Ford’s first Model Ts came in grey, red and Brewster Green, but the paint shop that Mark Nichols, the OEM's Technical Leader of Paint Research, knows is used to a lot more variety

There is no proof that Henry Ford ever said people could have Model Ts “in any colour, so long as it’s black”, but there must be paint shop managers out there that sometimes wish this was the case. With customers now able to choose from a myriad of colours that come with scratch resistant coatings, the paint shop has become a complicated place to work.

And on top of that, these days the whole process has to be environmentally friendly. Energy consumption, recycling, diversity and quality are all high on the tick list. Mark Nichols, Technical Leader of Paint Research in the Ford’s Materials, Research and Advanced Engineering department, paints a picture of the sort of changes he has seen over the past ten years. “A decade ago our Atlanta assembly plant was making the Taurus sedan. It was relatively straightforward, with a car coming down the line roughly every 60 seconds. Today, that same vehicle is now being produced at Chicago assembly plant along with the Taurus X, Mercury Sable and the new Lincoln MKS luxury car. And they will be coming down the assembly line as the same speed as before. So it means the same paint shop now has to deal with four different vehicles using the same application equipment and facility.”

Finding the energy
Having a diverse range of vehicles moving down the line and responding accordingly is a challenge but once the process is put in place it is manageable. Energy usage, however, is more complicated. “Energy usage has become one of the primary drivers of the modern paint shop,” says Nichols. “With the cost of energy so high – and there is no reason to believe that it will return to past levels – we have to put in place the most efficient systems possible. However, that is easier said than done, as we also have to take into account environmental and quality issues. “Ford has carried out extensive internal studies to look at things like cost, quality and the environmental impact of all the potential paint systems that can be adopted; and you have to take a system’s approach and not just look at one layer.” This approach involves adopting a consistent strategy across its entire business. For example, by looking at the entire process we can see where different steps can be either modified or even eliminated altogether. The “compact process” is part of the answer says Nichols.

“Most of the major automotive companies are developing similar strategies that either shrink or eliminate steps in the painting process as they look for greater efficiency. This obviously implies cost savings, but typically there is also an environmental benefit.”

An example of this is the three-wet paint system that has been introduced at Ford. “This is where we have taken out the primer booth and primer oven, and now apply three wet layers together,” says Nichols. “This is a benefit to us from an efficiency standpoint but it's also one for the environment because we stop using one booth and an oven meaning that we generate less carbon dioxide, burn much less natural gas and use less electricity.”

Ford also favours high solid solvent-borne materials. “Our strategy is not water-borne but solvent-borne high solids and that is because you can use abatement equipment to capture those solvents. Water-borne technology still contains a great deal of solvents. However, water as a solvent is very hard to get out of paint at low temperatures so you have to add a great deal of heat to remove it. This results in more natural gas being burnt or electricity being used. All this has an impact on carbon dioxide emissions so we have very carefully and systematically said that we are not going to move to waterborne paint. One of our European plants, for example, coverted to high-solid, solvent-borne form instead of going to water borne due to environmental and cost reasons.” This is a very different strategy to many of the other OEMs says Nichols. “I think that, as time goes on, more [of them] will adopt this strategy. As the cost of fuel goes up, the energy you have to spend to get that water out of the paint becomes a bigger and bigger cost. This is why we are very much in the solvent borne camp. For the same reason we are not using any slurry materials.”

Pride in the pre-treatment
Other trends that Nichols has observed in the paint shop revolve around pre-treatment and electrocoat. “There are a great many things going on there,” he says. “For example, I think one of the things we can point to with pride is the introduction of the zirconium oxide-based pre-treatment that replaces zinc phosphate. It has efficiency benefits for us as it's a more compact process with fewer stages. It also has an environmental benefit as it uses less water and less energy while also producing around 90 per cent less sludge. It's therefore a huge winner for us both from an environmental and efficiency point of view.

“I think the big push for electrocoat was the introduction of lead-free electrocoat and now it is improvements in smoothness. A smoother electrocoat will, in principle, translate into improvements in the appearance of the top coat. So I think that is one thing that we and others are looking at very hard without giving up corrosion performances and the other attributes we are after.” Talk of corrosion brings back memories of the rust bucket that used to be such an eyesore on the roads. Annual safety inspections, such as the UK’s “MoT”, in which a car three years or older is subjected to a stringent “health” check by authorised garages, has got many of them off the roads. However, the quality of the pre-treatment, the quality of the paint and how it is being applied have also played their role.

“We don’t just make our cars look good for the first three years but want them to look good for ten. We are a leader in paint quality. Good corrosion performance goes hand-in-hand with emissions today. You don't see red rust on vehicles that are seven or eight years old anymore and that is because we have very good electrocoat treatment systems nowadays. It’s a requirement that the paint is corrosion free and remains shiny for ten years.”

