Building 3D track

[ralphrobertson]

Seeing the talk about laser cutters, readers of this thread will have seen my posts regarding making timbers from card using a laser. I have had a laser for 3 or 4 years now and I bought it from Darkly Labs in Australia. Expensive? Perhaps and certainly more than the Chinese offerings but I have never regretted spending on the Emblaser 2, it has proved a reliable work horse and has produced many buildings and bits and pieces for Slattocks Jnc, the P4 layout of the Manchester Model Railway Society. Since purchasing this they now make a kit so you can put your own together and they are now upgrading the Emblaser 2 to a more powerful system. Take a look at Darkly Labs and see if it is something for you. Have I ever regretted buying from Australia (I am in the UK) - no never. If I have a problem I email them at the end of the day and when I wake in the morning I get a response. Parts come within 2 days and so far I have only had to replace fans which I stock up on. Overall an excellent product which I would recommend to anyone interested in getting a system they can take out of the box and switch on and start cutting.

Ralph

 

[Terry Downes]

@Terry Downes

Hi Terry,

I know nothing about laser-cutting, but that timbering base looks a bit over-cooked? It gives the impression that press-fitting the chairs into it would break the timbers apart? Are you intending to use smaller plugs and glue the chairs in place instead?

I suggest you don't change the height of the chair support pyramids. They are set at 3mm tall, and anything less makes it awkward to use flush cutters in removing the chairs from them.

You need to change the depth of the plug part of the chair for your thinner plywood:

View attachment 4314

The plug part of the chair comprises three sections.

The first section below the chair base is parallel-sided and a bash interference fit in the sockets at each end of the socket.

The second and third sections provide a taper lead-in, so that the chairs can be located loosely in the sockets before being pressed home.

View attachment 4313

Make sure you have set your model scale/gauge, and then click the chair / socket fit... button.

Press the Enter key about 16 times until you get to the above settings 1, 2 and 3, corresponding to the drawing above. They are stored internally in prototype dimensions but shown there at the model size (hence the importance of having your model scale/gauge set correctly in the control template).

The default dimensions showing there are for 4mm/ft scale and intended for use with 1/8" (3.2mm) timbering thickness.

For 1/16" timbering I suggest a first trial would be to divide all three of them by 2. Then it will likely need some further trial and error changes to get the best results.

The total plug depth needs to be less than the timber thickness to allow for any rough or broken remains on the bottom of the plug after snipping from the support.

More info in this topic: https://85a.uk/templot/club/index.php?threads/the-book-of-plug-track.529/

cheers,

Martin.

Hi Martin,
As always, thanks for your detailed reply. I will test the reduced chair plugs later today and let you know how I get on. Please keep up the sterling work with this topic. I'm constantly impressed with your level of detail and passion for your 'Hobby'
Regarding laser cut ply timbers... I purchased a very cheap Chinese Laser (Omtech 40W ~ £400) about 8 months ago to add to my modelling tools arsenal. I'm still playing with settings to achieve acceptable results and I have to say I'm very disappointed in the inconsistent results and very bad machine quality. I could go on and would like to share my results but, I'm not sure this is the right thread.

 

[Marsh Lane]

Martin,
I have been following this topic with interest, quietly in the background as I don’t have a 3D printer. But the results and possibilities are very interesting, and I agree with the earlier positing about recognition for your services to the model railway world! Sir Martin of Templot perhaps?!

From your current experience, do you feel that the Plug Track system would work for Code 55 N Gauge rail, or is that a step too far? Would the chairs be too small to reliably hold the rail accurately?

I recall you have said what printer and filament you have been using earlier in the thread. Is that, from your experience what you feel is best for this type of project, or merely what you chose when you bought it?

Keep up the development work, your doing a grand job.

Rich

 

[ralphrobertson]

I know nothing about laser-cutting, but that timbering base looks a bit over-cooked?

