DESIGN FOR MANUFACTURE HELPS STANNAH STAIRLIFTS TO REDUCE COSTS, IMPROVE INSTALLATION AND ADDRESS STORAGE PROBLEMS

In an economic climate where reducing costs, minimising risk and maximising speed to market is vital in order to survive, some might say that design for manufacture (DFM) is the most important element of the electronics design process. This is the stage where key decisions are made as to the components selected, how the unit is laid out and it sets the platform for how it can and will be manufactured. If mistakes are made, or if vital considerations are overlooked at this point, it can affect everything from unit cost, time to market and product sales, to the reputation of the company behind the product.

Zirkon Limited is a contract electronics manufacturing company based in Rugby and has been providing Stannah Stairlifts with electronics manufacturing expertise, including DFM, for 6 years. Tony Inskip, Director at Zirkon says that developing partnerships with customers is not only an important element of DFM but it is a vital element in developing effective and durable working relationships with the customer as a whole. “Partnerships can help to create an environment where knowledge and expertise can be offered on the entire product, which helps to add value to the customer’s business. An example of the benefits that this approach can deliver is highlighted in the work that we have done with Stannah Stairlifts.”

Having worked for a number of years on the manufacture of the Stannah Stairlifts product range, Zirkon was approached by Stannah Stairlifts to look at the design of the product. There were a number of reasons why Stannah Stairlifts felt that alterations were needed, the first of which was to improve installation reliability. The Stannah Stairlifts runs on a rail, and in some instances the rail can run across door openings. For situations like this there is a hinged rail section which can be raised to a vertical position, allowing the door to open. In the past it was the responsibility of Stanza’s installation engineer to programme the software system correctly within the control unit so that the chair recognised when the hinged rail was raised. Zirkon worked on changing the design to improve the performance yield, the reliability and the consistency of the performance of the radio link in part of the control unit. This means that the programming responsibility has now been taken away from the installation engineer, which has improved the reliability of the installation. This has enabled Stannah Stairlifts to provide a product that has more reliability and consistency in performance.

The selection of components and materials is an area where costs can be saved by outsourcing DFM to the same supplier that provides the product build. This is due to the fact that most suppliers use preferred components as standard from a wide, yet refined component base, and they also have manufacturing processes that are unique to them and specific to their machinery. This information is something that must be built into the DFM process. Even if the majority of the DFM is done by in-house designers, it would still be worth involving the manufacturing supplier at this stage because different suppliers have different processes, and one particular design may not be suitable for another supplier’s machinery or equipment.

Tony Inskip explains, “This can also help to reduce risk in DFM, because manufacturers like Zirkon will have knowledge of the selected components and materials, therefore it can be identified at an early stage if certain parts might not be suitable for a specific product design. This is something that an in-house designer may not be aware of as they aren’t heavily involved with the actual manufacturing process.”

Time to market of the product is dependent on reducing the production time as much as possible, which can in turn depend on the availability of the components. This is another area that can often be ignored or overlooked by in-house designers as they won’t necessarily be communicating with component suppliers on a regular basis, so they may not know whether a certain component has become obsolete or whether a new one is available yet or what components are currently on long lead times. There have been certain instances where products have been designed around unavailable components, and alternatives have had to be sourced at the last minute. It is also important to consider future-proofing components to determine how long they will be available for, in order to avoid unnecessary re-designs in the future.

The most recent work that Zirkon has done with Stannah Stairlifts is based on using the latest technology combined with modern chips in order to provide Stannah Stairlifts with improved features on its Stairlifts products, along with greater reliability at a lower cost. This has involved changing the frequency of the product from 433MHz to 868MHz, which is the new approved band. Radio chips controlled by the microprocessor have been introduced into the design, which enables Zirkon to produce frequencies that are suitable for both Europe and the USA, on a single common board, using fewer components. The software used for this is contained within flash memory, which allows Zirkon to programme the radio frequency of the product during the last stage of the manufacturing operation.

Peter Gilbert of Stannah Stairlifts says, “This has provided Stannah Stairlifts with greater flexibility; as well as assisting with reducing our overall stocking volumes and variants. As the radio frequency can now be set at the end of the manufacturing process, we no longer have to specify it at the point of the initial order. This enables us to be more responsive to changes in our customers volume mix. Parts can also be returned so that the frequency can be changed, which is a simple process, allowing the product to be reused instead of sitting in storage until it can be used in the next appropriate order.”

Stannah Stairlifts also wanted to introduce a lower cost version of its Stairlifts product. Zirkon was tasked with re-designing the control unit so that it was more cost effective, whilst maintaining the key features. To do this Zirkon recommended that infrared technology should be used instead of radio frequency as this would allow the controller to be simplified onto one circuit board and reduce the component count on the board.

Tony Inskip reflects on the effect that the downturn in the UK electronics and manufacturing industry has had on DFM. “There was initially a slight drop in the amount of work that was done in this area, as companies stopped investing in anything new. Since it became apparent that the downturn wasn’t going to be as severe as it was first anticipated, companies are beginning to regain their confidence and are starting to consider new projects again.”

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