1. Optimize the design
For extrusion dies, the level of design directly affects the condition of discharge, and to a certain extent, it is related to the service life of the mold. The design of the extrusion die is first to select a suitable extrusion ratio according to the profile to determine the tonnage and number of holes of the machine, so that the designed shunt hole forms a state of discharging balance, and in addition, the design and structure of stress concentration should be avoided as much as possible, and the force of each part of the mold should be uniform to ensure its stability. For the foreman with more complex screw holes, the hollow knife will be appropriately lengthened to strengthen the strength of the screw hole position. In view of the factors such as better tempering of the mold for heat treatment, better stress relief and better heating thoroughness, holes will be drilled in the middle of some large square tubes and rectangular foremen. If the diagonal of the profile is long and it is a square tube type, the thickness of the upper die will generally be thickened to better ensure its strength, and the bridge position will also be appropriately widened, so as to effectively avoid problems such as premature cracking.
2. Mold processing
The processing and manufacturing of extrusion dies are divided into mechanical processing and electrical machining. Basically, the machining is rough machining, and the main structure of the mold is completed; Electromachining is finishing, mainly re-processing important parts such as working belts. In order to improve the life of the extrusion die, it is quite useful to pay attention to some details during the processing process. In particular, through a situation after repair, we can analyze how to process better when the mold is replenished next time.
1. In terms of heat treatment, the general hardness value of the extrusion die is HRC47-HRC51, but for the hardness value of the large mold with specifications above ¢560, the lower limit value of HRC47 will be generally taken. Because this not only ensures the hardness of the mold, but also maintains the toughness required by the mold.
2. For the processing of the shunt hole, especially the porous mold, special attention should be paid to the symmetry after the processing of the manifold hole, and the loss of the tool should be paid attention to in the machining process to ensure the final dimensional accuracy. The work of the grinding room is to polish the mold brightly, in the process of rough beating, be sure to make the knife marks, diversion, transition positions, etc., all the bridge positions and the connection of the mold neck must be connected in an arc, so as to better heat treatment. So far, our company has effectively improved the surface finish of the mold according to the process of rough beating before hot and fine beating after fine beating, which is more conducive to smooth discharging and reducing friction.
3. The diversion plays an important role in balancing the feed for the extrusion die, so that the processing of the diversion has become the focus of attention. Generally, the processing of diversion is carried out in accordance with the design drawings. However, in order to improve the pass rate of the first machine and give full play to the experience advantages of the on-site processing personnel, our company conducts the processing of general diversion and perforation according to the experience value of the on-site processing personnel (from the summary of the usual mold repair situation).
4. The processing of the empty knife of the mold plays a vital role in its strength, especially the empty knife at the top position, the end point, the cantilever and so on. Under normal circumstances, in order to ensure its strength, the slope of the empty knife in a special part will be slightly increased, and the empty tool value will be taken to reduce the difference. IN ORDER TO ENSURE THAT THE WALL THICKNESS OF THE MOLD IS NOT TOO EARLY, THE FINAL WALL THICKNESS OF THE MOLD IS GENERALLY NEGATIVELY (0 TO -0.03MM).
