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TEMPLOT 3D PLUG TRACK - To get up to speed with this experimental project click here.   To watch an introductory video click here.   See the User Guide at Bexhill West.

  • The Plug Track functions are experimental and still being developed. Some of the earlier pages of this topic are now out-of-date.

    For an updated overview of this project see this topic.   For some practical modelling aspects of using Plug Track see Building 3D Track.

    The assumption is that you have your own machines on which to experiment, or helpful friends with machines. Please do not send Templot files to commercial laser cutting or 3D printing firms while this project is still experimental, because the results are unpredictable and possibly wasteful.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files. All files derived from Templot are © Martin Wynne.
  • The Plug Track functions are experimental and still being developed.

    For an updated overview of this project see this topic.   For some practical modelling aspects of using Plug Track see Building 3D Track.

    The assumption is that you have your own machines on which to experiment, or helpful friends with machines. Please do not send Templot files to commercial laser cutting or 3D printing firms while this project is still experimental, because the results are unpredictable and possibly wasteful.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files. All files derived from Templot are © Martin Wynne.

Building 3D track

Quick reply >
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
 
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@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.
 
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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
 
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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
 
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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?
 
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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.
20221020_110613.jpg


Edited for typo
 
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Last edited:
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):

index.php


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.
 
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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.
 
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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.
 
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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:

index.php


More about the MINIBO:

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

cheers,

Martin.
 
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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
 
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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:
264986972_Irishflatbottomtrack.jpg.a7726b5beda1f42e1caaa57acd676b77.jpg


1335144426_FBKiltimagh.jpg.b968b6101fb4d204fac38da70129042c.jpg
 
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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!
 

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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:

xf_thd.png


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.
 
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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:
264986972_Irishflatbottomtrack.jpg.a7726b5beda1f42e1caaa57acd676b77.jpg


1335144426_FBKiltimagh.jpg.b968b6101fb4d204fac38da70129042c.jpg
@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):


fb_hey_back.jpg



and screws with solid cast-iron clips:

fb_clip_fixings.png



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

fb_clip_dundalk_2004.jpg


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

fb_plinth.png


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.
 
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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
 
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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
 
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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.
 
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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:

mars2_settings.png


cheers,

Martin.
 
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Thanks Martin,
So my first print has finished.
I had arranged 5 copies of the raft on the build plate, and the print progressed I could see that number of chairs displayed on the front panel LCD.
But once finished with the build plate draining, it looks as though I only have 3 rafts!
:(
Now in the wash.
I assume that I should now filter whats left of the resin in the FEP tank (?) as it is sure to have bits in it!
Oh well. It is all part of the leaarning process.
Steve
 
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Hi Steve,

Bad luck.

It's strange to lose 2 whole rafts as they are chunky lumps of resin directly on the build plate.

Are you getting the exposure light over the full area of the exposure screen? During initial setup a logo image is displayed on the screen to check that.

How big were these rafts? The noises you heard may have been caused by the large area of them sticking to the FEP film in the bottom of the tank and breaking away from the plate. If so you will need to drain the tank, filter the resin for broken bits, and remove them from the film.

Did you shake the bottle of resin well before use? You may have an imperfect mix if it has settled in the bottom of the bottle. The instructions say to shake it well, but don't explain how to deal with the fact that it is then frothy when you pour it out. I have learned the hard way to shake it an hour or so before I need it and leave it to settle in the bottle. This is all the typical learning on the job that they never put in the instructions. :(

How do your Chitubox settings compare with mine?

cheers,

Martin.
 
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Hi Martin,

I am using the ABS like resin. Perhaps I didnt shake the bottle enough, as it certainly was not frothy!

I was missing the 2nd and 5th rafts.

I will filter remnants before using again, and certainly give the bottle a good shake, a bit like Halfords etch primer rattle can then.

I did get the logo image in the recatngle so I think that was ok.

I used the default chitubox settings, but will check them and compare.

The printed instructions are a bit useless because the screen images are illegible< so had to resort to viewing PDF in order to actually see the images of the control panel!

The Mercury curing looks good in the dark!

Just the job for All Souls Night next week!

At least I have 3 rafts of 20 off, 4mm S1 chairs to play experiment with!

Its just great to see them in the flesh at last.

