Die Casting Technology

There are three main forms of mold failure

1 thermal fatigue crack damage failure

Thermal fatigue cracking failure of die casting production, mold repeatedly stimulated cooling and heating effect, the molding surface and internal deformation are involved, and the repeated cycles of thermal stress, leading to tissue structure of two injuries and loss of toughness, causing cracks appeared, and continue to expand, once a crack expanding, and molten metal liquid impact, coupled with repeated mechanical stress crack accelerated expansion. Therefore, on one hand, die casting mold must be fully preheated starting. In addition, in the production of the die casting die in must be kept in a certain temperature range, so as to avoid the early cracking. At the same time, to ensure the mold production and manufacturing of internal no problem. Because of the practical production, the majority of the ineffectiveness of the die thermal fatigue cracking.

2 invalidity

Fracture failure of the shot under the action of force, die in the weak point of crack, especially the molding surface scribing traces or electric machining marks are not polished optically, or molded clear corner will appear first fine crack, when the grain boundary exists brittle phase or coarse grains, which is easy to break. And brittle fracture crack growth quickly, the mould invalidity is very dangerous factors. Therefore, on one hand where mold surface scratches, electric machining marks must be polished light, Zinc Die Casting even when it is in the gating system position, must also be polished. Additional requirements by use of the mold material of high strength, good plasticity, impact toughness and fracture toughness were good.

3 corrosion failure

Molten failure previously said, conventional die casting alloy zinc alloy, aluminum alloy, magnesium alloy and copper alloy, but also pure aluminum die-casting, Zn, Al, Mg is the more active metal elements, they and the die materials has the good affinity, especially Al easy to bite mold. When the mold hardness is high, then the corrosion resistance is better, and the molding surface if the soft point, then on the corrosion resistance of adverse.

The die failure of many factors, both external factors (for example, whether the mold casting temperature preheating, water paint spraying quantity, die casting machine, die size matching tonnage, high-pressure gate speed too fast, cooling water open and die-casting production synchronization, casting materials and components, the discretion of Fe the casting dimension shape, size, wall thickness of coating type, etc. ). There are internal ( cases of mold material metallurgical quality, blank forging process, the mold structure and the rationality of the design of gating system, the rationality of the design, mold machine ( EDM ) generated during the processing of internal stress, the mold heat treatment technology, including a variety of matching precision and smoothness requirements ). Die if the early failure, need to find out what the internal or external, for future improvement. But in actual production, corrosion is only die locally, cases of gate directly flushing part ( core, cavity) prone to corrosion phenomenon, and the hardness is easy to appear soft aluminum die casting alloys adhesive die.

AMBA Finds Optimism in US Mould Industry

Results of the American Mold Builders Association (AMBA) Summer 2005 business forecast show continuing optimism in the US mould making trade as business remains steady. Of the 124 survey respondents, 21% reported that current business is excellent (compared with 14% in the Summer 2004 forecast), 49% reported business to be good, and 26% said business is fair. Only 4% found business to be poor, and no one said it was bad.

Three-month projections solicited by the AMBA survey were roughly the same as last year: a large plurality of respondents (46%) expect their company’s business to remain the same, while 36% expect to do moderately better over the short term. Only 6% of companies participating in the survey projected any three-month decline in business.

Twenty-seven percent reported that quoting was up compared with three months before, 50% said quoting was the same, and 23% reported that quoting was down. Shipments were up for 41% of the respondents and the same for another 45%.

The forecast notes that profits are up for 27% of the respondents (compared with 21% a year ago) and about the same for 57%. Though profits were down for 17% of the respondents, that was a better report than the 21% who said in the Summer 2004 forecast that profits had declined.

Employment figures also are holding steady; 34% of the companies responding to the AMBA survey reported employment up and only 7% down, with the rest unchanged. Survey participants have an average of 22 shop employees and 4 design and engineering employees. The former work 46 hours per week, while the latter put in 48 hours.

AMBA is the largest industry trade association in the United States for mould manufacturers and affiliated companies, serving 325 member companies in chapters throughout the country.