There are several reasons for creating this miniature railway:
- I have been collecting model rail way parts more or less since birth. The STLs fit onto regular N-scale tracks (useful? Nooo....,but fun)
- The original locomotive in this project, "Krokodilen"/"The Crocodile", is rather famous amongst railway enthusiasts. A few years ago, the "real thing" visited Sweden, so I bought a ticket and went on a journey half way through Sweden for no other reason.
- A comic book, "Jag, Kalle Anka", containing some great Carl Barks stories formed Swedish youth of my age including myself. One story is about the poor part of "Ankeborg" (Duckville) where the kids dream about getting a model railway to share (and Uncle Scrooge thinks they shouldn't have one, of course). So, why not a simple construction free for everyone to share? A bit too late, I know :-)
- It's a bit of an excercise for a beginner to construct it in FreeCAD (I really really really lack a free form array able to follow a spline path)
- The 0.4mm nozzle train track print out is my first print ever using my brand new MMU2.0 unit (for the Prusa i3mk3 printer). I think it came out well!
- The 0.15mm nozzle train track print out is my second print ever using my brand new MMU2.0 unit (for the Prusa i3mk3 printer). I think it came out well! It is somewhat broken at the connections, I did still use it in the pictures instead of printing a new one for honoring this 1st print.
- The tracks are ready for being printed using conductive filament. The day I get my hands at some, I will print the tracks and mix them into my Minitrix N-scale model railway!
I deliberately did not add "useful item" to the list. And please be aware, to print this using a 0.15mm nozzle is nothing supported by eg Prusa. You will likely make some misprints, finding parts falling of the print plate etc. If you want a bit of a challenge, however, this might be a bit of fun. If you have never printed before, I recommend you to print something else first (it's not meant to be unfriendly in any way, it's just that first printing impressions should be positive).
ColorFabb, FIllamentum PLA
black, white, mint turqoise, pearl ruby red, gold happens, satin white
See details wrt settings for a 0.15mm nozzle in the custom section. Here is a brief summary:
Locomotive boogies (2pcs): 5h 43min (single part) or 13h 20min (3 materials, using wipe into one of the object) PLA Layer 0.10mm Nozzle 0.15mm No support Perimeters=5
Pingwaggon: 1h 40min (single part) or 7h 38min (4 materials) PLA Layer 0.10mm Nozzle 0.15mm support on build plate, print upside down
Straight track 104mm: 1h 33min (single part) or 2h 44min (5 materials) PLA Layer 0.10mm Nozzle 0.15mm support on build plate, Perimeters=30 is a must
Curve track 235mm radius 30deg: 1h 53min (single part) or 3h 7min (5 materials) PLA Layer 0.10mm Nozzle 0.15mm support on build plate, Perimeters=30 is a must
- Wheels and loose axis: 12min per 4wheels, 9min per 4axis PLA Layer (incl. 1st layer) 0.10mm Nozzle 0.15mm. Print with objects lying flat. Don't print all in one go (if a wheel fails to stick).
You will find the 0.15mm nozzle at E3Ds web shop, under "experimental nozzles". In case you don't want to print with a 0.15mm nozzle, either just scale up the STLs (a factor of 2 is needed for the rails when using 0.4mm nozzle, as this is equal to a single thread in the middle of the steel track). Or, change the parameters in the FreeCAD file and re-save into STLs that suit you better. Please remember, the structural details will NOT scale properly, you must do this manually (eg in blender). In FreeCAD, there is a possibility to create scalable objects (make a clone using draft WB, which will then be scalable. However, it didn't work immediately this time and honestly I didn't bother too much).
In case you do want to print with a single material, there is a single-material version of all STLs (same name, no "MMU..." text).
For slicing the parts for MMU-prints, please remember:
- Locomotive (both parts): Load the "MMUdetaljer" first
- Pingwaggon: Load the "...MMUpingvin" first
- Train tracks: Load the "...MMUpingvin" first
The reason for this is, these parts slightly overlaps the other objects, and the filament will stick better if "inside" the sides which will happen only if eg slic3r slices them in this order.
