- Turnkey solutions and specifications
- Aluminium – low weight – big headache?
- Sludge control technologies
- Wet-on-wet – the way forward?
- Powder clearcoat – good for BMW but not JLR
- Sourcing chemicals – the multi-supplier approach
- Primerless paint
- Colour matching challenges
- Matt finishes – will they ever be volume painted?
- Dream budget
Combining the finishing of upper-segment saloons, coupes and sports cars with premium SUVs and utility vehicles is a tough job without the added complications of aluminium bodies, as Chris Globe, Senior Manager, Paint and Plant Engineering, Jaguar and Land Rover (JLR) explains
Chris Globe has one of the most demanding jobs in the paintshop world, he oversees paint engineering at the company’s three UK plants : Halewood, in Merseyside - home to the Freelander 2 compact SUV and the recently revealed compact Range Rover, the Evoque. Solihull in the West Midlands, which is the main Land Rover plant, building and painting Range Rover Discovery and Land Rover Defender and Castle Bromwich, again in the Midlands, which produces the three Jaguar models, XJ saloon, XK sports car and the XF coupe.
Recent investments in paintshop by the JLR group have included some major investments and upgrades over the last 18 years, as Globe relates “We have built three new paintshops, the first was Solihull with an investment of £150 million launched in 1995. In 1998 we then built a new paintshop at Castle Bromwich and in 2000, we launched an almost completely new paintshop at Halewood. Since then, we have added some additional automation, particularly for sealing and liquid sound deadener.”
Turnkey solutions and specifications
The job of specifying conveyors, robots, painting systems etc is an oft-disputed area in paintshop construction and commissioning. How much has Globe and his team dictated the use of particular suppliers and how much they were guided by the integrator/paintshop builder?
“There are a fairly small number of players in the paintshop building market who can build something on the scale that we were looking for. We tend allow the turnkey contractor to put their interpretation on how to fulfil the functional requirements of the facility, as opposed to writing a very detailed specification and potentially forcing the equipment suppliers to change their standard equipment to suit our specifications. I don’t really like doing that, I much prefer to buy the standard equipment and incorporate it into our process.”
I wondered how the relationship between the various companies building a paintshop was managed at JLR. Who was the main contract manager overseeing all the elements of the build? Globe: “The paint shop at Solihull was installed some 15 years ago and the build was managed by the company’s then owners using different processes than those we might use today”.
Many OEMs insist on using their traditional conveyor, robot and even paint gun or bell partners, sometimes overruling their main turnkey paintshop supplier; Globe does not see this as a good way to work: “We concentrate on the process, we don’t start with a facility idea, we start with a process design – a bill of process. This is strictly laid down to meet the process, production and quality requirements. The main paintshop contractor is then invited to tell us how the equipment they recommend can meet those process and quality and production requirements. If there are any shortfalls in their equipment choices, we would ask them to modify their plans. In general, it is not a good idea to ask them to modify what should remain a standard piece of equipment.”
Some suppliers and experts in the industry view OEMs as being wedded to favourite turnkey paintshop providers but JLR has taken a more open-minded approach as Globe says: “The three paintshops built at Jaguar Land Rover sites in the last 20 years have been built by different providers; we don’t have one equipment supplier that we prefer instead we make a decision based on the best solution for the plant, products and processes.”
Aluminium – low weight – big headache?
Aluminium is central to Jaguar – and Land Rover’s target of lower emissions and better fuel economy while maintaining their position and performance and premium car makers. While it is a great weight saver, the material throws up a lot of challenges to both the bodyshop in joining technologies, and to the paintshop in dealing with the inevitable high sludge output in pre-treatment and e-coat, and in keeping surface finish quality to premium levels. Globe finds aluminium easier to deal with in some respects: “Our experience of aluminium in XJ and XK, which are 100% aluminium and not welded, they are generally riveted and bonded. Those processes are very clean and so we don’t have problems with weld residue in the way that steel bodied cars have weld balls and flash, which turn into loose steel particles in the body when we receive them into the paintshop. We don’t have these problems with our aluminium bodies. “As to surface finish, with the high quality of our stamping processes, in the paintshop we have a zero target for rework on A surface panels and we usually maintain this.”
