Sustainable thermoforming, and manufacturing as a whole, is quickly becoming more and more important. From a thermoforming standpoint, sustainability all starts with preventing plastic from becoming scrap in the first place.
Allied Plastics lists out how sustainable thermoforming is achievable through scrap rate reduction and what it takes to continually make a difference.
The Importance of Scrap Rate Reduction
When thermoforming operations happen, material is heated and formed over or into a tool, cooled, and then trimmed. Those trimmed pieces webbing between cavities, punched features, edge trim, startup pieces, and rejected parts all are from that initial sheet that was used to form a product. And that presents a lot of waste compared to material that’s used.
When this loss is reduced, sustainable thermoforming shows up in two key ways: source reduction and circular material use. Looking closely at circular material use, if scrap cannot be avoided, it can be regrouped and incorporated into a new sheet or appropriate future products.
Where Thermoforming Scrap Originates
Sustainable thermoforming happens by identifying sources of scrap and where it takes place.
| Scrap Source | Traditional Cause | Sustainable Consequence | First Response |
|---|---|---|---|
| Trim skeleton and web | Excess spacing between cavities, poor nest layout, or oversized clamp margins | High planned material loss per part | Improve multi-cavity layout, nesting, and trim design |
| Edge trim | Excessive sheet width or poor indexing | Continual and predictable loss | Match sheet width and pitch to tool geometry |
| Startup and changeover scrap | Heat-up, setup variation, and unproven project parameters | High loss on short runs and frequent SKU changes | Have a standardized setup, perform first-article approval, and monitor changeovers |
| Forming defects | Poor heating, plug assist problems, Weak vacuum or pressure, inconsistent cooling | Full sheet and energy are lost after value has been added | Stabilize process windows and maintain tooling throughout a manufacturing program |
| Trim defects | Misregistration, dull dies, and poor fixture control | Good formed parts become unusable at final operation | Improve trim tool condition, alignment, and registration |
| Cosmetic defects | Surface contamination, inconsistent material appearance, handling damage | Typically drive avoidable rejection in packaging and consumer products specifically | Control material handling, cleanliness, and incoming quality |
| Material variation | Sheet-thickness variation, moisture, regrind inconsistency, and color variation | Creates process instability and multiple downstream rejections | Specify and monitor incoming sheet properties, and promote documentation and sourcing. |
How to Improve Scrap Rate Reduction
Promoting sustainable thermoforming ultimately means improving scrap rate reduction and that starts first and foremost with improving part and tool layout. Design multi-cavity tools around the highest material utilization rather than the maximum cavity count. Reduce unneeded web spacing while preserving cooling, trim clearance, and tool strength. And match sheet width, index pitch, and cavity arrangement to minimize edge trim.
Secondly, design parts for stable forming. That might seem on its face, but poor part geometry creates more than just cosmetic difficulties. It increases the risk of thinning, webbing, tearing, uneven detail reproduction, and trim inconsistency – all of which results in scrap. This is all achievable through design for manufacturability reviews and focusing on the core principles of thermoforming design.
Third, stabilize the forming process. When thermoforming operations vary in your manufacturing program, so too does the scrap rate. When operations maintain the same measures in temperature, pressure, vacuum, cooling, material feed, and trim registration, the scrap rate remains the same throughout.
Four, reduce startup and changeover losses. Startup waste doesn’t have to been looked at as a normal cost of manufacturing, and it shouldn’t. A few ways to eliminate startup or changeover waste includes documenting a proven process recipe, using standardized operations, and confirming first articles before full production.
And lastly, place control on any and all incoming sheets. Thermoforming relies heavily on sheet consistency and when material comes back inconsistent, it’s likely going to lead to scrap waste.
Achieve Sustainable Thermoforming Operations and Contact Allied Plastics Today
Allied Plastics is the custom, heavy-gauge thermoforming manufacturing that OEMs, supplier programs, and other customer sources have relied on since 1995. From the beginning of our operation, we’ve promoted sustainable thermoforming operations.
From the products we manufacture like our reusable packaging, to our commitment to using sustainable materials and lowering our scrap rates year after year, we make a pointed effort to do our part in protecting tomorrow by being resourceful today. Our efforts in sustainability haven’t gone unnoticed either as we’ve been ISO 14001 certified for years now.
Practice sustainable thermoforming today and contact Allied Plastics ahead of your next thermoforming manufacturing program.