Die Casting Mold Structure Composition
Fixed Die: It is securely mounted on the fixed die installation plate of the die-casting machine, featuring a direct gate connected to the nozzle or pressure chamber.
Moving Die: Mounted on the moving die installation plate of the die-casting machine, it moves with the plate during the mold opening and closing process, forming the mold cavity and casting system. When the mold is opened, the moving die separates from the fixed die. Utilizing the ejection mechanism set on the moving die, the castings are ejected.
Die Casting Mold Structure Classification Based on Function
Mold Cavity: Outer surface includes a direct gate (pouring cup sleeve).
Core: Inner surface includes an inner gate and excess material.
Runner System: Mold runner (insert block).
Guide Components: Guide post; guide bushing.
Ejection Mechanism: Ejection rod (core pin), reset rod, ejection rod fixing plate, ejection plate, ejection plate guide post, ejection plate guide bushing.
Lateral Core-pulling Mechanism: Projection: Hole (on the side), wedging block, limit spring, screw.
Overflow System: Overflow groove, vent groove.
Support Components: Fixed die; moving die seat plate, pad (for assembly, positioning, and installation purposes).
This structure provides the necessary components for an efficient die-casting mold, ensuring proper mold operation and effective casting production.
Die Casting Mold Procurement
When selecting a die casting mold, choose a professional mold factory with a good reputation, advanced technology, and rich experience in mold manufacturing. Die casting molds are specialized precision machinery, and reputable mold factories possess precision machine tools suitable for mold production, ensuring mold dimensional accuracy. They have experienced senior mold technicians whose rich expertise serves as a valuable guarantee for the effectiveness of die casting molds. Additionally, these reputable factories maintain close relationships with material suppliers and heat treatment facilities, along with a well-established after-sales service system.
Effective mold design and manufacturing are the foundation for a long lifespan, low failure rate, and high efficiency of die casting molds. Opting for low-quality, inexpensive die casting molds may result in low production efficiency and high failure rates, leading to increased costs in terms of both production time and money.
Die Casting Mold Installation
Mold installation and adjustment workers should undergo training and be qualified for the job.
Ensure that the mold installation position meets design requirements, minimizing the distance between the mold’s swelling force center and the die-casting machine to ensure even force distribution on the machine’s main lever.
Regularly inspect the lifting eye bolts, screw holes, and lifting equipment of the mold for integrity, ensuring the safety of personnel, equipment, and the mold during lifting.
Periodically check for force errors on the die-casting machine’s main lever and adjust if necessary.
Thoroughly clean the machine installation surface and the mold installation surface before installing the mold. Verify the proper length of the ejector rods, ensuring they are of equal length and using a minimum of four rods placed in the designated rod holes.
Ensure that the pressure plate and pressure plate bolts have sufficient strength and accuracy, avoiding loosening during use. Use an adequate number of pressure plates, ideally tightened on all sides with at least two locations on each face.
Large molds should have mold supports to prevent sinking or falling during use.
Molds with large core-pulling features or those requiring resetting may need separate installation of moving and fixed parts.
Ensure the proper sealing of cooling water pipes and installations.
Adjustments after mold installation include adjusting the mold clamping tightness, injection parameters (such as fast injection speed, injection pressure, boost pressure, slow injection stroke, fast injection stroke, punch retreat distance, ejection stroke, ejection reset time, etc.). After adjustments, simulate the injection process twice with soft materials like cotton inside the pressure chamber to check the appropriateness of the adjustments.
Adjust the distance between the mold halves appropriately, stop the machine, and place the mold in the mold preheater.
Set the insulation furnace to the specified temperature and prepare the specified capacity ladle.
Correct Use of Die Casting Mold
Developing the correct die casting process, proficient operation by skilled die casting technicians, and high-quality mold repairs are crucial for improving production efficiency, ensuring casting quality, reducing scrap rates, minimizing mold failures, and extending mold lifespan.
Developing the Correct Die Casting Process
The die casting process reflects the technical level of a die casting factory. It combines the characteristics of the die-casting machine, mold, casting, and die-casting alloy to produce die-cast products that meet customer requirements at the lowest cost.
Determine the most reasonable productivity, specifying the cycle time for each injection cycle. Extremely low productivity is detrimental to economic benefits, while excessively high productivity often sacrifices mold lifespan and casting qualification rate, potentially leading to worse overall economic results.
