One of the main points when approaching the development of a product is its manufacture. First of all, it is important to clarify the distinction between a prototype and a final product. A prototype aims to demonstrate the operating principle of a device, mostly composed of the elements that will be present in the final device but that has been made in a “handmade” way. On the other hand, the final mass-produced products are the result of an industrialization process that bears little or no resemblance to that of prototypes. It is therefore key to understand well which guidelines are the most widespread to ensure that the recurring manufacture of your product is a complete success.
The importance of DfX
Within the electronics industry, one of the most widespread words is DfX (Design for Excellence). Under this denomination, it is intended to group a set of guidelines and recommendations that extend throughout the entire lifecycle of a product, from its design, through its launching on the market and reaching the end of its useful life.
These DfX are design guidelines used in decision making by the engineering team involved in product development to always opt for the best design option among all possible ones. Many times there are conflicts between them, so it is very important to prioritize them in order to resolve any incompatibilities that may arise between them.
Below, and by way of example, we cite some of the most important for the development of an electronic product throughout its entire lifecycle:
- DfO (Design for Obsolescence)
- DfM (Design for Manufacturing)
- DfA (Design for assembly)
- DfT (Design for Test)
- DfP (Design for Packaging)
- DfR (Design for Reliability)
- DfS (Design for Service/Maintenance)
- DfR (Design for recycling)
Among all of them, below, we are going to focus on one of the most important due to its criticality and impact on the final development of a product, the DfM.
DfM, or how to guarantee the manufacturability of your product
DfM is the process of ensuring that a design can be manufactured consistently by all the agents involved in the supply chain and achieve it with the minimum number of defects. This requires a deep understanding of best practices, as well as any limitations that may exist. In this way, the objectives of cost, quality, reliability, regulation/standards, safety and Time-To-Market can be achieved, which ultimately allow us to achieve customer satisfaction.
In fact, there are many authors who prefer to talk about Design With Manufacturing to refer to the DfM, as this makes it quite clear the interaction that must exist between the engineering team that designs the product and the suppliers in charge of manufacturing the equipment.
The foundation of a robust DfM system is a set of guidelines and tasks that help the product design team improve product manufacturability. This fundamental aspect will allow you to establish successful habits in order to make your own product a reality.
Here are some of the most common DfM practices :
- Know and understand the problems and defects associated with previous products that have already gone through the design process in terms of manufacturing, delivery, quality, repairability, etc. All this acquired knowledge will prevent you from making the same mistakes as in the past.
- Strictly related to the above, that acquired knowledge should not remain in the hands of a few people. It is necessary to implement strategies to disseminate this knowledge throughout the organization, as well as to prevent recurring mistakes.
- Standardize as far as possible the processes of design, purchases, assembly, etc. Only if you have clear and well-defined processes will you be able to replicate each and every one of the development phases of a product in an identical way and you will not leave anything to the free interpretation or the good work of those who execute it.
- Limit the use of components or custom-made elements to simplify tasks, reduce errors and simplify the standardization of operations.
- Simplify the design by reducing the number of parts. Reducing the number of parts is one of the best methods to reduce the cost of manufacturing and assembly of a product, and increase its quality and reliability. Also, using fewer parts means reduced purchasing activity, less inventory, simpler inspections, easier test protocols, etc.
- Work with a list of approved vendors (AVL, Approved Vendor List) or parts of the Bill Of Materials (BOM) standardized and already validated in the past for previous products. This not only simplifies the selection process, but also allows you to increase confidence that these components will work properly as they have been validated in past designs.
- Regarding to product envelopes, whenever possible, it is advisable to use single-piece structures from injection moulds, extrusion, etc. instead of using fasteners, bolts, etc. Remember, simplifying the number of components and assembly work will have a positive impact on the final cost of the product.
- Try to use parts that can develop more than one function in parallel, such as a structure used for both fixation and dissipation. You should always try to make the most of the available resources, and this type of double functionality can lead to significant cost and material savings.
- Employ error-proofing techniques by creating a visual and well-defined assembly process where the use of words is minimized and images, videos and photographs are used instead. No matter how educated or trained the group of people in charge of carrying out the assembly and assembly of the final equipment may be, it is always necessary to have documentation that is as self-explanatory as possible, so that it could be executed by anyone with access to the information. Additionally, designs that are easy to assemble manually are easier to automate in a more consistent, reliable, and high-quality manner.
- Avoid using the tightest tolerances of the manufacturing processes necessary to produce your equipment, not only to reduce costs, but also to minimize the rate of defects. In the end, manufacturers know their processes very well in nominal regime, but operating at the limit always carries risks and the failure rate is higher, which affects the cost.
In the electronics industry, the quality and reliability of any product is highly dependent on the capabilities of the manufacturer. Manufacturing defects and problems are one of the main reasons companies fail to meet warranty expectations, which can lead to severe financial damage as well as loss of market share. - Related to the previous point, it is key to design for maintenance. In addition to the warranty aspect, there is also the need for spare parts. For this reason, try to minimize disassembly steps and the number of tools required to access serviceable and replaceable parts.
- When problems of any kind arise, it is key to implement a root cause analysis process and problem resolution methodology to analyze, learn from, and prevent problems. Many times the root of the problem is not found and it reappears in the future because the real cause of the problem was not found. For this reason, it is worth spending some time to determine the true cause of a problem and not be satisfied with the first solution that is found.
- At the purely level of the components that make up the printed circuit board (PCB), we can mention aspects such as humidity and temperature sensitivity, ESD protection, having an adequate derating factor (ratio between the maximum stress level measured that a component supports and its value specified absolute maximum) to add robustness and reduce failures due to excessive variation in tolerance, etc.
- Finally, after the launch of the product and with the objective of continuous improvement always in mind, it is advisable to establish brainstorming sessions to collect the lessons learned and improve practices in all areas of the organization.
Conclusions
In view of the DfM aspects that have been discussed, it is easier to understand how 70% of the total manufacturing costs of a product are determined during the design phase.
A good part of the considerations that must be taken into account must be established from the beginning from the design phase. Otherwise, the more advanced the project, the higher the cost of implementing a solution. Conceiving from the beginning the complete lifecycle of the product does nothing but try to mitigate any possible problem that could eventually occur.
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