Characteristics of zamak

Zamak is an alloy composed of zinc, aluminum, magnesium and copper. According to the different percentages of these components the alloy has variable characteristics and can be used for the manufacturing of products for different market sectors. For an in-depth look at different types of zamak and their features, read the article ZAMAK molding in hot chamber die casting: chemical composition.

The characteristics of zamak that are particularly beneficial for the production of components for electronic products are:

Electromagnetic shielding

Zamak has good shielding properties with reference to Electromagnetic Interference (EMI). Therefore, it is especially suitable for the production of housings for electromagnetic cards because it is a product that requires a reduction of interferences

Heat dissipation

The properties of heat dissipation of zamak are similar, if not higher, to those of other materials. In this case, what makes zamak products competitive is the manufacturing cost of the product, the lifespan of the mold and the possibility to achieve products that do not need relevant secondary mechanical operations. For further information about this property of zamak, we suggest this case study: Zinc Heatsink Case Study: Loewe TV Heatsink.

Thin wall thickness and reduced dimensions

Zamak fluidity allows the achievement of a very thin wall thickness and of an extremely high level of detail in components of reduced dimensions. This is particularly important in the case of electronic products, which usually are characterized by very small dimensions and by a great number of details.

Stiffness and anti-vibration properties

These properties of zamak are especially relevant in case of electronic products employed in critical environments. In the industrial field, for example, electronic connections of some kinds of machine tools could be exposed to mechanical stress or vibration. It is evident that in cases like the one just described, zamak offers a protection and a vibration damping capacity that plastic could not offer.

To discover something more about chemical, physical and mechanical characteristics of zamak read the Zinc Association Engineering in Zinc, Today’s Answer, which contains very detailed information on these subjects.

Zamak components for electronic products: characteristics and competitive advantages

Let’s now analyze some zamak components for electronic products to examine their characteristics and competitive advantages.

Hard disk case

In this hard disk case we can observe how zamak properties contribute to the functionality of the product in several ways. Indeed, the case is anti-vibration and this allows the hard disk to work in stable conditions. Furthermore, as you can see in the picture, the product has both very small particulars and thin thickness. Specifically, directly during casting phase thanks to zamak it has been possible to realize the honeycomb grid that allows heat dissipation in the server through air circulation. With other materials the grid could have been achieved only through secondary operations, such as shearing, with unavoidable consequences in terms of timing and costs.

Housing for steering wheel lock

This housing hosts the electronic card of the steering wheel lock. In this case it is the properties of electromagnetic shielding and stiffness of zamak to make the product competitive compared with other similar products manufactured with other materials. As a matter of fact, the shielding allows the electronic card to function in optimal conditions without being subjected to the interference of near electromagnetic fields. Then, for this particular product, stiffness makes zamak especially competitive compared to plastic. Often when plastic housings are installed electronic cards tend to bend, whereas  the stiffness of zamak leads to a higher protection, thus extending its lifespan.

Device for checking, counting and separating banknotes

As far as this product is concerned, zamak has replaced stainless steel, thus cutting production costs and the need for mechanical operations and finishing. This has been made possible by the properties of zamak and especially by the capacity of the alloy to reach thin wall thickness and a high degree of detail. In this way the customer has obtained a product that does not need to be assembled, manufactured with molds with a long lifespan, which need little maintenance and with scrap rates close to zero.

Housing for corporate network connectors

The housing for corporate network connectors is illustrative of the properties of shielding, stiffness and resistance of zamak. For these kinds of products, shielding properties of zamak allow freedom to the electronic designer, who can mitigate the drawbacks linked to the electromagnetic waves without special precautions, but only through the choice of the most suitable material. Stiffness and resistance of the material make the use of the component suitable for particularly critical environments, such as production departments of a plant.

Conclusions

With this brief overview on zamak components for electronic products we have analyzed how some properties of zinc alloys allow the achievement of competitive and effective products. However, these are not the only components for the electronic industry that can be manufactured in zamak. For a more comprehensive overview visit our website www.bruschitech.com in the Services page.

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The term automation defines the introduction in a manufacturing company of technical tools and processes aimed at reducing or even eliminating human operations. Indeed, the most relevant benefit of automation is the reduction of workload for the operators, which consequently leads to additional advantages such as reduced lead time, costs reduction and achievement of quality standards requested by clients. Automation can therefore contribute to production process improvement, enhancing accuracy, precision, productivity, robustness and consistency of outputs.