My experience shows that the material is very hard and/or your head is moving too slowly. If you are able to, try using 2 passes to cut lowering the head by half the thickness on the second pass and set it on a much faster speed. Alternatively try using poplar ply which is a much softer ply and is readily available. SLEC Poplar ply I use the rule that if I can cut it easily with a Stanley knife then my laser will cut it easy, if it needs more than one cut then it is a hard material and will be a hard cut on the machine which is why I always use card first. I do use poplar ply but never use MDF. If you see burn marks like that to me it indicates your birch ply is very hard.

Why don't you get some mounting board (£4 or so an A1 sheet from most stationers) and try making the timbers from that and change the plug sizes to match 1.5mm thickness (see my posts for how I did it). Why everyone wants to use ply sleepers beats me, modellers back in the 1950s used card on their layouts and it worked for them so why not for us too?

Hope this might help.

Ralph

 

[murphaph]

A question which has probably already been answered. If so, apologies.

Is the idea that the rail is threaded through the chairs in one go while they are all "lined up" on the raft and then the xuron cutters comes in to separate from the support pyramids or are they supposed to be snipped off and slid onto the rails one by one?

 

[ralphrobertson]

Personally I always slide a pointed piece of rail through the chairs as soon as they come off the printer after an IPA wash, this clears any residue that might be left in the jaw. As the rail is in position I then break all the chairs from the bottom support pyramid by pushing the rail back and forward and then when they are free from the base I use a cutter to trim the remnants off. If necessary I run a file over the bottom of the plug too. Note: I am talking about S1 chairs here for plain track, I have no experience of 3D printing for turnouts preferring to use ply and rivet.

Edited for typo

 

[Martin Wynne]

A question which has probably already been answered. If so, apologies.

Is the idea that the rail is threaded through the chairs in one go while they are all "lined up" on the raft and then the xuron cutters comes in to separate from the support pyramids or are they supposed to be snipped off and slid onto the rails one by one?

Hi,

I snip them off the raft one at a time, and lay them out in the required positions on the paper template. Making sure that the keys are on the outside of the rails, and in some cases selecting chairs which have the keys facing in the correct direction.

Then slide them one a time on the rail. knowing that they are all in the correct order.

It's not really possible to slide the rail through them on the raft, because as it ages the raft tends to curl up (differential shrinkage):

This has no significant effect on individual chairs, but it means they are no longer aligned with each other on the raft to slide the rail through.

Also, sliding the rail through on the raft would mean they need to be arranged in the correct order on the raft. Which makes the bunching process for 3D printing very tricky, unless you waste a lot of resin and space printing them directly at the template positions. Bunching them up already requires some ingenuity with partial templates, adding a text label to the raft, and keeping a careful note on the paper template of which is which.

But your workshop, your way of doing things. Templot is just a tool to assist you.

cheers,

Martin.

 

[Martin Wynne]

Regarding laser cut ply timbers... I purchased a very cheap Chinese Laser (Omtech 40W ~ £400) about 8 months ago to add to my modelling tools arsenal. I'm still playing with settings to achieve acceptable results and I have to say I'm very disappointed in the inconsistent results and very bad machine quality. I could go on and would like to share my results but, I'm not sure this is the right topic.

@Terry Downes

Hi Terry,

Thanks for your report about the Omtech.

I have moved some of these posts to this topic as they are not directly related to the Templot program.

So yes, do please share here your experiences and results with your laser cutter.

I was also very disappointed -- with the Silhouette Cameo blade cutter. I imagined that it might be able to cut timbers and sockets in card, following glowing discussions on other forums. In practice it was utterly useless for anything thicker than 10 thou; the driver software runs on the computer and not on the cutter, taking over 30% continuous cpu use potentially for hours, leaving the computer running hot, slow, and barely usable for anything else. Also there were bugs in the DXF import making accurate dimensions very tricky to get right. It would have gone in the bin, but for its saving grace of being usable as a pen plotter on roll paper.

