A buyer’s guide to production measurement automation
Production is the key process in bringing the end user products into the market. For our customers, this involves production technology validation, traveling to the factories, meeting tight line ramp-up deadlines and ensuring that production costs are within the business case for the product. In a later phase, the focus moves into production line efficiency improvements and maintaining the systems. Equipment vendor capabilities and level of experience has significant influence on the level of required effort. This blog is outlining our experience for how to create successful projects, a checklist for the key ingredients.
Saying "Well planned is half done" makes perfect sense in measurement automation. In fact, the key for successful projects is to understand production automation targets, measurement, interfaces and delivery logistics. When setting up the project, this understanding provides a solid starting point for the project.
In general, production automation aims at generating value as improved compliance, cost level, quality of results, yield and overall efficiency:
- Compliance: the key target of production measurement and calibration is to ensure that the manufactured units meet the product specifications, i.e. the product quality.
- Cost level: automation provides tools for improving the line throughput and reducing the labor costs. Typically performance metrics are units per hour (UPH), resource level and CAPEX costs.
- Quality of results: automation provides both enhanced accuracy and repeatability when compared to a manual or a semi-automated process, measured by Gage Repeatability & Reproducibility (GRR) metrics or similar.
- Yield: test automation provides the data for the yield improvement (percentage of non-defective items of all produced items).
- Overall efficiency is a combination of the above mentioned items, measured typically with Statistical Process Control (SPC) for continuous monitoring and development.
Successful projects have typically well-defined targets for the automation. The production automation targets provide priorities which have a big impact on the technological choices used in the station design. This target setting also enables possibly needed priority discussion already at the concept design phase to find the correct balance e.g., between UPH, measurement accuracy and cost. Having these discussions and setting achievable targets is important - no surprises should occur in the later phase of the project.
Measurement definition provides the purpose for the test system. This is typically defined in the form of a test list. A test list is created to establish understanding about the relevant phenomenon to be measured, the necessary measurement data for the test result (e.g., to define pass/fail thresholds) and a necessary level of test configurability. The test list is examined hand-in-hand with the production automation targets and performance targets such as the measurement accuracy, resolution and repeatability requirements. Measurement definition makes it possible to create a system concept:
- To find and select the best-suited measurement method and sequence, the key operating principle for the measurement.
- To screen and select the measurement instruments (e.g., camera, optics, illumination, and other sensors)
- To define the actuators providing the required performance (e.g., motion accuracy)
- To develop mechatronics 3D illustration about the system (including moving axis, measurement sequence)
- To create concept description including functions of sub-modules and their interaction as a complete system
Interfaces define how the test system is operated and what the sequence of actions in each interface is – for a production line station the interfaces include:
- Operator interface – how the operator interacts with the system, including system safety
- Physical interfaces – including cabinet size and shape as well as electrical, pneumatics and data interfaces
- Material handling - the way to move and physically interact with the device under test (DUT)
- DUT communication - identify and interact with the DUT software or firmware
- Measurement instruments and actuators – the equipment for control, actuation, sensing and data acquisition
- Data analysis – analyzing the raw data to produce the measurement results
- Reporting – providing the measurement results for the host system, e.g., factory data management or manufacturing execution system (MES)
- Configuration – toolset for setting up the system, making calibrations and configuring the test list, pass/fail criteria and system parameters
- Test sequence – the procedure to carry out the measurement sequence using all the interfaces
Well-defined and designed interfaces enable validation of system parts and the system as a whole. Having a well-thought-out sequence of actions is important for system reliability. Parallelism enables improved UPH e.g., by completing the analysis of previous DUT in parallel with measuring the next DUT. System level design is an area where the experience is very valuable; this enables performance, innovative designs, maintenance and use of proven technology platforms.
The purpose of delivery logistics is to create the demand-supply network for the station which is suited for the needs of factory locations and processes. Work at the factories is typically split into three phases: pre-production, line ramp-up and sustaining-mode production. Defining the delivery logistics to meet the demands in each phase is important – making it possible to meet the schedules and produce good quality prototypes and products. Delivery logistics involves:
- Station manufacturing – parts lead times and availability, incoming quality check (IQC), assembly quality control, burn-in, testing and outgoing quality check (OQC), packing
- Shipping – lead time for shipping and customs, delivery term used, cost level of tariffs, factory incoming shipments procedures
- Pre-production builds – arrangements for tools, resourcing and access rights, on-site work for installing, setting up and calibrating the stations, developing the best fit test sequence and pass/fail thresholds, validating the station accuracy and repeatability
- Production ramp-up – similar to pre-production but without development, focus on GRR for the stations to ensure station to station variations are within limits
- Sustaining production – OSS including on-site and off-site support, station performance monitoring and improvements, spare parts, repairs, maintenance and periodical calibrations
Work at the factory is fast-paced. This is the point where everything comes together – including the product hardware and software and the stations in the production line. Experience in the delivery logistics helps quite a bit in preparing, making things run smoothly and dealing with unexpected changes.
OptoFidelity can deliver turnkey production measurement and calibration systems – this statement is backed by 100+ different purpose-built systems that OptoFidelity has developed for volume production. Our systems are designed to fulfill the customer-specific measurement needs and used by world-leading manufacturers of smartphones, tablet computers, AR/VR devices, laptops, vehicle infotainment systems and industrial smart machinery.
Based on several years of experience, OptoFidelity has developed standard products and technology platforms to efficiently combine software, robotics, camera technologies and sensors to create demanding test systems. This gives a head start for the projects as the OptoFidelity platform frequently provides a large part of the needed overall implementation.
We at OptoFidelity are always trying to find ways to improve our working methods to support our customers’ needs – we have built our expertise and capabilities since 2005. Currently, OptoFidelity provides operations and service support for an installed base of 5,000+ pieces of measurement equipment in China, Vietnam, Taiwan and the USA. Our philosophy is to work close to our customers in both R&D and production, and we have design teams in the USA, Finland and China who are easy to work with. OptoFidelity provides delivery logistics with test equipment manufacturing in China and Europe. As a team, we have special expertise in mechatronics, optical metrology, signal processing and software as well as system design for production equipment. Together with special application expertise for measuring smartphone sensors, AR/VR technology, displays and touch UI, we can provide unique value for our customers.
OptoFidelity also has a range of standard solutions including:
- TOUCH – touch sensor testing for finger and stylus use cases
- HMD IQ – near eye display testing
- BUDDY - near eye display performance testing
- FUSION – all in one tester for smart devices
- FLOW – material handling automation for wafers
Standard solutions are tailored to support customer-specific measurement and interfaces.