Local solutions to legislation
Asked whether paint shop technology is being driven by the need to meet legislative requirements around the world, Nichols responds that it is a balance between being a “good citizen” while developing systems that are economical and meet the needs of the business. “It’s certainly true that we have legislative requirements that are different around the world but I don’t think we are driven by them to the extent that we are planning processes or systems simply to meet them. We think more strategically and globally, and try to come up with solutions that are both economical for us while also being good global citizens. Typically that goes beyond what a local requirement might be.”

And local is one of the words that are not far from Nichols’s lips. He is a great believer that the one-size-fits-all answer is not the right one, especially in paint shop technology. “You can do global technology approvals where the same materials might be used in different regions but there are many reasons why this is not really practical. For example, different equipment means it’s not always possible for a solution relevant for North America being used in China or Europe. Obviously a global approval is more efficient but sometimes it does not account for local taste in colours that may not be achievable with certain technologies. It usually means that there isn’t one answer to that question.”

Scratching the surface
As if to highlight this, Nichols then refers to his observations about car buyers and owners in North America and Europe. “I think our customers, and not just Ford ones but all automotive ones, see scratch and chip resistance as being very important. This is a big hitter in customer satisfaction surveys. They want to see better scratch and chip resistance meaning that we are continually looking to improve that. However, I think you run across very real limitations when it comes to scratch resistance.

“We’ve done very extensive clinics in North America looking at how customers feel about scratch resistance and the type of blemishes they care about and you get very interesting answers. In North America our customers are concerned about what we call fracture scratches, deep scratching you get from things like keys, tree branches or doors banging into the vehicle in car parks. However, they care less about any paintwork blemishes that come about from carwashes. In Europe, though, people in general are really very concerned with carwash scratches which are very much finer with a marring type of effect that looks like swirl marks on the surface.

“What we learn from all this is that we have to improve scratch resistance depending on the market. So, for Europe, people are concentrating on ways of making paintwork more resistance to carwash brushers, while in the US we’re looking at how we can develop a paint that resists deep fractures. Improving resistance to fracture-type scratches is difficult. You might have the best organic coating in the world but it cannot resist someone who is intent on running his key down the bodywork.”

Finding the right cure
Ultra-violet (UV) curing is another area that Nichols believes has a great deal of potential. Ford is looking at the practicality of this technology and assessing what the benefits might be. “We have done a great deal of intensive work on UV curing and I think it has a place in our technology portfolio,” he says. “In particular, there are two things that make it attractive: one is that it can inherently be a very low-energy process and save us an enormous amount in CO2 emissions. Secondly, it also has very good scratch resistance.

“It is also probably the only realistic route to 100 per cent solid, meaning zero-solvent, liquid coating that could be used. For all thermally-cured systems it’s hard to envisage a way of getting all the solvents out. With UV curing, though, it’s done every day in other industries so has to be considered a realistic potential path for 100 per cent solid coating for the car. The problem is that there are not yet any materials out there yet that look like they have the long-term durability that we require. “There are also problems with processing with regards to shadows and how the coating is cured on a three-dimensional vehicle. There is a plasma chamber that is being worked on by Dürr and Ciba that looks very promising from a process standpoint. And our colleagues at Volvo are also looking at it. So there is plenty of activity going on in this area. “We are also looking at UV curing in the US and we have a very attractive process to use in our repair systems. If you have a small defect on the car in the assembly plant, there are obvious advantages to repairing only the blemished area rather than repainting the entire vehicle.”

Lessons in lightness
Although every industry has its own special needs and requirements, lessons can be from one another. “We talk to aerospace colleagues, for example, because we are trying to make our vehicles much lighter and there are new materials continually being introduced to our industry. The question in some cases is how we should treat and paint them, and the aerospace people are the ones with the answers as they have been contending with the same issues for far longer. While there may not be a direct like-for-like comparison, we are able to learn from their experience. I talk to my paint colleagues in other industries as there are always interesting things going on out there which we need to learn.” Nichols talks about polymers as a case in point. “There is very interesting work being done in this area, in particular with very carefully controlled molecular architecture giving better properties that perform better in the field. I also know that there is interesting work going on in renewable resources and using them as some of the monomers that make up the polymers that are put into the binders. However, at the end of the day we are not a formulating company but one that buys things from various suppliers. “It means that we have a very close collaboration with our Tier One and Tier Two suppliers from a research standpoint. We also have research projects with all our major paint suppliers, working on the development of paint processes that may be ten years down the road but which may be important one day.”

When it comes down to it, though, it is the colour of the paint, and the perceived quality that are so high on the agenda of many buyers. “You have to remember that paint and the colour of the car are emotional points for many people. Anybody you know who buys a new car will be asked what colour they’ve got,” says Nichols. “There was a survey from three or four years ago that showed that the vehicle type was the primary differentiator when purchasing a vehicle followed by the sticker price. Number three on the list, although, to be fair, that might be changing right now with the current credit squeeze, was the colour.

“Different surveys have shown that if people cannot get a car in the colour they want from a dealer then around 40 per cent of them will buy a car from a different dealer and manufacturer. It means that it’s absolutely vital to get it right in every possible way.”