[China Aluminum Industry Network] 1 Introduction Dies play an important role in the extrusion process of aluminum alloy profiles. Reasonable mold structure is an important guarantee for product forming and dimensional accuracy, especially in controlling the microstructure and mechanical properties of hollow aluminum profiles. The mold processing is an important part of achieving the mold designer's concept and ensuring the mold structure accuracy. However, due to the limitation of the performance and accuracy of processing equipment, and the uneven level of processing personnel, it is often the case that there are more or less defects in the manufactured molds, which brings unnecessary trouble to the subsequent extrusion production. It also delays the delivery date of some products. Our company has adopted a series of measures to control the quality of molds, and the precision of molds has been steadily improved. The following is a detailed description of the quality problems encountered by our company in the mold processing and the control measures taken.
2 The quality of mold processing 2.1 Processing process is prone to processing defects due to the performance of the manufacturing equipment and precision and operator level and other factors. The molds that cause processing do not exactly match the design drawings but are not scrapped. This results in an incompletely qualified mold, which is both a defective and a defective mold. These molds can cause quality problems in profile products during extrusion production. For example, the precision of the machining of the die of the die has an impact on the quality of the profile products, such as framing, dragging aluminum, partial walls, and line lines; the angle of the working belt is not correct. Will affect the formation of profile products. Figure 2 shows the proportion of the company's statistical processing defects on the quality of the product. It can be seen from the figure that the proportion of work belt and air knife defects is large, and the rest of the defects are more balanced. 2.2 The causes of the defects and the impact on the quality 2.2.1 The working belt accuracy is not high The working belt is directly in contact with the metal aluminum, and it is in contact with the profiles. Forming and dimensions play a key role. However, due to inaccurate segmentation of the working belt when machining personnel are milling the electrodes, no arc transition is used between the high and low working belts, which may cause the surface of the molding material to form bones or bone shadows. In addition, the working belt angle is not correct, flatness is not enough, often due to the relatively thick line cutting pattern, the amount of polishing is too large, the level and habits of the polishing staff cause the work belt with a positive or negative angle, making the mold out of the material in use become Blocking or speeding up, misdirecting mold designers or molders, and making profile molding difficult. The poor smoothness of the work belt and the chamfering of the inlet and outlet are not enough to cause the mechanical deformation of the profile surface to increase.
2.2.2 The size of the empty knife is too large or too small When milling the multi-core hollow knife, because the rough milling core is integral, the wall thickness between the cores is not processed, and the processing personnel often pre-determine the size of the empty knife according to the drawings. Processing, it is easy to cause a small knife at the core of the empty knife is too large and the stability is poor, resulting in uneven wall thickness of the profile that is biased. In the cantilever part where the size of the air knife is smaller, especially near the working belt part, the spark does not strike the plug mold, or the aluminum drag is coarse, or the electrode is off center when the knife is set, so that the empty knife of the cantilever part is not Uniform, that is, the side of the knife is large, while the side of the knife is small, the cantilever is biased to one side or broken when squeezing, resulting in die scrap.
2.2.3 Diverting hole, welding room, diversion finish, smoothness and taper are not enough for diversion die machining. The triangular dead zone often appears at the diverting die core and the diverting bridge. This is mainly because the milling cutter is in the pendulum. Insufficient or inconsistent angles are caused by too few times. During the extrusion production, the metal flow in the area is not smooth, and the welding performance is poor, which causes the profile to have a yin and yang surface or an increase in surface line lines at the place. The smoothness and flatness (some taper) of the diversion chamber are insufficient. Mainly when fine milling or grinding plane, the workpiece is unevenly placed, or the milling processing speed is too slow. If the taper is not enough, the taper is not accurately ground when the milling cutter is used. These defects will cause the thickening of the line of the profile to increase.
2.2.4 Diverting bridge chamfer is not rounded, the feeding hole (groove) is not smooth
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