FEATURE
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Not off the shelf

Warren Clark and David Robson discover what happens when standard catalogue products just won't do

Thousands of photonics components are sold each week, the majority of which are plucked from standard offerings in brick-like catalogues. Such is the precision nature of the world of photonics, that inevitably there are some instances when a standard issue product will not perform the required function. To this end, many photonics distributors offer a custom assembly service, which can mean anything from constructing a laser system to the customer’s specification using standard components, through to developing and designing an entirely bespoke system using newly-created elements.

When to choose custom assembly

‘The decision to opt for custom assembly can be driven by any number of factors,’ says Mike Elliot of Elliot Scientific, a company with custom assembly expertise in mechanical design, lasers, optics and cryogenics, among others. ‘It might be that it is more efficient to do so than hire staff and invest in hardware in order to create a short-run component or product. More often than not, it is simply a case of not having the expertise to achieve the desired aim. Any customer looking for a custom assembly solution should assess the breadth of knowledge of the provider and ensure they have demonstrated a capability in similar projects previously. Some customers have an initial concept drawn, which may have more complexity than is necessary. We can review this and offer a less complicated design conceived by engineers that fully understand manufacturing costs and end use of the device.’

‘There are always going to be limitations to catalogue offerings, so there will always be custom applications,’ says Sam Sadoulet, director of engineering and R&D at Edmund Optics, which has seen a dramatic increase in customers seeking bespoke solutions.

‘Customers may want customised systems to reduce the size and number of elements in the system, and to deal with different environmental conditions. Optical engineers are expensive, so not every customer has their own, but they can use our experience to develop and optimise components.’

Paul Ellis of Sifam Fibre Optics says: ‘The level of integration really depends on the customer, but it usually begins with a requirement for a discreet component that was ultimately going to be used in an optical system. We then provide some kind of added value, which might be integrating that component with electronics or motion control, for example.

‘Some years ago, we were principally a component provider to the telecoms industry, and in most cases, the telecoms customers looked after their own integration. That has changed significantly in recent years, and we are selling more and more to the biomedical (for use in optical coherence tomography), aerospace (optical backbones for on-board communications) and industrial (mainly fibre lasers) sectors. Coupled with that has been a shift in the way our business breaks down, with custom assembly now representing around 50 per cent of our business, as opposed to 10 per cent a relatively short time ago.

‘With the change in sector has come a change in the level of expertise. Unlike telecoms, many of these newer customers do not have sufficient experience in fibre optic assembly, nor do they fully understand the complexities of fibre. Thankfully for us, they seek out that experience and expertise from companies like ours. They will arrive with an idea of what they want their system to do, but not necessarily how to achieve the outcome. We will feed that idea through our design team, which includes CAD engineers, optical engineers and electronics engineers. Once it gets to the prototype stage, a key element is to test and measure every aspect of the assembly to check that it works. Indeed, much of our expertise is used in this part of the process, since it is one skill to be able to design and construct an assembly, but another to carry out sufficient testing to ensure that the components all work efficiently.’

Identifying the problem

‘Customers often come to us with a problem that they need solving,’ says Mike Elliot. ‘That problem may require anything from 1 to 200 units or so. Any longer run than that and it’s beyond what you would define as “custom assembly”. At the opposite end of the scale, it’s rare for a customer to want a single unit created, but it does happen and we’d always been keen to discuss such a need.

‘The nature of the problem can vary, but it might involve a space constraint for example. Sometimes, customers already have an idea or a concept of how their solution might look, while others come to us with no idea of how to solve their issue at all.

‘We would review the problem with them and then present the customer with some initial concepts. This would usually be in the form of a 3D drawing (we use SolidWorks to create this), that the customer can rotate and get a real feel of how it might look. The customer would not be able to see the internal workings of the product at this stage.

‘If the customer is happy, we would then proceed to manufacturing one or two prototypes, and then on to the required volume if everything is in order.’

‘There are two ways things can play out,’ says Sadoulet. ‘In the first case, customers present us with a blueprint, which they want built. This can seem simple, but it can often get customers in to trouble, if the specifications are not optimal for their application. I would advise them to ask their vendors for help with the specifications –the assembler can advise customers what can be changed to reduce cost, but improve performance. Our job is to inform customers of various trade-offs when producing components.

‘Once the design has been decided on, we go through quoting activities. This should be over within days, but it depends on the nature of the beast. Customers should be worried if they are given a fixed price by a manufacturer for unique applications requiring bespoke lenses, because there are many subtleties in the production process that need to be resolved by producing prototypes of the components. Obviously, with generic lenses, a fixed price should be expected. Once this is done, the manufacturing can be ramped up to higher volumes. If a problem arose in this step, you would need to go right back to the beginning, which could mean months of extra work. No matter how much you simulate the production with a computer, there’s always a certain amount of black magic involved. We continually optimise the production throughout the component’s lifecycle.

‘The other case would involve a different development of the specifications for the system. They may present us with prototypes, that have provided a proof-of-concept, but it may be that it doesn’t have a high enough resolution. We spend a lot of time up front to understand what they need and translate this into the component specifications. There are different payment options for this: some companies may charge consulting fees; others will provide it as an addition service. It’s very open-ended. The development time will be longer for this situation, so customers need to be sure to approach us early so that the component can be produced on time.’


A screengrab from a 3D drawing used by Elliot Scientific during the custom assembly process. Customers can rotate the prototype design through 360°.

What to look out for

‘The lead-time is generally very long in optics,’ warns Sadoulet. ‘If you want a component to be produced more quickly, it costs an arm and a leg. I would advise people to get going ahead of time, otherwise you’ll pay through the roof. Be sure that consultants can “design for manufacture”, and do it properly. I would stress that most people don’t make vendors work hard enough. Some have so much expertise, and customers should exploit that. Also, don’t wait until the last minute for the optics of a system.’ Such is the increase in custom assembly that it is inevitable that the industry may come full circle. ‘It’s in the nature of the business we do that just about every customer needs a different solution,’ concludes Ellis. ‘We’re still in the early days of fibre optic assemblies, and it may be that over time some of these “custom” assemblies become off-the-shelf products.’