The Model S vehicle, developed and manufactured by Tesla, the world's most prominent electric vehicle manufacturer, has 250 patents. Its all-aluminum body combines lightweight and high-strength properties. In addition to the body, most of its front and rear suspensions are made of aluminum. From a manufacturing point of view, the car is produced in a different way than other cars. Through the real production video of the following Tesla factory, you will learn more about the Model S car from the selection of raw materials, stamping, welding, painting to final assembly production process, and read the absolute knowledge!
Since the aluminum alloy material is sensitive to heat, if the conventional welding process is used, there is a problem that the strength of the material is lowered, and since the heat is easily deformed, the dimensional accuracy of the all-aluminum body is not easily controlled. So, how does the Tesla factory overcome the difficulties of the aluminum alloy welding process?
Introduction to CMT Cold Metal Transition Technology
In 2005, Austrian Fronius Welding Technology International Ltd. introduced the CMT (Cold Metal Transfer) cold metal transition technology, which achieved the first connection between steel and aluminum in the world. Compared to traditional MIG/MAG welding, the CMT process is really a “cold transition”.
In the case of CMT droplet transfer, when the current is almost zero, the droplets are sent to the molten pool by the withdrawal of the wire, the heat input is rapidly reduced, and the continuous heat output to the weld is very short, so that the welding is performed. The process of cooling a seam significantly reduces the amount of deformation of the thin plate and at the same time enables the weld to form a good bridging capability, thereby reducing the assembly clearance requirements of the workpiece and the accuracy of the fixture. CMT can weld ultra-light sheets with a thickness of only 0.3mm.
CMT has an extremely stable arc. The length of the arc can be detected and adjusted mechanically. Regardless of the surface condition of the workpiece or the speed at which you want to weld, the arc is always stable, and the welding process is almost non-splashing and has no burn-through.
DeltaSpot Resistance Spot Welding Technology Introduction
The Fronius DeltaSpot resistance spot welding process is a new technology developed for aluminum welding. Its innovation lies in its unique electrode strip. The invention of the electrode strip brings unprecedented advantages.
Extremely high process reliability, each resistance solder joint can achieve 100% repeatability: the base metal and the electrode are protected by the electrode strip, and the electrode strip moves between the electrode and the base material to be joined to achieve a continuous welding process. Ensure a constant level of quality across multiple shifts.
A new effective electrode is used for each solder joint: due to the protection of the electrode strip, the electrode tip avoids wear from the base metal and avoids contamination by zinc, aluminum or organic residues. Under such protection, the service life of the electrode is significantly improved. In the welding experiment with an aluminum plate (AlMg3 alloy), the electrode has a service life of up to about 30,000 solder joints.
No splash on the soldered surface: Since the electrode does not make direct contact with the base material, a spatter-free soldering effect is ensured. Especially when welding aluminum sheets, the coating of the electrode strips optimizes contact with the aluminum material, avoiding splashing and consequent damage to the components.
With the electrode strip, the heat input can be precisely controlled: three-plate connection (two thick plates, one thin plate) is a big problem for traditional spot welding. Solder joints are formed within the slab range and are not sufficient to hold the sheet. The DeltaSpot's electrode strips have a targeted control of the depth of the solder joints through its additional heat input. Therefore, the low heat in the thin plate range can be compensated by the high resistance of the electrode strip. In this way, the solder joints are sufficiently deep into the thin plate. At the same time, the shape of the solder joint is more symmetrical, and the weld seam in the range of the thin plate is larger.
DeltaSpot not only excels in aluminum welding, but also has incomparable advantages in welding different thicknesses/different materials, such as: high standard solder joint appearance, high-strength steel material welding on surface coating. DeltaSpot weldable base metals include: high strength steel, surface coating materials, aluminum, stainless steel, titanium, magnesium, composites, etc.