Die casting is short for pressure casting. It is the liquid or semi-liquid metal, under the action of high pressure, with high speed filling die casting cavity, and under the pressure of rapid solidification and obtain a casting method. The die casting die used is called die casting die. Pressure is often used in die casting from several to dozens of mpa, and the initial filling speed is in the range of (0.5 ~ 70)m/s. Therefore, high pressure and high speed are important characteristics of die casting. Ti Hao machinery is the main machine tool spindle, rotary thimble, lead screw, shaft processing, CNC lathe processing, tool handle tool rod, chuck joint rod for the company's main products, quality assurance, trustworthy!
Die casting mold installation
- The installation position of the mold conforms to the design requirements, and the distance between the center of the mold expansion force and the die casting machine is minimized as far as possible, which may make the force of the die casting machine big bar more uniform.
- Always check whether the bolts, screw holes and lifting equipment of the mould lifting ring are in good condition to ensure the safety of people, equipment and mould during heavy lifting
- Check the force error of die casting machine bar regularly and adjust if necessary.
- Wipe the machine mounting surface and the mold mounting surface thoroughly before installing the mold. Check whether the length of the jacking rod is appropriate, whether all the jacking rods are of the same length,and the number of jacking rods uesd should not be less than four, and placed in the stipulated jacking rod hole.
- Platen and platen bolts should be of sufficient strength and precision to avoid loosening in use. The number of platens should be enough, it is best to press on all sides, not less than two places on each side.
- Large molds should have mold bracket to avoid mold sinking dislocation or falling in use.
- Molds with larger cores or molds requiring resetting may also require separate installation of moving and fixed molds.
- The cooling water pipe and installation shall be sealed.
- Adjust the mold after installation. Adjust die closing tightness. Adjust the ejection parameters: fast ejection speed, ejection pressure, booster pressure, slow ejection stroke, fast ejection stroke,punch and EJection distance, EJECTION stroke, EJection reset time, etc. After adjustment, put soft material such as cotton silk into the press chamber to simulate the whole process of injection twice to check whether the adjustment is appropriate.
- Adjust the closing mold to the moving and fixed mold with appropriate distance, stop the machine operation, put in the mold preheater.
- Set the holding furnace at the specified temperature and equip the scoop with the specified capacity.
- Before production, ensure the integrity of the mold, properly connect the neutron tubing and control switch circuit of the mold with neutrons, ensure that the conductive part of the metal is not exposed, and select the control program before operation.
- The die WITH THE pull-back device must be equipped with the pull-back rod, and the thimble must be returned after ejection, otherwise the die cavity will be damaged.
- Open the mould twice and pull the core mould obliquely. When the mould is opened, the front part of the back mould must spring off first, otherwise the mould core will be damaged.
- The mould with a slider above and around the mould must be fixed with an appropriate spring.
- The mold with slider core, core pulling and complex structure and easy clamping should be fully preheated before production (all parts of the mold cavity must be oiled before preheating of the mold)
- The correctness of cores must be confirmed for molds with orientation requirements or cavities shared.
- Verify that each cooling water channel is unobstructed.
The formulation of correct die casting process, the correct and skilled operation of die casting workers and high quality mold maintenance are very important to improve the production efficiency, ensure the quality of die casting, reduce the rejection rate, reduce mold failure, and prolong the life of the mold.
Develop correct die casting process
Die casting process is the embodiment of the technical level of a die casting factory, it can correctly combine the characteristics of die casting machine, die characteristics, casting characteristics, die casting alloy characteristics and other production factors, with the lowest cost, to produce die casting products to meet customer requirements. Ti Hao Machinery is machine tool spindle, rotary thimble, lead screw screw, shaft processing, CNC lathe processing, tool shank shank, chuck joint rod for the company's main products, therefore, must pay attention to the selection and training of die casting process engineers. The DIE casting PROCESS engineer is the general technical person in charge of the die casting production site. In addition to formulating the correct die casting process and revising the die casting process timely according to the changes of production factors, he is also responsible for training and improving the mold installation and adjustment workers, die casting operators and mold maintenance workers.
