Key selection guidelines for selecting 3D resins

Key selection guidelines for selecting 3D resins:

any material may appear more or less rigid or flexible depending on their thickness
metal foils are flexible but thick metal parts are rigid
soft rubber films are flexible but very thick parts are rigid
each material appears flexible up to certain thickness at which starts to appear more and more rigid while increasing its thickness
rigid materials with rod shapes do bend upon pressure below certain thickness
flexible materials with rod shapes do not bend upon pressure above certain thickness
identify the smallest and thinnest part or "minimum feature size" of your 3D printable object.
identify the minimum required relative rigidity of the minimum feature size

thicker feature sizes will appear more rigid thanks to their thicker sizes
avoid selecting too rigid materials for your application needs since excessive rigidity results in reduced toughness or excessive fragility, such as "eggshell-like" materials: glass, ceramics, etc,..which are rigid but fragile!
avoid selecting too flexible materials for your application needs since excessive flexibility results in reduced toughness, flexural strength and tear resistance, such as too flexible and easy to break elastomers
for rigid materials select the minimum required rigidity of the smallest feature size of your prints to maximise mechanical strength since thicker parts will appear more rigid
for flexible materials select the maximum and the minimum required flexibility of the smallest and biggest feature size of your prints to balance or average both to satisfy your needs

Typical experimental findings and thumb rules by decreasing Shore values. From D90 downwards!!

the higher the Shore D (above D90 range) the higher the rigidity (Young´s modulus) but due to excessive rigidity, mechanical properties such as flexural strength and impact resistance can decrease
the higher the Shore D (D70-D90 range) the higher the rigidity (Young´s modulus) and mechanical properties of most rigid materials
in the Shore D50-D80 range, sometimes softer D60 resins can be more rigid and mechanically resistant that harder Shore D80 resins, consequently the natural hardness-rigidity-strength direct proportion "formula" can be reversed. This happens with some of our unique Engineering 3D resins which contain highly resilient bio based building blocks, which are ideal for designing eco friendly ultra resistant functional engineering bio materials!
From Shore D50 downwards materials increase their flexibility but decrease their mechanical strength. Choose our NextGen 3dresyns for engineering or our Bioflex 3Dresyns for biocompatible flexible materials
the higher the Shore A the higher the mechanical properties for most flexible and elastic materials: choose as high as possible Shore A resins for maximum overall mechanical performance
From Shore A50 to A10 materials become very soft and typically are elastic and prone to have poor mechanical strength. Choose our elastic NextGen 3Dresyns for engineering or our Bioflex 3Dresyns and Bioelastic 3Dresyns for biocompatible elastic materials

Key selection guidelines for selecting engineering functional materials:

Our Enginering 3Dresyns "like" engineering materials are ideal for Engineering functional applications where ultra high durability and mechanical performance are required. These 3Dresyns contain bioplastics from renewable resources and are more environmentally friendly than petroleum based plastics.
Our Enginering 3Dresyns "like" best high performance engineering plastics are supplied with access to all our colors and functionalities. They are supplied with a relatively low or high viscosity for even increased overall mechanical performance:

High Viscosity versions exhibit increased mechanical properties and are ideal for printers having heating systems for printing at >25ºC
Low Viscosity versions exhibit relatively lower, but still quite high, mechanical properties and are ideal for printers without any heating systems for printing at <25ºC and >25ºC
Learn more about the Benefits of printing with heated printers

Other key selection guidelines for selecting "green" biocompatible materials:

Both, our Monomer Based MB and Monomer Free MF 3D resins exhibit similar strength for each Shore value
Monomer free MF versions do not contain any monomers, consequently the risk of causing skin irritation is minimised