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  • 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 Some of the earlier pages of this topic are now out-of-date.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 post.   For some practical modelling aspects of using Plug Track see The Book of Plug 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.

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

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Manchester
You can flatten resin printed bases by putting them into a cup of very hot water, flattening them and then putting them in a cup of cold water to fix. I printed a few bases on my resin Anycubic Photon using Anycubic standard grey resin directly on the baseplate without any curl but I have used this flattening method with other things I have printed.

The quality of the Mars shines through with those photos, my Anycubic is nowhere near as sharp as those images.

Ralph
 
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Martin Wynne

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Enjoy using Templot?
Thanks.

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
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Any recommendations on an FDM printer? I've been looking at the Anycubic Kobra Max, which has a 400 x 400mm print area, seems ideal for timbering bases.
@Nick Allport

Hi Nick,

Congratulations on your hi-res photo of the chairs. I find it extremely difficult to photograph the translucent material and capture detail, but you have managed for the first time to show the random rotations on the square screw heads in 4mm/ft scale:

nick_chairs_photo.jpg


Many thanks for posting that. :)

The rail seats do look rather angular, but they get mostly hidden under the rail, and a good scoosh of paint will fill the corners to replicate the fillet radii on the prototype castings. The paint is needed to protect them from long-term UV exposure which may cause them to become brittle. This might be another reason to prefer the ABS-Like resin, although no-one has been doing this stuff for long enough to know for sure. Yes, that resin uses the same print settings as the standard resin (as far as I know).

Regarding FDM printers, it is a constantly moving feast of new printers as the various manufacturers try to leap-frog over each other. I can't make a recommendation because I can't possibly buy them all to try! In any event all the latest printers appear to be currently out-of-stock in the UK after the recent Black Friday frenzy, and are quoting deliveries into February.

But a few of the relevant points which we have been discussing here.

1. For a timbering brick we must be able to create a flat print of constant thickness all over. Which is not a typical use for these printers, so doesn't feature much in the specs. It relates to the levelling of the build plate.

Some printers claim to be "auto-levelling", but are no such thing -- nothing gets changed. All that happens is that the Z height of the nozzle is adjusted while printing the first layers to compensate for any variations in the surface of the build plate. Which itself tends to be a flexible tin sheet with nothing to hold it dead flat. This "auto-levelling" ensures that the first layer adheres properly to the build plate, but does nothing to ensure the dimensional accuracy of the finished part over a wide area.

For the test timbering bricks I have been using a rigid glass build plate with manual screw levelling at the corners (on Neptune 2S). By this means I have managed to produce timbering bricks which are a constant thickness within about +/-0.025mm (+/- 1 thou) all over, and repeatable.

It seems that Elegoo have recognised the need for manual levelling by re-introducing it as an option on their latest Neptune 3 Plus and Neptune 3 Max printers, having removed it on the previous Neptune 3 and Neptune 3 Pro printers. They call it "Auxiliary Levelling":

"Auto Bed Leveling + Auxiliary Leveling: The non-contact high precision sensor automatically scans 63 points of the hotbed to compensate for any unevenness and inconsistencies of the printing platform. You can also use the hand-twist knobs under the build platform for auxiliary leveling to achieve a nice first layer."

I can't find whether other manufacturers are or will be doing the same, but if not that would be a definite vote for the Neptune 3 Plus and Neptune 3 Max printers from me. On a printer without screw adjustments it's possible to level a rigid build plate by using card packing under the corner clips, but a screw adjuster is much easier to use and repeatable.

2. Z-precision. For accurate Z thickness dimensions it needs a twin Z-screw. The Neptune 2S has only a single Z-screw and I have had to modify it to be sure of getting consistent results.

3. Extruder. The Neptune 2S has a bowden-tube extruder, unlike my older BIBO printer which has a direct-drive extruder. I was expecting that the bowden tube might cause problems with stringing from the nozzle, but I have found that by using an aggressive retraction setting it produces results just as good as the BIBO. The snag is that this stresses the bowden tube end fittings, and I have already had to replace one of them. I wondered why there were 2 spares included with the printer!

So I would definitely go for a direct-drive extruder if possible. Again this is a change for the Neptune 3 range from the Neptune 2S. In theory the heavier direct-drive extruder head means a slower printer, but it's hardly relevant when printing precise parts. It might make a difference if printing large chunky parts as fast as possible. FDM printing is slow regardless, but runs unattended for hours while you get on with some modelling.