Cheers
Steve
 
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When I drained the tank there were two rafts stuck to the FEP . The chairs supports had started printing but it looks like at one end of the raft they got stuck and pulled the raft base off of the build plate.
I have filtered the resin & cleaned up ready for a other go another evening, thanks for the help an e encouragement,
Steve
 

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When I drained the tank there were two rafts stuck to the FEP . The chairs supports had started printing but it looks like at one end of the raft they got stuck and pulled the raft base off of the build plate.
I have filtered the resin & cleaned up ready for a other go another evening, thanks for the help an e encouragement,
Steve
@Steve_Cornford

Hi Steve,

Hmm.

It seems very strange to me that the rafts printed completely, but then parted company from the build plate later in the process. How firmly attached were the successful rafts? Mine are firmly attached to the plate and need the window scraper worked around them to release them.

Did you degrease the plate before using it to remove any traces of grease or contaminants from the manufacturing process? Likewise the FEP film.

I recently purchased a spare build plate. This speeds up an evening's production by printing the next batch of chairs while you are washing and curing the previous batch (assuming the first batch prints 100% and the tank doesn't need to be cleaned out).

When I went on Amazon to order it, I was surprised to find that there were two options for the build plate surface. A sand-blasted finish (as my original plate), or something described as "CNC Turning CD Pattern" finish. I have no idea what that means, and Google is no help, but I assume it means the plate has a finish similar to a CD disk. Which would certainly be smoother than my sand-blasted plates and may not stick so well. Is it possible your printer has been supplied with such a plate?

Yes, I'm still using Chitubox v1.6.5 as supplied with the machine. Also the original firmware (which I believe is also from Chitubox, as is the control circuit board in the printer).

I'm aware that there are upgrades available for both, but I've carried on using the originals for two reasons -- my first results were so good I didn't see any reason to change; and while I'm constantly experimenting with the chair design I didn't want to add a fresh set of variables into the mix. I will try the equipment upgrades when I have got the designs nearer to completion.

The most significant difference seems to be the exposure time per layer -- I'm using 2.2 seconds, you are using 2.5 seconds. That probably doesn't make much difference to the appearance of the chairs, but it might change the dimensions a little, and the fit of the rail, and the fit of the plugs in the sockets. It might also change the required shrinkage allowance:

resin_shrinkage.png


That's one of my fears with plug track -- that some users might report rubbish results because they are not sticking closely enough to the printing conditions I have been using in creating the program.

cheers,

Martin.
 
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This does happen sometimes Steve. Run it again and it will probably work. The most common problem I have is the print separating slightly from the build plate at one end and from time to time I get a curl at one end too but as usually happens the next try works fine. Its not that often something ends up sticking to the FEP and needs scraping off. One thing I have found is that on my machine it doesn't do to put too much on the build plate, the suction can really make one hell of a noise so I do try to keep a wide border to the edges. Its better to be able to repeat successful prints than tearing your hair out trying to find out why it doesn't work. Keep trying, it will come out right.

I must say I use the supplied Photon slicer (V1.3.6) and have never moved on to working with anything else, this seems to work for the few things I print on the printer. Supports I find hard work so if there is something I want to print with a flat base I print directly to the build plate. Recently I have printed about 100 strips of coping stones in 7mm for the club layout, all printed on the base plate. These did curl up a bit as they cured but putting them in boiling water, then straightening them and then putting them back in cold water sorted that all out. I think a lot depends upon the resin, usually on the bottle there are parameters given for the settings that are supposed to be used.

I hope this helps and keep at it, a resin printer is a very useful tool not only for track making!

Ralph
 
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Hi Martin,

The three that were left on the build plate were attached firmly, I had to use the yellow plastic scraper supplied.
Or should I have used the metal bladed scraper supplied?

No, I did not degrease the build plate after removing the plastic protective film, nor did I degrease the FEP plate.
So a recomendation to future owners would be to perform a degrease using IPA before first use?

My build plate has a silvery, sparkly mottled finish, so I would assume it is a sand-blasted one.
I think I will order a second build plate and see if i get a choice.

I think you are right about aiming for consistent reults, so will amend my exposure time to 2.2 seconds.

Another aspect might be ambient temperature, and as I have not yet switched on our central heating I surmise that I was operating at less than the recomended 20 degrees minimum temperature.

