Case study
How to Automate the Assembly of 26 Product Variants
Context – Who Is Our Client and What Problem Did They Face?
Our client manufactures specialized components for automotive headrests. Despite their small size, these parts play a critical role in passenger safety. Therefore, their quality and manufacturing precision must be unquestionable.
Additionally, the plant produces customized products for multiple end customers. As a result, there are as many as 26 product references, differing in geometry and color variants.
The robotic component assembly system therefore had to be both flexible and highly precise.
Main Project Goals
- System Flexibility
Assembling 26 different product references requires rapid process changes while maintaining high quality and productivity.
- Increased Production Volumes
The system was designed to support high production volumes.
- Automation of Precise Manual Operations
Previously, component assembly was performed manually. Robots took over these tasks, while operators supervise their operation and workstation changeovers.
- Product Quality Control
Full traceability of every component and complete process monitoring guarantee that only products meeting all requirements leave the assembly line.
Planned Results
- Increased production efficiency.
- Reduced cycle time and minimal operator involvement.
- Maximum process automation.
- A production process adaptable to multiple variants without requiring extensive and time-consuming modifications – fast changeovers.
- Full traceability of every component through vision inspection and laser marking.
- High safety and quality standards.
Robotic Assembly and Automation
Process Flow at the Workstation
Stage I. Preparation and Feeding of Components (Pick & Place)
- The process begins with loading steel components, pins, and springs into VIBE Industries vibratory feeders. Each component type has a dedicated feeder controlled by the PLC system.
- Vibratory bowls ensure separation, queuing, reorientation, and precise positioning of components in the final nest.
- Polymer components, buttons, and caps are delivered to the station using the FlexiBowl system. Vibrationally dispersed parts are identified by the FlexiVision vision system, which transmits coordinates to the FANUC SCARA robot for picking.
Stage II. Loading, Laser Gates, and DMC Traceability
- The main production process starts with manual loading of polymer housings onto pallets at the loading station.
- Laser gates minimize operator errors by verifying the presence and height of input components.
- The central point of the workstation is a 3-position rotary table that ensures the correct sequence of operations. One of these operations is UV laser marking with DMC (Data Matrix Code), enabling full traceability of each component – the so-called “birth certificate.”
Stage III. Robotic Assembly and Vision Inspection
- The FANUC SCARA SR12iA robot picks components from the VIBE and FlexiBowl systems and places the sets onto pallets at the ST30 process station.
- At this station, pins are assembled into buttons, with the process monitored in real time by Cognex In-Sight 2800 vision systems.
- Simultaneously, a 6-axis FANUC robot positions the housings in the assembly zone. After successful inspection, the press-fit (snap-fit) process of inserting buttons into housings takes place.
Stage IV. Final Inspection and NOK Zone
- Final vision inspection confirms assembly correctness. Components that do not meet requirements are automatically directed to the NOK zone.
- The entire process is supervised by dedicated PLC software, ensuring repeatability, safety, and full process control.
Biggest Challenges During Implementation
- Safety-Critical Process (ST30 Station)
- Challenge: precise press-fitting of pins into the housing. The process required balancing safety and usability: easy enough to remove under normal conditions, yet stable during collisions.
- Solution: monitoring every “click” using force sensors and process parameter control.
- Result: compliance with customer requirements and stable, repeatable assembly.
- Geometry Changes in Polymer Components After Conditioning
- Challenge: some components are made of polymers subjected to conditioning. Water absorption increases flexibility but may also alter part dimensions, making gripping and transfer more difficult.
- Solution: adaptation of grippers and assembly parameters to dimensional variability.
- Result: stable process performance and maintained quality despite natural material deviations.
Technologies and Solutions
Results
Assembly of 26 product variants on a single robotic workstation
Less than 10 minutes changeover time between variants
Cycle time reduced to as little as 30 seconds
100% product quality control
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