Using AOI false call reduction software increases first pass yield by 42 percent

Reducing false positives

Siemens Rastatt, which is part of Siemens AG, develops, manufactures and markets products and systems for heating, ventilation and air conditioning (HVAC) technology in Rastatt, Germany. Their products are used in a variety of applications, including forced-air burners, boilers, alternative heating systems and industrial plants. Siemens Rastatt provides complete system solutions as well as controls, actuators, valves, automatic burner control systems for oil and gas burners and associated test equipment.

Their components are found in residential boilers and larger systems, such as in airports. They are also used in industry; for example, in drying equipment in paint lines of major car manufacturers.

Siemens Rastatt has four production lines and each one includes an automated optical inspection (AOI) machine to check the printed circuit board assemblies (PCBA) on its products. The first pass yield (FPY) was only 60 percent and of the remaining 40 percent, 97.5 percent were false calls.

“Whenever the AOI detects a potential error, an operator must check the board manually,” says Tobias Morlock, head of process and technology (manufacturing) at Siemens Rastatt. “It requires time but it also leads to what is known in the industry as ‘alarm fatigue’ and eventually the operator will unintentionally make more mistakes and tend to be more likely to approve a faulty board, which will be discovered only later in the production process. This led to greater overhead and losses.

“Usually, we would ask our AOI experts to optimize the machine settings to decrease the level of false results. The AOI machine vendor offered a partial solution that helped to manually optimize the process. We were using that solution, but it provided limited help. When we became aware of the new Siemens Digital Industries Software solution, we tried it and were happy to see better results.”

Siemens Rastatt adopted Opcenter™ Intelligence AOI False Call Reduction (FCR) software, which helped improve their initial FPY by 42 percent without any additional effort by their AOI experts. Opcenter Intelligence is part of the Siemens Xcelerator business platform of software, hardware and services. Using Siemens Xcelerator enables customers to accelerate their digital transformation at scale.

Siemens Rastatt analyzed several artificial intelligence (AI) solutions. Most of the solutions required additional effort for integrating and developing interfaces for machines and implementing hardware, etc.

“The huge benefit of using Opcenter Intelligence AOI False Call Reduction was that we got a complete package from a responsible partner that operates on its own and provides a finished solution,” says Morlock.

“Opcenter Intelligence fits perfectly with our needs. We are always looking for innovative technical solutions and using Opcenter AOI FCR enabled significant improvement with reduced effort, which customers benefited from as well.

One of the big advantages of Opcenter AOI FCR is that it is a SaaS solution that significantly reduces the effort on our side. It was completely ready to be integrated into our AOI machines. It took less than 12 weeks to go from the first discussions to the start of commissioning. Twelve weeks later we started the operation phase successfully.”

With Opcenter Intelligence AOI FCR, an AI model is generated from AOI measurements data and operator-classified data. Concerns regarding escapes or slips are addressed in the assessment stage. Models are then validated to prove they have equal or better accuracy than the baseline.

The AI model is deployed to the shop floor on Siemens Industrial Edge devices and receives measurement data in real time from the AOI. The Industrial Edge platform provides decentralized and local data acquisition, analytics and transfer capabilities. In addition, it allows the user to deploy any software rapidly and reliably on to the shop floor, which reduces complexity and information technology (IT) costs by providing edge device and application lifecycle management (ALM) functionalities. Further, the Industrial Edge ecosystem provides secure data handling in production by using industrial grade hardware.

Using Opcenter Intelligence does not require the customer domain experts to have knowledge of Industrial Edge as it is covered by the AI lifecycle.

The AI consumes measurement data and outputs a decision: for instance, is the board a false call or potentially a real error? The result is delivered before the operator needs to check the board, saving time and effort. The AI is consistently more accurate than the operator and fewer mistakes are made deciding whether a real or false error has occurred.

Opcenter Intelligence AOI FCR is integrated into the four production lines. The AI result is seamlessly integrated into the testing station without disrupting the regular user experience of the operator.

Siemens provides full support

There were a number of keys to success to Siemens Rastatt’s implementation of Opcenter Intelligence AOI FCR: It does not require any AI expertise or user training and implementation was intuitive and rapid. The solution can be used out-of-the-box (OOTB) and the AOI experts do not experience any changes in their user experience.

The key factor is the seamless integration with the customer infrastructure and Siemens’ continual updating and refining of models. Machine learning operation services are used to continually optimize the availability and performance of models.

“The great thing about Opcenter Intelligence AOI FCR is you get the entire solution from one source,” says Morlock. “That makes it easy and fast to implement. Siemens Digital Industries Software does everything in the background. That helps us to focus our resources on more important tasks.

“Because of the smart solution from Siemens Digital Industries Software, the implementation was very quick. They provided a complete package of SaaS, including finished and tested interfaces to our AOI machine. Thanks to the remote access to our data, Siemens Digital Industries Software can work and optimize the AI in the background without any additional effort from us.”

Siemens Rastatt expects to use Opcenter Intelligence AOI FCR to drill down and configure the AOI parameters to directly impact the FPY at the source, and leverage AI to explore the routing of good boards sequentially. They are also considering using it as part of shop floor automation and for component analysis.