4. Build plate area. The bigger the better, but it does increase the cost! The larger printers are also taller, which might be a nuisance and you may not have any use for the increased model height in 4mm/ft scale.

cheers,

Martin.
 
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AndyB

Member
Hi Martin,

Yes, direct-drive extruder, dual Z-drive steppers and a thick, heated, glass plate. The leveling on mine had four screws, one at each corner which is daft when you are using plate glass. A three-point attachment is much better (I did modify mine.)

And if the Z-limit uses a lever-arm microswitch, remove the arm and arrange for the motion to hit the button on the switch. That improves repeatability quite a bit.

Cheers,
Andy
 
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Nick Allport

Member
Location
Portugal
You're right there don't seem to be any Elegoo Neptune printers on Amazon anywhere at the moment. I've been trawling through reviews overnight and the Creality Ender 3 seems to tick a lot of boxes. And I have an Amazon voucher from my Dad for Christmas that would cover more than half of the current price :).

However I'd like to persevere with the resin printer a little bit more with timbering. Is there an stl of an S4 plug sleeper on it's own? I'd like to try printing it at 25 degrees with supports and seeing if that then stays straight.

Cheers, Nick
 
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Martin Wynne

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Enjoy using Templot?
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Please do not send requests for help direct to me via email.

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However I'd like to persevere with the resin printer a little bit more with timbering. Is there an stl of an S4 plug sleeper on it's own? I'd like to try printing it at 25 degrees with supports and seeing if that then stays straight.
@Nick Allport

Hi Nick,

It's only a few clicks to create whatever you want in Templot.

Here are a couple of STLs for single sleepers in S4/P4. One solid, one with sockets under the chairs. I have done the Formware mesh fix on them ready to print.

These are both 3.24mm thick (to contain chair plugs). If intending to use them with integral chairs, you could obviously make them thinner.

With sockets, you would normally want to add the side flanges to stiffen the sides of the timber.

Or did you want a short section of timbering base? Everything is optional, you just need to decide what you want to do.

s4_sleeper1.png


s4_sleeper2.png


cheers,

Martin.
 

Attachments

  • s4_sleeper_solid_fixed.stl
    1.3 MB · Views: 9
  • s4_sleeper_sockets_fixed.stl
    1.5 MB · Views: 8
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Martin Wynne

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@Nick Allport

Hi Nick,

Here is a short timbering brick:

s4_short_brick.png


n.b. these files have been exported as the 3D for CAD option, i.e. no shrinkage allowance included. To get your chairs to fit, and to get the track gauge exactly to S4/P4, you will probably need to make a scaling allowance in the Chitubox slicer.

cheers,

Martin.
 

Attachments

  • s4_short_brick_fixed.stl
    1.2 MB · Views: 7
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Martin Wynne

Admin
Thread starter
Location
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Info
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Enjoy using Templot?
Thanks.

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
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You're right there don't seem to be any Elegoo Neptune printers on Amazon anywhere at the moment.
@Nick Allport

Hi Nick,

Amazon seems to remove items which aren't available for immediate delivery, and suddenly re-instate them when they are. This makes it difficult to browse and compare the different designs when you are just looking for what's on the market.

This Austrian supplier allows you to order in advance, and has some Neptune printers listed. They are saying the Neptune 3 Pro will be available in a couple of weeks:

https://www.3djake.uk/elegoo/neptune-3-pro

Portuguese site: https://www.3djake.pt/elegoo/neptune-3-pro

On past experience, the printers will reappear on Amazon UK on exactly the same day they are shown as back in stock on the above site (I don't know about Portugal).

This will presumably be new stock from China, and it's possible the next batch of Pro printers will have sprouted "Auxiliary Levelling Screws" to match the Plus and Max versions. If not, it would need card packing for levelling (if you get a rigid glass build plate for it).

(The Ender 3 printer has a single Z-screw and is not a direct drive extruder -- but less expensive of course.)

cheers,

Martin.
 
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Nick Allport

Member
Location
Portugal
Thanks Martin. I'll hold out for the Neptune 3 Pro then. Doing a bit of workshop remodelling to make room for this stuff at the moment. Then I'll be back in action and can try the timbering bases again in resin.

Thanks, Nick
 
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Martin Wynne

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.
I'll just leave this link here:


Martin.
 
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Martin Wynne

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And it's available for less than $40,000!
Think I wll be spray painting the plug track prints for a while longer!

$40,000 today, $400 tomorrow. But what price the ink?

