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Two-Shot Injection Molding: Bike Seat
A cost-effective solution was successfully implemented to address this technically demanding and potentially labor-intensive challenge faced by our customer. By leveraging the two-shot injection molding approach, we achieved significant cost savings and ensured consistent production quality and repeatability.
1. Customer's Scenario
2. Key Problems Faced by the Customer
3. Proposed Solutions
4. Results Achieved
5. Conclusion
- Enhanced Durability: Complete elimination of moisture leakage, ensuring the part meets high-quality standards.
- Process Optimization: Over 70% process reduction achieved by eliminating unnecessary material handling and assembly.
- Quality Improvement: By manufacturing the part in a single injection molding process, the production quality yield improved by more than 100%.
2. Key Problems Faced by the Customer
3. Proposed Solutions
4. Results Achieved
5. Conclusion
Customer's Scenario
The need for a two-shot injection molding solution arises as the customer encounters challenges in developing and manufacturing a multi-component part requiring the integration of two different thermoplastic polymers.
Key Challenges Faced by the Customer
The primary challenges in part development and production include:
- Selecting appropriate thermoplastic polymers that meet stringent cosmetic and functional requirements.
- Assembling and bonding two separate hard plastic polymers with differing mechanical properties.
- Integrating the soft thermoplastic with the hard plastic frame.
- Ensuring the part passes lifetime durability and waterproofing tests.
Our Proposed Solution
a. Two-Shot Injection Molding: The Best Way Forward
After evaluating the part geometry and its requirements, we determined that the most cost-effective and robust solution is to develop and produce the part in a single injection molding cycle using a two-shot injection molding process.
We proposed and implemented geometric modifications to the CAD design, making it feasible to manufacture the part using this innovative approach.
b. Challenges Encountered
- Material Interaction:
A key challenge was preventing the second-shot material from melting or deforming the first shot during the second molding cycle. This required meticulous material selection and processing adjustments.
- Delamination Risks:
Another significant issue was the potential for delamination between the individual components after molding, particularly for the soft thermoplastic bonding with the hard plastic.
- Limited Bonding Area:
The assembly was confined within a very tight package, limiting the bonding area between the hard and soft thermoplastics. This posed risks of delamination during cycle testing or even failure during use. To address this, we reviewed the entire assembly, including the internal electronics, and incorporated additional contact points to enhance bonding strength.
- Objective
The double injection molding approach was selected to simplify the manufacturing process, reduce production costs, and enhance the overall functionality of the final part. This innovative solution ensures a robust, efficient, and high-performance outcome.
Results
The part was successfully developed and produced with the following outcomes:
- Enhanced Durability: Complete elimination of moisture leakage, ensuring the part meets high-quality standards.
- Process Optimization: Over 70% process reduction achieved by eliminating unnecessary material handling and assembly.
- Quality Improvement: By manufacturing the part in a single injection molding process, the production quality yield improved by more than 100%.