I let the build plate drain for 10 minutes, and then swopped it onto the 45 degree plastic holder for a further drain before washing.
This operation is a bit tricky, and I think could be improved by having a catch tray supported on legs that slides betwwen the resin tank and the the build plate to catch any drips whilst this process is performed, rather than let the drips go anywhere else.

As far as curing is concerned what duration are you using?
I can imagine that too long and the result would be brittle chairs that would lead to frustration, too short and they might not be strong enough.

Regards Steve
 
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message ref: 5153
Upon performing a more thorough clean of the FEP plate I noticed when angling the tray about 45° in the reflection of sunlight what appears to be an array of indentations that match the positions of the 100 or so chairs that are on the 5 rafts (20 per raft). Not so much indentations but as though the FEP sheet has been compressed at those points so I suspect that maybe the A4 sheet of paper I used was too thin and this has resulted in too much pressure so I will try a recalibrate.

edit to correct chair & raft numbers
 
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message ref: 5155
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Hi Martin,

The three that were left on the build plate were attached firmly, I had to use the yellow plastic scraper supplied.
Or should I have used the metal bladed scraper supplied?

No, I did not degrease the build plate after removing the plastic protective film, nor did I degrease the FEP plate.
So a recomendation to future owners would be to perform a degrease using IPA before first use?

My build plate has a silvery, sparkly mottled finish, so I would assume it is a sand-blasted one.
I think I will order a second build plate and see if i get a choice.

I think you are right about aiming for consistent reults, so will amend my exposure time to 2.2 seconds.

Another aspect might be ambient temperature, and as I have not yet switched on our central heating I surmise that I was operating at less than the recomended 20 degrees minimum temperature.

I let the build plate drain for 10 minutes, and then swopped it onto the 45 degree plastic holder for a further drain before washing.
This operation is a bit tricky, and I think could be improved by having a catch tray supported on legs that slides betwwen the resin tank and the the build plate to catch any drips whilst this process is performed, rather than let the drips go anywhere else.

As far as curing is concerned what duration are you using?
I can imagine that too long and the result would be brittle chairs that would lead to frustration, too short and they might not be strong enough.

Regards Steve
@Steve_Cornford

Hi Steve,

I haven't used either of the supplied scrapers. But that's just me. They are useful additions to my toolbox, but for both the FDM and resin printers I'm using a cheapo window scraper from the pound shop:

window_scraper.jpg


It's just a Stanley knife blade in a holder, but therefore much sharper and thinner than the supplied scrapers. It also has a clip-on plastic blade cover/scraper which has a sharper edge than the supplied plastic scraper.

(It's also a very useful tool for general modelling, cutting and chopping.)

Ralph says sometimes these things just happen. Well maybe, but I think there has to be reason. For the rafts to detach from the build plate they can't have been properly stuck to it when formed. Some possibilities crossing my mind:

1. Tank not properly located in position. There is a slight recess to contain it, but it's quite easy to knock it out of position while tightening the clamp screws. Don't ask! The noises you heard might have been the build plate catching on the tank?

2. FEP film uneven and not stretched tight enough across the base of the tank. It should "twang" when tapped.

3. Build plate not flat. Have you tried a straight-edge against it?

4. If both missing rafts were at one end, build plate not properly levelled, or it moved after levelling. Have you tested the level again after printing?

5. Z-zero not set low enough. When levelling I have the plate tight against 4 small pieces of 80gsm office paper, one under each corner, such that they can be dragged out, but only with some force. After tightening the levelling screws (gradually from one to the other and back, in the order recommended in the instructions), I lift the head and return it to Z-zero to check that the papers are still tight.

6. Contamination on build plate. Before use I always degrease it in the IPA to remove any grease or fingerprints, and blow it dry with an air blaster (or hair dryer). I've had one of these for years, and it's come in very handy recently. It blows quite warm after a while (motor cooling). Unlike hair dryers it has an input filter for clean air:

https://www.amazon.co.uk/Dusters-EG-1000-UK-Electric-Air-Duster/dp/B073F9NY1X

A less expensive option would be aerosol air dusters.

7. Resin not uniformly mixed. My resin is definitely streaky when not well shaken. That may be because it is well past the labelled shelf life (but seems to work fine).

8. Air bubbles trapped in resin. The printing seems to go better if the tank is well-filled. Leaving it to settle after pouring is probably a good idea.

