Main Body Parts:
This body has been designed as a 2mm thickness shell, so to better print it, use 0.48-0.5mm perimeter thickness.
To print the main parts as we did, you will need to rotate them 78º. Rotate cabin and rear part +-78º until the plane surface which separates them is against the bed. You should not need supports for cabin and rear parts.
If you want to keep same layer alignement for the front part, rotate it also 78º until the plane short cut near rearviews is paralell to the bed. Add the needed supports to the part to be able to start building, but avoid high supports, as the higher zones of the part has been modeled to avoid them.
The Bumper can be printed as is, but you will need to rotate the trunk so the rear flat surface is against the bed and add a few supports to hold the surfaces where rear lights are installed.
These parts has some overhangs which can be correctly done in 0.2mm height layers and with 0.48mm perimeter thickness, at last in all visible zones.
Why 0.48-0.5mm perimeter thickness?¿?
The idea for a "perfect shell" is avoiding as much retractions and travels as possible. For that reason, if the shell is 2mm thick, with 0.5mm perimeters you should have just the inner and the outer perimeters in most of your layers, avoiding solid and standard infills which use to produce this kind of retractions and travels.
"Optimize" the start and order in which perimeters are done can be the right choice for many things to print, but if you want the best result possible in your main body parts, you will have to choose, if your slicer allows it, the best point to align most of the starts/ends of the perimeters. The start and end of perimeters and their near zones are more susceptible to lead into little errors, like blobs, underextrusion at the start of perimeters after big travels or after many consecutive retractions... So the idea is to hide this points of each layer in a less visible place of the part... So the inner side of the part could be good to us.
A very fine tuned 3d printer won't fail after big travels and many retractions in a row, specially if new, but many others could have these kind of little fails which lead into a worse finish of the part.
So for those of us, choosing a point in the inner side of the part could be good, but if you choose a point of the inner shell where the starts of perimeters will print along the inner shell, better than better. That way, if some underextrusion at the beggining of perimeters occur, it will be in the inner side of our part.
For the detail parts, you will need to take out the best of your knowledge about 3D printing, as some parts are quite little and many of them will need supports.
With the exception of the rearviews (TPU better) all of them can be printed in PLA.
You will need to be able to print 0.08, 0.1 or 0.12mm layers to achieve as much quality as possible
You will need to find the best position in which you think it will print better. Think about how it will look with the rest of the parts, but also try to find a position in which adding a few supports most of the part can be printed.
Going beyond the limits:
Very probably you will need to reduce your perimeter thickness to 0.4 OR MORE! to be able to accurately print some of the detail parts. For those of us with 0.4mm nozzles, we are supposed to never use perimeter thickness lower than 0.48mm for a correct extrusion, but for some particular cases, specially small parts without big travels or great overhangs you can go thinner and thinner.
I have printed as low as 0.2 or 0.25mm perimeters with a 0.4mm nozzle... but... how can that be done?¿? If you make very thin layers, lets say 0.1mm but use very thick perimeters, then your WOH value will be too high, leading into not very good results while printing some characteristics... I have printed little parts with 0.12x0.24 perimeters, 0.12x0.36, 0.1x0.33, 0.1x0.25... The limit, as they are little "fast" low weight parts, is your patience ;)
If you are going to go beyond limits, remember to have a very good first layer, probably thicker and higher than the rest, and your extruder primed before the first layer starts... I mean maybe free extruding 20mm filament at the begining and printing some skirt lines before first layer of the part is printed
Windows, the final challenge!
Ideally, you will print the window frames in one material and the cristals in some transparent PLA or PETG... But specially the frames can be really tricky to print due to their extra thin profile.
If you don't mind to paint the frame black, you can print the "1piece" version of the windows which can be a little easier. Try to find the perimeter thickness that fills the profile shape as much as possible, and a thin height so the WOH doesn't get too high. Give it a try, and if you can't get rid of it I will try to supply you an easier to print version, but it won't be such as stylized as this one.
Sinking a little:
Sometimes, for some parts, in some positions, you can "sink" the part in the bed a very little distance to have a good first layer. At least, I use to "sink" some parts, in a place that is not visible and doesn't affect functionallity. So sometimes sinking it 0.05, 0.1, 0.15, 0.2 mm can give you inner and outer perimeter in the first layer, while if you don't do it, you practically start building your part all over supports.
For some of the parts, specially the big ones, you want a good inter-layer adhesion so remember to print in the high range of PLA, something between 210 and 220 if you can, as your layers will stick to the previous one much stronger. This could lead into more stringing or into some underextrusion after big travel and some oozing, but if you use fast travel speed these effects will be reduced.
GENERAL PRINTING PROFILE:
For the big parts (fast profile):
- 0.2mm layer height
- 2 perimeters, 5 tops and 5 bottom
- 0.4 to 0.48 perimeter thickness, depends of the part
- 15-25% infill normally, 1000tops/bottoms if 100% solid weight differs a little
- 70mm/s general speed, 50% for outer perims, 80% for solid infill and supports
- 240mm/s travels, quite fast, if your printer allows them
- 400mm/s2 accel for printing moves
- 2000mm/s2 accel for travels
- 220ºC for PLA or less if reduced general speed, 45ºC Bed, printed over crystal
- 50% layer fan (needed in overhang zones specially, 100% for bridges)
For the detail parts:
- 0.1mm layer height
- 3 perimeters, 10 tops and 9 bottom
- 0.25 to 0.4 perimeter thickness, depends of the part
- Solid infill, 1000tops/bottoms
- 40mm/s general speed, 50% for outer perims, 80% for solid infill and supports
- 200mm/s travels, quite fast, if your printer allows them
- 400mm/s2 accel for printing moves
- 1200mm/s2 accel for travels
- 210ºC for PLA or less if reduced general speed, 45ºC Bed, printed over crystal
- 60% layer fan (up to 100% for layers faster than 5s)
Anyway, I use to review and adapt these parameters for each part I print. One profile to rule them all would be good, but I have not found it already