Establish the correct die casting parameters. Ensure that the casting meets customer quality standards while minimizing injection speed, injection pressure, and alloy temperature. This is advantageous for reducing machine and mold loads, lowering failure rates, and extending lifespan. Based on the triangular relationship among die-casting machine characteristics, mold characteristics, casting characteristics, and die-casting aluminum alloy characteristics, determine parameters such as fast injection speed, injection pressure, boost pressure, slow injection stroke, fast injection stroke, punch retreat distance, ejection stroke, holding pressure time, ejection reset time, alloy temperature, mold temperature, etc.
Use water-based coatings and formulate strict and specific spraying processes. Consider factors such as the brand of the coating, the ratio of coating to water, the amount of spraying (or spraying time) for each part of the mold, compressed air pressure, the distance between the spray gun and the forming surface, and the angle of spraying direction relative to the forming surface.
Based on the actual die-casting mold, determine the correct mold cooling plan. A proper mold cooling plan has a significant impact on production efficiency, casting quality, and mold lifespan. The plan should specify how to initiate cooling when starting a few mold cycles, and how to gradually open the cooling water valves at specified intervals over a few mold cycles. The cooling intensity of the cooling system should be adjusted on-site by the die casting process engineer to achieve mold thermal balance in collaboration with spraying.
Specify different lubrication frequencies for different sliding parts, such as punches, guide posts, guide bushings, core-pulling mechanisms, ejector rods, reset rods, etc.
Develop die casting operation procedures for each die-cast component and train and supervise die-casting operators to follow these procedures.
Based on the simplicity, age, and stickiness criticality of the mold, determine the appropriate preventive repair cycle for the mold. The appropriate preventive repair cycle should be the number of die-casting cycles where faults are expected to be eliminated but have not been eliminated. Repairing molds that have already eliminated faults during use and cannot produce continuously is not recommended.
Based on the simplicity, age, and criticality of sticking, determine the stress relaxation cycle for module retirement (usually performed every 5000-15000 cycles) and whether surface treatments are needed. This includes treatments like nitriding, with a depth of 0.33 and a maximum of 0.55.
Implementing Correct Die Casting Operations
Die casting operators should undergo training and be qualified before taking on their responsibilities.
Strictly follow die casting operation procedures, ensuring precise control of the cycle time for the first mold, with an error of less than 10%. A stable die casting cycle time is crucial for the comprehensive efficiency of a die casting factory. It significantly impacts product quality stability, mold lifespan, and failure rates.
Adhere to the mold cooling plan strictly. Proper mold cooling is an effective method for improving production efficiency, casting quality, mold lifespan, and reducing mold failures. Incorrect water cooling operations can cause fatal damage to the mold. If die casting production is stopped, the cooling water must be shut off immediately.
Properly handle the actions of pouring, skimming, ladling aluminum, and pouring the runner. Ensure that the metal poured into the pressure chamber is free from oxidation, and minimize fluctuations in the metal poured. The manual pouring error should be within 2-3%.
Clean the mold on time, removing any metal deposits that accumulate on the parting surface, mold cavity, core, runner, overflow groove, exhaust passage, etc. This prevents the mold surface from collapsing during mold closure, blocking the exhaust passage, or causing incomplete mold closure. Avoid using steel tools to touch the forming surface during cleaning.
Spraying is one of the most important and challenging die casting operations. Strictly adhere to the spraying process. Incorrect spraying can lead to unstable product quality and early damage to the mold.
Lubricate sliding parts according to the specified schedule.
Pay attention to the mold clamping tightness, regularly check the condition of the mold plates and mold supports, and prevent the mold from sinking or falling during use.
When a mold completes its repair cycle or reaches the specified production batch, stop production and retain the final die-cast product (preferably with the gating and overflow systems). Send it for repair along with the mold.
Wetron die casting
With over 15 years of die casting technology, Wetron highly involved the product development with our top-rated customer, more than 200 new aluminum parts launched each year. From concept–tooling design–tooling build to manufacturing, we pride ourselves in resolving the most demanding of die casting requirements. Our dedicated team is here to support you at any stage. Contact us directly if you have an idea in mind.