Surface treating cylinder walls

Beijing, China — Chinese drivers like to overload their trucks.

Beijing, China — Chinese drivers like to overload their trucks. Drive any highway and it is not uncommon to see several trucks pulled over to the side of the road while a flat tire or broken axel is being repaired. It's easy to understand then why a truck owner tries to get as much mileage out of a truck as possible. At 200,000 kilometers on the engine they still think a truck has some life left in it. About 150,000 more kilometers it seems.

So it shouldn't come as a surprise, but it does, that laser surface treating cylinder liners is a big job shop business in this busy, bustling economy.

DaHeng Laser (China DaHeng Laser Engineering Co. - www. is a leading supplier of high-power CO2 laser systems for heat treating the cylinder walls of automobile and truck engines. Since the company was founded in 1987 it has supplied more than 200 units for hardening the wear surface of the cast iron cylinder liners used in commercial vehicles as well as those used in repairing engines for agricultural equipment and tanks.

The process is quite simple, a cylinder liner is placed on a rotating table and a 45° mirror mounted on a rotating piston indexes down into the cylinder so that a defocused beam pattern produces a screw, sine wave, or helix heat-treated pattern on the cylinder wall. Using a new type of CNC control system, a Chinese menu, and graphic tracking, this system is relatively easy to start up in the many job shops that have been set up around China expressly for this application.

Luan Guishi, general manager, told ILS that soon every town in China would have such a repair job shop. This means that the market for the cylinder heat treat machines should remain steady for several years to come.

This application was first developed by Avco Everett Metalworking Lasers (Everett, MA) in the early 1970s, which resulted in an installation of several Spectra-Physics (now Rofin Sinar) high-power CO2 lasers at the General Motors Electromotive Plant in LaGrange, IL, where they heat treated diesel engine cylinder liners.—DAB

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