Casting burr

Description

The gap between the divided faces of the mold, the gap of the joint portion of the slider, the gap of the core, the gap of the push pin, and the like, the infusion of the soup, and a thin protrusion protruding from the side of the product occurs.

the reason

The accuracy of the mold, the slider, the push pin hole, etc. is insufficient, and a gap is generated due to thermal deformation of the mold, and a cast burr occurs. Further, when the temperature of the soup, the temperature of the mold, the speed of the injection, the pressure of the casting, the setting of the castable area, etc. are not good, the casting burr occurs.

Countermeasures

* Improved mold processing accuracy.

* Increase in mold hardness.

* Appropriate clamping force.

* Appropriate for die casting conditions.

Check mark

Description

When the plaque is formed on the surface of the hole, this shape is written on the surface of the casting, which is called a flaw that has a detrimental appearance.

the reason

During the casting process, the heating and cooling of the thermal cycle causes the mold to shrink and compress the thermal stress. The very fine crack on the surface of the mold that occurs due to this thermal stress is called a plaque, and this crack is written on the product, called a plaid mark. The plaque marks are caused by improper casting conditions, improper mold material and strength, hardness, improper mold cooling such as external cooling, and the like.

Countermeasures

* Reduce the difference between mold and soup temperature and reduce thermal shock.

* Preheat the mold before casting.

* Strengthen internal cooling and remove outside cold.

*Mold material. Heat treatment should be the most appropriate to improve strength and hardness.

* The mold should be fully ground to reduce knife marks and wear marks.

Sweat

Description

A spherical metal bead produced by the edge of the die-casting material or the corner or end surface. The chemical composition is a kind of reverse segregation compared to the average composition (base metal composition).

the reason

The surface of the mold is shrunk due to the shrinkage of the edge or the corner portion, the surface layer of the die-casting material is solidified slowly, and the solution of the internal solute is concentrated due to pressurization, etc., and the void portion of the mold and the die-cast product generated under the solidification shrinkage is extruded. Concretion. When the amount of solidification shrinkage is small, reverse segregation is formed.

Countermeasures

*Enhance the cooling of the corners of the edges.

* Reduce the temperature of the soup.

* Reduce the casting pressure and optimize the pressurization time.

*Select alloy type (alloy with small solid-liquid coexistence range)

Blow up

Description

The air or gas entrapped near the surface of the die-casting material, which bulges after expansion at the time of mold opening or heat treatment.

the reason

The cause is the same as the stomata, due to the flow of the soup or the temperature of the mold. The shape of the product, the closed air near the surface, the gas, expands when the mold is opened or left. Further, in the heat treatment process such as T6, when the strength of the alloy is lowered, the air and gas which are closed in the product expand and bulge.

Countermeasures

*According to the measures of the stomata.

* Pouring the riser scheme and optimizing the exhaust scheme.

* Appropriate type and amount of lubricant release agent.

*Mold opening time. Appropriate mold temperature.

* Point cooling settings.