Our Goal Must be Zero Waste in Molding

Jeremy: Resin is the raw material used in injection molding processes to form plastic components. It is polymerized from either organic or synthetic sources, with synthetic being the most common. Within injection molding, there are two common polymer families: thermoplastic, which is recyclable, and thermoset, which isn’t. Resin is a versatile material and an essential part of many TE products. However, it also represents one of our biggest CO₂- and waste-reduction opportunities.

Christopher: Our first step is to avoid resin waste by using alternative molding methods. Where this is not possible, we regrind old resin for reuse. If neither method is feasible, we consider external re-compounding. In fiscal year 2023, TE avoided buying approximately 9,500 metric tons of virgin material by using regrind and external re-compounding. This prevented approximately 57,000 metric tons of CO₂ emissions. We simultaneously reduced resin waste by 9 percent through smarter design. Our goal must be zero waste in molding, so we still have some work ahead of us. 

Jeremy: There are several ways to guide the molten plastic into the molds to create our thermoplastic parts. These systems include full cold runner, full hot runner, or a mix of both. Anything produced beyond the plastic part is referred to as waste. Cold runner waste can be recycled as regrind since thermoplastic resins can be remelted. In comparison, the full hot runner system, also known as direct gating, is the only melt delivery system that doesn’t generate waste. Therefore, an intentional focus on mold and product design to facilitate the use of direct gating is necessary to save additional resin waste. While transitioning towards direct gating can pose both financial and technical challenges, the benefits become apparent in large high-volume production operations.

Christopher: Direct gating shows that sustainability and productivity can go hand in hand. Generally, the sprue is considered a non-value-adding element in the molding process and is unrelated to lean molding principles. Even if excess sprue can be recycled into regrind, it necessitates additional handling, consuming time, energy, maintenance and ultimately proving unnecessary. By expanding the use of direct gating, we are helping to reduce resin waste and increase our production efficiency. In addition, direct gating runs as a closed process, so we can minimize the risk of injuries for our colleagues. 

Jeremy: In one of TE’s business units, we set up an international task force at the end of 2023 in collaboration with Operations leaders. Our goal is to define where it makes sense to use direct gating at TE plants through a technical evaluation procedure. We assess factors like available space for a direct gating nozzle on the product surface, the possibility of design changes, and investment costs. If the answer is ‘yes’ to all these factors, we plan to switch to direct gating. So far, we have been able to review a cluster of several products. The result was that almost all of them could be direct gated, reducing resin waste to zero. Our goal in 2024 is to collaborate with mold design experts and product engineering teams to identify more products for direct gating and continue to reduce resin waste further.