Rob R

Not clever. Just another one of the Dark Arts.....

David, This probably belongs on the other 3d thread but here will do. Once you have drawn the CAD and saved it, usually as an .stl file but others are available, you have to run it through a "slicer" program. This does what it says on the tin and slices your .stl into the individual layers and writes that in G -code, a fairly universal machine control code, so that the printer knows what to do and where. This is the same for resin printing as well as FDM . It is the Slicer that lets us, the human bit, have control of the process. You can set (or tweek the pre-set) the thousand and one parameters that can make or break the final print, speed, temperature, line width etc and part of that is the generation of supports, either auto or manual. Why do we need supports? You can't print in thin air so any overhangs, etc will need a sacrificial support structure printing as part of the process. Pictured below is a screen shot of the sliced file for the 7mm MGWR open that is printing right now. The green is the support, here mostly for the projecting ironwork, the S scale version doesn't need as many supports. All good fun.

After 12 hours you end up with a square lump. and after removing the supports (a bit like shelling a prawn) we have a 7mm 7 ton van. This was done at 0.08mm layer, anything finer would have taken far to long.

Probably not. A lot of the CAD is "copy and paste", it is the compromise between drawing it dead scale and reliably printable that takes the time, that and getting the prototype info in the first place. Ideally flat sides need doing in a material that can be glued with MEK or similar (PETG), easly done but just another stretch on the learning curve.

Printing flat with FDM printing (the hot glue gun type) doesn't always make it quicker for the whole "kit" as the volume of filament to be extruded is very much the same. It is possible to get a better quality print but as the face sat on the build plate will not have any detail it is best suited for vans and coaches. My current fiddlings are to see if the technique can produce consistent prints of suitable quality for open wagons, I know I can with resin printing but there are potential issues with H&S side of things and the smell isn't always domestically acceptable. It is a "hobby within a hobby" and I appreciate it is not every ones cup of tea but it has the potential to allow more modelers to wander off the beaten rtr track and explore new projects including just about everything steam era in Ireland.

Good Luck

I should be printing stuff for the SSMRS stand at Railex but I have been distracted again. Broken window pillar was ham fisted me getting the supports of. Never mind, it was only a quick trial print. SLNCR Railcar B if you were wondering..... The test print, from a Recreation 21 file, has done it's job. Looks nothing like the real thing so I won't bother with the 18 hour print for the rest of it.

I know, but that is how the file came and it is too big to stick into my usual cad program to chop it up. Was only playing to test the limits of the machine anyway. Would also really need to print things in PETG 'cos you can stick that with MEK.

8 and a half hours later. The eagle eyed amongst you wiĺl have noted that I broke the chimney and the cab steps while getting the supports off. No great loss as they were going anyway along with the splashers - far too close together. Ok for a first attempt, might have another go at 0.4 layer height but this was just a "quick" test because I really wanted one of the railmotor versions. Probably heading for 15 hours with the smaller layer height. Not sure what is going on with the cab side and end either. More playing needed. Good fun.

Got bored playing with wagons From a Recreation 21 file to be found on Cults 3d. It's not the best but useful as a test to see what can, and cannot, be done.

I am starting this thread to act as a repository for 3dp questions, answers, project updates etc. that are Irish Railway related. Open to all, not just for me. First off, with the 7 ton MGWR update elsewhere, a couple of photos of the latest FDM printed MGWR open wagon. 4mm and S scale. A bit more work needed yet but we are not too far off.

After a quick squirt of primer. I am starting a new thread "Irish Railways 3d printing" so we don't clutter up this thread with other stuff. 7 ton van on hold until the file gains some buffer holes.

The first stage is drawing the CAD. Well, not just drawing, it needs designing to suit the production process. It is time consuming but satisfying and can be done by anyone with a half decent pc or laptop. Accurate prototype information helps a lot, there are loads of cad files out there, not always the freebies, that look nothing like the real thing. Having done the CAD you can always contract out the printing - there will always be a club or forum member willing to test it out for you. As for a bigger manufacturer pushing in, it is likely that the home produced 3d print will have already saturated the market and just how many Cork and Macroom cattle trucks do we need anyway?

Doh! I didn't spot that!

Beware, there are a million and one more variables to play with in FDM printing than resin - you still need a bigger bin..... Unpainted, you can't see the layer lines in the flesh. Lets see what it looks like with a coat of paint. Might print a 4mm one tomorrow.

I can't see the layer lines in the flesh but the camera picks out every single one. I'll give it a squirt of primer tomorrow.

Thank you. As the old adage goes, the quickest way to make a small fortune with model railways is to start with a large one......

I will of course need to run it past Maitland, it is his file after all.

Oohh goody. Does that mean we have converted you to S?

At approx 3 times the volume, I am guessing a 14 hour print unless a 0.4 nozzle can do the detail in 7mm, in which case probably about 8 hours. Not impossible, let me think about it.

All in good time.

First print on the go. Enlarged 119% for S scale Elegoo Centauri Carbon, 0.2 nozzle, Sunlu PLA 2.0 filament in a fetching olive green. 4 1/2 hour print (ish) Will post another photo later when it's done.

I appreciate that they usually have to be made to fit but that one doesn't seem to fit very well...

It does seem to have an "I bodge it and run" quality to it. Was the saddle tank just lying around the works , off a long scrapped loco?

For those of you in the UK and going to RAILEX Aylesbury on the 23rd/24th May you will have the unique opportunity to see both of the late Trevor Nunn's layouts together. As part of the S Scale Model Railway Society's 80th Birthday celebrations, the Risbourough and District MRC have very generously allowed us to have 4 (yes 4!) S scale layouts with a display and demo stand. The layouts are East Lynn and Nunstanton, Trowland, Blakey Rigg, Arcadia. If you are visiting Railex please feel free to introduce yourself - if I am feeling really bored on Trowland you might get a controller thrust into your hand Regards Rob Rayner Hon Sec