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Overcoming Inspection Challenges for Automotive Assembly Applications

Posted By Chi Ho Ng on July 18, 2014 at 10:00 AM

Quality control is especially important in the automotive industry as people’s lives are put at risk when vehicles are not manufactured correctly. Not meeting quality standards can threaten an automaker’s reputation, ultimately damaging the brand and the business. Consequently, implementing a good inspection system in the manufacturing process is essential.

Inspection for automotive assembly applications has its own set of challenges. Automotive assembly lines typically have hundreds of inspection points. These inspection points include in-process monitoring, individual subassembly monitoring, and critical inspection of many points on the assembled bodies in white. Many inspection points must be monitored to ensure that components fit properly and connecting features are aligned correctly during the installation process. During final assembly, vehicles need to be inspected for proper geometry. Having a proper inspection solution in place provides confidence that consistent product quality levels are met during in-process and at final product assembly.

Conventional inspection systems are often complex and expensive to implement into existing facilities due to the amount of componentry and labor required. There is room for improvement to streamline the inspection process to optimize efficiency. Here, we will examine some of the challenges of inspecting automotive assembly features with conventional systems.

Challenge #1: Inspecting many types of complex features with a variety of materials


Assembling large objects such as automotive bodies and their subassemblies require the inspection of many types of complex features including surfaces, holes, slots, nuts, and studs. These features also vary in materials and color from stamped steel, aluminum, to plastic and composites. If a different inspection solution is required to handle each type of complex feature for each type of material, this puts on added complexity that should be avoided.

But what if there is one inspection device that doesn't require complicated setups and can handle all these variations?

The consistency of using one solution such as a 3D smart sensor across the manufacturing floor simplifies the inspection process and produces huge savings in training costs, as employees would only need to be trained on one system. A device that is simple to setup provides the flexibility to change the critical parameters such as the selection of measurement parameters and exposure settings, depending on the type of feature and materials that need to be inspected.

An inspection solution that has a common technology platform across different scanning technologies (displacement, profile, and snapshot) gives manufacturing facilities even more flexibility. Having a consistent user experience enables different scanning technologies to be easily implemented in one station to measure complicated applications.

Challenge #2: Inspecting multiple features of a part

Conventional solutions typically require multiple inspection cycles for different features in order to inspect multiple features of a part. As I mentioned in challenge #1, this is often the case since each feature on the part has its own requirements. If features need to be inspected one at a time, this slows down the entire inspection process.

Efficiency is optimized when multiple features are inspected at one time simultaneously instead of inspecting each feature one by one. By implementing an inspection solution that is capable of inspecting multiple features of a part at one time, cycle time is greatly reduced.


Conventional solutions require sending data to a computer and computing 3D measurements one at a time. Efficiency is optimized when 3D smart sensors can make several measurements simultaneously as shown in the photo. The power of built-in measurement tools in the sensors allow calculations to happen in parallel.

Challenge #3: Conventional inspection systems require additional componentry and software that may come from multiple sources.

Implementing conventional systems are often labor intensive to setup due to the amount of componentry and software required. These additional requirements often are disguised as hidden costs that can make implementing an inspection system costly. For example, robotic inspection stations can be complex, with multiple PCs distributed throughout the cell for processing and analysis and with multiple communication chains. 


In conventional inspection solutions, one dedicated computer is required for each set of sensor and robotic arm. The computer communicates with the robotic arm and the sensor separately.

The cell using 3D smart sensors provides a simpler, more robust solution than conventional solutions. 


Using a smart sensor, a dedicated computer is not required as it communicates directly to the robot controller. 

With the use of a 3D smart sensor for an inspection system, cell configuration can be simplified. What makes a 3D smart sensor ‘smart’ is its ability to make 3D measurement and control decisions (sorting, pass/fail, alerts) all within the device with no PC required. It scans shapes, measures critical dimensions, and communications to factory floor equipment all from a web browser. This eliminates the need for a dedicated computer for each set of sensor and robotic arm. The smart sensors communicate directly to the robot controllers with simplified cabling.

With measuring algorithms integrated into the sensor, no additional software is required. This greatly reduces development costs as measurement tools eliminate the need for development of application specific software.

Simplicity of setup with all functions contained inside the sensor also enables in-process diagnostics and troubleshooting. Sensors can be moved to different locations in the assembly line to collect data and determine which operations are introducing variations. 

By reducing the complexity of design, operation, and maintenance, the total cost of ownership can be very attractive with the simplified inspection solution that results in cost savings.


Written by:
Chi Ho Ng
Product Group Manager of LMI Technologies 

Chi Ho Ng is responsible for guiding new product strategy and working with strategic partners to develop new market opportunities at LMI. He also oversees the application engineering group, establishing processes and nurturing a customer-centric culture. Chi Ho will be a presenter at the Automotive Manufacturing Technology & Material Show (AMTS) on August 11-13, 2014 in Shanghai, China. 


Posted by Chi Ho Ng