So yes, we need reports of all experiences and results with machines and methods for building plug track.

cheers,

Martin.

 

[Martin Wynne]

Personally I always slide a pointed piece of rail through the chairs as soon as they come off the printer after an IPA wash,

@ralphrobertson

Hi Ralph,

I'm a bit puzzled. Does that mean you are threading the rail through the chairs while they are still soft? Before any UV curing?

Does that work ok? On my printer they are very delicate at that stage and easily damaged. Do you UV cure them with the rail through them, or remove it for curing? If the rail is in place, does it prevent the UV light reaching all parts of the chair?

cheers,

Martin.

 

[Martin Wynne]

Martin,
I have been following this topic with interest, quietly in the background as I don’t have a 3D printer. But the results and possibilities are very interesting, and I agree with the earlier positing about recognition for your services to the model railway world! Sir Martin of Templot perhaps?!

From your current experience, do you feel that the Plug Track system would work for Code 55 N Gauge rail, or is that a step too far? Would the chairs be too small to reliably hold the rail accurately?

I recall you have said what printer and filament you have been using earlier in the thread. Is that, from your experience what you feel is best for this type of project, or merely what you chose when you bought it?

Keep up the development work, your doing a grand job.

Rich

@Marsh Lane

Hi Rich,

Thanks for your kind words.

The answer about smaller scales is that I don't know. If you set your scale/gauge in Templot in the usual way, the 3D files will be for that size. But how well they will print I don't know. Perhaps someone here has tried it. Anyone?

It's not really possible to test it without some small bullhead rail. What bullhead rails are available in the smaller scales? I haven't done anything yet for flat-bottom rail.

Looking at what I have done so far my feeling is that it would probably be ok for 3mm/ft scale, but below that (TT-120, N, 2mm/ft) it would likely need some changes.

I can only report my results with the machines and materials which I have here. I'm quite pleased with the results, but whether they could be a lot better using something else I have no way of knowing.

What I do know and have learned the hard way is that relying on reviews on YouTube and other web sites is meaningless. The only way to find out what works for what I want to do is to get one and see. Obviously I can't do that for every machine on the market, so it's all down to luck in what machines I have obtained and am using. For all I know other machines would have been much better. Which clearly would be the case for industrial-grade 3D printers rather the inexpensive home printers from Amazon.

The Elegoo Mars2 Pro with "ABS-like" resin is used pretty much as it comes out of the box, with the default settings.

But for BIBO FDM printer I have spent many, many hours over the years trying different settings. If you have looked in the Cura slicer software you will know that there are hundreds of different settings which can be used. I haven't yet posted the Cura file with my settings for the 4mm/ft timbering bricks, but I ought to do that soon.

What really surprised me is that the little child's toy FDM printer, which I have named MINIBO, can produce results of equal quality to the BIBO after some tweaking of the GCODE file. It's unfortunate that the work area is so small, but for 2mm/ft scale it might be just the job:

More about the MINIBO:

https://85a.uk/templot/club/index.php?threads/another-fdm-printer.340/

cheers,

Martin.

 

[Marsh Lane]

Martin,
Thanks for the detailed reply, which is pretty much what I expected you to say. Keep up the good work though. You really are pushing boundries that should be pushed.

Rich

 

[murphaph]

Martin, you say the ABS like resin is quite tough even when thin. Do you think this might make "Irish chairs" (as used with flat bottomed rail all over the network) possible at some stage? These were as you probably know far less substantial than chairs for bullhead rail and were more like a base plate with a pair of screws acting as a clamp on the foot of the rail. The advantage of this very slimline mounting was that with copperclad sleepers you could kind of get away with simply soldering the rail to the sleeper and the tiny bit of solder residue at the joint could suggest the presence of the base plate screw heads, at least in 4mm scale and smaller. Now you are raising the bar in this area, I would rather put in more bullhead rail with your resin chairs than flat bottomed rail soldered to copperclad sleepers. But of course if someday in the distant future I thought just maybe some "Irish chairs" might be on the horizon I would be more patient I think ;-) What do you reckon, will it ever be technically feasible to resin print such things in a durable way in 4mm scale?

