Category: die casting mold

Production of the die casting mold

Production of the die casting mold is one of the three elements, structure reasonable mold die-casting production can proceed smoothly, prerequisites, and guarantee the quality of castings hand ( machine under qualified rate ) plays an important role in.

Due to the characteristic of the die casting process, the correct selection of the process parameters is getting high-quality casting decision factors, while the mold is able to correctly select and adjust the parameters of the premise, the mold design is essential to die casting production of various possible factors are expected to reflect the integrated. Aluminum Die Casting If the mold design is reasonable, it is encountered in the actual production problems, the high qualified rate of casting machine.

die casting mold
die casting mold

Conversely, the mold design is not reasonable, case casting design moving mould parcel force is basically the same, but mostly in the fixed mold gating system, and put the shot after punch can not feed the die casting machine production, cannot be produced normally, castings have been stuck on the fixed die. Although the fixed mold cavity finishes playing very light, because the cavity is deep, still stuck in the fixed mold phenomenon. So in the process of design, we must make a comprehensive analysis of casting structure, familiar with the die-casting machine ‘s operating process, to understand the die casting machine and process parameters can be adjusted odds, lies in the different situations and to consider the mold filling characteristics, processing methods, drilling and fixed form, in order to design a practical, satisfy the production requirements of the mold.

The beginning has been told, the filling time is very short, the liquid metal pressure and the flow rate are very high, the die is an extremely poor working condition, coupled with the rapid cooling and heating of the alternating stress impact, both on the service life of the die has a great influence on. Aluminium Die Casting The service life of the die is usually through careful design and manufacture, under normal use, combined with good maintenance under the natural damage cannot be repaired, in which the scrapped before, die-casting module (including the casting production of scrap number).

Gravity die casting

Content:

  1. Introduction
  2. Die casting machine
  3. Gravity die casting
  4. Advantages compared to sand molding
  5. Limitations
  6. Applications

Introduction:

  • Die casting process

Main drawback of sand molding process:

Mold needs to prepare for each casting produced.

The specialty of die casting process:

A “metallic mold” is used to prepare sand mold with which larger number of casting is made. The metallic mold is known as “die”.

Die casting process:

  • Mold material: metal or alloy.
  • Types of die casting process:
  • Gravity Die casting (permanent molding).
  • Pressures die casting.
  • Cold chamber pressure Die casting
  • Hot chamber die casting
  • Unlike gravity die casting in pressure die casting the molten metal is forced into a permanent mold cavity under pressure.
  • The pressure varies from 20 to 2000 kg/sq.cm. And is maintained till the solidification stage is reached. The weight is for the most part acquired by compacted air or using pressurized water.
  • Die casting machines
  • Die casting machines perform the following functions.
  • Holding the two die halves firmly together. Closing the die
  • Injection molten metal into the die casting mold
  • Opening the die
  • Ejecting the die casting out of die

Gravity Die casting

  • The casting is called gravity die casting because the molten metal is poured into the mold under gravity only, no external pressure is applied to force the liquid metal into the mold cavity (opposite to die casting).

Permanent molds

  • Permanent molds are made of grey cast iron in two halves (having high resistance to thermal shocks), alloy steels (for very high temp. and withstanding surface erosion) or non-ferrous alloys.
  • The inner surface of the molds is coated first with refractory and with lamp black or core oil. This is done in order to reduce the chilling effect on cast prevents the adherence of molten metal to the mold.
  • Pouring cups, risers, gates, sprues are present in the mold.

Advantages

  • Compared to sand casting following are merits
  • Closer dimensional tolerances.
  • Smoother surface and better appearances.
  • Fine-grained metal structure. (Because of the chilling effect.)
  • Mass production is more economical.
  • Low shrinkage and gas porosity.

Think – “climate toys can be delivered with this procedure.”

 Limitation

  • Lasting mold costs were substantially more than sand for
  • Suited for small/ medium-sized non-ferrous casting only.
  • Several defects like stress and surface hardening may be produced due to surface chilling effect.
  • Since the gating system is cut in mold halves, once machined, it cannot be changed.
  • The extremely high temp of molten metal makes this method unsuitable for steel casting.

Applications

  • Carburetor bodies.
  • Refrigeration casting.
  • Oil pump bodies.
  • Connecting rods and automotive pistons.
  • Typewriter segments, etc.