In previous blogs we discussed the value of involving your electronics manufacturing services (EMS) provider in design for manufacture (DFM), and some of the common mistakes that can occur when it comes to electronic assemblies. This blog post explores the importance of DfM in the even more complex and multi-disciplinary world of mechatronic assembly.
Design for Manufacture, also known as DfMA (Design for Manufacturing and Assembly) is the optimisation of a product so it can be built more efficiently and cost-effectively while improving quality and performance. In electromechanical assembly, DfM ensures that your designs can manage tolerance stacking and allow for faster production, greater automation, and ease of testing within complex, integrated systems.
Complex mechanical products are costly to manufacture — but even more costly if you get your designs wrong. According to research published in Science Direct:
"70% of the engineering changes which delay production are implemented to correct design issues that affect assembly, cost & quality".
Where mechanical systems, sensors and product housing must all align with pinpoint precision, even the smallest flaw in assembly can lead to significant production delays or performance issues. Ensuring consistent, reliable manufacturing of integrated systems requires exceptional attention to detail during the design process.
As the infographic below illustrates, making changes to a product in the design stage is much less costly and more impactful than trying to make changes once the product has been launched.
When it comes to ‘drawn items’, such as metalwork, you may well have a favourite supplier. But for each part have they really understood what you need? And can they make it to specification? Are they capable of producing the automated part placements and material properties that can suit robotic grippers and sensors where appropriate. Suppliers should also understand how to meet tighter tolerances required for robotic assembly. Nearly right" items won’t be good enough.
You need to leverage your EMS provider’s expertise in the supply chain to ensure quality and consistency across the board.
Breaking down complex system designs into smaller, interchangeable modules allows for more flexible and scalable manufacturing processes. It also facilitates easier repair, upgrades, and customisation of products in the future.
Surface finishes—particularly cosmetic finishes—can often be subjective and lead to discrepancies in quality. Clearly define and communicate your standards early on, especially for visually sensitive parts. Set measurable finish criteria to avoid misunderstandings and ensure consistency across suppliers and production batches.
Consider using 3D printing for low-volume, high-complexity parts or rapid prototyping. This reduces tooling costs and allows for more design flexibility. Combine traditional methods like CNC machining with modern techniques such as 3D printing for efficient, scalable production.
Each part in your assembly must have well-defined tolerances. These tolerances should account for both automated precision and manual assembly variances. As automated systems become more prevalent, even minor misalignments can disrupt mechatronic processes. Use 3D modeling and digital twins to simulate and optimise how components will fit together and interact in different tolerance build-up scenarios.
Simplifying your design is key to reducing assembly complexity. Apply methodologies such as Boothroyd Dewhurst’s approach to eliminate or combine parts by questioning whether each component:
Fewer parts not only make assembly easier but also reduces programming complexity and minimises production cycle times. This approach can also lower your environmental impact by reducing material usage and assembly energy costs, aligning with your sustainability goals.
With the rise of collaborative robots (cobots) working alongside human operators, assembly spaces must be designed with both in mind. Cobots need access to certain areas of the assembly, which requires more precise spacing, while humans need ergonomic design considerations. Large-format mechatronic machines may require heavy lifting equipment such as overhead cranes during or after production and the appropriate spacing for operators to use these. And where assembly lines are designed to be fully automated, consideration of raw material, utilities on the shop floor (electricity, compressed air lines etc) and overall production flow is required. Balancing these needs ensures seamless interaction and safety in modern factories.
ESCATEC’s DfM optimisations of Pfizer’s cold-chain flight case ‘data-loggers', included the semi-automation of production lines with soldering machines and automated screwing processes. During the pandemic, these automated solutions worked alongside human labour to significantly reduce production times of life saving technology.
For wiring-heavy assemblies, provide a detailed wiring schedule that includes cable type, size, color, length, and termination points. Wiring processes are increasingly aided by automated cable routing systems and smart diagnostic tools that can check wiring in real time. Incorporating digital tools and precise schedules will help ensure accuracy and efficiency.
Custom tooling can be a major cost driver and can significantly increase lead times. Wherever possible, standardise your parts to use existing tools. Custom tooling should only be used if justified by high-volume production or if it significantly improves the efficiency of the process.
Testing protocols should be integrated into the design from the beginning. Modern testing setups often involve both automated test equipment and human operators, especially for final checks like safety and functionality. Design your product to accommodate test probes, sensors, and other connections needed for earth bond testing and other critical evaluations. Incorporating IoT-based diagnostics can also help streamline this process.
DfM is a collaborative effort that involves multiple disciplines working together to optimise the design. The goal of a cross-functional DfM process is to evaluate the design at all levels—whether it's the component, sub-system, or system.
For this reason, it’s crucial to involve your EMS partner early on in the design process, along with other stakeholders to make the joint manufacturing and procurement decisions that can improve efficiencies.
Getting this process right helps ensure a cost-effective product build, shorter lead times, and greater product quality and reliability. Particularly when a number of drawn items are involved, getting it wrong can be costly, which is why it’s recommended to talk through the details of your project with your chosen EMS partner, so they can advise you on the best approach.