Stress and Strain Properties of 3D Printing Resin

Stress and Strain Properties of 3D Printing Resin

Technical Characteristics for DruckWege Resin in Comparison

Every material has its characteristic values, which can be determined using harmonised test methods. The most important factors here are which values and properties are to be made comparable and which areas of application the materials are expected to have after implementation of the model. For functional and prototyping resins in particular, knowledge of the material properties coupled with the correct exposure times is an important prerequisite for selecting the right raw materials.

Tensile tests with DruckWege Resin

A central test setup is carried out according to ISO 527-1 with tensile testing with defined sample sizes for plastics. The test specimen geometries, test speed and measured value acquisition are defined so that the stress-strain diagram can be determined. The characteristic parameters that are determined from this are, among other things, the following:

  • Modulus of elasticity in tension
  • Yield stress
  • Elongation at yield strain
  • Tensile stress at break
  • Elongation at break
  • Tensile strength

The number of samples, which are particularly important for statistical relevance, is important here. In 3D printing in particular, the replication accuracy of the models is high, but there may be differences in the results for sample orientation, support of the models by supports, offsets or different irradiation sources.

In the following, the DruckWege Resins Standard (represented in red), PRO, PRO Flex and Dental Model have been compared.

Elongation properties of tensile specimens

The elongation at rupture indicates the permanent extension of the tensile specimen after rupture, always related to the initial gauge length. It characterizes the deformability (or ductility) of a material.

Where on the one hand the dimensional stability of the materials Standard, PRO and Dental Model is desired, on the other hand there is the significantly higher elasticity of the Flex material.

Especially in the dental field, hard and less elastic materials are important for raw forms compared to deep-drawing splints or as templates for bridges or for general impression processes for silicones or other elastomers.

Modulus of elasticity and tensile strength

The modulus of elasticity is a material characteristic that describes the proportional relationship between stress and strain during the deformation of a solid body in the case of linear-elastic behaviour. The modulus of elasticity is thus the proportionality constant in Hooke’s law and at the same time provides a possibility for comparison of the elasticity of materials. In simple terms, the smaller the modulus of elasticity, the more elastic the material. The PRO Flex, for example, is located in the region of a rubber, at least in terms of its modulus of elasticity. Other evaluation criteria, such as surface hardness, must also be taken into account.

The tensile strength describes the maximum mechanical tensile stress that the material can withstand and is calculated from the maximum tensile force achieved in relation to the original cross-section of the specimen.

All values are given in the data sheets of DruckWege. Furthermore, the requirements which are placed on materials from the point of view of safety, which are specified in the safety data sheets, apply. Further analyses on DruckWege Resins can be found here on surface accuracy.