If you have a four material only (well, I had to write it, my apologies :-) MMU (eg Prusa MMU1.0), just skip "...MMUpingvin" when printing the train tracks, as the track will be complete without it.
Just add a motor, WiFi, voltage regulator and off you go! :-)
The item was constructed using Freecad, Inkscape and Blender. I use the "freecad-daily" updates (which I strongly recommend for any freecad user). I have not tried using the construction with the freecad stable release.
If you prefer to edit the design, in the freecad-document you can change the major parameters (eg curve diameter, track length) easily by adjusting parameters in column B in the spreadsheets included in the freecad document (one spreadsheet contains train track information, a second spreadsheet contains locomotive information). You can change everything to eg H0 scale simply by changing a bunch of parameters in the two sets of column B. Changing the length (and radii) of a (curved) track is done by changing B16 (for straight) or B38 and B39 (for curved) track. Recomputation can take a long time for FreeCAD (360 degree 96mm radii takes 30 minutes on my average age I7), don't give up (too early), give it a chance.
The finishing details on the locomotive is generated as vectors by Inkscape, then constructed as volumetric STLs by Blender. If you are not familiar with Blender, give it a try some day - it is one of my absolute favourite softwares - suitable for generating fantastic movies as well as single 3D objects, all at a computational speed, ease and freedom that eg FreeCAD just cannot compare with. Don't stay with only one or the other, learn to use them both, you won't regret it!
0.15mm nozzle slicing info
As there is no slic3r PE definition files for 0.15mm nozzle with MMU2.0, I provided my personal settings. They work well for me, as long as you are careful to clean the print plate well, make the PLA stick without warping even though it is quite thinly printed. Then again, I have hade the MMU2.0 for 6 days now, so please don't expect all settings to be perfect.
In brief, the settings I use are as follows:
- Layer=0.10mm, Perimeters=30 (very important for the train tracks and pingwaggon), Brim width=2mm, solid top=6, solid bottom=3, 10% infill
- Build plate support, pattern spacing=2mm rectilinear, dont support bridges
- Nozzle=0.15mm, speed=25-50mm/s (see Prusas definition for 0.25mm nozzle for standard i3mk3), infill=200mm/s, first layer=15mm/s,
- extrusion width (all of them)=0.15mm, bridgeflow=1.0
- Bed temp 75 (layer1) +70 degree (all others). It can be printed at 60 (standard).
- Purging volumes: unload: 30 load: 10 ( if black, then unload: 50, if white, then load: 40 )
Setting variations for the various objects to be printed (changes from the settings as just defined):
- Single wheel (need 16pcs): No brim. Inner side at print bed. Don't print all at once, they don't always stick properly to the print bed as very small
- Loose axis (8pcs): First layer height=0.1mm, print lying down (print standing gives poor strength)
- Locomotive boogie (2pcs): support=off, Perimeters=5
- Locomotive transformer body: support=off (yes, the pantographs will actually print well w/o support), Perimeters=5
- Pingwaggon: Print upside down. you MUST set Perimeters to a large value, eg 30
- Straight track: support spacing=1mm. rectilinear grid support, you MUST set Perimeters to a large value, eg 30
- Curved track: support spacing=1mm, rectilinear grid support, you MUST set Perimeters to a large value, eg 30
For the prints, I use Black and White PLA, ColorFabb's "Gold Happens" (PLA Extrafill) and, for the look of the locomotive nicknamed "The Crocodile": ColorFabb's "Mint Turqoise" (PLA/PHA) and Fillamentums "Pearl Ruby Red" (PLA Extrafill).
I under-purge the colors slightly, giving the output a rougher look (mixing the black for the boogie section with the red for the details). Actually, slic3r PE's "fill in this object" suits the locomotive well, as the mix when printing with the same color scheme almost improves the look.
A wheel pair with axis is included for vertical print. It will be smoother, however fragile. It can be printed using Nylon (slow speed, turn on fan!), however not much use.
Do not use a 0.15mm nozzle to print filament containing fill (eg algae, brass, ...). I once challenged it, and numerous cold pulls, needles etc finally removed the stop, and reshaped the tip to a useless state at the same time.