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Avoiding the Pitfalls in Electronic Device Development


Nigel Harley of MLE Creative Electronics outlines a five-stage process that will deliver a successful medical electronic device design project.

The challenges posed during the design of a medical electronic device can be avoided by working within a clearly defined framework. This should be built on the foundation of adequate planning, realistic time scales, dedicated quality review processes and efficient communication between all of the project’s stakeholders. These factors are important, whether a company designs its device in-house or elects to work with a third party. To optimise the planning and completion of a medical electronic device design project, ML Creative Electronics has divided the project into a proven five-stage process (Figure 1).

Figure 1:Five steps to great designs.

Assessing feasibility
The product development cycle starts with a feasibility study aimed at identifying the risks associated with delivering a product in accordance with the proposed specifications (Stage 1, Figure 1).

At this stage it is important to be aware of specification bias. The details of the specification are often strongly influenced by the specific requirements and opinions of the stakeholder who provided the most input during product conception. This can lead to problems later in the design process as other stakeholders get involved and request changes that generate significant time and monetary costs. To circumvent this problem, it is important that all of the major players involved in the project are consulted and that adequate communication exists to avoid confusion over the intended specifications, goals and timelines of the project.

As well as helping to accurately delineate the design specification, it is also important to understand the funding details of the project. This ensures that the expectations of the stakeholders will be met and that adequate funds will be released at each milestone as the project progresses. It is especially important to realise that the product development process is non-linear, in terms of time or funding requirements. For example, it can be difficult to accurately define how long it takes to create a working prototype. In addition, the development of a prototype involves substantial material costs, whereas other stages of the development process require less capital investment. Therefore, the flexibility to accommodate the varying requirements of each stage of the design process is paramount to successful completion.

Often, it falls to the project manager to review these milestones. However, occasionally the CEO will also need to review and agree these factors and incorporate them into the development plan (Table I). This is also an opportunity to anticipate any monetary, organisational, temporal or technical stumbling blocks that may potentially cause unnecessary delay in the development of the product. In this way appropriate contingency plans can be developed.

Once an initial specification has been agreed and potential design risks identified, a bench study is conducted (Stage 2, Figure 1). The aim at this point is to validate and prove that the features defined in the final specification can be successfully incorporated. This excercise will identify those features that are likely to prove too challenging to implement and require a compromise between feature value and feasibility of delivery.

Eliminate errors early

Although these first two stages of the process may seem simple and fast to complete, the most common error made during the design process is to enter the prototype stage too early. This can be the result of underestimating how much time is required to develop an accurate, workable specification. Mistakes such as this have a serious impact later because a series of backward changes will be required to rectify them. This "ripple effect” will require changes in the product design and redrafting of the supporting regulatory documentation. This is a costly exercise that wastes large amounts of time, money and materials. 

Although concurrent design and engineering are possible to achieve, the concurrent approach requires extensive resources and emphasises the need to create an accurate specification that includes continuous reviews by all members of the team. This helps to minimise total costs and maximise efficiency.

Once the feasibility aspects of the project have been thoroughly investigated, a pre-prototype review is undertaken. At this point it is advisable that all paperwork has been completed concurrently with each design step. This helps to keep the project on track and maximise the accuracy of documentation. It is also recommended that the advice of a third party regulatory consultancy or a Notified Body is sought as early as possible during the design process (Table II). Early involvement of the chosen Notified Body ensures its input during the development process and it will be familiar with the product when it comes to final approval. It also means that design decisions are validated by independent advice. This reduces any potential risks at later stages and facilitates the production of the first engineering prototype (Stage 3, Figure 1).

Prototype and preproduction stages
The engineering prototype is a working demonstration of all the cardinal functions of the product. Production and reviews of these prototypes is an iterative process, ultimately culminating in the development of a representative prototype (Stage 4, Figure 1). This takes the form of a "turnkey” design, with the aim of identifying any mechanical hardware limitations affecting the final design and testing to ensure that the product meets the agreed specification laid down during the early stages of the project. 

When these verification checks have been performed the project can move to Stage 5 of the process and the construction of pre-production pilot units. The development of these pilot devices should quickly lead to the creation of the final product, providing all the necessary documentation and regulatory requirements have been met (Table II).

Measuring success
Upon completion of the project, it is imperative to identify successes and potential improvements to the process. The most important step is to obtain customer feedback to ascertain whether the device accurately fulfils its intended function. This ensures that the product is adopted by end users, who subsequently drive sales.

This outcome is especially important to satisfy the investors, who will want to see that project milestones have been met and that the final product will yield an acceptable return on investment. By defining and reporting project successes, it is also easier to create and maintain positive lasting relationships, internally and with customers/suppliers. Critical feedback will also provide the opportunity for process improvement and for increasing efficiency, accuracy and profitability.

Maximise success
There are several ways to maximise the likelihood of successfully designing an electronic device. It is important to have a focused accurate plan and to commit adequate time to getting it right. This includes assessing the feasibility of the project and any relevant time constraints, and ensuring that the expertise and funding resources exist to achieve realistic goals. The restrictions and opportunities imposed by regulatory bodies should also be identified early in the process. This will ensure that the final design of the product is developed against accurate and detailed specifications, as agreed on by all the project stakeholders and within the limits set by external bodies.

The five-stage approach recommended here takes into account these factors and is designed to reduce the impact of costly, late-stage changes (Figure 2). This involves insisting on frequent project reviews and efficient communication between team members to keep the project on track. This methodology helps to keep everyone focused on the team’s targets and drives the design process through to delivering a revenue-generating product. By utilising a proven development framework, it is possible to successfully achieve this goal, on time and to budget.

Figure 2: Late stage changes in the product design and redrafting of supporting regulatory documentation are costly.


Examples of devices designed using the five-stage process: Plasmajet, POWERbreathe and Lifesys.

Nigel Harley is Director of Strategic Development at ML Electronics Ltd, Brickworth Lane, Whiteparish, Salisbury SP5 2QE, UK 
tel. +44 (0)179 488 5790 
e-mail: enquiries@ml-electronics.co.uk


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