9. Something else. :)

cheers,

Martin.
 
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message ref: 5156
Another aspect might be ambient temperature, and as I have not yet switched on our central heating I surmise that I was operating at less than the recomended 20 degrees minimum temperature.

I let the build plate drain for 10 minutes, and then swopped it onto the 45 degree plastic holder for a further drain before washing.
This operation is a bit tricky, and I think could be improved by having a catch tray supported on legs that slides betwwen the resin tank and the the build plate to catch any drips whilst this process is performed, rather than let the drips go anywhere else.

As far as curing is concerned what duration are you using?
I can imagine that too long and the result would be brittle chairs that would lead to frustration, too short and they might not be strong enough.
@Steve_Cornford

Hi Steve,

I don't know about temperature, but it would have been the same for all the rafts, so can't explain why some stuck to the plate and others didn't. I did do some printing one very warm evening back in the summer when the temperature was over 30 degrees, and there was no obvious difference in the results.

The 45-angled drip holder is a very awkward thing to use and needs a tin lid under it to catch the drips while you are positioning it. Lately I haven't bothered with it and just leave the print to drip normally for longer after the printing finishes. This has the advantage that you can leave the red cover on undisturbed while it is dripping, so no risk of stray UV on the surplus resin before it gets quickly dunked in the first wash.

For curing I couldn't find any time recommendations. I have been using 4 minutes for the 4mm scale chairs, which the machine divides into two lots of 2 minutes in each direction. The time would obviously depend on the bulkiness of the model, if UV needs to penetrate a long way through the translucent resin to reach the core. It also means that any model is always going to be more fully cured on the surface than at the core.

In 4mm scale the chairs are quite tiny in comparison with the typical models the Mercury is designed for. I place a ring of 5 upturned fish-paste jars on the turntable and put the rafts on top of them. This lifts the rafts more centrally into the beam of UV light and allows it to reach the underside of the rafts through the glass. Sainsbury's Salmon & Haddock for preference. :)

I don't think it's possible to overdo the curing unless you left it on for hours. The chairs will continue to harden in ordinary daylight until they get painted, so leaving them in the machine longer simply accelerates that process by a day or two.

With the "ABS-like" resin I haven't yet found any evidence of chairs getting too brittle, even after several months. The situation might be different with the standard resin or other makes of resin.

The most infuriating thing about the Mercury unit is that at switch-on it defaults to UV curing. It would be very easy to accidentally start curing the unwashed parts and begin hardening the surplus resin. It's blindingly obvious that it should default to washing mode at switch on. As it is you have to be very sure that you have switched to washing mode before pressing Go. Also it's annoying that it won't wash without the yellow lid on, which prevents you assisting the washer by swishing about in the tub with a brush.

cheers,

Martin.
 
_______________
message ref: 5157
Upon performing a more thorough clean of the FEP plate I noticed when angling the tray about 45° in the reflection of sunlight what appears to be an array of indentations that match the positions of the 100 or so chairs that are on the 5 rafts (20 per raft). Not so much indentations but as though the FEP sheet has been compressed at those points so I suspect that maybe the A4 sheet of paper I used was too thin and this has resulted in too much pressure so I will try a recalibrate.

edit to correct chair & raft numbers
@Steve_Cornford

Hi Steve,

I also have such impressions on the FEP film after every print. I think it is a normal part of the process.

It's not possible for it to be caused by too much pressure, because the chairs are quite soft before they are cured. Under pressure they would simply flatten. Recalibrating the zero setting won't make any difference, because by the time the chairs are being formed the build plate is about 5mm above the zero position.

There were some spare FEP films in the the box. I haven't used any of them yet, but clearly the FEP is regarded as a disposable item and presumably this accumulation of marks causes it to become life-expired.

p.s.If you get a 100% print and print again in the same resin, you don't actually get to see the marks or worry about them :)

cheers,

Martin.
 
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message ref: 5158
@Steve_Cornford

Hi Steve,

A further thought crossing my mind is that I think you said you were reducing the width of the chair plugs? And I said that I wasn't too happy about that?

The reason is that it increases the area of chair base each side of the plug, which is flat on the underside.

