Project: Motor Housing with Embedded Metal Inserts
Client: Electronics Manufacturer | Industry: Industrial Electronics | Timeline: 6 Weeks
Project Overview
An electronics manufacturer required motor housings with precisely positioned metal inserts for their industrial motor product line. The housings needed to securely hold metal bearings, shafts, and electrical contacts while maintaining tight positional tolerances and excellent structural integrity.
The challenge was to automate the insert loading process to achieve high production volumes while ensuring perfect positioning of every insert. Manual placement was too slow and inconsistent for their quality requirements.
Technical Challenges
This insert molding project required solving several complex engineering challenges:
- Insert Positioning: Achieve ±0.02mm positional accuracy for 8 different inserts per part
- Bond Strength: Ensure metal-plastic bond withstands motor vibration and thermal cycling
- Production Speed: Meet customer’s requirement of 500 parts per day
- Consistency: Maintain quality across 100,000+ unit production run
- Material Compatibility: Bond steel, brass, and aluminum inserts with engineering plastic
- Electrical Properties: Maintain proper insulation between electrical contacts
Our Engineering Solution
Automated Insert Loading System
We designed and implemented a fully automated insert loading system:
- Vibratory bowl feeders for each insert type (bearings, shafts, contacts)
- Servo-driven robotic placement system with vision verification
- Positional accuracy of ±0.015mm (better than ±0.02mm requirement)
- Automatic insert orientation and quality checking before placement
- Cycle time of 38 seconds including all insert loading operations
Mold Design
Precision mold design ensured proper insert encapsulation and part quality:
- Multi-cavity mold (4 cavities) for production efficiency
- Precision insert pockets with location verification sensors
- Optimized gating system to prevent insert movement during injection
- Conformal cooling for uniform temperature and reduced cycle time
- Quick-change insert fixtures for fast mold setup and changeover
Material Selection
We selected materials for optimal performance and bonding:
- Housing Material: 30% glass-filled Nylon 6/6 for strength and dimensional stability
- Bearing Inserts: Precision steel bearings with special surface treatment for bonding
- Electrical Contacts: C360 brass with tin plating for conductivity and corrosion resistance
- Shaft Inserts: 12L14 steel with knurled surface for enhanced mechanical lock
Production Results
The automated insert molding system delivered outstanding results:
- Production Rate: 600 parts per day (20% above requirement)
- Positional Accuracy: ±0.012mm average (better than ±0.02mm requirement)
- Bond Strength: 12.5 N/mm pull-out strength (exceeding 8 N/mm requirement)
- Quality Rate: 99.7% first-pass yield
- Labor Savings: 75% reduction in labor cost vs. manual assembly
- Lead Time: 6 weeks from project kickoff to production parts
Quality Assurance
Comprehensive quality control ensured every part met specifications:
- In-process vision system verifying insert presence and position every cycle
- Statistical process control (SPC) monitoring critical dimensions
- Pull-out strength testing every 100 parts for bond verification
- Electrical testing for insulation resistance and continuity
- Full dimensional inspection with CMM for first article and periodic checks
Customer Benefits
The insert molding solution delivered significant value to the customer:
- Eliminated 4 secondary assembly operations (bearing press, contact insertion, etc.)
- Reduced part count from 12 to 1 integrated assembly
- Improved product reliability with consistent insert positioning
- Reduced warranty claims by 60% due to improved assembly quality
- Enabled production scaling without additional labor costs
Have an insert molding challenge? Contact TakumiTech® for innovative solutions.