In the process of high pressure casting of aluminum alloy, if the injection speed is too high in the low speed stage, on the one hand, a lot of air will enter the mold cavity through the pressure chamber, on the other hand, the aluminum liquid will billow in the pressure chamber, resulting in the increase of the air content of the aluminum liquid, thus affecting the quality of the die casting. If the injection speed is too low, the casting will be cold insulation and bad forming.The specific requirements of low speed are in the low speed interval (0.1-0.5 m/s), uniform or uniform acceleration to gently promote the metal molten liquid, to avoid the metal liquid to produce turbulence and dissolve into the gas, so as to reduce the gas content of the metal liquid, but also make the gas in the mold cavity easy to discharge smoothly. Generally, the injection velocity of this stage is relatively low, generally within 0.1-0.5 m/s. At present, the general calculation formula of low speed can not be directly analyzed from the filling forming effect, resulting in a large deviation of the calculated results. The production personnel only depend on the experience and the repeated debugging to determine the speed parameters in the low-speed stage, which on the one hand causes the process instability and a large number of trial production wastes, on the other hand prolongs the development cycle. Longhua die casting machine co., LTD. Has 38 years of experience in die casting machine production, and cooperated with hefei institute of Chinese academy of sciences to develop the latest and most scientific die casting machine production technology, which can completely solve the problems of die casting such as pores, sand holes and so on, and greatly improve the quality and precision of casting. Longhua die casting machine co., LTD., a professional die casting machine manufacturers, die casting technical experts.

  Today, Longhua Technology will share with you the basic structure and working principle of natural gas compressors. 1.Basic structure  Natural gas compressors are reciprocating piston compressors, which are mainly composed of three parts: moving mechanism (crankshaft, bearing, connecting rod, crosshead, pulley or coupling, etc.), working mechanism (cylinder, piston, valve, etc.) and Body. There are also three auxiliary systems, namely the lubrication system, the cooling system and Regulation system.   Movement mechanism: including crankshaft, connecting rod, crosshead, piston rod, etc. The motion mechanism is a crank-link mechanism that changes the rotational movement of the crankshaft into a reciprocating motion of the crosshead. Usually, the driving machine drives the crankshaft to rotate through a coupling or a flywheel (belt pulley). The crankshaft is connected to the large end of the connecting rod, and the small end of the connecting rod is connected to the crosshead. The crosshead is limited to the body slide and can only perform reciprocating motion.   Working mechanism: Including cylinder, piston, air valve, etc. The working mechanism is the main component to realize the working principle of the compressor. The cylinder is generally in the shape of a barrel, and there are several inlet and exhaust valves at both ends. The body is used to support and install the entire movement mechanism and working mechanism, and it is also used as a lubricating oil tank. The crankshaft is supported on the body by a bearing. The slide on the body supports the crosshead. The cylinders are fixed on the two arms of the body. . 2. Working principle   The reciprocating compressor uses a crank and linkage mechanism to change the rotary motion of the driver into the reciprocating motion of the piston. The cylinder and the piston together form a working chamber to achieve gas compression. The piston reciprocates in the cylinder to allow the gas to complete the air intake in the cylinder. , Compression, exhaust, etc. The intake and exhaust valves are used to control the gas entering and exiting the cylinder, and the pressure of the gas is increased during the compression process, thereby achieving the purpose of pressurizing the gas.

Release agent has been widely used in die casting production. It is an important part of mold cooling. It has important applications in the fields of metal die casting and vacuum foamed sheet, which can effectively extend the service life of the mold. Next, Longhua Die Casting Machine will introduce the concept, application characteristics and use of release agent. Overview of release agents 1. Definition and role of release agent 1. Definition: Release agent is an interface coating used on the surfaces of two objects that are easy to adhere to each other. 2, role: to form a layer of inert coating between the mold and the mold, so that the mold can be easily removed from the mold, improve the wear resistance and scratch resistance of the final product, it can make the surface of the object easily detached, Smooth and clean. Second, the principle of release agent       Since the lubricant substance (release agent) is easy to adhere to the metal surface (mold surface), a static lubricant film layer is formed due to adsorption, thereby reducing the friction between the polymer (mold) and the processing equipment (mold) , Produces a significant film release effect and improve the surface finish of plastic parts. Classification of release agents 1. Classified by adding method / usage: internal release agent and external release agent. The former is directly added to the molding plastic; the latter is coated on the surface of the cavity of the mold. 2. Classified by chemical composition: inorganic, organic and polymer. (1) Inorganic release agent (2) Organic release agent (3) Polymer release agent 3. Classified by function / application: Metal demolding: die-cast aluminum (magnesium, zinc), casting, forging, etc .; and rubber, fiberglass, plastic, polyurethane, concrete. 4, classified by shape: powder, liquid and emulsion (can be atomized). 5. Classified by service life: conventional release agent, semi-permanent release agent. 6. Classification by form: solvent-based release agent, water-based release agent, solvent-free release agent, powder release agent, paste release agent Application of release agent     Mold release agents are used in various molding operations such as concrete precast parts, products, glass fiber reinforced plastics, metal die casting, polyurethane foam and elastomers, injection molded thermoplastics, vacuum foamed sheets and extruded profiles. Advantages of release agent: 1. Demoldability (lubricity). When forming a uniform thin film and a complex shape, the dimensions are accurate. 2. Good mold release continuity. 3. The appearance of the formed object is smooth and beautiful, and does not cause dust adhesion due to the application of sticky release agent. 4. Superior secondary workability. When the release agent is transferred to the molded product, it has no adverse effect on processed products such as electroplating, hot stamping, printing, coating, and adhesion. 5. Easy coating. 6, heat resistance...

