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Talking about the Importance of Die Casting Die to Die Casting Production

2020-02-05

    Foreword: There will be quality problems with different factors in the production process of die casting. In addition to the instability of the system caused by the failure of die casting equipment, equipment performance and quality, there are some auxiliary equipment (such as die cylinder, punch, cooling pipe network, etc.) Accuracy and the quality of auxiliary materials can have a certain impact on the production of die-casting (such as mold release agents, lubricating beads, cooling water), and the purity of aluminum liquid will also bring corresponding instability factors (such as scrap products, gates, The proportion of overflow block and cleaning material), and control of melting process.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    Although the above-mentioned various causes cause a great disadvantage to the production and quality of die-casting, these problems are relatively intuitive and relatively easy to solve. In the process of die-casting production, common and difficult-to-resolve quality problems often trouble us. An enterprise (such as air bubbles. Pores, slag holes, pinholes, cracking, chipping, strain, deformation, misalignment, cold material, cold grain, cold grain, cold casting, looseness, shrinkage, mold flying, etc.), It even hinders the development of die casting (high cost and low efficiency), and the leading cause of these difficult and frequent quality problems is what die casting molds do.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    From the above analysis, we can understand that the improvement of efficiency, the guarantee of product quality, and the good economic benefits are closely related to the development, design, and maintenance of molds. In the past, technicians used the quality of the entire die casting production process, Efficiency, revenue and cost control are divided into: molds account for 60%, machine performance accounts for 15%, accessories and accessories account for 5%, process parameter debugging accounts for 10%, and manual operation accounts for 10%, as a basic management of the entire process of die casting production Standard, but with the wide application of die castings in various industries, especially in recent years, it is widely used in high-end equipment and equipment (such as automobiles, high-speed rail, communications, aerospace, etc.), and its quality requirements for die castings are more stringent. Various industries have also made corresponding technical standards. Therefore, I believe that in the past, the management and control division of the die-casting production process should be advanced with the times and be re-integrated, so that we can better understand and identify and better control production. Run the process data control of each process to maximize our revenue, so I personally think that the improvement of product quality is the first It has higher requirements for the performance and stability of the equipment, and has a deeper understanding of the quality and use of auxiliary materials (release agents, lubricating beads). Of course, the die-casting mold is also continuously improving the design capacity and service life (such as increasing Point cooling, fine core cooling, front die ejection, inclined ejection, internal core pulling, surface electrodes, etc.), so the process control (quality, efficiency, profit, etc.) of the die casting production chain should be divided according to Moulds account for 45% (design pouring, cooling, size level, manufacturing level, mold life, quality of parts in the mold, etc.), die-casting equipment accounts for 20% (equipment failure rate, system performance, system stability, etc.), auxiliary materials 5% (release agent, particle beads, lubricating oil, etc.), accessories 5% (punch, tie rod, shooter, joint, pressure plate, etc.), smelting occupies 10% (purity of aluminum water, temperature control of aluminum water, Proportion use of new and old materials, quality of melting and insulation equipment, etc.), technical process parameters account for 10% (slow casting machine speed, high speed, pressurization, injection start to end position, spray water, gas size and time, water spray Location, mold temperature field Control, vacuum equipment quality, vacuum body design, vacuum time, etc.).(Bengbu Longhua Die Casting Machine Co., Ltd.)

    At present, die-casting equipment is basically automatic or semi-automatic in production, so manual operation accounts for 3% (the operator's proficiency in the equipment, the knowledge of the die-casting process, etc.), and the cooling water quality accounts for 2% (the size of the cooling water and the temperature field of the mold). Control, water quality, etc.).(Bengbu Longhua Die Casting Machine Co., Ltd.)

    From the past to the present, we have divided the quality control of the die-casting production process. The molds have dominated. For this reason, we can understand that the core of die-casting production lies in the design and manufacturing quality of the molds. Must have a clear understanding, sufficient awareness, the mold design, production and maintenance as a top priority of special project management, the enterprise will be able to move forward and develop better.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    The following points should be paid attention to in the design and manufacture of die-casting molds and common quality problems in the production process. I would like to share my views and share them with colleagues (for reference only).(Bengbu Longhua Die Casting Machine Co., Ltd.)