Examples of what I mean:

 

[ralphrobertson]

I'm a bit puzzled. Does that mean you are threading the rail through the chairs while they are still soft? Before any UV curing?

Does that work ok? On my printer they are very delicate at that stage and easily damaged. Do you UV cure them with the rail through them, or remove it for curing? If the rail is in place, does it prevent the UV light reaching all parts of the chair?

Hi Martin,

I thread the rail through the chairs after an IPA wash to clean the slot out and then remove the rail again. Then I leave the chairs in the window to get the sun for a week or so to cure properly. The base stays flat unlike the photo of yours. I don't do any UV cure and I am using Anycubic standard grey resin. I did have some of the ABS like resin but that ran out and I had some of this stuff so I used that. It works fine and all the track I have laid so far is ok, it holds the gauge well and no jaws have broken.

I did actually remove a small section of track to lift the height to match some ply track and the chairs seemed very strong despite the fact that the resin isn't ABS like. I ripped up the card sleepers and pinged off the resin chairs and glued in some rivetted sleepers to get the levels better. Let's see how it works in the longer term but so far so good. I have had trains run up and down the track extensively whilst testing and it works perfectly - if I get chance I can film a clip and post it. Don't forget this is only straight track and not turnouts!

If anyone is interested here is the STL file I used but remember the plugs are set to my needs for 1.5mm card and Karlgarin 4mm bullhead rail (available from Phoenix Paints Phoenix rail). I set up 3 rows of this file on the file for the Photon and it prints fine. It sticks to the build plate well and I rarely get a failed print and I have printed 20 or more of these trying out various settings. Apart from changing the socket settings in Templot I didn't play with any settings for the jaw, it seems to work perfectly for me. I have both ply and rivet track detailed with glued on C&L half chairs and Templot generated chairs and card laser cut sleepers so we will see on the layout how they compare given time.

Ralph

Edited - software changes the word thread to topic so had to change it! Its done it again! I mean t h r e a d gets changed!

 

[Martin Wynne]

Edited - software changes the word topic to topic so had to change it! Its done it again! I mean t h r e a d gets changed!

@ralphrobertson

Hi Ralph,

Yes, it's a script which I added intentionally to the forum software.

XenForo uses the term "thread" for forum discussions:

I changed it to "topic" throughout when I set up this new forum. For compatibility with the old forum and most modern web sites. It also offends my sense of logic, because you can't have a "thread" with only a single post.

If you want to use the word "thread" in a post with its original meaning, select one letter within it and change its colour to black.

(This adds extra CSS to the HTML code and prevents the script finding it.)

I have asked on the XenForo user forums for a built-in or add-on option to use "topic" instead of "thread" throughout -- and been dismissed as a raving lunatic.

cheers,

Martin.

 

[ralphrobertson]

Don't worry Martin, I could change it to slide instead which is what I did in my previous entries.

 

[Martin Wynne]

Martin, you say the ABS like resin is quite tough even when thin. Do you think this might make "Irish chairs" (as used with flat bottomed rail all over the network) possible at some stage? These were as you probably know far less substantial than chairs for bullhead rail and were more like a base plate with a pair of screws acting as a clamp on the foot of the rail. The advantage of this very slimline mounting was that with copperclad sleepers you could kind of get away with simply soldering the rail to the sleeper and the tiny bit of solder residue at the joint could suggest the presence of the base plate screw heads, at least in 4mm scale and smaller. Now you are raising the bar in this area, I would rather put in more bullhead rail with your resin chairs than flat bottomed rail soldered to copperclad sleepers. But of course if someday in the distant future I thought just maybe some "Irish chairs" might be on the horizon I would be more patient I think ;-) What do you reckon, will it ever be technically feasible to resin print such things in a durable way in 4mm scale?

