
 
_______________
message ref: 1915

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
These chairs and timbers are stunning, I am very impressed especially with the detail of the chairs, would it be an answer if either the holes were a tad bigger or the chair plugs a tad smaller, as it may just be that the hole and or plug sizes may vary ever so slightly in the printing process ?
@Hayfield

Thanks John. Everything will be adjustable to suit your own machine(s), or a friend's. :) See:

https://85a.uk/templot/club/index.php?threads/3d-printed-track-from-templot.218/post-1854

The problem is getting good dimensional consistency from FDM (filament) printing. So 90% of the sockets are just right, but the rest are too loose or too tight. I've been fiddling with the settings in the Cura slicer software and now got it quite good. For best results of course you would resin-print the timber base instead, although it might be a bit fragile when pressing chairs home using the standard resins (whereas the PLA PLUS toughened polymer I'm using on my filament printer really is tough, easily a match for injection moulded flexi track).

The reason for using a filament printer is the build size. The work area of the home 3D filament printers is typically about 4 or 5 times larger than for the home resin printers. For example the usable area on my little Elegoo Mars resin printer is ony about 5" x 3". That's fine for producing a batch of chairs, but very small for the timbering base units. Any typical track formation in 4mm/ft scale would require multiple resin base units, needing to be connected or stuck down in perfect alignment. But just a couple of filament-printed bases would be enough to cover most track formations.

But everything is still very experimental. My initial objective is to get 228a released in the next few days, and then see what if anything folks make of it. While they are doing that I can get on with creating the special chairs. :)

cheers,

Martin.
 
_______________
message ref: 1918

Hayfield

Member
Location
Essex
Martin

This is well beyond my skill sets and I will wait for some enterprising or friendly person to supply parts, happy to be involved in the building side but not in the printing bit
 
_______________
message ref: 1919

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
_______________
message ref: 1920

Martin Wynne

Admin
Location
West of the Severn UK
Info
Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add helpful replies.
I've added an option to put a bottom flange on the side of the timbers, to be hidden under the ballast:

bottom_flange1.png


This stiffens the timbers alongside through-hole sockets,especially for plain track sleepers as above. This should eliminate any need for the blind socket option.

Through-hole sockets offer several advantages:

1. if you plug in the wrong chair, or need to replace it, you can easily push it out from below.

2. if a chair is a bit loose, you can inject some glue around it from below.

3. no risk of a chair bottoming in the socket if you have left some remains of the support pyramid on it, or there is some debris in a blind socket.

The full-depth sprues are important for filament printing. They allowing "combing", meaning that the nozzle can reach all parts of every layer without any need to jump across open areas. Such jumps leave stringing on small components, regardless of the retraction settings I've tried. It's much easier to cut a full-depth sprue than clean up a part suffering badly from stringing. Just a tap with a sharp wood chisel does it*. But for resin printing you would probably set the sprue depth to about half timber depth, just enough to hold the timber spacing.

in the flesh:

bottom_flange4.jpg


The top surface has been given a quick rub over with a Garryflex block (or emery stick), followed by a rinse under the tap to remove the sandings.

There is an option to show the flanges on the printed templates, if you want to attach these timbers to a template for construction.

The cruel bit (4mm/ft sleepers, 3.3mm wide):

bottom_flange2.jpg


* this could also remove the unavoidable rounded corners on the timbers if you set the timber length a fraction longer than usual. But in practice the rounding is barely visible.

cheers,

Martin.
 
_______________
message ref: 1921
Top