The sticking point

Eureka's Joining & Fastening Round Table event concluded that much greater knowledge and consideration of joining techniques is needed.

The event began with discussion of the results of Eureka's survey into joining and fastening. This revealed that, while respondents rated their knowledge of mechanical fastening and welding as fairly good, more than half described their knowledge of adhesive technology as either 'poor' or in need of 'brushing up'.

These results did not surprise the panel. It was felt generally that lack of knowledge of adhesives has tended to negatively affect people's views of the technology. Nick Bennett suggested that poor knowledge had led to companies having bad experiences in the past, which in turn had shifted their thinking away from many adhesive solutions, saying: "Modern project management techniques look at the end gain and detail what went wrong. The next guy comes along and looks at it and says 'we had a problem with that adhesive' and potentially there's a negative knock on effect in terms of the perception of the technology as a whole."

Ewen Kellar took up this point, saying: "Often the adhesive will be blamed and it's nothing to do with the adhesive. It could be to do with the surface preparation, it could be to do with the way it was applied or, critically, it could be down to the joint design because adhesives are stress sensitive. More often than not, it's to do with other things. The whole concept of how the adhesive should be applied and what's required can be massively misunderstood, but rather than examining that, people invariably just say 'the glue doesn't work'."

One of the key problems, it was felt, was that adhesives – being a chemical rather than mechanical solution – did not represent an intuitive process as far as most engineers are concerned. Peter Frank said: "We're more and more used as a society to being able to get something out of a box and using it straightaway. After all, who reads instructions? We're used to everything we buy being intuitive and the problem with the adhesives we're talking about is that they're not intuitive in that sense. You have to read the instructions…As a customer, I'd say that, if I were buying a glue, I'd phone up and ask for help, but if I were buying a mechanical fastener, I'd think it was obvious and wouldn't bother. And then I'd probably get it wrong and realise it wasn't obvious, but I think that's the way people think."

According to Ged McGurk, this is a common problem. He said: "With an adhesive, they all look the same coming out of a tube and squeezed onto a join, but they all have vastly different qualities. People think they know what they're doing, but in fact they don't have enough knowledge."

The sheer speed with which adhesive technology is advancing is another problem, according to Nick Bennett. "There are so many adhesives out there," he said. "The technology's advancing all of the time. There is absolutely no way I could be up to date with all of them. So I will tend to ask an expert when I don't have enough knowledge. But at least I know what I don't know."

Acknowledging this issue, Colin Chapman said that the only way to address it was on a case-by-case basis rather than trying to educate everyone about the benefits of every possible adhesive. "We'll establish the application area and try to give them a push in the right direction in that specific case," he said. "We accept that education is the biggest issue – at university level and at company level. The snag is that someone will use an adhesive and say they know everything about adhesives and then you'll find out that they're using the wrong adhesive."

A fundamental lack of education about the technology was felt to be another major problem. Said Ged McGurk: "I wouldn't be at all surprised if those who considered themselves good on adhesives would be at a much lower level relative to those who considered themselves good on mechanical fastening. A number of the problems with adhesives stem directly from a lack of awareness and knowledge of the subject. If you go right back to college courses, the number of those who will have spent more than half an hour in their three-year undergraduate programme studying adhesives will be very low. And yet they will all have a good understanding of mechanical fasteners and of welding."

On this point, however, Nick Bennett disagreed. Despite their self-assessment, he did not agree that the knowledge of mechanical fastening systems was everything it could be, saying: "I don't necessarily think that they do have a good knowledge of mechanical fastening. We have lots of experiences where someone has specified what they think is a simple nut or bolt and they get the torque wrong and the bolt fails after a while. There are so many issues we've seen when people say 'well, it's just a nut and bolt, isn't it?' and you have to say to them 'No, it's not'."

Phil Kempson agreed, saying: "We do have a lot of cases where engineers say they do understand the technology and say they do know how to design stuff in. Particularly with our captive hardware, we'll get people coming to us and saying there's a quality issue or the screws are falling out, but in fact 99 times out of 100 it's an application issue. It's that the panel's not prepared correctly or the whole diameter's wrong or the material's too hard or they're trying to install it too close to the edge of the panel. It's stuff like that rather than the product itself.

"When it comes to specifying our more specialised products like quarter-turn fasteners, we've got to make sure the customer's got the right length of stud or the materials are right. It's exactly the same as we've all experienced with customers: they say they know how to do it, but when it comes down to it, there are lots of issues."

It was agreed that, in order to be successful, the sale of joining and fastening products needed to be a consultative sales process. However, it was also acknowledged that there were difficulties with this, Phil Kempson saying: "I think the difference is that we'd like to think it's a consultative sell and we think we'll help them through it, but they just think 'All I need is some glue or nuts and bolts'."

However, the most fundamental problem, many believed, was a failure to educate engineers about joining and fastening methods at schools or colleges. On this subject, Ewen Kellar was emphatic, saying: "I think there's a critical thing about pre-industry knowledge at colleges and universities on fastening and joining. I'm continually amazed by how little time is spent on fastening and joining. They're doing three years and it's probably only two or three lectures in all that time – of which adhesives will only make up a small part. They're spending all this time learning about materials and their properties and they're doing nothing about how to join it together! It's atrocious."

This, it was believed, has led to a situation where joining and fastening methods were not being considered properly at the design stage. Said Nick Bennett: "We sell a lot of hinges. Customers will design a brand new product and then think 'we'll fit a hinge later'. And then they get to the stage where they need it, ask for a hinge that does a certain job and we have to tell them it's physically impossible and won't work."

Colin Chapman agreed, saying: "We have the exact same problem with adhesives. What adhesive you're going to use on a joint design is usually the last consideration."

This failure to assess joining methods is, believes Nick Bennett, has deep roots. He said: "I wonder whether most designers get into the focus of thinking they know what they need to do to make their product, but the bits on the edges like adhesives, fasteners or nuts and bolts get left until later because 'that's the easy bit'. So they focus on what they do, but they get to the point where they need to talk to us and suddenly it doesn't work."

Ged McGurk, on the other hand, suggested that joining methods were considered at design stage, but in insufficient detail. "They'll usually consider how they want to bond or join something, but they generally won't allow that to influence their choice of materials. So, by the time they come to us, we have to tell them they've chosen the worst possible material they could have picked. Among all of the performance criteria they have used to select their materials, bonding capability has never been on the list. That's the challenge to the industry to make sure we can give them a solution, but the whole design concept would have been so much more successful if they'd done that evaluation up front."

Paul Fanning

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