Examples of what I mean:

@murphaph

Hi (please sign your name when addressing me by name),

Bullhead track design has remained essentially unchanged for 100 years, and was very similar before then. So the bullhead plug track will be usable, or at least recognisable, for a great many different prototypes and periods.

Whereas flat-bottom track had a myriad of fixing designs in use before the Pandrol clip was adopted as the almost universal design worldwide (invented 1957).

So even if we could find an FB design which stands a reasonable chance of being 3D-printable, there would be an immediate flood of requests for some other design. It's a minefield I'm very wary to enter. In any event there is no immediate possibility of doing that while I'm fully occupied developing the bullhead plug track, but it would be great if someone else jumped in.

Most of the older designs of FB fixing use some form of wire spike or flat clip which would be too thin to be 3D-printed with sufficient strength to be usable, at least not in 4mm/ft scale, and that probably includes the Pandrol clip too.

Two designs which might have enough heft above the rail foot to be 3D-printable and work, would be the Hey-Back clip (printed as a solid clip):

and screws with solid cast-iron clips:

Here's another example of your "Irish chairs" (plain screws without clips) at Dundalk in 2004:

At present you can sort-of represent FB baseplates by switching off everything else from the export:

I will try printing some small clips on there and see how they work, but first I need to find some FB rail.

cheers,

Martin.

 

[murphaph]

Cheers Martin and apologies, I have added a signature now. Hopefully it works

I totally understand that you are 100% committed to working on bullhead etc. and that Irish FB rail has essentially no priority. Irish track combined bull head with a lot of FB sections so one can get away with bullhead for sure but it's nice to hear that you think at least one of the variants might just work in plug track.

All the best,
Phil

 

[Steve_Cornford]

Finally managed to get time & space to unbox the Elegoo Mars 2 Pro.
Have started printing some S1 chairs... Hoorah.
But....
Is it normal for the build plate to go up and down? I assume that it is after each slice in order to encourage the resin to flow in and out of the bits it is printing. It is a bit noisy when it does this.
Any advice thankfully received, Steve

 

[Martin Wynne]

Finally managed to get time & space to unbox the Elegoo Mars 2 Pro.
Have started printing some S1 chairs... Hoorah.
But....
Is it normal for the build plate to go up and down? I assume that it is after each slice in order to encourage the resin to flow in and out of the bits it is printing. It is a bit noisy when it does this.
Any advice thankfully received, Steve

@Steve_Cornford

Hi Steve,

Yes that's the normal way it works.

The next layer is formed against the FEP film in the base of the tank (I use a 2.2 second exposure time after the first few layers). The build plate then lifts to pull it off the FEP and allow fresh resin to flow in underneath. It then goes down again and stops 1 layer thickness higher than before. The process then repeats.

What sort of noises? It's normal to hear some quiet sucking, plopping and swishing noises. If the sucking noise is very loud it may mean that a raft is covering too great an area of the build plate. They will go away once it has completed enough layers for the raft to be clear of the FEP.

If they are mechanical noises you may have something loose in the vertical slide which needs looking at. On the Mars2 Pro the internal air filter fan is also quite noisy.

Another thing to check is that after levelling the plate the adjusting screws are tightened very firmly. I wrecked one print when the build plate moved during the print, even though I had tightened the screws to what I thought was firm enough. If the plate has come loose it could cause some noises (and the print will be useless). Likewise the top clamp screw attaching the build plate to the machine.

Good luck!

cheers,

Martin.

 

[Martin Wynne]

p.s. Steve,

These are the Chitubox settings I use. They are I think mostly the default settings for the Mars2 Pro. The results have been fine (with "ABS-like" resin) so I haven't done much experimenting with them:

cheers,

Martin.