Cover mainly refers to the car covering the engine, chassis or constitute the cab, the car surface and the internal thin plate plate parts. Compared with the ordinary stamping parts, the cover has the characteristics of complex shape, thin material, high surface quality requirements, good rigidity, large structure size and mostly space surface. The stamping process of the cover is generally carried out by blanking (or shearing), forming, trimming, punching and flanging. Cover forming process mainly to deep drawing (drawing), mainly including bulging, flanging and bending and other ingredients. In most cases, forming is the key to the manufacture of such parts, which directly affects product quality, material utilization, production efficiency and manufacturing costs.
On the mold material, ordinary mold is usually used HT300 or HT250; molding part is usually large, medium-volume production using MoCr cast iron and other alloy cast iron or ductile iron, small batch using HT300; repair part of the material if the thickness of less than 1.0mm, (7CrSiMnMoV).
Deep drawing, trimming and flanging is the most basic process, in which the drawing process is a more critical process, it directly affects the product quality, material utilization, production efficiency and manufacturing costs.
There are many types of tools involved in the processing of the molds. In the processing of the guide plate, the discharge plate, the platen groove, the support surface and the jack hole, it is necessary to use different diameter milling cutter, corn cutter, end mill, drill bit and tap Such as cutting tools.
Of course, we are more concerned about the cover mold surface processing. For different purposes, different levels of the car, the surface quality of the expression is not the same. The cover itself is a sheet metal sheet, which is deformed after stamping. If the design is not enough to consider, it is entirely possible to test the production of parts of the larger error to repair the place. Relative to the plastic mold, the cover mold precision grade and surface roughness requirements are not high. Cover mold is characterized by large size, the need for large-scale machine tools for processing.
As the market competition becomes more and more intense, mold suppliers are increasingly sensitive to the cost of the tool. Or, for high-end tools, there is a higher processing efficiency and service life requirements.
For the rough surface processing, commonly used a willow-shaped blade ball end mill. The main cover mold manufacturers are using high mountains R218.20 cutter, cutting part of the diameter of 30mm, blade material for the PVD coating F25M. Due to the high rigidity of the design and the number of effective teeth (K = 2), this high metal removal rate of the tool can withstand very high feed. The R218.20 has a unique blade seat with a positioning dowel to avoid stress concentration of the locking screw and to prevent rotation of the blade. The chip space is large and contains a large circular surface, making the tool stronger at the center. On the same blade there are two cutting edges that are very light cutting. High-strength blades and blades make this kind of cutter the greatest safety and reliability, making it suitable for unmanned production. The "S" curve of the cutting edge of the blade facilitates the reduction of the cutting force and has a constant cutting front angle along the cutting edge. The axially positive rake provides smooth cutting and allows for cutting upwards and strengthens the center to collapse it. By using a rear corner that is adaptive along the cutting edge, a very low cutting force is generated at a smooth geometric angle, resulting in improved tool life. Generally speaking, the life of the tool to reach more than ten hours.
For the finishing of the surface, it is recommended to use the high mountain Minimaster small devil end mills. This kind of tool in the mold processing industry has a high reputation in the cover mold manufacturers are also widely used. Mountain MINIMASTER small devil milling cutter is a versatile, adaptable system, arbor material, including steel and high-density anti-vibration materials. It is a unique small-diameter end mill system that can be combined into a different solution that combines the ability to provide optimized reachability with maximum stability and safety. Minimaster small devil system consists of a wide range of blades and arbor, blade and arbor combination of more than 600 kinds, the diameter range of 6 ~ 20mm. Minimaster is also an economic solution. For the deeper angle of the surface, it is very suitable for the Minimaster Minuster with a 6,8, the overall length of the carbide cutter is often not enough.
The choice of tool and the correct use is one aspect, the efficiency of mold processing is also reflected in the machine function and programming. When the vertical angle processing, the ball knife cutting point line speed is zero, and in the vicinity of the tip of the cutting line speed is very low, affecting the surface quality of the mold. Such as machine tool permits, according to different cavity with different processing angle, so that the dip angle to achieve a better cutting diameter, in order to obtain better linear speed.