    One: A good die-casting mold starts with the research and development of castings. The performance and technical requirements of castings are customer demand standards. Customers will not easily consider whether mold manufacturing and die casting production processes can meet the technical standards required for castings, but the structure of castings often cannot meet the technology of die casting molds and die casting production. And process conditions, so this requires a comprehensive review of the early structure and technical requirements of the casting. First, whether the design and manufacture of the die casting mold can meet the technical requirements of the casting. It is to evaluate the production equipment capabilities of castings and its own technical strength, the third is the expected production efficiency and qualification rate, the fourth is the mold manufacturing cycle, cost and life, the fifth is the number of orders, return benefits, and the sixth is customer trust.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    Two: After the above confirmation, it is necessary to start from the first step of mold design.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    1: mold ranking, that is, positioning the mold, positioning first considers market demand, monthly, annual output, positioning purpose is to consider the cost of mold manufacturing (the main reference is who will bear the cost, is the full payment or product sharing, customer requirements to provide The number of good products, the cost of copying molds, etc.).(Bengbu Longhua Die Casting Machine Co., Ltd.)

    2: Determine the size of the mold, first consider the size of the mold meat. In addition to the reservation of the surrounding parting surface, the mold runner, horizontal runner, injecting gate, exhaust position, overflow groove, core drawing method and size And the number of core pulls, the cooling system, whether a temperature control system, vacuum exhaust, and the size of the mold meat affect the future mold life, whether the sealing material can be controlled, the deformation of the mold meat is reduced, and whether the design structure needs a front top Equipment, etc., to determine the size of the mold meat, taking into account the size of the mold base.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    3: Thimble ranking, confirm whether the customer has any requirements for it. The second is the size and number of thimbles. The third is to consider whether the ejection and balance of the product are affected during production. The fourth is to consider whether the location of the thimble affects the water transport system. More, it will increase the cost, it will also have a certain impact on the life of the mold, but it can play a good role in exhaust, and has a good auxiliary effect on ejection of complex parts and exhaust.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    4: For cooling system, it is recommended to adopt straight-through cooling as much as possible. When the through-flow cannot be solved, use spot cooling or fine core cooling. Try not to use circulating cooling. Pay attention to the mold temperature control. The point cooling effect is not optimal. And, the cost is high, the loading and unloading is cumbersome, and it is not conducive to production, but it can be used in combination with straight-through and spot cooling, which basically meets the ideal design requirements.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    5: The size of the gate sleeve, the diameter of the projection area is large, and the small side is opposite. This will cause many problems such as specific pressure. For example, if the diameter is large, there will be more waste, the specific pressure will be smaller, and the impact of the flow rate on the mold It is small and has corresponding benefits to the life of equipment and molds. It is suitable for product castings with less complicated structures. The gate sleeve is small, the material reduces burning loss, the impact speed is fast, the filling performance is good, and the casting with complicated structure is used more.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    6: The mold structure is fragile, and the cracked and aging protruding parts are designed with inserts as much as possible. If the original body manufacturing method is used, it will bring a lot of inconvenience to future production. Exhaust the structural parts, but the original method can reduce costs in manufacturing, short manufacturing cycle, and also beneficial to the life of the mold. For example, the use of inserts can shorten the replacement and maintenance time in the die-casting production, which is more convenient and faster. 2, and the biggest benefit can play a better role in exhaust.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    7: The design of runners and gates, whether direct pouring, horizontal pouring or gate design, plays a vital role in the molding of the product. If the mold is the core of the die-casting production, then they are the molds. The core of the design is to introduce the aluminum liquid from the pressure cylinder into various parts of the cavity. The flow rate, filling time, flow direction, temperature in the cavity and the need to maintain a smooth flow during the filling process The control of temperature, protection of impact-prone parts, and the sequence of the molten aluminum flowing out of the cavity must be perfect design. The wide and long dimension of the sprue is the first important part to introduce the molten aluminum, and the width is too wide to affect the flow rate. If it is too long, it will release the pressure. If it is too thick, the above two defects coexist. For example, if such a runner is designed, they will increase the mold temperature of the runner and be difficult to control. It will easily break the material handle, generate more waste, and increase filling. Time, but they all have a common advantage, the flow rate is stable, so careful consideration should be taken in the design. (Reference data, generally below 400 tons, the length of the sprue is 20nn-40mm, the width is generally 15mm-25mm, 10mm-15mm, 630 to 1000 tons machine, 35mm-65mm long, 30mm-50mm wide, 15mm-25mm thick, 1250 to 2000 tons machine, 45mm-80mm long, 35nn-65mm wide, 30mm-45mm thick ,)

