Design of large-scale die-casting mold
Large-scale casting mold for high reliability and long life, and die-casting machine , die-casting process is an effective combination of casting production system, optimize the die-casting mold design to improve the technological level, provide a reliable guarantee for the die-casting production, the large pressure mold design direction to pursue.
Die-casting mold structure
typically die molds the basic structure include: financial Cup, forming inserts, mold bases, guide parts, core-pulling mechanism, introduced institutions, and thermal equilibrium systems.
mold design and development process shown in Figure 1, from the graph can clearly see that mold design stage of the work done by the designer and the mold design of the whole idea, including some related to the standard certification design and development process, the design phase of the defects may have a certain preventive effect.
first, the use of rapid prototyping technology and a reasonable casting three-dimensional software modeling, preliminary identification of sub-surface, casting system location and mold thermal equilibrium systems.
As requested, two-dimensional drawings into three-dimensional solid casting data, according to the complexity of the casting and thickness shrinkage determined in a reasonable (and generally the 0.05% ~ 0.06%), good sub-surface to determine the location and shape, and under pressure casting machine data selected location of injection and the diameter of the punch and die casting of parts of each number on the casting for rational distribution, then the gating system, overflow row three-dimensional modeling system
Second, the flow field, temperature field simulation, and further optimization of die casting system and the mold heat balance system.
To castings, gating system and row overflow data processing system after the input die casting process parameters, alloy boundary conditions of physical parameters such as data, using simulation software can simulate the alloy of the filling process and the liquid alloy in the mold cavity to within can also be carried out and the temperature field simulation of solidification simulation (Figure 3), further optimization of gating system and identify mold cooling point position. The simulation results in order to express the form of pictures and images throughout the filling process in liquid alloys of direction, temperature field distribution of information, the analysis can identify possible defects in the site. In the design of the follow-up within the gate by changing the location, direction and additional set of Java packages and other measures to improve the filling effect, the prevention and elimination of casting defects.
Third, according to 3D model mold design of the overall structure.
We conducted simulation can die general layout, specific, including the following:
(1) According to the die casting machine data, mold design general arrangement.
Identified in the General Layout of the location of injection and punch diameter is the primary task. Determine the location of injection to ensure Casting in die-casting machine at the center of plate, and die-casting machine of the four rod core pulling mechanism can not interfere with each other, injection location related to the casting from the cavity of the smooth ejection; punch diameter directly affects the size of injection ratio, and thus affect the die casting mold clamping force required for the size. Therefore, to determine these two parameters is the first step we start with the design.
(2) design forming inserts, core.
Consider forming inserts the main strength, stiffness, sealing material surface size, set between the splicing block, putting and cooling point layout, a reasonable mix of these elements is to ensure mold the basic requirements of life. For large die is considered especially vulnerable parts of the mosaic and the sealing material surface with the manner in which to prevent mold damage and the early run of aluminum die-casting process key, is a large mold Exhaust and mold processing technology needs of . Figure 4 shows mold forming part of the mosaic structure with 10 modules.
3) design mold and core pulling mechanism.
Small die-casting mold can use standard mold, large-scale mold must mold the stiffness, strength calculation, to prevent mold casting process due to elastic deformation of the impact of die-casting dimensional accuracy. Pulling mechanism design, the key is to grasp the activities with the gap between components and component inter-positioning. Mold process to consider the work of thermal expansion of the impact of the sliding clearance, large mold co 0.2 ~ 0.3mm gap in between, forming part of the docking space in between 0.3 ~ 0.5mm, according to die to choose the size and heat. Formed between the slider and the slider seat positioning with side button. Core-pulling mechanism of lubrication is also the focus of the design, the factors that directly affect the die casting mold for continuous reliability, excellent lubrication system is to increase labor productivity an important part of casting.
(4) heating and cooling channel layout and the choice of heat balance components.
As high-speed high-temperature liquid at high pressure into the mold cavity, to bring mold inserts a lot of heat, the heat is designed to take away the mold issue must be considered, especially for large die-casting mold , heat balance the system directly affects the casting of size and internal quality. Quick installation and accurate control of flow is a modern mold heat balance system development trends, the development of modern processing industry, the selection of heat balance components tend to direct use of design patterns, component manufacturing company that provides direct two-dimensional and three-dimensional data elements, the designer With the use of on-demand, can guarantee the quality of components can shorten the design cycle.
(5) Design Launch.
