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In the composite manufacturing industry, production tooling commonly requires preheating for molding. The most commonly used method for preheating is indirect heating, in which heat is transferred from heat sources to the materials by convection and radiation. However, in the case of direct heating, in which heat is generated directly within a material by passing an electric current through it, the tools are preheated through joule heating. In this project, we manufactured a self- heating mold for direct heating. The manufacturing process involves 3D printing self-heating tooling, in which resistive wires are embedded into the tool at every so number of layers using a programmed 3D printer. Thermal characterizations were performed on the self-heating tool and a thermoset composite layup process was performed to study the suitability of the mold.
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Strategic cost and sustainability analyses of injection molding and material extrusion additive manufacturing
Abstract Economic and environmental costs are assessed for four different plastics manufacturing processes, including cold and hot runner molding as well as stock and upgraded material extrusion three dimensional (3D) printers. A larger stock 3D printer was found to provide a melting capacity of 14.4 ml/h, while a smaller printer with an upgraded extruder had a melting capacity of 36 ml/h. 3D printing at these maximum melting capacities resulted in specific energy consumption (SEC) of 16.5 and 5.28 kWh/kg, respectively, with the latter value being less than 50% of the lowest values reported in the literature. Even so, analysis of these respective processes found them to be only 2.9% and 3.8% efficient relative to their theoretical minimum energy requirements. By comparison, cold and hot runner molding with an all‐electric machine had SEC of 1.28 and 0.929 kWh/kg, respectively, with efficiencies of 9.9% and 13.6% relative to the theoretical minima. Breakeven analysis considering the cost and carbon footprint of mold tooling found injection molding was preferable at a production quantity of around 70,000 units. Parametric analysis of model inputs indicates that the breakeven quantities are robust with respect to carbon tax incentives but highly dependent on mold costs, labor costs, and part size. Dimensional and mechanical properties of the molded and 3D printed specimens are also characterized and discussed.
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- Award ID(s):
- 1914651
- PAR ID:
- 10401148
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Polymer Engineering & Science
- Volume:
- 63
- Issue:
- 3
- ISSN:
- 0032-3888
- Format(s):
- Medium: X Size: p. 943-958
- Size(s):
- p. 943-958
- Sponsoring Org:
- National Science Foundation
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