    In short, when designing direct pouring, we pay attention to the length and width structure of the product to ensure smooth flow when introducing the runner, and to ensure the flow speed and aluminum water flow, and to prevent excessive inlet mold temperature and waste caused by burning. Loss of waste.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    When designing the runner, there are generally two ways to enter the water, one is the large spout, and the other is the split flow type. (Ladder split type) This is mainly set according to the product structure. When designing the cross flow, it is very important to choose the location of the split flow. Of course, the shunt is the first step of filling into the gate, and it contains the flow, flow rate, and stability. The pressure transmission is the most critical part of the entire die casting process. Not only that, the shunt must also enter the cavity. Aluminum liquids cannot easily impact each other or collide too early, so as not to cause vortex to form gas, change the flow direction, reduce the velocity and injection force. When designing the length and thickness of the runner and the deceleration part, the length and thickness should be considered first. Whether it can meet the flow and stability and pressure required for the introduction of the shunt. Too short or too thin will cause insufficient space for the molten aluminum introduced by direct pouring, which will cause the molten aluminum to enter the shunt channel smoothly and orderly, and even cause pressure relief. If the design Too wide or too thick, it will affect the velocity of the molten aluminum, which will weaken the impact force after the molten aluminum enters the cavity, resulting in untimely pressure transmission and burning. More than expected.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    The deceleration part must not be too complicated. When ensuring normal water entry on both sides, reduce the deceleration part as much as possible, so as not to cause excessive rolling of the aluminum water, which will affect the flow rate and reduce the pressure.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    Generally, the joint of the horizontal pouring and the split port usually adopts a 45-degree oblique angle. The angle greatly affects the flow velocity and weakens the force. The flow velocity can not be stable. The flow velocity is too small and the impact on the mold surface is large. Concentration can even weaken the transmission of shot force.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    The main design of the inner gate is set according to the location of the shunt. It is worth noting that the angle and angle of the gate's water inlet directly affect the direction and speed of the water inlet, and will also cause cross impact, forming eddy currents to weaken the pressure and prolong. Filling time. However, the reasonable use of the angle of water penetration and the reflection force of aluminum water in the cavity can change the flow velocity and direction to achieve the filling quality we need. This is the result of the combination of hydraulic knowledge and die casting work experience. The highest level of technology application is the goal that our die-casting technical workers are relentlessly pursuing.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    8: The overflow groove is an important part of the layout of the die casting mold. Usually everyone is accustomed to using the overflow as a cold discharge, gas discharge, auxiliary ejection, and equalizing the temperature of the mold. However, using the overflow properly, it can change aluminum. The flow direction and flow rate of the liquid can achieve our unexpected filling effect.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    9: Recognize the value of mold manufacturing and market value. In the development of molds, many die-casting companies always consider the cost of mold manufacturing as the first priority, but ignore the vital effectiveness of mold quality in the production process. Only considering cheap molds, starting from the search for manufacturers, it has laid a bad factor for frequent production stagnation in the future. There are many mold failures, frequent maintenance, non-smooth production, low efficiency, high scrap rate, and fast aging. Early cracking caused the entire casting processing process to be unsmooth, the plan could not be produced as expected, increased manufacturing costs, delayed delivery, quality could not meet customer requirements, and lost customer trust. Such a mold resulted in a company Irreparable market value.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    Therefore, in the early development of the mold, consider the cost, but it must not be stubborn. The quality of the mold must be guaranteed to fully reflect the core value of the mold in the production of die casting.