It's very difficult to print anything with a large horizontal under surface. The first layer of which will be printed as a delicate wafer only 0.05mm thick (2 thou). This has to be pulled away from the FEP film by whatever it is attached to below it in the model. If that is a small area in relation to the area of the wafer, there is a chance that the wafer will break from it and remain stuck to the FEP film. Once that has happened the print can't complete properly. The stuck wafer will receive more and more UV exposure and get quite hard and firmly stuck.

This is the reason many models are printed at an angle raised on supports, so that there are no horizontal under-surfaces.

Tipping the chairs at an angle wouldn't work because it would create a reverse under-surface on one side.

In the chair designs I have allowed for all this with angled bottom faces on the plugs, but I can't do that on the chair base, otherwise it wouldn't sit flush to the timber surface. That's why the chair base overlaps the plug by only 1 inch scale all round, and in the larger scales that may need reducing further.

chair_base_overlap.png


There is also a small horizontal area on the bottom of the chair keys. So far that seems to be working ok (and even that is not prototypical), but again in the larger scales the keys may need to be angled down on the bottom surface (in the opposite direction from the prototype).

I don't know if any of this explains your noises or the marks on the FEP film, but it is worth bearing in mind. Obviously it can't explain why some rafts behaved differently from others.

cheers,

Martin.
 
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message ref: 5159
Hi Martin,
My first print was for S1 chairs all with the default dimensions.

The good news is that last night I had another session having thoroughly cleaned the FEP and the build plate, and without changing any other settings (eg exposure time) the 5 rafts of S1 chairs worked perfectly!

After that I produced some other prints, each time cleaning the build plate thoroughly (but did not clean the FEP as I had left the resin in the tank.
All prints were successful. 4mm S1 rafts, EM P1 slide chair rafts,EM LH B switch rafts.

I then produced a new .STL containing S1 chairs with plug width reduced by 0.3mm (to achieve plug width of 1.7mm) so that I could experiment with my out-sourced laser cut timbers and trackbed, also an .STL of same but locator plugs.
Then a print contaning 1 locator raft and 4 S1 rafts printed without problems, but I will need to inspect them closely to ensure that all is well with the chair bases.

My initial conclusion is that it was my mistake in NOT thoroughly cleaning the build plate after removing the protective film, and also not cleaning the top surface of the FEP (it did not have any protective film, only the bottom surface had one)
Once I had cleaned the top surface of the FEP, the IPA did not "wet" the surface, but was inclined to run away, indicating a fairly clean surface to me.

Anyway it feels good to have achieved some successful prints so thank you all for all your help and suggestions

Steve
 
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message ref: 5160
@Steve_Cornford

Hi Steve,

Great! Glad you have now made a good start. :)

If you get good results with the narrower plugs (pics?) I might look at doing the same with some of the smaller chairs, for improved angular alignment in the sockets.

cheers,

Martin.
 
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message ref: 5161
Hi Martin, pics as promised.
4mm S1 chairs plug width -0.3

When I came to use them in the plywood timbers (example of which I have previously sent you) they were in fact too loose@
So I then tried some 4mm S1 default chairs and they were fine.
Steve
 

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message ref: 5165
Hi Martin, pics as promised.
4mm S1 chairs plug width -0.3

When I came to use them in the plywood timbers (example of which I have previously sent you) they were in fact too loose@
So I then tried some 4mm S1 default chairs and they were fine.
@Steve_Cornford

Hi Steve,

Thanks for posting the pics.

Something strange there. Several months ago I tried my default S1 chairs in your plywood timbers and they wouldn't fit. Just to be sure I wasn't dreaming I have just tried them again and they still don't fit.

As best I can measure, your sockets are 1.85mm wide (code75 bullhead rail is 1.9mm high, and it doesn't fit through).

The chair plugs are 2.0mm wide immediately below the chair base, so it's not surprising they don't fit. They can be forced into the sockets, but that causes the sleepers to swell from 3.3mm wide to 3.5mm wide.

If the sockets were intended to be 1.7mm wide, it seems your laser-cutter is cutting oversize. This is evident in the sockets looking a fraction too long in the other direction. There is a cutter kerf correction available in Templot, it would seem that you may need to increase it.

This is how it is intended to look immediately below the chair base:

plug_bash_fit.png


The plug dimensions (pink+red) are taken directly from the prototype at 1" inside the chair base all round, so the plug is 6" x 12.5" (2.0mm x 4.17mm in 4mm/ft scale).

