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How to avoid defects in hot chamber hpdc

by Stefano Polli October 26, 2016

avoid defects in hot chamber hpdc

Hot chamber hpdc is a die casting process in which high pressure is used to force molten metal through a mould.

The use of pressure let the metal flow through the die and leads to great qualities of castings especially when a perfect surface is needed.

In hot chamber hpdc, the supply of molten metal is an integral part of the casting machine for the manufacturing operation.

With zinc alloy pressure die casting it is possible to achieve very high quality standards: the manufacturing is precise and allows a wide variety of finishes even in massive productions.


How is possible to avoid defects in hot chambers HPDC?

The Zinc alloy has become one of the choices materials for a large range of mass produced die cast components: from electronics to ornamental parts for the automotive industry security from hydraulics and pneumatics to security.

Finishing criteria are becoming more critical, costs and reject rates must be taken into consideration very seriously.

Reducing number of defects is a key issue in parts manufacturing: even minor surface blemishes which can occur throughout the manufacturing process may cause rejection, loss of time and resources as a direct consequence.

In hot chamber hpdc the die caster should consider any possible cause of defects, such as

  • alloy chemistry
  • metal temperature/handling
  • casting design (a major controlling factor in the investigation of casting defects)
  • die design (calculation of runner and gate sizes, casting geometry, die temperature, heating and cooling phases)
  • ejection
  • die lubrication

It is important for the die caster to understand which defect can occur and to be able to identify causes and possible remedies available to resolve those issues.

The element that most influences the casting quality is the gate that leads the alloy into the die.

The simulation of filling and solidification phases may therefore predict possible defects caused by non-uniform liquid flow, high temperature gradient, local increase of velocity, and other issues. With this instrument it is possible to optimize the entire production with positive effect on the final product in terms of esthetics and efficiency and on the duration of die life.

Die casting simulation software allows to simulate the feed, calculate the alloy flow and temperature, and the presence of gas or porosity in the finished product.

Thanks to the simulation it is possible to identify the best configuration for the feeders that convey the alloy into the die to achieve the best results in terms of precision and reliability, reduce risks to a minimum and achieve savings in time and resources. 

The simulation can influence important decisions in the technology of die casting components which affects esthetical quality, scrap reduction, mechanical characteristics, maintenance and life cycle of the die, and optimization of set up parameters.

In hot chamber hpdc, good quality die castings are not achievable without good quality dies and every step can cause a defect if not properly executed.

The design of the die is essential to ensure casting quality, cost effectiveness and long term manufacturing processes.

The number of shots, die cycle times and minimal scrap are all influenced by  the die design process and simulation is an essential tool to obtain reliable and high-quality products avoiding the costs of trials and the production of expensive moulds or patterns.


 

Bruschi offers to customers a co-design partnership to identify every possible margine of improvement and suggest alternative solutions to maximize the performance and quality of the final product, reduce costs, and speed up the time to market. 

Our technical staff is available to support your designer’s inventiveness and to develop innovative and creative solutions together.

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