News

The surest way to attract management's attention in any industry is to come up with a way to save the company money.

That certainly holds true in the auto industry; even more so, if you can combine cost savings with reduced emissions. Just to put the frosting on the cake - combine those two with improved quality.

Success in this respect, especially in an industry that produces millions of products annually, can be measured in fractions of a per cent or cents per unit.

The scientists and engineers at Mazda's Technical Research Center in Hiroshima, under the leadership of Takakazu Yamane, have developed a new process that reduces the cost of painting a new vehicle by an astonishing 20 per cent.

The same process also cuts the emission of volatile organic compounds (VOCs) by 45 per cent and of CO{-2} by 6 to 15 per cent - and improves paint quality while reducing energy consumption.

The multi-part process includes the paint and the manner in which it is applied.

Mazda scientists developed "internal control polymers" that prevent the various coats of paint from mingling.

In conventional paint systems employed at auto plants around the world, an "e-coat" is applied to the bare metal to ensure proper bonding of the primer.

The vehicle is then put in a bake booth to dry that coat and then the primer is applied - again followed by a session in the oven.

Now the vehicle is ready for the colour and clear coats, which lately can be applied one on top of the other.

The last step is one last trip to the bake booth.

The Mazda team looked at the overall paint process with an eye on three areas:

1) reduce the use of nasty chemicals,

2) reduce the amount of energy used and

3) improve the quality of the paint job itself.

Paint booths use nasty solvents like xylene and toluene. The baking process uses tremendous amounts of energy and that situation is made worse by the need for additional air conditioning to keep working conditions in that part of the plant within acceptable comfort ranges.

The new eco-friendly three-layer wet-paint system developed by the Mazda team uses low-solvent paint, a new coating system and a new robotic application process.

A new water-borne process and "internal control polymers" prevents the various layers of paint from mixing or mingling, eliminating the separate booth currently used for the application of the primer coat and the necessity to bake that coat dry before applying the colour coat.

The primer, base and clear coats are sprayed one after the other without baking in between.

Obviously the new process is a well-guarded secret, but Yamane said it includes decreasing the molecular weight of resins used and reducing colour "turbidity."

As an example of how complex the process is, he said, "because the interface control polymer has a different solubility parameter to the low molecular weight resin, it moves to the surface of the primer coat where it forms a highly viscous barrier separating primer and base coats."

The polymer then melts away in the final and single baking step and the surface becomes smooth.

Robots are commonly used in the painting process because of the ability to program them to get a consistent application, vehicle after vehicle - and for different vehicle shapes.

But the new process at Mazda includes a rotary nozzle instead of the conventional reciprocating one, and suitably reprogrammed robots.

Instead of the paint head moving up and down and side to side, the new unit ensures more of the paint ends up on the vehicle and less in the air and subsequently on the ground where it has to be washed away with solvents to an energy-gobbling incinerator, which in turn produces pollutants. It also means less paint is used.

The new process is going into production at both the U1 and U2 plants at Mazda's 2,200-acre Hiroshima facility, which builds 480,000 vehicles a year.

A new CX-7, Mazda5 or Mazda2 rolls out of the U2 plant every 72 seconds on average.

And now, thanks to Yamane and his troops, each one has higher-quality paint and costs less to produce.

globeauto@globeandmail.com