Die-casting alloy consists of nonferrous metals and ferrous metals. Widely colored nonferrous alloys are classified as follows:
lead alloy
Low melting point alloy tin alloy
zinc alloy
Nonferrous metal alloy
aluminium alloy
High melting point alloy magnesium alloy
copper alloy
Second, the manufacturability of die-casting structure
1, wall thickness
< 1 > The minimum wall thickness and normal wall thickness of die castings are usually based on the casting area.
< 2 > in order to ensure good molding conditions of castings. The outer edge of the casting machine should maintain a certain wall thickness.
< 3 > when there is an insert on the casting, the metal layer around the insert should be thickened. So as to improve the wrapping force of the insert. The thickness of the metal layer is directly selected according to the insert.
2. Casting holes
Die casting can inject relatively small holes, the relationship between hole sources and holes.
3. Casting fillet radius and draft angle
The diameter of casting fillet is related to the wall thickness.
4, spiral suction
Leave 0 as suction force of die-casting external thread. 2-0。 3 mm additional allowance. The inner screw suction is generally die-cast bottom hole, and the inner screw suction is reworked. The internal thread suction port can also be directly die-cast.
5. Convex suction, direct suction and net suction
(1) For convex suction and direct suction, just introduce the direction of mail mode.
(2) Mesh suction is mainly used to reduce or eliminate defects such as flow marks or patterns on the surface of large flat die castings, and the shape of the mesh should be conducive to mold manufacturing and demoulding.
6. Words and symbols
The text size is generally not less than the No.5 font specified in GB 126-74, the protruding height of the text is more than 0.3mm, generally 0.5mm, the minimum width of lines is generally 1.5 times the protruding height, taking 0.8, the minimum spacing of lines is more than 0.3mm, and the draft angle is10-0.
7, casting accuracy and machining allowance
See table 4-1-13 for the dimensional accuracy of (1) and parts that can be delayed. For assembly dimensional accuracy, see.
(2) When processing die castings, a smaller value should be selected.
Third, die casting equipment
1, die casting machine type and technical parameters
2, die casting machine selection
< 1 > clamping force
< 2 > when the capacity is insufficient.
The capacity of the die casting machine is greater than the total amount of molten metal poured for the first time.
G bet > (V 1+V2+V3)r/1000 (kg)
G injection-combined injection capacity of compressor, KG
V 1- die casting volume, CM3
V2—— total volume of gating system, CM3.
V3-residual volume, CM3
R- alloy specific gravity, g/cm3, zinc alloy 6.3-6.7, aluminum alloy 2.6-2.7, alloy 1.7- 1.8, copper alloy 8.3-8.5.
(3) Push the workpiece by hand.
It is estimated that the mold opening thrust should be less than the maximum mold opening force and thrust of the head-selecting die casting machine.
(4) Molding size
A. The installation size of the mold should be adapted to the template size.
B the die casting machine should be able to tighten the die surface after the whole die, and the total thickness of the die after die clamping is greater than (generally 2000) the minimum die clamping distance of the die casting machine.
C. the casting can be taken out smoothly after the die casting machine opens the die. After subtracting the total die thickness from the maximum die opening distance of the die casting machine, there should still be a distance to take out parts (including castings).
4. Typical structure of die casting mold
(A) the basic form of the mold and its composition
fundamental form
(1) non-porous mold body
(2) the role of mold structure
(2) Key points
(3) The arrangement of inlays in thick plates
Apprentices learn a lot. It depends on what apprentice you are studying. If you want to design, of course you need mold design!
At present, molds are still very popular. I wonder what will happen in a few years!