Creating Elastomeric Parts with 3D & 4D Printing
3D and 4D Printing of Thermoplastic Elastomers, Rubbers, and Silicones
The use of 3D printing to create prototypes and devices from elastomeric and polymeric materials has appended the design functionality for new materials including uses in biomedical devices enabling rapid development. The process ability and functionality of rubbers and elastomers make it a challenge to employ 3D printing methods for additive manufacturing. The transition to a final phase or cross-linked structure results in new properties in combination with the processing method. This is more evident with the choices of 3D printing methodologies (FDM, SLA, SLS, VSP) which can make use of blended or formulated compositions. We have demonstrated the 3D printing of biomedical grade thermoplastic polyurethanes (TPU), silicones, and rubberized epoxies. However, 4D printing allows the design of new materials and applications based on integrating the chemistry of conversion with the printing mode. This presentation demonstrates the fabrication of concept objects and elastomeric actuators based on the use of biomedical grade TPU melts and extruded viscous solutions.
Rigoberto Advincula | Professor, Case Western University
ACEO® - 3D Printing with Silicones
Liquid silicone rubber (LSR) is a high viscosity, addition-curing material used in a variety of applications, from healthcare to automotive, due to beneficial properties such as low-temperature flexibility, high elasticity, mechanical performance, and bio-compatibility. LSR is traditionally processed via injection molding, which requires expensive tooling for each new model or part. In order to bypass this limitation and quickly iterate designs, WACKER developed the first industrial 3D print process for silicones and provides its 3D print services under the ACEO® brand using true LSR without any plasticizers. ACEO® offers materials in varying color and hardness in the Shore A range, allowing the design of multi-functional and even multi-material parts with both hard and soft components to deliver complex engineering designs.
Sarah Burke | Technical Specialist, Wacker Chemical Corporation
Inert ToughRubber: Robust, 3D printed elastomers for high-throughput, DLP-based additive manufacturing
Inert ToughRubber (ITR) is a family of silicone based, 3D printing elastomers from Adaptive3D designed for high-throughput additive manufacturing. Utilizing the excellent surface finish and resolution of DLP and possessing a broad range of hardness’ (20 to 80 Shore A), high elongation (>400%), and excellent Tear Strength (> 20 kN/m), ITR can be photopatterned on an array of existing DLP printers at voxel sizes of less than 100 microns. ITR is a materials solution for applications requiring chemical resistance, strain tolerance and high toughness. Adaptive 3D is an emerging high-growth company providing photopolymer resins to the growing additive manufacturing market in several key segments: consumer, medical, transportation, industrial/electronic and oil and gas.
Walter Voit | CEO and Founder, Adaptive3D Technologies
Networking Break
Session II: Liquid Silicone Rubber Solutions
Connected Healthcare Transformation
Developments for elastomers in the health care market. Wearable Medical Devices. Driver and Trends. LED Technology Transformation.
Marie Crane | Healthcare Market Leader & Healthcare Business Development, DuPont
1 + 1 = greater than 3! Growing importance of 2 shot molding, technical solution and case study of LSR in combination with PSU
The demand for two- or multi-component (2K / 2shot) parts has increased rapidly in the last five years. Thanks to the 2-component injection process, parts can be produced in one process, without further assembly, and installed directly after the injection molding process. For example, housing covers are fitted with seals, silicone membranes connected with the necessary holders, and electronic components covered with a completely sealed surface and optics made of silicone. Use of only one 2K (2shot) production cell allows space to be saved or utilized for other purposes that would normally be used to manufacture other assembly parts.
While previously, many individual parts had to be painstakingly checked and measured after production, the 2K process means that only one part now needs to be sent to Quality Assurance for inspection. This frees up resources at the often expensive test equipment, which can then be otherwise used. Apart from standard materials such as polyamide (PA) and polybutylene terephthalate (PBT), it is now possible to combine materials which were previously nearly impossible to implement and combine, such as polycarbonate (PC), polysulfone (PSU), and even polypropylene (PP), with liquid silicone.
