Our pellet extruders are designed to work with a wide variety of thermoplastics. Even so, not all polymers are suitable for large format additive manufacturing. There are several reasons for this, including:
- Viscosity of the material: the viscosity of the polymer must be carefully controlled to ensure that it can be printed consistently and accurately. If the viscosity is too high or too low, the printed object may be distorted or may not hold its shape.
- Melting point: the melting point of the polymer must also be carefully controlled. If the temperature of the pellet extruder is too high, the polymer may degrade or break down, resulting in poor print quality. For instance: Polyvinyl chloride (PVC) is a thermoplastic, but it’s not commonly used in the industry because it releases a toxic hydrogen chloride gas when heated excessively.
- Adhesion: the polymer must be able to adhere to the printing surface and to previous layers. If it does not adhere properly, the printed object may warp and fail.
- Mechanical properties: the mechanical properties of the 3D printed object must be carefully considered. For example, if the polymer is too brittle, the printed object may break easily. If it is too flexible, it may not hold its shape.
To address these issues, polymers may need to be specially tailored for large format 3D printing. This can involve modifying the molecular structure of the polymer to control its viscosity, melting point, and adhesion properties, as well as its mechanical properties to make sure that the warpage of the material is as less as possible. Additives may also be added to improve printability and reduce the likelihood of defects.
There is a lot of R&D involved in making these polymers suitable for large format 3D printing. This is also the reason why prices per kg of these new materials are much higher compared to already existing materials on the market like injection molding grades.
CEAD's pellet extruders can handle a wide range of materials. You are not limited by only using specially tailored materials for large format 3D printing. We use a lot of injection molding grade materials in our processes as well. Our special large format print bed design plays a key role in the success of this.