Quality in electronics manufacturing
Outsourcing electronics development and production is a sensible option for many companies in order to shorten time-to-market and reduce costs. At the same time, quality can often be improved. However, a prerequisite for products that are technically and economically convincing is a product development process that really produces quality.
Product quality is indispensable if you want to hold your own in the market and satisfy your customers. However, quality is not an absolute term. According to the valid standard for quality management, EN ISO 9000:2005, quality is defined as "the degree to which a set of inherent characteristics meets requirements". Quality thus indicates the degree to which a product, good or service meets existing requirements.
"These requirements can now differ depending on the product," explains Hermann Schweizer, Managing Director at Bavaria Digital Technik GmbH. "In this context, quality can only ever be realized to the extent that it corresponds to the intended use of a product. Anything else would be technical overhead that ultimately no one should pay for." In
No technical overhead
In this context, the IPC-A-610, launched by the American Association Connecting Electronics Industries (IPC), is of interest, as it now has a very high status worldwide in the entire process chain for the manufacture of electronic products.
The quality must correspond to the intended use
For example, the IPC with acceptance criteria for electronic assemblies is the guideline for many contractual partners, and this across countries, regardless of whether it is the USA, Asia or Europe. It sets quasi-global standards for the entire process of electronic devices and defines the relevant topics such as material, design, production, assembly, data, etc.. In addition, it distinguishes in principle between three quality classes: ordinary electronic products (class 1), electronic products intended for a specific purpose (class 2) and high-performance electronics (class 3).
"As a service provider in electronics manufacturing, we speak in this context of a duality of quality requirements," Schweizer continues. "Because if you exclude 'ordinary electronic products' for once, our customers come from two areas: Either we develop and manufacture products for them for the industrial sector with high reliability requirements or they are high-performance electronics for special application areas, for example aerospace, medical technology, etc."
For both areas, the specialists at Bavaria Digital-Technik have defined the corresponding product development processes, which are then adhered to in close consultation with the respective customer and tailored to the respective product (Fig. 2). The individual development and production stages always keep the end product in mind and are designed to produce the quality that is ultimately desired. Important criteria
Quality at every stage
are the (lowest possible) time required for realization, minimization of rejects, rework and repair as well as safety and failure rates.
"After all, our customers want to have satisfied customers themselves and, if possible, never see a product again after it has been shipped ", says Schweizer.
Focus on the end product from the start
The individual process steps follow the IPC recommendations and concern procurement and logistics as well as supply chain management (SCM). The foundation for the quality requirements of the end product is therefore already laid in the development and design phase, for example with the specifications of materials, surfaces and auxiliary materials, a production assessment and the definition of the quality-accompanying processes such as FMEA (Failure Mode and Effects Analysis). Classification, handling, packaging and shipping of the components used are further points that need to be considered early in the development and design process. For some products, for example, certain components must not come into contact with moisture, either during shipping or storage, in order to avoid (expensive) re-treatment. For other products, however, this is less critical.
Acceptance criteria and supplier qualifications must therefore also be included from the outset. "What has not been considered at one stage of the process chain is difficult or even impossible to rectify at another point," summarises Schweizer. "We therefore keep the risks low from the outset, or consciously control them, so that there are no surprises afterwards and we develop products according to IPC Class 1 or Class 2, which can then also convince in terms of quality and price." Depending on the intended use of the end product, for example, the geometries and surfaces have to be calculated in the design phase, impedances and the necessary insulation have to be defined, the heat dissipation and connection surfaces have to be planned and the production aids have to be specified.
Process chain with a lot of know-how
Production and test
The production processes and technologies used are then assigned criteria in accordance with the IPC, because the "class" requires different levels of severity when fulfilled. This means that class 2 requirements would not be sufficient for class 3. This applies, for example, to the characteristics of the conductor paths, the design of the solder joints, pin lengths or mechanical fastenings. "The tendency here is to always try to meet the higher requirement," Schweizer continues. "However, it is definitely noticeable in the price if we can run the machines for SMT or THT assembly faster for class 2 products, for example."
The IPC criteria also come into play in the final testing and reworking phase. "A great deal of know-how is required here," emphasizes Schweizer, "since, for example, in the case of optical inspection (Fig. 3), one should not be satisfied only with the defined threshold values. Our 'learning inspection library' supports us a lot here." The electronics specialists then demonstrate their classification know-how once again in the final stage of the process chain, where rework is involved. Handling, cleaning, repair techniques and tools used must also be oriented to the respective classification here. "At the end of this process, there is then a product that is technically and economically convincing because it corresponds exactly to the classifications required for its intended use," Schweizer continues. There are examples of this across all industries. Example: A control unit for automotive lighting complies with IPC-A-610 Class 2. When redesigning on a single-sided circuit board, a key point was cost optimisation combined with high reliability requirements. In the case of the electronics developed for the safety sector (Fig. 4), which comply with Class 3, the focus was on mechanical strength and insensitivity to environmental influences.