The socket dimension (green) are then set so that there is an easy fit or small clearance at the sides of the plug, and an interference overlap (red) at each end of the plug to create a bash fit. In the FDM bases this causes the plastic to be deformed sideways into the green clearance spaces, creating a firm interference fit and an accurate track gauge. In the CNC milled bases, the MDF material compresses to produce the same result. The idea of a bash fit is that it is more tolerant of variations in socket size (caused by the fixed printer resolution) than a traditional engineering press-fit.

I'm not too sure how this would work best in plywood bases, and without my own precision laser-cutter to conduct experiments it is difficult to find out. I imagine the red overlap might need to be increased to achieve a firm fit, by reducing the socket length. Alternatively you might need to abandon the idea of a press-fit and glue the chairs in place.

How well does the rail fit in your chairs? I'm interested to know if the 2.5 seconds exposure makes any difference.

cheers,

Martin.
 
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message ref: 5166
Hi Martin,
You are correct of course, as I made a slight mistake.
I believe I sent you 2 sheets containing a couple of Left Hand B7 OO-SF turnouts and a couple of sections of plain track.
One piece of plywood was 3.2mm thick and only had sockets plus timber labels, the other was 1.6mm thick with both timbers, sockets and timber labels (or in the case of plain track sleepers).
The laser cutting service also supplied me with another piece of 1.6mm plywwod where they had "bunched" a quantity of plain sleepers to show me that by "bunching" the quantity of laser cuts and therefore length of laser cutting overall was reduced, and this dramatically reduces the cost as it is priced mainly by the sum of the lengths of cut.

The two pieces I sent you had been cut from templates exported with -ve adjustment to socket width (from memory -0.25), which when compounded with their quoted kerf of 0.2mm. Based on the theory that their system needed a line drawn in the middle of the kerf, I halved the kerf giving 0.1, but then as there are two kerfs involved in a socket doubled this to give me 0.2mm again. All this theoretically gave me a socket size of 2.0 - 2*0.25 + 0.2 = 1.7mm.
I believe this pre-dated the enhancement to Templot 2D/3D export that added kerf parameters for lasers.

When I went to try out the locators and S1 chairs I made the mistake of using some sleepers from the "bunched" sheet of ply!
Now that you have pointed out your results, I have gone back to basics.

First I measured the height of the nickel silver bullhead rail (obtained from Scalefour stores some 4 or 5 years ago) with a pair of digital calipers and a micrometer screw gauge. This appears to be 1.94/1.95mm.
This rail did not fit in my copies of the sheets I sent you, however it did fit through the sockets of the sleepers from the "bunched" sheet.
These were the sleepers that I used when I used the -0.3mm locator plugs to stick them with gorilla wood glue to the 3.2mm sheet of ply (intended to simulate a laser-cut sockets only sheet of cork underlay).
Having remove the -0.3mm locator plugs I found that the -0.3mm S1 chairs were loose, so then tried the "default" S1 chairs which were a bash fit. Perhaps aided by the fact that the sleepers were glued down.
I measured the width of the -0.3mm locator plus and they appear to be 1.74mm.

I have now gone back to the drawing board and printed a set of S1 chairs and Locator plugs with default settings, and measured the locator plugs before and after curing as being in the range 2.05mm to 2.07mm.
However in doing this I did have to revert the Chitubox software to v1.8.1, as the Mars 2 Pro could not recognice the .ctb file produced by v1.9.4. I tried producing the v1.9.4 file several times but it would not recognise it, despite the day before recognising 1 file produced by v1.9.4. Having convinced myself that it was not something I was doing wrong in the saving or copying process, I googled & found that it was a known problem that either meant upgrading the firmware in the Mars 2 Pro or reverting to v1.8.1, which I did (as it seemd the safer option).

I am still using the default of 2.5 seconds exposure.
(I note that Elegoo seem to recomend 8 seconds for the ABS like grey resin)
I am now in the process of printing another set of S1 chairs and locator plugs, and will then measure these to see if i get any consistancy.

I am thinking that locator plugs are easier to measure than chairs.
I suppose it is the equivalent to etching a 10cm scale
with 1mm increments on an etch design, or for that matter the calibration lines that Templot prints for ensuring our templates are printed to the right size.

Picture of "bunched" sleeper sheet to follow, the design of which was performed by the laser cutting service.

Steve

edited for typos






.
 
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