I'm going to have a 3D printed facia for an OEM radio fitted into a car. It'll be nothing complex and as I use Inventor on a daily basis for work that bit I can manage.
I'm wondering how to get the smooth surface finish. Do I print it slightly oversize and allow for sanding or do I need to put some filler in and sand it?
traditional way (which I've never tried) is print in ABS and acetone vapour smooth it.
on the droid building group they use a spray putty like Motip, sand the bejesus out of it then paint. This gives a perfect finish but seems like an awful lot of work!! Again, not done it personally.
What I [I]have[/I] been doing lately, is getting a guy I know who does car spraying to lacquer the 3d prints. This gives an incredible feel/finish for virtually no effort (from me anyway!!) You can still see the layer lines but they are way less noticeable especially if you use a filament such as Prusa Galaxy Black.
It depends on the material.
Sand, a few coats of filler primer, with more sanding, with a final coat of paint is probably going to give the best finish.
Following with interest..
My printer (ender 3 v3se) arrived today..
I've already printed a few bits I designed myself...
Nest Thermostat bracket.
I've white filament arriving tomorrow.. So will reprint in a more suitable colour!
This is fun!
DrP
Yep, can confirm that misting ABS with acetone works well. I however recommend not doing it in a confined airtight space without a mask! ABS is obviously not available on a lot of cheaper open machines - ABS like a warm enclosed print chamber.
You can design the part and orientate the print on the printer your way out of much of the worst of the layering.
DrP - What printer was that with?
He put it in the post - a (Creality) Ender 3. Pretty much the default cheap hobbyist printer and amazingly good for the money. I run 8 Creality machines and a BCN3D Sigma. You could buy all the Creality machines and a lifetime supply of filament for the price of the Sigma and in truth whilst it does some clever things the Creality quality of finish is practically identical.
Another ender 3 owner here, I only ever bother with PLA and seldom finish beyond a bit of light sanding.
If I was trying for a smooth finish I'd just skim body filler across the cosmetic faces, wet 'n' dry to a smoothed surface and then rattle can paint it.
Alternatively you could try facing it with some adhesive backed vinyl in your preferred colour/texture.
3D printed parts are normally very obvious, especially when you use lots of radiuses...
I've just ordered a magnetic bed for my ender 3 as im going to print some miniatures we designed with the kids on heroforge (how much fun is that!)
I just embrace it. It is how 3D printed parts look. Much like Hope parts look nice with their CNC milling marks or carbon fibre with an exposed weave. I certainly wouldn't spend ages finishing the first one. Print it, fit it, see how it functions. There will probably be some tweaks and improvements to make you want to print a mark 2.
Does the actual part have to be 3D printed? Too many people think of it as the final product but I've had some good results using the print as a mould or template for other processes. ie print slightly smaller and vacuum form plastic around it.
You’d still need to finish it otherwise all the imperfections in your 3D printed tooling will pass onto the part being formed.
For most plastics a high build primer, and sanding through grades of paper and then painting/lacquering will give the best result.
Many 3D printed plastics are oleophilic, so do benefit from sealing.
For metals, vibratory grinding, sanding, etching and plasma polishing are the most uniformly effective methods. Slurry polishing can work, but it’s highly geometry specific.
We shot peen our parts but I'm guessing you mean how to finish a hobby level desktop FDM printer rather that professional or industrial level.
Even then over large flat surfaces it's better to add a surface texture rather than try to achieve ultra smooth. Most vapour smoothing to smooth makes. Surfaces look like they have melted a little.
yeah, Prusa machines have a textured build plate option (works best with PETG) so if your front-facing surface is flat this can be printed face-down and takes on the textured finish, does a great job of making it not look like a normal 3d print! I've seen people do a similar effect on other machines by printing onto a textured sticker e.g. carbon-fibre wrap.Even then over large flat surfaces it’s better to add a surface texture rather than try to achieve ultra smooth.
Cura slicer has a 'fuzzy' option which adds a 'roughened' texture to a surface.
Obviously this won't apply on the surface that lies on the build plate.
For what the OP is after, some kind of filler & sanding would probably be the way forward.
Printing at a lower layer height might reduce the amount of filling/sanding.
What material are you intending to use. PLA doesn't cope very well with the temperatures that can be reached in a car on a hot summers day. I think even PETG is marginal.
or the topmost surface, only the vertical perimeters.Cura slicer has a ‘fuzzy’ option which adds a ‘roughened’ texture to a surface.
Obviously this won’t apply on the surface that lies on the build plate.
Although that reminds me, had forgotten about the "ironing" option, which can produce a surprisingly decent finish on the top surfaces (so depends on print orientation) although can also massively extend the print time!
PLA definitely not suitable. I've produced a few facias from PETG and none have come back melted lol so I'd be more than happy using that. Think the transition temp is about 85°, I guess in theory the very top of the dashboard could get hotter than that on the hottest UK summer day if in direct sun, I cannot see the area where the stereo would be or indeed the overall ambient temp of the cabin getting that hot though!What material are you intending to use. PLA doesn’t cope very well with the temperatures that can be reached in a car on a hot summers day. I think even PETG is marginal.
zilog6128
or the topmost surface, only the vertical perimeters.
That's true but depending on the part, how you place it on the build plate prior to slicing can mean you don't end up with any horizontal faces, so you can get 100% coverage.
Ironing works pretty well if you want a nice smooth top face, but yeah can take bloody ages. I have used it previously just to try it out but never really persisted with it.
Regarding the material choice in a car - yeah, I have no direct experience of PETG in a car. I'm sure I've seen people on some of the FB groups complaining about PETG warping when left for extended time in their cars - most of these are Americans though, so perhaps an overall hotter environment than we would see and for a longer period of time?
Could also be down to using cheap materials that aren't as robust.
