The surfaces of most 3D prints I’ve seen are flat and have rough surfaces. As a humble neophyte I presume I have not seen it all. So please do tell, what are the best materials to use for small objects that require the highest “polished” surfaces which could be deemed saleable for short run products that do not need to go to injection molding?
Can finished products be buffed for example?
Which materials are best to use with casting resins/epoxy coatings?
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Typically SLA and DLP printers will give you a smooth surface on your models. FDM printers will have a rougher surface. These traits are from the processes in which the models are built with each of these processes. All printers have their pros and cons though and you should first determine what your project goals are before determining what material needs to be used… Jewelry, structural parts,etc.
What are you looking to get involved with in 3D printing?
I use a Formlabs SLA printer with Castable resin mostly. I get a great finish on my prints!
Definitely saleable and awesome for making jewelry!
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I currently use a FFF printer with ABS primarily. My options for post processing and achieving an excellent finish include:
Sanding. Starting at 400 Grit and increasing grit fineness up to 1200 I am able acheive a smooth finish with no evidence of layer lines. I print anywhere from 100 to 200 microns.
Acetone wash. Using a felt tip pen filled with acetone I am able to apply a very thin varnish of acetone and then wipe away with a damp cloth immediately to get a smooth glassy finish.
Bead Blasting. With a blasting cabinet I use either PP or Glass substrate and bead blast my models to achieve a uniform finish and hide layer lines.
Painting parts with a high build primer also helps to hide surface imperfections. Finishing with my choice of Acrylic Lacquer or Enamel give parts a look that you would never tell has been 3D printed.
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We have excellent results with our dlp system for smooth surfaces. We also can use a special post processing technique that can produce a high gloss finish without loosing accuracy.
Very useful comments thank you all however nobody had anything to say yet about integrating with casting resins of which there are three types: polyester, polyurethane and epoxy.
I have cast a nylon bolt into polyester resin. When cured I turned the bolt out and discovered workable threads in the cast that being the objective I wanted to determine. Learning about adherence with other types of material used to print is of considerable interest to me and I surmise others. Using resins that may not bond will require building keys into a part which is easy of course. With the creative crowd I am in conversation with I think you’re all interested in this application and I think it both interesting and important to determine what kinds of surface bonds if any the resins can, will or won’t make with respective filament material types.
I also realized I made a newbie error by going tangential asking the question about resins that has little or nothing to do with finishing per se. So I’m going to start another topic and in my next life I am going to take inorganic chemistry classes.
You can use any printer and material, just use mold release and nothing will bond to your mold surfaces.
I have no idea how this is at all related to your original question, but, good luck!
Id like to more about this casting method though. Did you create the mold via 3D printing? Is that what you’re asking about?
Lots of great comments in this topic eh?
Disclosure: I do not have a printer of my own yet.
What its about is product development I am involved with. Recently I delved into resin casting and the next natural progression turned to using 3D print to make various types of product parts and assemblies which would be integrated with casting resin.
YouTube has many videos and while they all seem to focus on jewelry and such the creative mind will visualize many use cases.
Good news to hear about your actual use case Marcus. My inquiry is basically about bonding between the resins and the various filament materials used for printing. You no doubt design inconspicuous keys to lock disparate parts together but my growing experience with casting results in many observations: excessive heat which can crack or warp adjacent parts being a concern.
I’ve also wondered if casting resin and printed filament material can form a “weld” so to speak given the right match of materials and resin type.
This is a Local Brand; manufactured here in the center of the United States! 
, I purchased this filament from makergeeks.com, I love their Filaments! They never clog my custom or my stock extruders. The T-rex was printed in red PLA at 230 degrees celsius, it printed shiny! but it is an iridescent shiny. It is cool I can not do This awesome filament true justice with text. I have printed with several different PLAs and makergeeks is by far the very best!!! I love their natural PLA! PLUSS I always get it super fast! Once you try these filaments you will never order anything else I promise…and 24 buck a kilo with free shipping! http://www.makergeeks.com/mafigrbag2kg.html , I don’t know these filament manufacturers other than by their product.
The Form 2 Gives a glass like appearance at 25 microns of resolution, or at 50 for that matter lol
abs can be fumed and made glossy or you can always sand prime and paint , or maybe even heat gloss with a clean flame…
The “blue” print pic is a formlabs casting resin,
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Good info in your comments I will be looking into SLA and DLP printers. My use case is integration of printed objects with cast resin which are primarily polyester resin, polyurethane resin and epoxy resin.