Introduced organizations can be divided into mechanical and hydraulic launch of two forms of introduction, the use of equipment, machinery introduced the launch of agencies to achieve their release action, the hydraulic launch is the use of molds with hydraulic cylinders to achieve their release action. The key design is to introduce organizations to launch the center and off together to the center of concentric-type force, which requires agencies to launch a good introduction of oriented, rigid and reliable job stability. For large die is greater than the weight of introduction agencies, introduction agencies between components and type box is easy because the mold behave Ershi putting skewed, so that there launch cable wiring, and mold release body heat expansion of the influence particularly large, so components and module frame between the launch position and the push plate guide pin and a fixed location is important, these mold of push plate guide pin generally fixed in the template, the template, between the horn and the mold box large diameter circle or square key sales position, so you can maximize the elimination of thermal expansion effects on the introduction of institutions, if necessary, bearing and the guide plate can be used to support launch of components at the same time introduced in the design of institutions should pay attention to lubrication between components . North American mold designers typically increase dynamic simulation box on the back of a special lubricating grease board putting strengthen the introduction of elements of the lubrication. Shown in Figure 5, the dynamic model box at the bottom of increased oil board, with oil hole connected Road and putting off work when filling oil, lubricant can be introduced institutions, to prevent catching.
(6) orientation and positioning mechanism design.
In the mold structure, orientation and positioning mechanism is to die stability was the most important factor, but also directly affect the die casting dimensional accuracy.
Mold of the guide mechanism including: mold-oriented, core pulling orientation, introduction of orientation, general orientation components to the use of special materials of friction pairs, play a role in reducing wear and abrasion, while a good lubrication is essential to every a friction pair should be set up between the necessary lubricating oil. Specifically, the large slide-oriented structure is commonly used copper lead guide sleeve and hard form of column-oriented, with good positioning with the form, to ensure a smooth slide operation, accurate place.
Mold positioning mechanism including: static and dynamic type inter-positioning, launch reset position, forming between the slider and the slider position, Block, trellis-type frame with the launch of some orientation between. Movement-based orientation is an activity between the nature of the position, with higher accuracy requirements, small die inserts can be used directly between the concave forming surface orientation, large-scale die-casting mold positioning mechanism must be specific as to eliminate thermal expansion of the Die positioning accuracy, several other positioning structure is positioned between components, a fixed position, usually with a round pin and square key positioning. Shown in Figure 6, forming inserts between the concave surface orientation, to ensure accurate positioning between dynamic and static type, to prevent mold the wrong side.
(7) vacuum, compression, exhaust and other design agencies.
In addition to the above structure, some die there is a vacuum system, extrusion bodies, wave plate exhaust and other special requirements. Vacuum system design is mainly enclosed form of design, make mold forming part of the normal between the mold temperature to maintain a good seal, generally use the silicone rubber seal. Extrusion mechanism design is key to the amount of compression time and compression control, to ensure compression effect. Wave plate exhaust vent is a concentrated form of the exhaust wave plate method commonly used, especially in the thickness of thin aluminum alloy die castings , high pressure tight requirements documents and magnesium alloy die-casting is widely used on ; wave plate gap to be large enough, but can not make alloy die-casting process in the production of liquid splash, wave plate gap generally control 0.3 ~ 0.6mm.
Fourth, the organization of expert review and the revised design of mold assembly Figure 2D.
Die three-dimensional design is complete to organize experts to design and processing technology of the assessment, through the evaluation to improve and perfect the design of the irrational structure of assessment include the following: assessment gating system, heat balance system assessment, core pulling structural assessment, assessment-oriented institutions launch of the assessment and processing of appraisal. Perfect wisdom through our entire mold design process.
Fifth, proofing and mold parts and a blueprint for processing.
The design and development of the completed mold blueprint for proofing and out, and the onward transport of a process to mold the processing and manufacturing.
Die-casting mold machining process
and reasonable processing operations can improve processing efficiency, and significantly improve the die life, to ensure casting dimensional accuracy.
1. Machining process
die-casting mold main process flow shown in Figure 8.
2. Reasonable choice of forming inserts
forming inserts on behalf of the entire life basically die of life, so a reasonable way of materials and heat treatment is critical. Forming inserts generally use 1.2343, Dievar, ADC3, PH13 and other heat-resistant mold steel.
3. Select the appropriate heat treatment,
material heat treatment methods are generally materials manufacturers technical guide or sale of specified heat treatment plant, mainly for roughing after the vacuum quenching, to stress after finishing treatment.
4. Surface heat treatment
of aluminum alloy die-casting mold is more harsh working conditions, requires a higher heat fatigue, heat conductivity, wear resistance, corrosion resistance, toughness, red hardness, and good mold release and so on. Alone, however, a new mold material applications and the necessary heat treatment process is difficult to meet the mold of use requirements, must be all kinds of surface treatment technology into its surface in order to mold high-efficiency, high precision and high service life requirements. In recent years, a variety of die casting mold surface treatment of new technologies emerging, but in general can be divided into three categories:
(1) Improvement of the traditional heat treatment techniques.
(2) surface modification technology, including surface thermal diffusion, surface phase transformation strengthening, electrical discharge enhanced technology.
(3) plating technology.
The article by: Dong Morinami casting net contributor to the Chinese.
Wishsino Die Casting Group.