Bob Pelletier | Sales USA dosing systems, ELMET
Modifying LSR Properties with Third-Stream Additives
NovationSi™ features innovative Liquid Silicone Rubber (LSR) third-stream technologies with a customized approach. Considering that LSR pumping systems have advanced in delivery accuracy (+/-0.1%) of third-, fourth-, and even fifth-stream additive injection, there are opportunities to customize LSR properties in situ of the Liquid Injection Molding (LIM) process. Typically, these streams are used to add colorants to the LSR and NovationSi is a key supplier of color dispersions. Considering that LSR is a thermoset, and therefore reactive, additives can also be used to dramatically change functional properties of the cured article, thus opening the possibilities to do so much more. Through RDAbbott’s model of APPLIED CURIOSITY for superior technical service, and NovationSi’ customized approach to third-stream technologies, unlocks the potential of LSR to truly modify the cured article in ways never practically considered. As an example, a method of creating a silicone foam is demonstrated. That is, in your LSR molding process, set up NovaSperse® foaming additive via third-stream injection, dial in 2 to 10% additive, and you get cured silicone foam that is non-toxic and closed cell. Densities of the molded article are half what they would be in solid form so the cured article floats on water yet retains the superior properties silicone rubber inherently provides. Think fire-stops, thermal insulating, light weight fabrication, and ultra-soft sealing.
Rick Ziebell | VP of Technology, R.D. Abbott Company
Investigation of the Post Curing Process of Liquid Silicone Rubber using Mechanical Tests Methods and Gas Chromatography
The goal of the project is the analysis of the post curing process. For this purpose, the process-relevant parameters such as temperature and time are considered. After the samples have been produced in the injection molding process, they are exposed to different curing times and temperatures. Subsequently, the mechanical properties (in particular hardness, tensile strength and elongation at break) are investigated. For the analysis of volatile components, which can emit from the material, measurements using gas chromatography coupled with mass spectrometry will be used. Standard materials are to be compared with low volatile types.
Annette Rüppel | Scientific Assistant, University of Kassel, Germany
Networking Break
Advanced LSR Simulation Technologies To Optimize The Design And Molding Process
Continuous improvements in part design, mold design, and molding processes are essential for maintaining a competitive edge in the ever-expanding LSR Healthcare molding market. By using advanced CAE simulation technologies, design phases can be shortened, molding process can be predicted, and molded parts can be optimized. To achieve these results, the shear sensitive viscosity behavior of LSR materials should be simulated to accurately predict flow behavior and shear-induced heating effects. New fully automatic BLM (Boundary Layer Mesh) technology can create accurate mesh density in required areas. High shear rates in thin film or pin gates and thin wall thicknesses can cause shear-induced heat which influences viscosity, flow behavior, and flow-induced premature scorch and cure effects. In this paper, several practical examples will demonstrate how advanced mesh technologies can be used to better predict shear-induced material flow behavior and how to optimize vent and over-flow placements. In addition, heat balance inside a high cavitation LSR mold with a narrow cavity spacing requirement will be evaluated. Lastly, optimizing heater placement and heater wattage to avoid cold spot conditions that could influence overall cycle time and part cure behavior will be examined.
Srikar Vallury | Engineering Manager, Moldex3D
Session III: Trends in Thermoplastic-based Materials
The Future of Thermoplastic Elastomers to 2024
Content and main talking points to be determined.
Bruce Lambillotte | VP Consulting, Smithers
Combining Plastics for Enhanced Recycling
Of all commercial plastic, nearly two-thirds consist of polyethylene (PE) and isotactic polypropylene (iPP). Recycling of these two materials is complicated and costly due to challenges in sorting polyolefins from one another as well as the physical phenomenon of phase separation and poor interfacial adhesion. In this talk, a novel catalytic system capable of synthesizing block copolymers of iPP and PE is presented along with the properties these materials exhibit when added to PE/iPP blends. The effects of molecular weight and block copolymer architecture on interfacial adhesion and compatibilization will be discussed. For example, iPP-b-PE copolymers improve adhesive forces between Ziegler-Natta grade HDPE and iPP to the extent of cohesive PE failure, similar to the properties observed in metallocene grade LLDPE/iPP (hot-tack polyolefins). The block copolymers further improve mechanical tensile and impact performance of PE/iPP blends when added as a third component in small amounts (<1 wt%). A proposed mechanism of adhesion will be discussed along with the potential for enhancing the recyclability of plastic waste.
James M. Eagan, Ph.D | Assistant Professor, Department of Polymer Science, The University of Akron