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    10; Several points should be paid attention to in the manufacture of molds. One is to avoid sharp corners absolutely. The second is to try to eliminate the location of excessive stress concentration. The third is that the mold surface can not be machined, and the electrode processing traces, so as not to easily cause stress and premature fatigue of the mold material. The four-cavity mold surface should not be over-polished. If the mold surface is too bright and too bright, it will lose its heat dissipation function and cause premature aging and cracking. Five places where there are irregularities, including steps, increase the arc position as much as possible to avoid stress concentration. Increasing the arc surface can also improve the fluidity of the molten aluminum.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    11: Do a good job of mold maintenance and maintenance. A good mold depends not only on design and manufacturing, but also daily maintenance and maintenance can extend the life of the mold, improve production efficiency, and reduce manufacturing costs. We all know how to do basic maintenance and maintenance, but it is also difficult to do well in the production process. First of all, we must understand and understand the mold, understand the characteristics of the mold, understand the importance of the mold, and train employees and managers. Combining with education, so that everyone understands this truth, mold can play a greater role.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    Our usual maintenance and maintenance procedures and processes are traditional methods. Here I introduce a simple and more effective maintenance method. In the spare time of the mold, clean and polish the mold meat, put it into the electric box and start to heat up, the temperature rises to 500 degrees (not higher than the last annealing temperature), stop heating up, and reduce the temperature to about 300 degrees. Take out the mold meat and air-cool it to form an oxide film on the surface of the mold meat. The oxide film can increase the flow of aluminum water and prevent direct impact of aluminum water. The mold surface also plays the role of tempering and stress relief, which not only saves costs but also facilitates maintenance and production. This method can be performed at any time. The more times the effect is better, the equipment can be made or purchased. The equipment is convenient to operate and the mold Can increase lifespan by 40%. Maybe you can try it.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    12: Analysis of common quality causes of die castings. Common quality problems are manifested as shrinkage, shrinkage, looseness, porosity, air bubbles, slag holes, pinholes, cold lines, cold materials, cold partitions, deformation, misalignment, strain, Cracking, chipping, under-casting, etc., the factors that cause these qualities are many, but the main reason is the quality of the mold, by the adjustment of equipment performance and parameters, and the quality of the molten aluminum is also an important factor. To solve these reasons First of all, it is necessary to clarify the reason and the type of screening. Many people will confuse pores, slag holes, and pinholes, and treat cold grains as cold materials, and cold materials as cold spacers. Such an understanding and understanding is difficult to make. Correct judgment and wrong judgment will lead to different solutions. Of course, the result will not be ideal. An incorrect judgment will not only delay time but also cause great waste. We use pores and slag holes. The pinhole is taken as an example to explain. The inside of the stomata is smooth and the holes are relatively regular. The reasons for the stomata are mainly that the gas is not discharged smoothly, the cavity is vortex, the structure is complicated, and there is no exhaust flow channel.     The flow and air passage are not ideal, the filling time and the gate flow are incorrect, the material temperature is high, the remaining water in the cavity is too much, the aluminum water contains gas, and the aluminum water speed is too fast. The slag holes are characterized by pore shape and internal unevenness. Most of the factors that cause slag holes are low mold temperature, low material temperature, unstable pressure, and aluminum liquid contains a variety of impurities. The main reason for the pinholes is that the aluminum liquid contains oxides, and the aluminum water has a small amount of fine slag. (Residues from the furnace when cleaning the furnace wall, deposits from the holding furnace) There are also certain factors for the low material temperature and mold temperature. After such meticulous screening and clear judgment, we can come up with effective solutions in a timely and correct manner, so that the production is orderly and smooth, the quality is guaranteed, and the customer is satisfied with the die casting supplier.(Bengbu Longhua Die Casting Machine Co., Ltd.)

    The above is my shallow understanding and knowledge of die-casting molds and die-casting production. If it is helpful to you, I am very pleased and hope that more colleagues can provide valuable suggestions for the optimization, quality improvement, Work together to maximize benefits.(Bengbu Longhua Die Casting Machine Co., Ltd.)

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