Introduction
The key elements of die-casting technology include equipment, molds and processes. Various quality problems will occur during the die-casting production process. In addition to the instability of the system caused by equipment performance and quality, there are some accessories (such as melting cups, punches, etc. and process parameters accuracy and auxiliary materials may cause hidden dangers to quality. The impure aluminum liquid will also cause instability factors (such as scrap, slag packages, new and old materials matching, etc.) for die casting. Although the causes above are the large disadvantages for production and quality, these problems are relatively intuitive and easier to solve. In the production process, common and difficult-to-resolve quality problems often plague die-casting enterprises, such as leakage, bubbles, caught casting, thermal deformation, cold lap /cold shut, misrun/short shot, aluminum sticking, burr, etc., and the main reason for these frequent quality problems is often the performance of die-casting molds, efficiency improvement, product quality assurance, better economic benefits are all closely related to mold development, design, use, maintenance. In the past, technicians divided the quality, efficiency, and revenue control of the entire die casting production process according to experience with 65% of molds, 10% of machine performance, 10% of process parameters debugging, 15% of others, it can be seen that the die-casting mold plays an important role in the process control of the die-casting enterprise, However, the problem of low mold support capability, which is dominant in the division of the control of the die casting production process, is still very prominent. Most of the die-casting molds of die-casting companies are basically outsourced to design and manufacture. The level of independent design is not high, the technical ability is weak, the ability of on-site mold maintenance support is poor, the level of new product mold management is low, and The long lead-in period will lead to the disadvantage of the company in obtaining new orders. We must clearly understand that the core of die-casting production is the ability of mold support. The success or failure of the mold is a watershed in the development of die-casting enterprises. Ensuring capabilities and escorting the company's rapid development is also one of the company's key topics.1 The main measures to improve the support capacity of die-casting molds
1.1 Improve the design management of casting drawings
The design of the casting drawing is independently completed by the enterprise. Whether the design of the casting drawing is reasonable or not has a lot to do with the quality of the mold. However, companies do not pay enough attention to the design management of casting drawings. Sometimes casting drawings are commissioned by mold suppliers. In fact, a good die-casting mold begins with the development and design of the casting. Most customers do not consider whether the mold manufacturing and die-casting production process can Technical standards required for castings. Objectively speaking, many customers' product designers are not very familiar with the die-casting process and mold process. The structure of the casting often cannot meet the technical conditions of the die-casting mold and die-casting production. The disadvantage is the company's technical staff rather than the mold supplier. Therefore, the first is to require the technical personnel of the enterprise to conduct a comprehensive review of the preliminary structure and technical requirements of the casting, thoroughly understand the technical requirements of the drawing, and fully check whether the design and manufacturing of the die casting mold can meet the technical requirements of the casting (Negotiate with the customer if cannot meet); Second, the design of the casting drawing is required to be completed independently by the enterprise, and a reasonable casting drawing may lay a good foundation for the next mold design.
1.2 Improve the ability of independent mold design
The internal drawing management of most enterprises is chaotic. Each set of replica molds has various design versions. There are not complete drawings. The spare parts are poorly interchangeable. Quality problems occur repeatedly. These are all due to the outsourcing design of the mold design. There are various design styles for different mold suppliers. The internal technical staff did not design in person and lacked training opportunities. The end result is that mold technicians lack the ability to understand the drawings and cannot identify the drawing errors. At the same time, the different review standards of the mold program and the large randomness of review restrict the improvement of the mold design level of the enterprise.
(1) Improve mold drawing management. Ensure that the mold drawings are complete, correct and standardized, and ensure the accuracy, uniqueness, and effectiveness of the mold drawings.
(2) The mold program review process is solidified and the drawings are reviewed. Develop a clear and reasonable process (clear responsibilities, clear time points in each link, clear input, and output. The review includes a complete mold design plan, gating system, overflow system, cooling system, motion system, ejection structure, etc. Before the mold plan review, do a good job of simulation data of die casting mold filling, use die casting simulation software to simulate the mold filling and solidification process with high accuracy, accurately locate potential appearance defects and problem points, quickly verify different design solutions, reduce the number of design changes and reduce Late mold failure rate and casting rejection rate.
