The Irish Railways 3d printing thread

[leslie10646]

On 4/7/2026 at 12:44 PM, Mayner said:

 In a way some 3D prints are not unlike some of the more 'challenging/ropey loco and stock kits produced in the past by MTK, El Crappo & Jindenco/Falcon brass. Interestingly some resin manufacturers now produce 'machinable' 3D print resins.  Like the kits of the past modifications to fit the chassis, could be down to design or material or to keep the customer occupied.

A modeller who largely pioneered 3D printing for model railway use in New Zealand has transmissions parts (gears and flywheels) and gear boxes 3D printed in aluminium from his own CAD work and I have had lost wax brass castings produced from my 3D CAD work (brass details castings JMD 52 Class /D17 (buffers, raised firebox step ring etc).

I was lucky/spoiled in that the Auckland 3D print shop that produced the prototypes for the JM Design CIE Goods Brake in 2020-1 produced consistent high quality prints in a suitable resin, down side was printing 'small scale models" was more bother than it was worth! 

Eventually selected a Chinese print shop that consistently produced high quality prints using a similar resin,  after trialling print shops in New Zealand, Singapore and China main issue was original Auckland and current Chinese supplier used a suitable resin (stable and not too brittle!)

Protototype and production models printed with separate roof body and (rigid) chassis (detaiul added in production version) no sign of warping/distortion after 5 years. 

One piece Chinese printed wagon chassis. (this was a spare/reject on of the brake levers broke most likely during clean up stage)

 

Having had a few of @Mayner's kits through my hands, I can testify to the excellence of his Chinese "printer".

[Maitland]

Not exactly achieved perfection so far. Suspended until I get a whole load more IPA and wife is out (she doesn't like the smell - of the resin, I mean). This was done with the Mono 4, standard resin and settings as Photon Workshop default (the biggest lump of loco body printed so far), then with thinner layers (0.03 v 0.05) and bigger support contact areas for the rest. It didn't seem to make much difference. In both cases I ended up with a lot of resin stuck to the FEP film.

One problem seems to be that the print eventually peels away from the build plate. Levelling? I wonder if tightening the levelling screws - necessarily done with one hand holding the plate down - is moving the plate slightly. Perhaps a spring in there somewhere would help. Some sites recommend slightly roughening the surface with fine emery paper. I've got a small sheet of glass somewhere to ensure it stays flat. Also I'll try PTFE spray on the FEP film to encourage it to let go.

Room temperature hovers around 20 at the moment (this is the cool side of the house) but it won't stay that way, and I can't wait for a heatwave every couple of year. It was probably about the same yesterday when I did the prints.

The detail achieved isn't phenomenal - the rivet detail on the tank scarcely shows up against the build striations and the ironwork on the van is missing in places. On the upside, the strength of the product is alright. Throwing it across the room didn't break it.

[Rob R]

Hmm....

I don't know your machine but for the van I would increase the initial layer exposure time, making sure the build plate is extra clean.

My build plate is quite rough (but level) now after 3 years or so of use. You can also tweak the retraction speeds and acceleration, slow them down a bit.

 

For the loco, try putting it at an angle (front at about 25 degrees up for starters). The photo doesn't show the layering 'cos it's a bit dark but a vertical face like the tank sides shouldn't really show any layering at all.

Are they medium supports on the loco?

If they are try adding some heavy supports to keep it in place.

I have not tried using a ptfe spray so I can offer no help there.

I am also (usually) using a Transclucent water washable resin which is runnier than the grey stuff and not far off the 16k resin which is almost like water, to me the various standard grey resins all seem a bit gloopy.

I suspect the "grey" is just an inert filler - slate dust?

Keep plodding on.

Try printing some of the standard Test Pieces to fine tune the settings a bit, small changes can make a big difference.

Rob

 

[Rob R]

This is how I have supported the 4mm version of the MGWR 7t van for printing on my Elegoo Mars 2pro and hopefully the supported .stl is attached as well.

 

4 MGWR 7 ton van body V0.5 supported.stl

[Flying Snail]

1 hour ago, Maitland said:

On the upside, the strength of the product is alright. Throwing it across the room didn't break it.

Rigorous, scientific method - I like it . I hope that it wasn't the result of frustration with the trouble you encountered. Hopefully you'll be able to work it out with the help of Rob and others here  

[Rob R]

Don't rely on the "auto generated "supports being right.

For the world of fantasy miniatures they work great. 

For model railways, full of straight lines, right angles and smooth flat surfaces they are a starting guide at best.

Off to play with the Sligo tank now. I was resisting but..........

[Maitland]

Hang on a mo, I'll post the latest stls on Github.

You can see the striations better in this photo. Both horizontal and vertical.

[Maitland]

About supports: I'm pretty sure Photon Workshop uses AI to create the supports. For a start, it supports things like individual rivets, but nothing like consistently, , and it doesn't do it on both sides of a mirrored design. It puts in little support branches that, like the Leek and Manifold, start nowhere and end at t'same place. But I haven't a clue yet where to put them manually, so I've got to start somewhere. I might try a downgrade to Photon Workshop- it's possible the latest release is a bit experimental.

