1. Pressure casting is referred to as die casting. Die casting is a process that uses molds and machinery to quickly fill cavity with molten metal under pressure, changing from liquid to solid to form required product.
2. From injection chamber method, it can be divided into: hot chamber die casting (commonly used for zinc alloy) and cold chamber die casting (commonly used for aluminum alloy). According to pressure, it can be divided into: low pressure casting (such as automobile wheel shell) and pressure casting, from exhaust method is divided into: ordinary die casting and vacuum die casting.
3. What are die-casting alloy materials? What characteristics do they have?
Commonly used materials suitable for die casting are: zinc alloy, aluminum alloy, magnesium alloy and copper alloy.
They have following characteristics:
①. It has good fluidity in liquid state;
②.Have relatively fixed melting point and freezing point;
③.Small shrinkage rate;
④. Has certain high temperature strength;
⑤. It has good processing performance and corrosion resistance.
4. What are main components of die-cast aluminum alloy? What are impurity components?
Main ingredients are: aluminum, silicon, copper, magnesium, manganese, zinc, etc.
Impurity components include: iron, zinc, copper, tin, aluminum, sulfur, phosphorus, etc.
Different alloy grades have different requirements for their main components and impurities.
5. What are main defects of die castings?
Generally speaking, there are undercasting (not full of material), cracks, deformation, cold insulation, cold lines, shrinkage, pores (sand holes), mechanical strain, adhesive mold strain, delamination, wrong mold, slag inclusion, surface air Holes, blisters, fleshiness, lack of flesh, etc.
6. What is temperature of aluminum alloy liquid suitable for die casting production?
Generally 650℃~720℃

 

7. What are characteristics of die-casting production?
(1) High production efficiency, can realize mechanized or automated production;
(2) Good product quality: A. High dimensional accuracy and high surface finish; B. Good mechanical properties; C. Good interchangeability; D. Clear outline, thin and complex casting wall, patterns, patterns, text, etc. can be obtained High definition;
(3) Good economic effect: A. Excellent economic indicators; B. Low cost of die castings; C. Parts can be assembled;
(4) Die-casting equipment and mold investment costs are high and are not suitable for small batch production. )
8. What are main parts of a die-casting machine?
Die-casting machine is mainly composed of a closing mechanism, an injection mechanism, an ejection mechanism, a power (hydraulic) system, a control system, a lubrication system, a cooling system, etc.
9. What is tonnage of die-casting machine named after?
Tonnage of die-casting machine is named after maximum mold clamping force (clamping force). For example, 180T die-casting machine has a maximum mold clamping force of 180 tons.
10. What is function of mold closing mechanism of die casting machine?
Function of closing mechanism is to install fixed mold and drive movable mold part of die-casting mold to open or close mold.
11. What is nominal pressure of hydraulic system of die casting machine?
Generally it is 12 MPa (or 120 kg/cm²).
12. What is function of injection mechanism?
Injection mechanism is a key part of die-casting process, which allows metal liquid to be filled from injection chamber into mold cavity at a certain speed and pressure.
13. What are cycle action steps during normal production of injection punches?
General steps are: slow speed (injection head moves from beginning to the time it passes injection chamber gate)
One fast (injection head allows molten metal to enter runner and sprue)
2. Fast (make metal liquid flow directly into inner gate from beginning to fill mold cavity)
Pressurization (moment when molten metal fills mold cavity, pressure of injection cylinder rapidly increases to a certain value, compacting filling metal, and maintains it for a period of time) Tracking (while opening mold, injection head continues to press against remaining material of gate sleeve some distance ahead)
Return (injection head returns to its original state and completes a cycle)
14. What are basic technical parameters for production of horizontal cold chamber die-casting machines in my country?
There are (1) mold clamping force (KN), (2) injection force (KN), (3) ejection force (KN), (4) ejection stroke (MM), (5) movable platen stroke (MM) , (6) Mold thickness (MM), (7) Injection chamber diameter (MM), (8) Injection specific pressure (MPa), (9) Maximum projected area of casting (CM2), (10) Maximum metal pouring amount (Aluminum alloy) (KG), (11) System working pressure (MPA), (12) Internal spacing between body columns (MM), (13) Main motor power (KW).
15. What process parameters can be adjusted during die-casting production?
(1) Molding thickness, (2) Mold closing speed, (3) Mold opening speed, (4) Mold closing time, (5) Slow injection speed (6) Fast injection speed, (3) Slow injection stroke, ( 8) Quick pressing stroke, (9) Injection pressure (specific pressure), (10) Tracking stroke, (11) Tracking delay, (12) Ejection stroke, (13) Ejection speed, (14) Ejection delay hours, (15) cycle time, (16) aluminum material temperature, (17) mold temperature, etc.
16. What is role of nitrogen bottle of die casting machine?
It plays role of accumulating energy. When fast injection is required, accumulator quickly releases a large amount of hydraulic oil to accelerate injection head. When pressurization is required, accumulator instantly releases pressure to pressurize injection head.
17. What is function of lubrication system of die casting machine?
Lubrication system of die-casting machine is generally an independent system. It is set to automatically lubricate sliding and rotating parts of closing mechanism at regular intervals, which plays a key role in ensuring normal operation and service life of machine.
18. What is function of hydraulic system of die-casting machine and what are its main components?
It provides power for die-casting machine to complete various actions, and is mainly composed of an electric motor, an oil pump, an oil cylinder, various control valves and pipelines.

 

19. What is function of cooler?
It plays a role in cooling and protecting hydraulic system.
20. Why do injection rod and injection head need to be equipped with cooling water for cooling?
Because cooling water installed in injection head of injection rod has following functions:
(1) Block heat from being transferred from injection rod to hydraulic system;
(2) Reduce wear of injection head at high temperature;
(3) Accelerate cooling of remaining material to prevent remaining material from sticking to nozzle and mold opening due to insufficient cooling of remaining material, causing mold to explode. Aggravation causes unstable process parameters;
(3) Too high oil temperature accelerates aging of sealing ring;
(4) Oil temperature is too high, making hydraulic oil prone to deterioration, leakage and loss.