On two occasions this year, Invotec, Europe’s leading manufacturer of time-critical, high-technology PCBs, proudly announced its achievement of European Space Agency approval, initially for sequential rigid circuits and more recently for sequential flex-rigid circuits.
Aware of the extremely high standards demanded by ESA, and that very few PCB fabricators have ever been successful in gaining approval, I took the opportunity to visit Invotec Managing Director Tim Tatton at the company’s Tamworth, UK, headquarters to learn about the challenges his team had faced and overcome during the qualification programme, and the commercial benefits that were being realised as a result of their efforts.
Pete Starkey: Hello, Tim. It's good to see you again and congratulations on your achievement!
Tim Tatton: Thanks, Pete, and welcome back--you’ll see a few changes since your last visit. Nothing stands still! We are continuing our investment programme to keep ahead of the technology, rationalising the shop-floor layout and installing a complete new laboratory facility.
Starkey: That will make an interesting story for another day, but I would like to talk specifically about your ESA qualifications: What was involved in attaining them and what they add to your scope as a PCB manufacturer? I looked on the ESA website--there aren’t many on their approved suppliers list, several approvals are expired or suspended, and you seem to be out on your own in terms of your capability.
Tatton: That’s true, and we estimate sequential rigid and sequential rigid-flex technologies represent about 70% of the European requirement for space PCBs. The overall market value is estimated to be of the order of 10 million euros, significant for specialist European manufacturers, but not so attractive to the major North American or Far Eastern volume fabricators in view of the service levels involved. The other ESA-approved manufacturers in mainland Europe don’t have our level of capability; they’re smaller than us and are arguably too dependent on the space market, which can be very cyclical.
Our long-standing identity in the aerospace and defence sector has always been a differentiator, and we are recognised for our focus on niche areas: Very high technology, extremely high quality standards, and an extraordinary level of service. But the demands of the space industry go far beyond those of, for example, civil aviation.
Starkey: Can you give some examples?
Tatton: Clearly, safety is the critical priority for civil aircraft, but their electronic systems are designed with multiple redundancies so that in the event of a failure, there is usually a back-up system to maintain functionality until the aircraft can be grounded and a replacement module fitted. The commercial consideration is that while an aircraft is grounded it is not generating revenue. In the case of a satellite, the reliability issue is magnified to another level--because of constraints of weight and physical space, multiple back-up systems are just not practicable and the cost of failure is colossal. For example, last year, the European Space Agency launched the Gaia satellite, an unmanned space observatory. It’s currently about 1.5 million kilometres from Earth. It cost a billion dollars to develop and launch.
Starkey: Yes, that puts it in perspective. So how do these considerations affect the role of the PCB manufacturer?
Tatton: Traditionally, the focus has been on inspection and test. But you can’t inspect quality into a product--you have to get the materials and processes right so that you can manufacture the quality in in the first place. Inclusions in laminates are a known source of latent short circuits; we’ve been working with our laminate suppliers for the last five years to help them eliminate inclusions at source and at the same time we have made substantial investment in clean-room facilities and working procedures to avoid inclusions during manufacture. We have earned a lot of credibility with the space OEMs over the many years we have been supplying them, with a whole suite of approvals that demonstrate our process excellence, including NADCAP and AS9100 Rev C accreditation in addition to all of our OEM approvals, many of which call for capability beyond the scope of current ESA requirements.
In particular, our Tamworth factory is the only ESA-approved facility with a full in-house HDI capability and we are looking forward to working with ESA to develop new standards for the use of HDI in their designs. Because ESA operate a traditional system, much like the old MIL-Spec, it can take a long time for technology advancements to become incorporated. As a consequence, OEMs have where necessary developed their own individual specifications.
Starkey: What about the smaller space contractors?
Tatton: A number of smaller companies and research institutions engaged in commercial space projects do not have the resources for formally qualifying their PCB suppliers. Since the announcement of our ESA approvals, we have had many approaches from such organisations, several of which we weren’t previously aware of. Although technically they may not need ESA approval, they see it as a de-facto standard and call it up anyway.
Starkey: These opportunities aside, Invotec must now be in a very strong position to address the mainstream space sector.
Tatton: We have been very pleasantly surprised. Since our initial announcement in January this year, we have had orders from 20 different customers in 12 different countries, plus around 20 further new enquiries, several of which from outside Europe. It takes very careful management to assimilate so many new customers, particularly when each of them has their own special requirements, but we have the right engineering and quality assurance resources to support them and I’m pleased to say that we have coped pretty well.
Starkey: And what pressures are placed on your manufacturing capacity?
Tatton: This sort of work is well within our manufacturing capability. We have many years’ experience of the sort of technologies involved. In terms of capacity, it fits smoothly into our production flow; we are, by nature, a low-volume, high-mix, high-reliability PCB manufacturer. There are some challenges, for example in front end engineering, electrical testing and final inspection. ESA are extremely cautious and demand high-voltage electrical testing on many of their designs. It’s not practicable to build grid-test fixtures for such complex boards in such small quantities, so we have to adapt our flying-probe testers to suit.
Starkey: What are typical characteristics of ESA work?
Tatton: Often large boards, all polyimide, high layer count--generally 20- to 30-layer sequential build, and with finish requirements like reflowed tin-lead with a minimum of 2 microns at the knee of the hole, often in combination with fully-encapsulant electroplated gold over nickel. And the QA testing requirements are not for the faint-hearted. Look at the active circuit area on this panel and compare it with the area dedicated to coupons for a whole catalogue of release tests. The job probably spends as long in inspection and laboratory test than it does in manufacture, but that’s the reality of ESA work.
Starkey: How long did it take to go through the qualification procedure?
Tatton: It was a three year programme--pretty challenging--with many iterations of test coupons. We were sponsored by Airbus Defence and Space, a division of Airbus Group that was part of EADS Astrium before they re-structured. We had been supplying them with high-reliability HDI product for 10 years in advance of the ESA approval and we are now able to support their ESA-qualified requirements, a big benefit to them as well as to us. And our ESA accreditation represents a formal acknowledgement of our technological and manufacturing capability as well as the strength of our commitment to ultra-high reliability.
Starkey: Tim, you already mentioned the unprecedented market response following the announcement of your approval. Are you able to disclose what proportion of your business is attributable to ESA work?
Tatton: It’s obviously an area of rapid growth for us, and currently constitutes about 5% of our turnover. We believe that we can progressively increase this to 15%, which will represent a significant share of the European space market. From our point of view, that’s a manageable share in view of the year-on-year variance in demand, and puts in a much more secure position than companies with 60 to 70% of their turnover committed to the space sector. We have the strength and resources to cooperate with our customers to find ways to control and manage change, where change is necessary, to realise meaningful continuous improvements.
Starkey: Sounds like a pretty good strategy to me, Tim. Thanks for sharing your experiences with us. Every success, and please invite me back to see your new laboratory when it’s ready.
Source: PCB007 - http://www.pcb007.com/pages/zone.cgi?a=102320&artpg=1&topic=0