Stamping and riveting tend to use lubricants to facilitate deep draw pressing and tool maintenance but this is usually cleaned off in pre-treatment wash as Globe says: “Our cleaning and phosphating process at the start of the paintshop is designed to remove these contaminants and/or neutralize them. Our process can be designed to cater for these elements and this is actually more straightforward than trying to cope with the variability one gets with steel bodies.” Jaguar’s model range construction does make life easier for their paintshops; like Audi, where there are several mixedmaterial (aluminium, magnesium and steel) body elements, the XJ and XK cars are fully aluminium aside from some brackets and reinforcing pieces: “There are some non-aluminium components on the car but they are pre-coated before being fixed to the car to avoid galvanic corrosion, either way they are not A-surface visible parts,” says Globe.
Full plant output at the various JLR plants is not 100% aluminium though. As Globe says: “We don’t have any exclusively aluminium body-producing plants; at Castle Bromwich for example, although the XK and XJ are allaluminium, the XF is not. It is steel frame construction with some aluminium closure panels. So, our phosphate processes have to be able to handle mixed metals, aluminium and zinccoated steel.
Sludge control technologies
In pre-treatment, Jaguar use a process that can deal with up to 70% alumiunium content as Globe says: “We use a modified zinc phosphating process in all three of our plants, called a two-step system, from our chemical supplier Henkel. “This reduces the amount of etching that occurs on the aluminium substrate, the problem with aluminium in the pretreatment stage is that it produces large amounts of sludge in the phosphate bath. This sludge is very fine and light and stays in suspension in the tank that is very difficult to remove. The two-step process reduces the amount of sludge, which of course is very important for environmental reasons as sludge has to go to landfill as it has no calorific value to help it burn in an incinerator.
This sludge from aluminium components in pre-treatment is reckoned by most paint chemists to be five times the amount generated by steel parts and it pollutes the phosphate bath and can stop the conversion process. Fine filtration in the bath can deal with this but this of course uses a lot of energy. Globe: “We use a scavenge system that is constantly filtering the bath contents but the amount of sludge needing removal is reduced by the special phosphating system.
“We have developed a process at Solihull using hydrocyclones, a process a bit like a Dyson vacuum cleaner, to remove some of the sludge and we were sceptical about this system as the (aluminium) sludge is very low mass and hydrocycloning relies on differing densities of material but it seems to work well.”
Wet-on-wet – the way forward?
Globe is not convinced by the trend towards wet-on-wet in water-borne applications, certainly not for existing facilities at JLR: “We have tried to make a business case to convert existing paintshops to use wet-on-wet as the savings that can be made with it are not huge compared to the cost of running the process and the cost of the materials. We have yet to prove the durability and appearance level of the process to be as good as our current paint systems.”
I pressed Globe on the big energy and equipment savings that could be made by having less oven time (and thus less energy used) and a shorter line, but he is not persuaded on the conversion of existing facilities: “We have already got the ovens that would be extra to the wet-on-wet process so would make no savings there, the only savings would be made in energy consumption. We could switch one oven and the primer booth but the colour booth would need to be longer than at present but when you compare these savings with the additional cost of the process, it really does not pay back in a normal amortization timetable.”
Powder clearcoat – good for BMW but not JLR
Where BMW use the ‘dry’ clearcoat system in many of their paintshops to great success; APS knows of no other OEMs using it. When I ask Globe about it he says he is not persuaded: “When it was first conceived the emphasis on environmental savings was all about VOC emissions; powder has almost zero VOC emissions so that is a good solution. But now, the environmental pressure is not just on VOCs, it is concerned with CO2 emissions. Powder uses more energy in the bake ovens; they must be longer and hotter. When one looks at the total environmental impact picture, I am sure there is neither a business nor an environmental case for powder clearcoat, especially converting an existing facility. But one must take a holistic view on the environmental of the whole finishing chain; including total lifecycle impact including the manufacture of the base material.” Globe does not see the process becoming more popular at other carmakers: “We are a niche manufacturer so it is not for us and it is difficult to see anyone else taking it on in the industry.”
Advances in solvents used in clearcoat have come a long way from the particularly poisonous carriers used in the past and so capturing the waste safely has become easier and more effective: “Not all of the solvent is released to atmosphere in the booth, some is carried on the vehicle into the ovens and of course they do incinerate a lot of the remains. All of our materials comply with the regulations governing hazardous emissions.”
