Lowering injection molding costs is a systematic project that requires optimization across multiple stages, including design, material selection, production, and management.
I. Design Stage: The Decisive Factor (Where 70% of Cost Savings Are Determined)
Excellent “Design for Manufacturability” (DFM) is the most effective way to reduce costs.
- Optimizing Part Design
Uniform Wall Thickness: This is the most critical principle. Uneven walls lead to sinking, warping, and internal stress, increasing the reject rate. Strive for uniform wall thickness and use ribs to achieve the required strength.
Simplify Geometry: Simplify the part’s geometry as much as possible without compromising function. Reducing complex curves, undercuts, and sliders can significantly decrease mold complexity and cost.
Use Standard Components: Incorporate standard screws, snap-fits, etc., wherever possible in the design. Avoiding custom, special structures can lower subsequent mold and assembly costs.
- Optimizing Mold Design
Optimal Number of Cavities: Select the number of cavities based on annual production volume. More cavities are not always better; excessive cavities increase mold cost, required machine tonnage, and energy consumption. Find the balance through scientific calculation.
Implement Hot Runner Systems: For large parts or high-volume production, hot runner systems eliminate waste material from cold runners, saving material and shortening the cycle time.
Efficient Cooling System: Cooling time typically accounts for over 70% of the total injection cycle. Designing uniform and efficient cooling channels can significantly reduce cooling time and boost production efficiency.
Appropriate Mold Steel: For high-volume production, using high-quality, wear-resistant mold steel (e.g., ASSAB series) may have a higher initial cost, but it offers a longer lifespan and lower maintenance costs, proving more economical in the long run. For low volumes, pre-hardened steel or aluminum molds can be considered.
II. Material Selection: Balancing Performance and Cost
Material Comparison and Selection: Choose a lower-cost material that still meets the product’s performance requirements (e.g., strength, heat resistance, chemical resistance). For example, switching from ABS to PP can yield significant savings.
Using Regrind: For non-cosmetic parts or internal components with lower strength requirements, consider blending a certain percentage of strictly processed recycled material (regrind) with virgin material.
Reducing Material Usage: Employ “lightweighting” strategies to reduce part weight without compromising performance, for instance, by using analysis software to optimize wall thickness and rib design.
III. Production Process Optimization: Driving Efficiency for Profit
- Optimizing Process Parameters
Reduce Cycle Time: Optimizing injection speed, packing pressure and time, and cooling time is crucial. Saving even one or two seconds per cycle becomes extremely significant over millions of parts.
Lower Melting Temperature and Injection Pressure: Reducing melt temperature and injection pressure, where product quality permits, saves energy and extends the life of both the mold and the machine.
- Promoting Automation
Using Robotics: Robots can automatically remove parts, detach runners, and insert components, enabling unattended operation. This drastically reduces labor costs, ensures consistent cycle times, and improves product uniformity. - Comprehensive Quality Management
Strengthen Process Control: Implement strict “First-Article Inspection” and “In-Process Inspection” regimes to detect abnormalities promptly and avoid large batches of defective parts. “Doing it right the first time” is the greatest cost savings.
Statistical Process Control (SPC): Use SPC tools to monitor the stability of key process parameters, enabling predictive control and preventing defects.
IV. Operations and Management: Details Make the Difference
Scientific Mold Maintenance: Establish a regular mold maintenance schedule, including cleaning, rust prevention, and replacement of wear parts. Well-maintained molds prevent costly unplanned downtime due to sudden failure and ensure consistent product quality.
Rational Production Planning: Optimize production scheduling to reduce the frequency of mold changes and machine setup time, thereby improving equipment utilization.
Build Strategic Partnerships with Suppliers: Develop long-term relationships with your mold and material suppliers. They can often provide valuable cost-saving advice and may offer better pricing and support.
Reducing injection molding costs is an ongoing, collaborative process. The most effective strategy is to start cost control at the source—the design stage.
At ATC-Mould, our integrated team—spanning quoting, design, processing, quality control, trial runs, and mass production—works in unison to deliver tailored, optimal mold solutions for every client.
We optimize your injection molding process and reduce costs through a multi-faceted approach, meticulously considering:
Cavity Configuration & Steel Selection
Gating Method & Cooling Line Layout
Mold Machining Precision & Trial Parameter Setup
Machine Tonnage Selection & Post-Production Fixture Design