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Ningbo Yinzhou Defa Aluminum Profile Accessories Co.,Ltd
Add:No.44 Lengshui'an Road, Yinjiang Twon, Haishu Zone, Ningbo, China
Aluminum Profiles Constantly Transform And Innovate

In recent years, with China's large-scale infrastructure investment and industrialization of the rapid progress of the whole industry, aluminum production and consumption of the rapid growth, and China has become the world's largest aluminum production base and consumer market. After nearly 10 years of rapid growth, China's aluminum industry has entered a new stage of development, and show a lot of new trends.

Moreover, with the construction, transportation, automotive and solar and LED industries such as the rapid development of aluminum extrusion products, high precision, high performance requirements, profiles cross-sectional shape with the complex, diversified, according to conventional common design , There are many deficiencies. Therefore, to get high-quality profiles, you have to in the production and life continue to learn and accumulate, and constantly transform and innovation.

Mold design is an important part, therefore, must be squeezed profile mold design system analysis, and through the production practice to gradually solve the problem.

One of the six main points of aluminum mold design

1. Size analysis of aluminum extrusion

The size and deviation of the extrusion is determined by the mold, the extrusion equipment and other relevant process factors. Among them, the mold size changes greatly affected, and the impact of mold size changes are: the elastic deformation of the mold, the mold temperature, mold materials and mold manufacturing accuracy and mold wear and so on.

(1) aluminum casting machine tonnage selection

The extrusion ratio is a numerical representation of the mold to achieve the difficulty of extrusion, in general, the extrusion ratio between 10-150 is applicable. Extrusion ratio of less than 10, the product mechanical performance is low; the other hand, the extrusion ratio is too high, the product prone to surface roughness or angular deviation and other defects. Solid profiles are often recommended for extrusion at around 30, with hollow profiles around 45.

(2) the size of the determination

The outer dimension of the extrusion die is the outer diameter and thickness of the die. The dimensions of the mold are determined by the size, weight and strength of the profile section.

2. Reasonable calculation of extrusion die size

When calculating the size of the die hole, consider the chemical composition of the extruded aluminum alloy, the shape of the product, the nominal size and its allowable tolerances, the extrusion temperature, and the coefficient of linear expansion of the die material and the extruded alloy at this temperature The geometric shape of the features on the section, and its changes in the straightening of the stretch, the size of the extrusion force and the elastic deformation of the mold and other factors.

For the thickness of the large thickness of the profile, the difficult to shape the thin-walled parts and edge sharp corners should be appropriate to increase the size.

For the wide and narrow width of the wide-width thin-walled profiles and wall profiles of the die hole, the size of the beam parts can be designed according to the general profile, and the thickness of the web size, in addition to considering the factors listed in the formula,Aluminum profiles still need to consider the mold Elastic deformation and plastic deformation and the overall bending, distance from the center of the cylinder and other factors. In addition, the extrusion speed, with or without traction device on the die hole size also has a certain impact.

3. Reasonably adjust the flow rate of metal

The so-called reasonable adjustment, that is, in the ideal state, to ensure that the product cross-section of each particle should be the same speed out of the die hole.

As far as possible the use of porous symmetry arranged, according to the shape of the profile, the thickness of each part of the difference and the circumference of the distance and the distance between the center of the cylinder, the design of unequal length of the sizing. In general, the thickness of the profile somewhere is thinner, the greater the circumference, the more complex the shape, the farther away from the center of the extrusion cylinder, the shorter the sizing here.

When the flow rate is difficult to control with the sizing belt,Aluminum profiles the shape is particularly complex, the wall thickness is very thin, far from the center of the part can be used to promote the flow angle or cone to accelerate the metal flow. On the contrary, for those parts where the wall thickness is much larger or close to the center of the extrusion cylinder, the obstruction angle should be used to supplement the obstruction to slow the flow rate here. In addition, the flow rate of the metal can be adjusted by using the process balance hole, the process margin, or by using the front chamber mold, the diversion die, changing the number, size, shape and position of the diversion hole.

4. Ensure adequate mold strength

Due to the very poor working conditions of the mold during extrusion, the mold strength is a very important problem in the mold design. In addition to the reasonable placement of the mold hole position, select the appropriate mold material, the design of a reasonable mold structure and shape, the precise calculation of the extrusion force and check the dangerous section of the allowable strength is also very important.

At present, there are many formulas to calculate the squeezing force, but the modified Beirley formula still has engineering value. Squeeze the upper limit of the solution method, but also have good value,Aluminum profiles with the empirical coefficient method to calculate the extrusion pressure is relatively simple.

As for the mold strength of the check, should be based on the type of product, mold structure, respectively, respectively. General flat molds only need to check the shear strength and bending strength; tongue mold and plane shunt module need to check the shear, bending and compressive strength,Aluminum profiles tongue and tip part also need to consider the tensile strength.

An important fundamental problem when strength checking is to select the appropriate strength theory formula and the more accurate allowable stress. In recent years, for the particularly complex mold, finite element method can be used to analyze the force and check the strength.

5. Working width of the band

It is much more complicated to determine the working belt of the split die than to determine the half-mold working belt, not only the thickness difference of the profile wall is close to the center, but also the case where the die hole is shielded by the branch bridge. In the mold hole under the diversion bridge, due to the difficulty of metal flow, the work belt must be considered thinner.

In determining the work belt, we must first find in the shunt bridge under the thinnest wall thickness of the metal flow resistance where the largest, where the minimum working belt is set to twice the wall thickness, thick wall thickness or easy to reach the metal Of the place, the work belt should be properly considered thickening, generally according to a certain proportion of the relationship, coupled with easy to move the correction value.

6. Mold hole empty knife structure

The die hole is the structure of the cantilever support at the outlet end of the die hole. When the thickness of the profile is t≥2.0mm, the straight knife structure can be used. When t <2mm, or with cantilever,

Common problems in mold design

1. The role of two-stage welding chamber

Extrusion die in the aluminum extrusion production plays a vital role, a direct impact on the quality of extrusion products. However, in the actual production, the design of extrusion die more dependent on the experience of the designer, mold design quality is difficult to guarantee, need to try and mold several times.

According to the lack of mold design,Aluminum profiles it is proposed to set up the optimal design scheme of the second-stage welding chamber in the mold, make up the defects of the mold in the mold processing, and avoid the defects such as the opening and the mouth of the material , And effectively solve the problem of uneven velocity distribution in the design. Thus, in the optimization scheme, the temperature distribution and stress distribution on the section of the profile are more uniform, and the material is improved greatly.

2. The role of secondary diversion

In the extrusion die design, for the wall thickness difference between the large solid, the use of two diversion. Example: The initial mold design by the ordinary mold and mold pad composition, the first on the machine is not ideal, the angle is too small, thin-walled part of the size of ultra-thin,Aluminum profiles ultra-small. Die repair even if the increase in thin-walled parts, playing low working belt is still not ideal.

Aiming at the shortcomings of the initial mold design, the second design of the baffle is put forward, and the optimization design scheme of the secondary diversion is put forward in the mold, which effectively solves the problem of uneven velocity distribution in the initial mold design.

Specifically through the thin-walled diversion straight,Aluminum profiles thick-walled parts in the outlet width of 30 degrees, and thick-walled part of the mold hole size slightly increased size, and the other hole angle of 90 degrees angle to open the mouth open to 91 degrees , Sizing work belt is also appropriate to make some changes.

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