(3) The 3D and 2D image files are required to be revised at the same time. Due to the short development cycle of die casting molds, if the normal development process often fails to meet the customer's development progress requirements, most mold suppliers will simplify the design process, resulting in the simultaneous mold design and manufacturing. The mold design only has preliminary 3D data and is not complete. These 2D design drawings are not conducive to the archival of drawings and standardized management and require the mold factory to provide 3D drawings and modify 2D drawings at the same time.
(4) Improve the drawings of the consumable parts of the existing production mold. Various changes will occur in the design, manufacture, and use of the mold, but these changes are temporary and have not been timely fed back to the formal drawings. It is required to regularly organize the mold drawings.
(5) The improvement of the mold design ability of craftsmen. Under the premise of mold development progress, the main designs of new product molds are changed from mold suppliers to internal designs and supplemented by external designs, and the design level of technicians is trained in time to improve the enthusiasm of technicians.
(6) Standardize die-casting molds, update and optimize old standards, reorganize standard documents and issue them. Due to the existence of design standards of various suppliers and poor standardization of internal molds, there are many problems in mold test, long commissioning cycle, poor mold maintainability, high maintenance cost, low mold life, and frequent quality problems, so the standard of the internal mold design and manufacturing of the enterprise must be solidified.
1.3 Improve mold manufacturing quality
Fully understand the value of mold manufacturing and market value, but when companies develop molds in the early days, they always consider the cost of mold manufacturing as the first priority, but ignore the critical effectiveness of mold manufacturing quality in the production process, and only consider Cheap molds, never care about the level of mold manufacturing, starting from the search for manufacturers, laid a bad factor for frequent production problems in the future, mold failures, frequent maintenance, poor production, low efficiency, high scrap rate, fast aging, early cracking, the plan cannot be carried out according to the expected production, the manufacturing cost increases, the quality cannot meet the customer's requirements, and the mold has caused irreparable losses to the company. Therefore, in the early development of molds or selection of mold suppliers, you can consider the cost and cost-effectiveness but must not hesitate. You must ensure the design and manufacturing quality of the mold and fully reflect the core value of the mold in the production of die casting.
(1) Supplier integration to improve the supplier's mold manufacturing level. Eliminate some of the mold suppliers with low manufacturing levels, confirm that the suppliers have advanced mold manufacturing equipment, establish objective and fair, rule-based mold supplier access procedures and standards, and ensure the quality of new suppliers.
(2) Establishing evaluation criteria for the basic strength of existing suppliers. Establish a strategic partnership with mold suppliers, help suppliers who are willing to improve and have the potential to improve, and gradually phase out inferior suppliers.
1.4 Optimize the mold acceptance process
The mold acceptance was all completed at the enterprise site. When the problem was found, the debugging had been delayed, the mold repairs were frequent, the drawings were not provided in a timely and incomplete manner, and the drawings did not match the actual objects.
(1) Part of the process of mold acceptance is moved forward. According to the complexity of the mold, it is divided into initial acceptance and second-phase acceptance. At the initial stage, people are sent to the mold factory for pre-acceptance of the mold, shortening the manufacturing cycle, and finding corrective actions when problems are found.
(2) The mold acceptance system has been improved, and the physical acceptance of the mold is qualified to ensure the consistency of the physical object and the drawing.
1.5 Improve the independent manufacturing capacity of die-casting molds
In terms of hardware, it introduces international advanced 5-axis machining equipment, mirror-spark electrical machining equipment, high-precision CNC lathes, precision high-speed electrode machining centers. On the upgrade of mold manufacturing programming software, mold technicians regularly participate in industry-level exchange training, must have the ability to make some precision die-casting molds.
1.6 Strengthen mold management
When it comes to the use of die-casting molds, many people imagine that the mold is simple. The maintenance of the mold is only a matter of the mold repair department. It has little to do with him, but it is actually the opposite. The fate of the mold is in the hands of the operator. The cooling water pipe is not installed, the hot mold is not enough several times, the lubricant of the moving part of the mold is not checked as required, the flying surface of the mold is not cleaned, and the slider is not processed. , Spray adjustment is not standardized, these may not cause the operator's attention, but often these are likely to cause the serious failure of the mold, how to control the use of the mold is one of the important factors to improve mold support capabilities.
