Resins for 3D Printing

SLA/DLP resin-based 3D printers offer a very high resolution finish

IFA 2015 Consumer Electronics And Appliances Trade Fair
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The common desktop 3D printers today are using the fused deposition modeling (FDM) method, with an extruder, a hot end, as they are often called, to melt a polymer (plastic) filament. There is another category that is rapidly developing known as desktop resin printers.

The 3D resin printers use stereolithography (SLA) or digital light processing (DLP) as the core way that they create layers. Instead of melting a strand of plastic filament, these printers use light to cure a light-sensitive, liquid photopolymer.

Many printer aficionados claim that DLP/SLA materials offer better resolution and more durability, but the 3d printer resin cost is often higher. However, DLP and SLA printers both print faster than standard extrusion printers. In the last few years, we’ve seen many FDM 3D printers get their start via crowdfunding. Now we’re seeing more resin 3d printers on Kickstarter and IndieGoGo, for example.

Because DLP and SLA printers both use photopolymers that harden when exposed to UV light, the resins are frequently interchangeable in these printers. That can be argued, of course, by the manufacturers who want you to use only their resins. You must be careful you are not voiding your warranty, to be clear, as I am not familiar with these various terms. Read the fine print!

With desktop resin 3D printers, there are basically three types of resins – standard, castable, and flexible. I call them standard resins, but you will find most resin makers call them “high detail resins” or “high resolution resin.” Fair enough.

 

  • High-detail resins offer a wide range of color choices. For example, Formlabs offers these in clear, white, gray, or black. In the Amazon Additive Manufacturing Products section of their “3D Printer Store” offers a wide variety of color options from MadeSolid and MakerJuice.
  • Castable resin by MadeSolid is used for casting. This resin leaves no ash, which makes it ideal for investment casting. It also has minimum expansion and shrinkage until actual burnout. It is designed with jewelers in mind and can be used with most of the heat schedules used by those making investment casts for jewelry. Asiga also is working on SuperWAX, a wax based photopolymer that can be used when casting platinum.
  • If you want to create a functional prototype that needs more strength than standard resin, MakeSolid offers Vorex. Right now, it’s only available in orange or black, but when its tensile strength is multiplied by its elongation, it requires a higher amount of energy to break than other resins. MakeSolid designed it for durability and impact resistance.
  • Some resins offer high-temperature resistances, such as Accura Bluestone and SOMOS 9120 (which is also chemical resistant) from Proto3000 or Asiga’s FusionGRAY. Most hi-temp resins endure temperatures that are hot enough to create vulcanized, rubber molds and to use in industrial applications.
  • Since 3D printing is also being used by the medical industry to create functional, unique medical devices, the need for flexible resin is great. Formlabs Flexible Resin and MakerJuice’s SF product lines both remain flexible when cured. Asiga’s Bio Range photopolymer resin is also in development. Because of skin sensitivity, items such as hearing aids must be made from special resins. Asiga wants to allow parts to be printed that will not irritate the skin even when the device contacts it all day long.
  • Autodesk introduced the resin-based Ember 3D printer. They are producing their own materials, Standard Prototyping Resin (PR48) is the name, but you can use other resins with their printer. 

    Again, it is important to check compatibility with your specific brand of printer before purchasing resins. However, most of these resins were designed for use in any 3D printer that uses UV rays to cure liquid resin.

    Some resins do require additional UV curing after they are printed, but this increases the durability of the final product. Although SLA and DLP 3D print materials haven’t quite reached the variability offered by extrusion printers, there are still many varieties, and more materials are on the way.