What are the common adverse phenomena of die-cast aluminum parts? What is the corresponding solution?

1. Common adverse phenomena include: wrinkling and wrinkles on the product surface.

According to Chapter 1 of Luo Qiquan's "Practical Manual for Die Casting Processes and Equipment Molds":

Surface wrinkles: irregular wrinkles formed on the surface of the product, mainly in the front section with thinner walls .

Wrinkling: The surface film of the cylindrical part near the insert is wrinkled. The surface part of the wrinkled surface varies depending on the state of occurrence.

2. Solution

According to Chapter 1 of Luo Qiquan's "Practical Manual of Die Casting Process and Equipment Molds":

Solution to surface wrinkles: exhaust thoroughly, Remove excess release agent. Adjust the position of the high-speed and high-pressure zone to prevent the solution from cooling;

Wrinkle solution: It is important to preheat the mold and produce under the set temperature conditions. Set the mold temperature at an appropriate range.

Extended information:

Die-casting machine design specifications

The design of die-casting parts must take into account the wall thickness of the die-casting part, the casting fillet and the demoulding angle of the die-casting part. Seven aspects include thickness, reinforcing ribs, casting holes on die castings and the minimum distance from the holes to the edges, rectangular holes and grooves on die castings, inserts in die castings, and machining allowances on die castings.

1. Casting fillet design specifications

Usually there should be rounded corners at the intersection of various parts of die castings (except at the parting surface), which can make the flow of metal fill smooth and the gas less Easily drained and can avoid cracks due to sharp angles. For die castings that need to be plated and painted, rounded corners can be plated evenly and prevent paint accumulation at sharp corners. The fillet radius R of die-casting parts should generally not be less than 1 mm, and the minimum fillet radius is 0.5 mm.

2. Design specifications for inserts in die-casting parts

First of all, the number of inserts on the die-casting parts should not be too many; secondly, the connection between the inserts and the die-casting parts must be firm, and at the same time It is required to have grooves, bulges, knurling, etc. on the insert; thirdly, the insert must avoid sharp corners to facilitate placement and prevent stress concentration on the casting. If there is severe galvanic corrosion between the casting and the insert, the insert must The surface of the part needs to be protected by coating;

Finally, castings with inserts should avoid heat treatment to avoid volume changes caused by the phase change of the two metals, which may cause the inserts to loosen.

3. Design specifications for wall thickness of die-casting parts

Thin-walled die-casting parts have higher strength and better density than thick-walled die-casting parts. In view of this, the design of die-casting parts should Follow this principle: on the premise of ensuring that the casting has sufficient strength and rigidity, the wall thickness should be reduced as much as possible and the wall thickness should be kept uniform.

Practice has proved that the wall thickness design of die-casting parts is generally 2.5-4mm, and parts with a wall thickness exceeding 6mm should not be produced by the die-casting process. The impact of too thick or too thin walls of die castings on the quality of castings: If the wall of the casting is too thin in the design, it will cause poor metal welding, directly affecting the strength of the casting, and at the same time causing difficulties in molding;

When the wall is too thick or severely uneven, shrinkage and cracks are likely to occur. On the other hand, as the wall thickness increases, defects such as pores and shrinkage porosity within the casting also increase, which will also reduce the strength of the casting and affect the quality of the casting.

Baidu Encyclopedia-Die Casting Machine