And does it need spraying to protect from UV? Oh, hang on ...

Martin.
 
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Nick Allport

Member
Location
Portugal
So I've had a few days reorganising my office/workshop so I can have a dedicated 3D printing area (I hadn't appreciated the height needed for the Saturn 2, especially when you need height to lift the lid off - I had to remove a shelf). Anyway I'm back up and running now.

Previously I had printed some of the bases with the integral chairs flat on the build plate, but they haven't stayed flat.

Yesterday I printed the short timbering brick with slots that Martin attached above, but at 25 degrees and on supports. I cured that for 1 minute and it's remained flat, and the base is quite flexible still (this is still with Standard Grey resin).

Adding a rail to it and clipping the chairs in is so satisfying (although I broke one of the loose jaws in my haste). But it's remained flat and looks really nice!

IMG_20230113_082016279.jpg


IMG_20230113_082000545.jpg


I'm still staggered by the quality!

What glue do you use to stick these bases down?

I'm pretty much decided that I'll order a Neptune 3 when they come back into stock at Amazon ES so that I have all the options, but at the very least I'm certain now that this is definitely the way forward with track-building.

Cheers, Nick
 
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Martin Wynne

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What glue do you use to stick these bases down?
@Nick Allport

Hi Nick,

Looking good!

We still need to experiment with different adhesives.

But you might decide not to glue them down. With the deep timbers it's possible to drill through the webs and pin or screw the bases to the trackbed instead. This avoids the issues of having to get the alignment dead right first time, weighting the track down, and waiting for the glue to set.

If you drill the screw holes a little oversize, you will have a bit of wiggle room to tweak the bases into perfect alignment. Or if it's too far out you could re-drill and have another go. It all gets lost under the ballast.

Then at a later date if you decide on a re-design you can lift the track easily, dismantle it and re-use it. Just don't put the screws directly under the rails!

The brick connector clips have a 1mm hole in them. If you print the corresponding target marks on the paper templates, you can use 1mm veneer pins to align the bases to the templates.

cheers,

Martin.
 
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I just use Gorilla wood glue to stick the resin bases down. So far no problems.
I print the bases flat on the build plate of the Mars 2 Pro, but I do reduce the web thickness to 0.5mm, seems to work for me, but Mars 2 Pro has a smaller build plate than he Saturn I think.
Steve
 
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Martin Wynne

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.
I regret to announce yet another tickbox:

loose_check_option.png


I said previously that loose jaws would be the only option for the check rails. I have changed my mind on that -- you can now select either or both or neither of the jaws to be loose on check rail chairs.

loose_check_option1.png


cheers,

Martin.
 
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Martin Wynne

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.
When I did the 2-part switch block chairs I mentioned that I wasn't entirely happy with them and might return to them at a later date. At that time it was before I discovered that the loose jaws option was entirely feasible, and even preferable in some cases. With solid jaws the chairs need to be bash-fitted with the rail in place. Which made it necessary to split the block chairs into 2 parts, each to be fitted separately.

This is the result, the current export from Templot (with the chair bases and rail seats omitted for clarity):


two_part_heel_chairs.png


pink = inner gauging jaws
blue = outer jaws
dark brown = keys
green = plugs
white = sockets

As you can see there are several places where the design is wrong, and differs from the REA drawings. At 1 the rib is not central between the chair screws. At 2 and 3 the middle jaws do not align properly.

This all seemed acceptable, if undesirable, and unlikely to be very evident in 4mm scale. But it is evident in 7mm and larger scales. With the chairs split in 2 parts it was difficult to do much about it.

But now with the loose outer jaws option there is no need to split the chairs into 2 parts. They can be one-piece chairs (as the check rail chairs). Even the unkeyed support jaw at A can be loose (although it doesn't really need to be), if the plug is in one piece.

So I have decided to revisit these chairs and redesign them as one-piece chairs with loose jaws. One step forward, two steps back -- which is frustrating, but I would rather do it now than get the crossing chairs done and still have the full design unfinished.

For those who don't like the loose jaws, the chairs can be printed all-solid. But in that case it will be necessary to slide the switch rail into the chairs after fitting them. Which might be tricky in some situations, such as within slips.

I'm writing this now, partly to explain the delay in progress. But mainly as advance warning that this design will change in the next program update -- if you have printed switch chairs or bases from the current version, you need to have printed sufficient matching chairs or bases, or at least exported the files for them, before updating.

cheers,

Martin.
 
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