Today, Longhua Die Casting Machine introduces some operation requirements of aluminum alloy die casting machine, let's take a look together! 1. Strictly monitor the die casting process The temperature of the molten aluminum in the holding furnace should be controlled at ± 3 ° C in order to stabilize the stirring temperature. The temperature after stirring must be adjusted according to the chemical composition of each furnace to ensure that the solid phase rate is stable at ± 2%. The temperature of the mold must be checked and controlled so that the alloy can be smoothly filled and orderly solidified. It is necessary to rationally formulate and timely adjust the process parameters of the die casting machine, and make regular inspections on the die casting to ensure the quality of the die casting. 2.Precautions for release agent spraying operation Pay attention to how much paint is applied to the release agent to avoid too much paint, too little or missing paint. More paint can be sprayed on the parts that are difficult to be demolded, and less paint can be sprayed on the parts that are easy to demold. When spraying paint, use a spray gun to move from top to bottom in layers to let the water accumulated in the cavity flow from top to bottom and blow excess water out of the cavity. The cavity is easily adhered to the mold, first spraying at a short distance to cool down, and then spraying at a longer distance to form a coating film. Do not spray too close to prevent paint water from flowing in the cavity. After spraying, use air to blow away the excess and accumulated paint in the cavity, especially pay attention to the paint in deep cavities or dead corners to prevent the water from vaporizing into a large amount of gas after the heat, making the casting appear pores. , Under casting, cold insulation, blistering, this has a very important role in eliminating the occurrence of pores in the casting. 3.Precautions for hot film of die casting machine After using the mold temperature machine hot mold, when starting the die casting hot mold, you can use the liquid alloy low speed die casting hot mold 5-10 mold, and then use the normal semi-solid alloy and semi-solid die casting parameters for die casting production, which can protect the mold, It can also prevent flashing and flying materials.

1. What is shot-to-shot specific pressure and how to adjust it?     Answer: The shot pressure is the pressure per unit area of the metal liquid in the pressure chamber. On the premise of ensuring product quality, use a lower specific pressure as much as possible. The specific pressure of lighting die casting is generally less than 50MPA. The larger the product wall thickness, the higher the specific pressure requirement. The more complex the product structure, the higher the specific pressure requirements. 2. What is shot speed and how to adjust shot speed?     Answer: The injection speed refers to the speed of the injection head during die casting. It is divided into slow injection speed and fast injection speed. Generally speaking, the injection speed refers to the fast injection speed. The size of the slow shot speed is that when the shot head passes through the sprue, it is better not to splash the metal liquid, generally 0.1 ~ 0.5M / S, and the fast shot speed aluminum alloy is generally 0.1 ~ 1.1M / S. The thinner the wall thickness of the casting, the faster the injection speed, the more complex the shape of the casting, the faster the injection speed, the larger the projection surface of the casting, the faster the injection speed, and the longer the casting ball path, the faster the injection speed. 3． What is the pouring temperature and how do I choose a pouring temperature?     Answer: The pouring temperature generally refers to the average temperature of the molten metal poured into the injection chamber and filling the cavity. Generally, the lowest possible temperature is used while ensuring the molding and the required surface quality. The casting temperature of aluminum alloy is 650 ℃ ～ 720 ℃, the casting alloy has good fluidity, and the casting temperature can be lower; the casting temperature of thin-walled and complicated castings can be higher; the mold is large, the heat dissipation is fast, and the casting temperature can be high some. 4． What is the mold temperature, and what is the mold temperature during normal production of aluminum alloy die-casting molds?     Answer: The mold temperature is the temperature of the mold during the production process. The temperature of the aluminum alloy die-casting mold during normal production is: 200 ° C to 280 ° C. Generally, the thinner the casting, the more complicated the structure, and the higher the mold temperature requirements. 5． What is the filling time? How to choose the filling time?     Answer: The time required for the metal liquid to start to fill the cavity is called the filling time. Filling time of aluminum alloy die-casting: 0.01S ~ 0.1S. The principle of selecting the filling time is: (1) the alloy pouring temperature is high, the filling time should be longer; (2) the mold temperature is high, the filling time is longer; (3) if the thick wall part is far away from the inner gate, the filling is The time should be lo...

