Putting the cart before the horse

Author : Peter Smith, Plexus

27 June 2016

As today’s complex medical device market continues to evolve at an ever-increasing pace, OEM’s are driven to achieve faster time to market requirements for new products.

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This drives situations where a manufacturer will be presented with a design which is not optimised for production, presenting manufacturers with challenges to ensure that already certified products are truly able to be manufactured efficiently without adding cost and, more critically, achieving the time to market target. 

Gone are the days when a customer’s relatively simple design would land on the desk, be checked, costed and kitted, with the supply chain in place, and then passed swiftly onto the assembly line. Shipping would follow in the accepted number of weeks, and then it was on to the next product. However, following best practice in this area can ensure the optimisation of product manufacturing and enable the product design to be ‘future proofed’ to keep up with an ever changing market.

In an ideal world, the manufacturer is onside at the earliest possible stage. With close collaboration from the concept stage, its design team will be able to influence the customer’s design for optimum manufacturability. However, frequently a product design arrives to be manufactured fully formed with all certification and regulatory approvals in place but having had no collaboration with the manufacturer. If that design went straight onto the assembly line, it is highly likely that defects and manufacturing issues would occur throughout the process and there would be quality issues.

Due to these regulatory approvals, it becomes difficult to adapt the design without compromising the full certification achieved. In this situation the only way forward is for the design team to make sure that the design can meet the demands of the manufacturing environment whilst maintaining the original elements that met the compliance requirements. It is not ‘back to the drawing board’, however the manufacturer will need to look closely at what can be adjusted during this commercialisation effort, considering how best to transition those designs through to production.  

To overcome these challenges, the manufacturer needs to examine the design from a different angle. It should retrospectively apply the designing for excellence mind-set that is the norm for the early stages of a product’s design and move forward with that into the manufacturing environment. It becomes more a manufacturing for design rather than design for manufacturing thought process. In the healthcare sector, development costs are very high so any delays or problems during the transition to manufacture can prove to be expensive and need to be avoided.

By using design for excellence tools, the team has the ability to optimise the manufacturing process, to look at where there are cost challenges and then identify what can be done to improve those. This all has to be accomplished whilst maintaining the original design that has already received approvals.

It might be that a leaded part has 20 leads to be soldered onto a PCB, all within a dense technology section of the board, and those leads need to be ‘a couple of zeros’ apart. It is highly likely that this has not been taken into account in the design and limited space is available. Had the customer and manufacturer worked together at the design stage this would not have become an issue.

On the design it is apparent to the manufacturer that the pads are too close, leading to the potential for a high number of solder shorts during production. Taking the design and reviewing it from a manufacture for design angle the solution would be to add a solder mask to prevent solder flow between those pads. Adding in a specialist inspection after production would also ensure that the part does not fail once in use.

In a further example, a leading Europe based medical technology company recently took the decision to outsource all manufacturing and aftermarket services for its molecular diagnostic system. The rationale for this was that it would free up time for its engineering team, which in turn would allow them to focus on their core competencies in R&D.

The customer had tight timelines to get its product to market ahead of the competition and therefore it needed a partner that could ensure a risk free transition of all manufacturing within a five month timeline and be able to utilise a structured transition process. This was critical for its success and long term business strategy. However, the partner’s design team was faced with the challenge that the original product design had not been optimised for manufacturing, as is the case with many legacy and in-house designed products.

In this case the customer wanted to work closely with the manufacturer to ensure the optimisation of the manufacturing. Therefore, the partner worked through a number of areas of design for excellence, starting with design for manufacture analysis that improved the layout of 3 boards enabling the manufacturing process to be optimised. They also examined the product’s test strategy – analysing the test sequence to ensure optimum results and determine the right production test strategy for each board. Through this activity, the customer’s design was able to be enhanced to ensure manufacturability as well as meet the customer’s time to market targets. 

In addition to this, they also added a level of future proofing to the device through ROHS and obsolescence analysis. Replacing all obsolete parts and redesigning several boards meant they were able to provide a robust design with ROHS conformity as well as extend the lifecycle of the product. They were also able to save the customer’s engineering team valuable time by delivering all certificates of conformance to complete the product‘s documentation file.

With product lifecycles continuing to extend, there is often a need to design in some level of ‘future proofing’. This is particularly true within the healthcare sector where it is such an expensive and highly regulated process to bring a new product to market, it is important to have the ability to optimise the lifecycle of products released to the market. Devices may remain in service for many years and need regular updating to keep pace with change. By implementing the correct ‘design for excellence’ approach to the initial design this need not present ongoing issues. Essentially, the development process often needs to anticipate future needs and ensure the product includes inbuilt upgradability.

Some future updates will purely be software modifications but others may require hardware changes. The designers need to look at the life ahead for a product when its development is in its infancy because hardware alterations and upgrades will also require certification. The canny designer will, therefore, even if it is not going to be utilised initially, get projected developments in place early on. This way it will pass verification and manufacturing tests and save time and money in the future.

The challenge is to turn a design not optimised for manufacture into one that is production ready, does not compromise the original certified design, with the minimum of delay and extra cost. While it is ideal to engage with a manufacturer in the very early stages of the design so that they can influence the manufacturability right from the beginning, it is not always possible. However, if manufacture for design principles are effectively applied, it becomes possible to deliver a fully functioning product within budget and on time as well as build in a level of future proofing to help extend the lifecycle of the product.

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