CASE STUDY

In Bruschi we are always seeking for innovative solutions that can help improving the productive process. In order to fulfill this aim, the production department has developed a project for reducing operators’ workload with the introduction of automation. This project concerned two specific components produced for a client of the sector of small appliances and has obtained excellent results in terms of reduction of manual activities of operators and increased productivity.
In order to define the two components to optimize among those available, engineers have conducted an analysis with the support of the Pareto chart, which has led to the following results:

• 20% output produced by 0,05% of components
• 60% output produced by 17% of components
• 20% output produced by 82,95% of components

Results show that 0,05% of components generates 20% of the output produced by the company: these components are known as runner products. The presence of few components that generate such a substantial output allow the introduction in the production department of a specific automation without reducing productive flexibility of the company.

Definition of project’s phases

After having selected the components, the different stages of the project can be defined. The iterative improvement process is indeed divided in four phases, with reference to PDCA cycle or Deming cycle:

• Phase 1 – PLAN
Definition of the problem, identification of the causes and hypothesis of corrective actions to reach expected objectives.

• Phase 2 – DO
Implementing corrective actions defined in phase 1.

• Phase 3 – CHECK
Collecting and checking data. Comparison between expected results and observed results.

• Phase 4 – ACT
Implementing corrective actions emerged from data analysis of phase 3.

The four phases of PDCA cycle have been planned using the following Gantt chart:

Phase 1 – PLAN

The first phase starts with the definition of the problem: a condition of misalignment between production capacity and client’s request, with hypothesis of producing both the components on the same die casting machine due to plant saturation. Therefore, the problem can not be solved producing the two components on two different die casting machines: it is in fact necessary to improve the production process of the components.
The identification of the root cause involves the study and the definition of the average duration of single activities, manual and automatic ones:

• Die casting – automated operation managed by the machine
• Pick up and lay down of the piece – automated operation managed by anthropomorphic robot
• Degating and reprocessing – manual operation managed by the operator
• Auxiliary activities – manual operation managed by the operator

Once average duration of every single activity has been calculated, improvement focuses on activities that can generate more benefits, so the ones that take up the most of the time of the operator. Manual activities that have been selected are reprocessing, raw-scrap division and die casting machine fueling: these activities take up 97% of the operator’s time.

The second step concerns the classification of operations on the basis of the added value they generate for the customer:

• VA = 0 % – Necessary Value Added activities: known, therefore paid by the client
• NVA = 3 % – Unnecessary Non-Value Added activities: unknown, therefore not paid by the client
• NNVA = 97% – Necessary Non-Value Added activities: unknown, therefore not paid by the client

First of all it is essential to work on NVA activities, in order to understand how to eliminate them. Secondly, NNVA must be analyzed and improved. Normally, VA activities can be improved but with little margin.

Phase 2 – DO

Phase 2 involves a cost-benefit analysis in order to identify the best solution between externalization and self-improvement through automation. Both the alternatives have been implemented:
• externalization of manual activities equal to 50%
• reduction of manual activities equal to 45%, through introduction of automation that operates automatic division of the pieces from the sprue runners and automatic recasting of the sprue runners

Phase 3 – CHECK

The third phase of the project involved collecting and checking data, with comparison between expected results and obtained results. Observation period after improvement actions have been implemented was of 240 working hours. Three numerical KPI (Key Performance Indicators) have been considered in order to evaluate the efficacy of improvement action:

1. OEE (Overall Equipment Effectiveness)
2. Average duration of manual activities
3. Tons of zamak recasted in the machine spot

The comparison of these indicators before and after improvement actions has highlighted +33% OEE and -95% manual activities, with a complete recasting of scrap material.

Phase 4 – ACT

Phase 4 has not concerned any action because after KPI analysis no anomalies were observed.

ACHIEVED BENEFITS

The project has led to several benefits for the production department, both direct and indirect ones.

Direct benefits:
• +33% OEE
• -95% manual activities
• Complete scrap recasting in the machine spot

Indirect benefits:
• Increase of client’s satisfaction. Met and reduced lead time thanks to productive capacity increase, improvement of superficial quality of the component and stabilization of degating and reworking processes
• Energy saving associated with immediate casting of raw material
• Reduction of waste due to handling associated with elimination of scrap transfer

This case study demonstrates the importance of automation in a productive system that is efficient and technologically advanced: through the introduction of automated systems it was indeed possible to meet qualitative and quantitative standards demanded by the client, meeting the requested deadline at the same time.

If you are interested in production process improvement, here are additional posts:
• Production process improvement in the die casting industry
• Casting process optimization: design of hot chamber injection system

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