Sourcing chemicals – the multi-supplier approach
Paint and primers, phosphating and pre-treatment chemicals from different suppliers are seen by many to be virtually interchangeable, I wondered how JLR choose between them and how often they review the latest offerings? Globe: “Our production principle is the Standard Bill of Process which means that wherever possible we want a standard process across all three of our paintshops because all of our products are in the premium category and all the quality requirements are the same. We try to have the same supplier per process across all plants. “We generally have a nominated ‘first tier’ supplier for each layer of paint - Henkel for pre-treatments and BASF for electrocoat and Dupont for all primers, basecoat and clearcoat. We don’t alternate between suppliers.”
Globe is very sceptical about primerless paints: “ I am very nervous about this, mainly as I am not convinced by its ultraviolet resistance. As electrocoat material is not UV resistant at all and relies on 100% ‘blocking’ of sunlight from the primer and topcoat layers, putting basecoat straight on top means any variability in the process could risk insufficient protection to the electrocoat and consequent damage – the topcoat basically peels off.”
Of course primer and primer surfacer coats can help to cover any imperfections in the A-surface, something which can be more common in aluminium bodies. Globe: “We are looking for a little bit of a filler element to our primer coats and one of the challenges with mixed substrates with different grades of aluminium, with slightly differing surface ‘texture’ characteristics. We also have various different types of steel, with different levels of zinc coating on and of course, thermoplastic parts. “All of these substrates have differing roughness or appearance and there has to a levelling process and primer is very important for that process, to achieve a fine premium finish.”
Colour matching challenges
All OEM trim and final lines are buying-in ready-painted hang-on parts, either from suppliers or from other divisions of their parent company. Much has written of the use of spectrophotometry as being the complete answer to colour and finish matching, giving data transferable electronically from OEM paintshop direct to supplier, in theory ensuring every piece matches its destination vehicle perfectly. But is there still a place for human visual confirmation or rejection of conformity? Globe thinks so: “We buy in a lot of hang-on parts ready-painted. In fact the only ‘loose’ parts on the car that are painted in-house are the fuel filler flap and some plastic fenders/bumpers. We have a very strict and complex colour harmony process with our suppliers to ensure we get good colour continuity between plastic parts and bodies. “We use the usual X-Rite machines for checking but there are cases where the machine does not always get it right so we also have a human colour team control process, a team of colourtested experts who, on a regular basis, do assessments around a car in various light conditions.”
Matt finishes – will they ever be volume painted?
The ultimate special edition paintjob for many younger (and some younger at heart) buyers is the matt finish. Commonly seen in black on limited-edition Mercedes and now Fords, application of matt finishes has traditionally been made in specialist paintshops commissioned by OEMs, or by wrapping with a film. The painted versions of these use refinish equipment (air-fed sprayguns etc) to apply the paint. I asked Globe if he could see matt paints becoming part of the OEMs automated palette of finishes: “As we understand it at JLR, matt clearcoats cannot be applied through spinning bells, the main reason being that one would get differences in matt and gloss level across the vehicle, where the bell application overlaps. “It is not an option to put matt paints through electrostatic spinning bells on a main line. If we were going to offer the finish, it would have to be hand-sprayed which would mean very low volumes and high cost. Any that we do are done out of house, at a specialist refinisher.”
A foil or film in a matt finish is a lot more practical and can look very good. Ford are offering this on the new Focus RS500 model. JLR have done a few cars using this process and Globe is more keen on this: “We have had a few cars done like this and it looks quite good, it is expensive though.”
One other serious drawback with matt paint is its susceptibility to marking, any scratches may appear as shiny areas and even applying a wax can cause glossing of the finish and is strongly discouraged by the paint makers. Globe sees warranty issues as a major problem in the making with offering matt paints: “We know that these finishes scratch more easily and show fingerprints etc, under normal usage by our customer and this could impact upon warranty costs.”
In our AMS magazine and in APS, I always like to ask vicepresidents of manufacturing, managers and engineers what would they spend an unlimited, ‘dream budget’ on. Chris Globe is fairly modest in his wishes: “My dream would be to have a ‘lights-out’ paintshop – as in powertrain machining, an unmanned, fully automated facility. We already have a high level of automation in the JLR plants, probably as much as is appropriate for our volume and level of premium products but to fully automate would in theory, remove all the variabilities in processes. And that is the dream of any engineering manager.”