Development of a Soda-Lime Glass Feedstock for Injection Molding

Area of Science:

• Materials Science
• Powder Technology
• Ceramics Engineering

Background:

• Injection molding is widely used for thermoplastics, metals, and ceramics.
• Glass part fabrication via powder technology methods is less common.
• This research explores glass injection molding using a commercial soda-lime glass.

Purpose of the Study:

• To investigate the feasibility of producing glass parts using powder injection molding.
• To develop and characterize a suitable feedstock system for glass injection molding.
• To optimize the process chain, including compounding, shaping, debinding, and sintering.

Main Methods:

• Compounding soda-lime glass powder (6.1 µm particle size) with binders like polyethylene glycol (PEG), polyvinyl butyral (PVB), and stearic acid (SA).
• Utilizing solid loads of 55 Vol% and 60 Vol% in the feedstock.
• Injection molding of various shapes, followed by water debinding (for PEG removal) and thermal debinding.
• Sintering the glass parts at temperatures between 660-680 °C.

Main Results:

• Feedstocks exhibited pseudoplastic flow behavior across a wide shear rate range.
• Low equilibrium torque values (2.5-5.5 Nm) were observed during compounding.
• Injection molded parts (disks, cuboids, plates) achieved good quality.
• Sintered glass parts reached density values close to 100% of the theoretical density.

Conclusions:

• The principal feasibility of glass injection molding was successfully demonstrated.
• A suitable feedstock system is crucial for achieving high-quality sintered glass components.
• This process offers a viable route for fabricating complex glass devices.