(1) Improve the ability of independent maintenance during the use of the mold.
(2) Establish a benchmark for die casting operators to disassemble and assemble molds.
(3) Strengthen the control of the mold cooling system. The cooling water is very important in the use of the mold. When the mold cooling water is used correctly, it can not only extend the life of the mold but also improve production efficiency.
(4) Strengthen the control of the hot mold. Avoid direct damage to the mold without hot mold pressurization.
1.7 Strengthen professional mold maintenance and mold management
(1) Improve mold files: Establish a complete mold file, including management of human storage, procurement, withdrawal, repair, maintenance, scrap, life, etc., that is, to establish a complete set of use of each mold in the factory Resume form, like a person's medical record card, is an important basis to ensure future maintenance and maintenance; improve the mold repair management account; mold file establishment, mold life management.
(2) Perfect mold management responsibilities (mold design, manufacturing, acceptance, maintenance, scrapping, etc.).
(3) All-round mutual learning (design, die-casting, repair, management) with advanced companies in the industry.
(4) Establish a preventive maintenance system for molds. Weak management of die-casting molds in enterprises and inadequate periodic maintenance are one of the typical weak links in the enterprise's mold support capabilities. A good mold depends not only on design and manufacturing but also reasonable preventive maintenance can also extend the mold life, improve production efficiency, reduce manufacturing costs. I know how to do basic daily maintenance, but how to do preventive maintenance is difficult. First of all, we must know and understand the mold, understand the characteristics of the mold, understand the importance of the mold, and train employees and managers. In combination with education, everyone understands this truth. The specific measures are as follows. According to the program, the annual weekly and monthly maintenance regular maintenance plan is formulated to develop a frequency list of key mold wearing parts replacement to ensure that some spare parts are forced to be replaced regularly after the mold is lowered. In order to solve the defects such as aluminum sticking and strain in the production process of the mold, the surface of the mold needs to be nitrided. However, in order to reduce the early cracks on the mold surface domestic molds.
Figure 2 Automatic mold clamping machine
Surface vaporization treatment is generally not recommended for foreign advanced mold manufacturers will use surface plating Titanium, surface oxidation, and other treatment technologies, it is recommended that the surface of the mold be treated with sodium ceramic coatings, which will improve the appearance of the mold, mold sticking and cracking. The advanced automatic ultrasonic mold cleaning technology is enabled (Figure 1). Early mold cleaning relies on manual gasoline cleaning, which has low efficiency and poor safety. The use of this technology can reduce labor intensity, improve repair quality, improve customer satisfaction, and strengthen customers Confidence in the ability of enterprise mold maintenance.
Apply mold laser welding and welding technology. The welding of the mold surface can not be avoided during the use of the die casting mold. The surface cracks, lacking material, and dents, and all of them need to be welded. Some companies have always used argon arc welding and electric welding to assist in repair. The impact of welding on the life of the mold is very large, but it has not attracted enough attention. Although the mold can be repaired in the short term, the life of the mold will be greatly reduced in the later stage, and it’s more likely to be with defects such as mold deformation, excessive size, surface cracks, and sticking. The laser welding method has less deformation and basically does not cause cracks on the mold surface.
Application of mold clamping machine for automatic mold matching (Figure 2). With the continuous use of the mold, the parting surface and sliding parts wear, the gap between the cooperation gradually increases, the surface burr becomes thicker, and the casting size is too poor. If it is not processed in time, the mold will stop working abnormally, production and delivery cannot be guaranteed, and hidden safety risks increase. The company's conventional mold matching method is driving and manual repair, which has high labor intensity and poor mold accuracy.
Poor safety, poor repeat accuracy, and efficiency, such as the introduction of automatic mold clamping machines, these problems can be basically solved. The mold clamping machine is a professional mold research and distribution equipment, which is safe and easy to operate, which can effectively shorten the mold repair cycle and make the mold production to be better safety guaranteed. Improve mold maintenance management regulations and strengthen the effect of periodic maintenance.