- Determine the most reasonable productivity and specify the cycle time for each injection cycle. Although LOW productivity is not conducive to improving economic benefits, high productivity is often at the expense of die life and casting pass rate, and the economic benefits of the general ledger may be worse.
- Determine the correct die casting parameters. Under the premise of ensuring that the casting meets the customer's quality standards, the injection speed, injection pressure and alloy temperature should be minimized. In this way, it is helpful to reduce the machine and die load, reduce faults and improve life. According to the characteristics of die casting machine, die characteristics, casting characteristics, die casting aluminum alloy characteristics isosceles triangle, determine the fast injection speed, injection pressure, boost pressure, slow injection stroke, fast injection stroke, punch following distance, push stroke, pressure holding time, push reset time, alloy temperature, die temperature, etc.
- When water - based coatings are used, strict and detailed spraying process must be formulated. Paint brand, the proportion of paint and water, the spraying amount (or spraying time) and spraying sequence of each part of the mold, the compressed air pressure, the distance between the spray gun and the forming surface, the Angle of spraying direction and the forming surface, etc.
- According to the die casting die to determine the correct cooling scheme. The correct cooling scheme of die has great influence on production efficiency, casting quality and die life. The cooling water opening method shall be stipulated in the scheme. The cooling water valve shall be opened to the prescribed opening degree several times apart from several die casting times when the cooling water valve starts to cool. The cooling intensity of the point cooling system shall be adjusted by the die casting process engineer on site, and the thermal balance of the mold shall be achieved with spraying
- Specify different lubrication frequencies for different sliding parts, such as punch, guide post, guide sleeve, core-pulling mechanism, push rod, reset rod, etc.
- Develop die casting operation procedures for each die casting piece, train and supervise die casters to follow the procedures.
- According to the complexity of the mold and the degree of new and old, determine the appropriate mold preventive maintenance cycle. The appropriate preventive maintenance cycle for the die casting die should be the number of die casting die times when the die will fail but has not yet failed. The mould has broken down in use, so it cannot continue production and is forced to be repaired, which is not the recommended method.
- According to the complexity of the mold, the degree of old and new, and the degree of risk of sticking the mold, determine the stress elimination cycle of the module (generally 5000~15000 molds for one time) and whether the surface treatment is needed.
Die casting training qualified on duty
- Strictly implement the operation procedure of die casting, strictly control the cycle time of the first die, the error should be less than 10%. Stable die casting cycle time is crucial to the overall efficiency of a casting plant. It has a decisive influence on product quality stability, mold life and failure rate.
- Strictly implement the mold cooling program, mold cooling is an effective method to improve production efficiency, casting quality, mold life, and reduce mold faults. However, the wrong water cooling operation will cause fatal damage to the mold. Stop die casting production, must immediately turn off the cooling water.
- The pouring column skimming, ladling aluminum and pouring column shall be performed in accordance with the standards, so that the liquid metal ladled into the pressure chamber does not contain oxide skin and the liquid metal poured into the pressure chamber has the least fluctuation. The error of manual pouring is controlled within 2-3%.
- The mold cleaning should timely remove the metal scale accumulated in the parting surface, cavity, core, runner, overflow groove, exhaust passage, etc., to prevent the collapse of the mold surface, block the exhaust passage, or cause loose closing of the mold. Do not use steel tools to touch the forming surface during die cleaning
- Spraying spraying is one of the most important and difficult die casting operations, which must be operated strictly according to the spraying process. Incorrect spraying will cause unstable product quality and early mold damage.
- Lubricate sliding parts in time according to regulations.
- Pay attention to the tightness of die closing at any time, often check the pressing situation of die plate and the support of die bracket, to prevent the die from sinking or falling in use.
- After the completion of a mold maintenance cycle, or after the completion of the specified production batch, the last die casting product (preferably with a pouring and draining system) should be retained and sent to the mold for repair
This is how to install the die casting mold correctly.