   In the last part, we talked about the equipment management of the die casting workshop. Today, Longhua Die Casting Machine will share with you another piece of dry goods knowledge: the installation and acceptance of the die casting machine equipment. (1) Installation of die-casting machine According to the drawing requirements of die-casting machine manufacturers, the traditional equipment installation method is to first build the equipment foundation and reserve embedded holes for the feet (see Figure 2). Then, put the anchor bolts into the grout, and then fine-adjust the equipment after the concrete has solidified. After the fine adjustment is completed, it will take some time for the equipment to be used normally after the surrounding oil and water tanks are completed. It basically takes nearly one month. In the actual installation process, considering that the above installation method takes too long, we can completely use the embedded steel structure to install the equipment. (2) Acceptance after installation The acceptance of the die-casting machine must first be based on the contract and the equipment test and acceptance record sheet, which is carried out one by one according to the acceptance items. When the manufacturer debugs the equipment, be sure to send someone to track the test and acceptance and record the test data.    Among them, the accuracy of the coaxiality of the pressure chamber is extremely critical, which directly affects the service life of the punch and the pressure chamber in the later stage. It is a mandatory inspection item for the newly purchased die casting machine. For PLC-controlled die-casting machines, the inspection of the scale-up board is easily overlooked. The function of the proportional amplification board is to control the output current in proportion to the magnitude of the input voltage, thereby changing the pressure and flow of the proportional valve to control the hydraulic system (if it is a single proportional valve, only the pressure is controlled). Specifically, if the total pressure of the digital adjustment system in the control cabinet is 0 to 14 MPa and the total flow rate is 0 to 100%, the pointers of the two ammeters should generally make     corresponding linear changes from 0 to 0.8 A. The linear error is allowed. About 2%. If the linearity error is too large, the linearity of the proportional plate will be insufficient, which will have a great impact on the adjustment of the die casting process parameters.    The supercharging and building pressure time cannot be measured specifically at the production site, and can only be estimated indirectly through the reaction of the pressure gauge pointer of the injection cylinder. The general approach is to adjust the boost delay, flow rate, and airbag pressure at a medium fast injection speed (such as about 3 m / s), watch the pointer of the injection cylinder pressure gauge change, and then close and clo...

  As we all know, the factors that affect product quality are people, machines, materials, law, and environment. The "machine" is the equipment. This article mainly refers to the die casting machine. It is one of the important factors to ensure the quality of the die casting. Without a well-equipped die casting machine, it is impossible to produce high quality die castings. Talking about equipment must involve equipment purchase, acceptance, and subsequent maintenance. Today, Bengbu Longhua Die Casting Machine focuses on a brief description of the equipment management work in the die casting workshop. Procurement of equipment   As the basic technical equipment of die-casting, the die-casting machine has a very important influence on many factors such as product quality, production cost and production efficiency in the production process. For this reason, the detailed selection of die casting machine and auxiliary equipment must be demonstrated. (1) Die casting machine selection Die casting machine selection is actually divided into two cases to distinguish. First of all, for companies that are just beginning to engage in die-casting production, targeted selection analysis should be performed. The main selection basis is the current product that needs to be produced. It can be verified according to related technical standards such as the projected area of the product and quality requirements. Detailed calculations in this regard can be found in some related die casting books. Secondly, for companies that have already purchased some die-casting machines, the selection of equipment for re-purchasing cannot be based on the current production of the product. It should also take into account the company's subsequent development needs and the consideration of the series of die-casting equipment. Sometimes, we will temporarily adopt a "big horse drawn cart" measure and temporarily purchase a larger die-casting machine for production. When the product batch is large and stable, we can customize and increase or decrease the equipment configuration according to the actual demand to achieve the special machine. The purpose of reducing procurement costs and improving labor productivity. (2) Die casting machine performance requirements The parameters of different types of die casting machines will have great differences, and should be selected according to the different needs of various enterprises. Excessive requirements for the performance of the die casting machine will inevitably increase the price of the equipment. For example, the air injection speed of a die-casting machine is a parameter to be considered. For companies that only produce aluminum alloy products, it is not necessary to choose a die-casting machine with an air injection speed of 8.0 m / s or more. Those who need to produce magnesium alloy castings It is obviously inappropriate for a company to choose a die casting machine with an injection speed below 6.0m / s. The performance a...

In modern production technology, die casting is a very common production form. Common die castings are aluminum alloy die casting and zinc alloy die casting. Today, Longhua Technology will briefly introduce the principle of die casting: Die-casting: (Press-casting) is to quickly press a liquid or semi-liquid alloy into a mold cavity under high pressure, and solidify under pressure to obtain a casting; 1. Inject metal First close the mold cavity, and inject metal liquid into the mold inlet through the injection hole on the pressure chamber; 2. Die-casting The injection punch advances, and the metal liquid is pressed into the mold cavity; 3. Take out the casting. After the casting is solidified, the core pulling mechanism pulls out the cores on both sides of the cavity at the same time. Remarks: 1. The mold cavity is made of a special alloy tool steel (such as 3Cr2W8V2), that is, the mold steel; 2. The cavity should be maintained at 120-280 ° C during die casting (depending on the specific die casting material); 3. The specifications of the die casting machine are generally expressed by the size of the clamping force; Of course, there is still a lot of knowledge involved in the process of die casting. It is impossible to understand everything in a small article. This time I just let everyone know the process of die casting. I hope you can pay more attention to Longhua Die Casting Machine and bring you more information.