As for accelerations etc, I haven't found them in any setup yet.

[Rob R]

Don't worry about the vertical lines, I suspect they will vanish under the first coat of paint.

Too late on the latest version of the Sligo tank, it's now printing but it is only 21p worth of resin.......

3dp can be incredibly frustrating but eventually the stars will align and you will be grinning like a Cheshire Cat.

 

Wash that van print and squirt some primer on it, it is surprising what vanishes and what shows up..

 

Edited yesterday at 10:51 by Rob R

[Rob R]

Supports.

Think of resin printing more akin to growing crystals (copper sulphate in O level chemistry?).

You need somewhere to start growing it from but that some where has to be strong enough to resist all the peeling and suction forces.

I usually use a good curtain of medium supports, sometimes with the odd heavy or 2 to beef it up and light supports for the delicate details, bridges etc.

As you can see, things the size of rivets are not supported.

There are some really good youtubes on supports, explaining it much better that I can and from first principles. Have a browse.

R

ps.The file in the screenshot 119% bigger than yours....

Edited yesterday at 10:59 by Rob R

[Maitland]

Latest files posted anyway. I've taken the fittings off the boiler, and made them separate, so they won't need a pile of supports to cut off. I think the boiler might be best printed vertical, arse end first. I think I've been a bit too clever with the boiler fittings though. I made a little recess in the boiler and thickened the fitting to fit it, but show a little of the rim. The idea is to avoid very thin surfaces with supports just where they meet the boiler. It worked for the chimney and the dome, but I think I'll change it to make the bottom of the recess flat

 

[Rob R]

Thanks for posting the latest files.

I'll have a play later.

R

[Rob R]

33 minutes ago, Maitland said:

About supports: I'm pretty sure Photon Workshop uses AI to create the supports. For a start, it supports things like individual rivets, but nothing like consistently, , and it doesn't do it on both sides of a mirrored design. It puts in little support branches that, like the Leek and Manifold, start nowhere and end at t'same place. But I haven't a clue yet where to put them manually, so I've got to start somewhere. I might try a downgrade to Photon Workshop- it's possible the latest release is a bit experimental.

As for accelerations etc, I haven't found them in any setup yet.

My bad.

Accelerations are on the FDM set up....

Lift and retract speeds are the beasties. Usually found in the Resin set up page of your chosen slicer. Also not all slicers are equal.

The slower they are, the lower the forces on the print. Downside is increase print time. A fine balance.

[Rob R]

Just drippng...

[Rob R]

A quick squirt of primer.

There is a crease in both sides where the cross sectional area changes at the start of the tank inner. Printing at an angle should sort that but may introduce other issues. 

The rivets are superb.

Thank you Maitland

 

 

 

Edited yesterday at 14:15 by Rob R

[Maitland]

At least I know what I'm aiming for. I'll thicken that whole side up. Sacrifices some of where I thought electronics might go though.

[Rob R]

Don't thicken it.

Put a chamfer on the bottom of the inner tank (inside the tank) so there isn't a sudden change in CSA.

 

[Darren.d]

I'm trying to replicate a 70s hornby wagon for 0 gauge.cant get the roof right at all.has anyone any suggestions?

[commerlad]

24 minutes ago, Darren.d said:

I'm trying to replicate a 70s hornby wagon for 0 gauge.cant get the roof right at all.has anyone any suggestions?

 

Dont print it, Use a cut open Beer Can for material instead. 

Just because you can 3D Print something it does not mean you have to.

[Darren.d]

Cheers for that. Will give that a try

[Mol_PMB]

1 hour ago, commerlad said:

Dont print it, Use a cut open Beer Can for material instead. 

Just because you can 3D Print something it does not mean you have to.

You’re absolutely right, it’s easy to get blinkered by the tools and materials in front of you.

On the other side of the coin I’ve just spent about 3 hours fighting with etched sheet metal to make some roof tanks that might have been better 3D printed!

 

[Rob R]

I suggest that an empty beer can is best...........

Paul,

A nice little 3d CAD starter project for you?

[Maitland]

Looks to me like the Hornby van has a single radius arc, but your van seems to have a multi- centre or elliptical end. 

You might have to empty several beer cans to make sure you get one that's properly emptied. Real ale or cheap Rioja man myself....

Oh and by the way I worked out why the ironwork was missing on the van. It's a long story, but essentially I used the wrong stl that didn't have it on. Version control?

[Rob R]

5 minutes ago, Maitland said:

 

Oh and by the way I worked out why the ironwork was missing on the van. It's a long story, but essentially I used the wrong stl that didn't have it on. Version control?

Been there, done that, still doing it......

[Mol_PMB]

6 minutes ago, Maitland said:

Looks to me like the Hornby van has a single radius arc, but your van seems to have a multi- centre or elliptical end. 

You might have to empty several beer cans to make sure you get one that's properly emptied. Real ale or cheap Rioja man myself....

Oh and by the way I worked out why the ironwork was missing on the van. It's a long story, but essentially I used the wrong stl that didn't have it on. Version control?

If you empty enough beer cans any shape of roof would look OK!