September AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | S E P T E M B E R 2 0 1 8 1 5 N ot only was fuel expensive in Eu- rope during the 1950s, it was im- ported from a Middle East seeking greater political independence from for- mer colonial rulers. A decade after the end of WWII, the European economies had finally started growing and people were beginning to look beyond a mass market of small cars with small engines and sluggish performance. The question was how to satisfy a growing desire for larger andmore comfortable carswithout bigger engines and lower fuel efficiency. Nowhere was this more apparent than France: By the end of 1950, Pan- hard’s Dyna X was getting old in a mar- ket that was changing rapidly. It was viewed as a small and quirky little car, out of style and in need of a modern successor. The Dyna X was a mixed met- al car with aluminum skins over a frame made of several large aluminum cast- ings supported by a steel underbody. It did not have a decklid, so the trunk space was reached from the inside by pivoting the back of the rear bench. At a board meeting on December 29, 1950, Panhard decided on a thoroughly revo- lutionary concept for a new model that would feature all-aluminum stamped construction. DYNA Z DEVELOPMENT The Dyna Z was to be spacious and aerodynamically efficient, with engag- ing driving dynamics and excellent fuel efficiency. By keeping the car as light as possible, Panhard could carry over the proven air-cooled two-cylinder en- gine and running gear, thus holding the budget within their limited invest- ment capabilities. The press introduc- tion was slated for mid-June of 1953 with a launch date in October at the Paris Motor Show. The engineering and manufacturing teams had 30 months to design, prototype, test, tool, and launch a completely new body and re- lated closures. As for the Dyna X, a Tier 1 suppli- er would deliver the completed body in white (BIW) with doors-on to Pan- hard for paint and final assembly. But this time, Chausson was responsible not only for the stamping tools, but for the production of the stampings and the body assembly as well. The assembly was done using new resis- tance spot welding (RSW) equipment developed by Sciaky and Languepin capable of 100 welds per minute. Care- ful optimization reduced the number of spot welds to about 3000 per car. Péchiney, as L’Aluminium français was now called, provided A-G5, a new alloy with 5% magnesium. A-G5 was a stronger yet more formable alloy for the underbody and other inner parts that were difficult to form. The other parts, including the skins, used alloy A-G3 (3% magnesium). Once again, de- veloping and launching the stamping tools proved to be the most difficult as- pect of the project. The experience gained with the previous model helped as did the new and improved formability alloys, but there was nothing the aluminum sup- plier could do to tame springback. In the early 1950s, there were no resourc- es and little prior art or lessons learned to guide diemakers in their fight a- gainst springback. High-strength steels were still in the future, so the diemakers were truly blazing a new trail. Higher strengths and more com- plex parts conspired against toolmak- ers accustomed to mild steel, resulting in multiple tool face recuts. Chausson would struggle for months to achieve acceptable fit and finish. Getting the newly developed high-speed portable spot weld guns to work took time. When the car finally appeared in public for the first time at the Paris Motor Show, Panhard had only completed nine cars. Two had been available for test drives by the motoring press, three were in use for final testing and development, and all four displayed at the show were not drivable. The bright spot was the glowing reviews: The new car was an impossi- ble combination of performance, effi- ciency, comfort, and roominess, with styling to boot. This was in part due to the incredible aluminum design, with a BIW and bumpers weighing less than 120 kg (265 lb). The six-passenger car had a wheelbase of 2570 mm (101.2 in.), an overall length of 4570 mm (180 in.), a width of 1668 mm (66 in.), and a height of 1430 mm (56.3 in.), similar to a 2005 Honda Civic. Its aerodynamic design provided stable behavior in crosswinds and enabled 130 km/h (81 mph) with an 850-cc engine developing 42 HP. The combination of advanced body engi- neering and aluminum resulted in a dry weight of only 710 kg (1565 lb), a weight savings of more than 25% compared to period competitors of the same size. Lower weight, superior aerodynamics, and an efficient powertrain combined to yield a fuel consumption equivalent to much smaller and slower cars. Single phase portable spot welders.