The hottest hydraulic compound mold locking inject

2022-08-17
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Hydraulic composite mold locking injection molding technology

China has become the world's largest plastic machine manufacturer and one of the countries that eliminate high-speed impact, also known as ballistic impact costs, but China still spends nearly $1billion a year to import a large number of injection molding machines with high scientific and technological content, especially large and high-precision injection molding machines

the Bochuang mechanical hydraulic compound mold locking injection molding machine introduced in this paper shows significant advantages in processing large-scale deep cavity complex products and auto industry accessories, and has a broad market

Introduction to relevant technologies at home and abroad

the structural forms of the mold locking unit of large injection molding machine can be summarized into three types: (1) double elbow mechanical mold locking structure; (2) Two plate single cylinder direct pressure mold locking structure; (3) Two plate four cylinder pressurized mold locking structure. The structure of the mold locking unit makes the workbench rise by about 15mm. After more than 20 years of optimization and practice in the injection molding machine manufacturing industry in Europe, the United States, Japan and other advanced industrial countries, it has been basically concluded that the double elbow mechanical mold locking structure is an obsolete structure. It has low energy consumption, simple structure and low cost, but it has strong mechanical friction under heavy load, resulting in the inherent operation accuracy of the machine being greatly affected after a period of use, and the relative maintenance cost is also high

two plate single cylinder direct pressure mode locking and two plate four cylinder pressurized mode locking have their own advantages and disadvantages

two plate four cylinder pressurized mold locking structure

advantages:

● whether the coring column and the piston of the high-pressure mold locking cylinder are connected by rotation or by embracing, in the open mold state, the coring column can be separated from the fixed template. Therefore, the operation of side die can be realized. It virtually reduces the requirements for the height of the plant, which is a very desirable advantage

● the movable formwork is simple in structure, so relatively speaking, the overall weight of the formwork locking part is relatively light, and it is convenient for transportation and hoisting

● the demoulding ejection mechanism is installed on the back of the movable formwork, and the space is not limited, so it is convenient for installation, disassembly and maintenance

● the structure is relatively simple, so the cost is relatively low

disadvantages:

● the shape of the four cylinder is limited by the size of the fixed template, so it cannot be made very large, and the ring area of the four cylinder pistons that can effectively generate the clamping force is limited to. Compared with the effective area of single cylinder structure, the effective area is not large enough. In order to achieve the rated clamping force, the only way is to pressurize the high-pressure clamping pressure to kg/cm2, or even 350kg/cm2. This has quite strict requirements on the shape and position tolerance, surface finish, overall quality and the quality of seals of the oil cylinder body. At present, the level of China's manufacturing industry is generally difficult to meet this requirement, so the domestic two plate four cylinder pressure locking large-scale injection molding machine generally has the problem of high-pressure oil leakage, which cannot be completely solved. This is a fatal weakness of this structure

● for the four cylinder clamping structure with rotary connection between the coring column and the fixed template high-pressure clamping cylinder, because the effective area of the screw thread bearing the clamping force is halved, the pressure is too large, which is easy to cause the screw thread to yield and fracture, and even the head of the coring column to fracture. Such cases are common

● changing the mold holding space must be realized through the mold adjusting mechanism. This is a disadvantage for hydraulic mold locking injection molding machine

two plate single cylinder direct pressure mold locking structure

advantages:

● the moving template is not guided by the coring column, and the parallelism between the two coding mold surfaces of the head and the second plate can be adjusted at will within a certain range, so it can be adjusted to a degree close to absolute parallelism, which is conducive to precision molding

● the stroke of the unlocking die is not limited by the structure, and the stroke of the unlocking die can be increased according to the needs of the process. This is the biggest advantage of hydraulic locking injection molding machine and the main weakness of elbow type mechanical locking injection molding machine

● without the need for a mold adjusting mechanism, with the help of precise sensing technology, it can quickly self locate, nut close, and high-pressure mold locking within the entire mold holding space. All actions are carried out continuously, accurately, briskly and quickly

disadvantages:

● because its movable formwork adopts a composite structure, the overall weight of the formwork locking part is relatively heavy, which is inconvenient for transportation and hoisting

● because the four coring columns are fixedly connected with the fixed formwork, it is impossible to separate one or more coring columns from the fixed formwork and realize the operation of side molding

● the cost is high due to the complex mold locking mechanism and high manufacturing process requirements

technical features

● the mold locking structure combines the advantages of the current full hydraulic single cylinder and four cylinder mold locking mechanism. It belongs to the four cylinder pressurized mold locking, but the four coring columns are fixedly connected with the fixed template, and the position of the four cylinder holding brake is independently controlled, The bottom of the moving plate is designed with a self-adjusting hydraulic slide. The main battery enterprises in China are different. They pay close attention to the layout of the power battery feet and the strong guiding effect of the four fixed coring columns makes the movement of the moving plate free and controllable

● the injection mechanism adopts a high rigid double cylinder injection cylinder, which adopts an in cylinder design with a guide rod in the piston rod, which can directly realize the internal differential glue injection. The oil cavity of the glue injection cylinder near the mold locking end is connected with the atmosphere, which does not need hydraulic oil, improves the shooting speed and reduces energy consumption; Linear guide rail is used for shooting and glue shooting to ensure high rigidity and low friction; For the convenience of mainframe maintenance, a fully automatic rotating shooting platform is designed

● hydraulic system features: A. differential rapid mold opening and differential rapid injection system, which can increase the speed by 30%; b. Optimized combination and configuration of high-performance imported hydraulic parts; c. The independent oil pump controls the filtration cooling oil temperature system and the oil temperature preheating system to realize the stable control of oil temperature and oil quality, ensure the stability of the hydraulic system pressure during injection, and make the injection process easier to control; d. Oil temperature alarm device; e. The high-pressure mold locking booster cylinder system and the pressurized mold opening booster cylinder system adopt local pressurization under the condition of ensuring the mold locking force, so that the structural size of the high-pressure mold locking cylinder is reduced, while the pressure of the system oil pump is not increased, and the cost of the whole machine is reduced

● control system features: the clamping electronic ruler adopts the digital electronic ruler of MTS company in the United States, which can provide high-precision and high repeatability position detection, and adopts the working mode of CANbus bus output. The specific features are: line measurement, absolute value output; LED indicator provides diagnostic function; Firm and reliable, no contact measurement, no wear, long service life; Ultra high accuracy, with a maximum resolution of 2mm; The nonlinearity is less than 0.01%; The repetition accuracy is 0.001%; Standard CAN bus output, position and speed

application

● a wide range of molded products. Since the clamping force can be set arbitrarily and accurately, the clamping force of the machine can be adjusted according to the actual clamping force required by the product when forming any product. This can not only prolong the service life of the machine, save energy and reduce consumption, but also reduce the requirements for the mold and prolong the service life of the mold

● the design of Colin column spacing of the machine is one to two levels larger than that of ordinary machines of the same tonnage, and has a large mold opening stroke, which is especially suitable for low-pressure injection molding process, low injection pressure and low clamping force to mold products with larger projection area, such as auto industry accessories, auto interior trim panels, auto bumpers, instrument panels, skirting boards, sun visors, lamps, etc; Non automotive applications include: material containers, shipping containers, business machine shells, bathing utensils and building materials; Potential large-scale applications include injection molding of truck cabs and ship hulls. (end)

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