We’re thrilled by the high level of interest and the questions that enriched the discussion, allowing for a direct exchange on real cases and daily challenges in the industry. A special thanks to our internal experts: Matteo Margiri, Andrea Panvini, Ermo Fusè, Matteo Colombo, and Marco Scaramuccia, for offering concrete insights drawn from their experience at Bruschi foundries, making the webinar even more relevant and practical.

Stay tuned for future in-depth events and updates on industry developments.

Thank you once again for your participation and interest!

The post Thanks to all the participants in our webinar on the comparison between zamak and aluminum in die casting! appeared first on Bruschi.

How to prevent cavitation?

In the molding of articles by means of zamak die casting, considerable difficulties can arise in achieving the surface quality of the casting to meet the customer’s aesthetic requirements.
In order to achieve a good surface quality of the die casting, i.e., without marbling, it is necessary for the liquid metal to reach all areas of the impression as quickly as possible and without yielding temperature. Hence the need for high pressures and high flow velocities in the filling phase.
High pressures give rise to the phenomenon called “water hammer” at the end of the filling phase, while high velocities generate flow turbulence, both of which are crucial factors in the occurrence of cavitation.
We have found in our experience that using liquid zamak injection speeds below 60 m/s significantly reduces the occurrence of the phenomenon in the mold surface – an important fact to consider when designing the mold and the process.

The use of simulation programmes to fight cavitation

A very useful tool used daily in Bruschi’s engineering area is simulation software.
With these programmes, the engineering team can simulate the filling of the product in order to design casting and vent channels capable of achieving the quality required by our customers without, however, causing premature deterioration of the mold.
During the realisation of projects, from the design phase to the production phase, with the simulation software it is possible to prevent all possible defects on the mold. In this way, Bruschi can to save time by predicting possible problems, achieving customer goals in the best possible way.
These simulations are of such importance that they are also taken into great consideration during the bidding phase to the customer, as they prove essential in anticipating any eventuality.

Conclusion

The aim of engineering is to solve the cavitation problem by studying the behavior of the fluid inside the molds on a daily basis. These evaluations are carried out using simulation software, with which Bruschi can visualise parameters such as flow velocity, pressure inside the mould and filling temperature of customer products.
Considering that each product has a unique geometry, different issues and new daily challenges arise and are addressed to ensure quality products for the Bruschi team and its customers.

The post The phenomenon of cavitation appeared first on Bruschi.

On the subject of mechanical strength, and more in detail, breaking load, in this post, we will briefly define the function of rupture tests in the structural quality control of zinc die castings during production. This article will also describe the instrument used to perform these tests to ensure compliance with the specifications of the component and some case studies related to the main topic.

Ultimate tensile stress: breaking strength test of a part or assembly

As anticipated, the ultimate tensile stress is the force that must be applied to a component to cause yielding and/or rupture and is measured in mega-pascals, indicated by the symbol MPa, which is the primary unit of pressure measurement, that is, of the force on the unit of surface.

In order to proceed with this test, the force is applied at a point of the piece predetermined and agreed with the customer to observe the load necessary to cause its breakage or yielding. In this way, it is possible to test the amount of force needed for the test piece to lose the specific mechanical properties, that is, the ability of the component to withstand external loads and, consequently, be unusable.

The execution of this process requires a specific machine for laboratory tensile/compression tests.

Therefore, this machine is extremely crucial because breaking strength tests are among the key elements for the functional verification of a finished product. Often individual zinc die-cast components are mounted in an environment or in an assembly that undergoes various stresses from the outside, and these forces, if not adequately considered and analyzed, could compromise one or more elements of the system by jeopardizing the function of the product itself. An obvious example of this concept is undoubtedly the steering group of a car that undergoes different stresses due to different drivers. The individual elements and the system must necessarily be able to perform their function without breaking even in the event of excessive forces applied by drivers with extreme driving styles. Consequently, avoiding malfunctions and ensuring the correct mechanical strength of steering components is an essential safety factor for the driver.

The ultimate tensile stress: real tests and computer simulations (FEM)

This kind of test can also be simulated within CAD (FEM) applications, but as the die casting process is known, also using vacuum technology, it does not allow the molding of parts with theoretical material density because, as a result of the volumetric shrinkage during the cooling inside the zones of the die-cast with a higher mass, microcavities are created, typically called shrinkage porosity, which could compromise the performance of the product in terms of mechanical strength. These density variations are not completely intercepted by the simulation software systems, which can be very useful in the design phase but which, in terms of production, could call into question the achievement of the required specifications due to the inaccurate results detected by the simulation program. For this reason, it is recommended to use simulation programs to define an idea of reality, a production guideline, and then, directly in the foundry, instead proceed with sample checks during the molding and verify in detail every single aspect related to mechanical strength.

Having constant real-time control over the production, cyclically checking on a sample basis, is therefore essential to verify if the production complies with the customer’s specifications. Thus, the advantage of using these control instruments directly in production involves continuous control and the ability to act in real-time to avoid any line interruptions.

In conclusion

As we have briefly observed before, the tests in production of the ultimate tensile stress do not replace the simulations, but they place side by side with different objectives. These are critical, periodic tests to ensure a reliable and specific process during production.

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In this blog post, the goal is to imagine the future trends and scenarios of this process, since modern die casting has embarked on a decisive path of evolution compared to a few decades ago.
Speaking of the zinc die-casting of tomorrow, one cannot ignore the opportunities offered by simulation software.

Numerical simulation in zinc die casting

The numerical simulation of all processes allows adding value to the die casting activity because it allows reducing the time to market, optimizing the testing and verification phase and thus obtaining significant cost savings.

Numerical simulations are normally already considered for the entire filling process (see blog post: “Simulation for HPDC: scrap reduction case study“), but their use could be extended more and more to the general study of the behaviour of the die-cast object during the withdrawal phase or in the detection of any internal tensions, up to analyzing any possible anomaly in its structure and surface.

In this way, the approach to die casting becomes much more structured, moving from empirical criteria (or “trial learn”) to data-driven methodologies, capable of allowing cost and resource savings and making more informed decisions.

Furthermore, process and product simulations can serve as a database to lead zinc die casting to the discovery of new application sectors. In Bruschi, for example, simulations on thin thicknesses have given useful results for different fields of use and also in the automotive field, thanks to the simulation activity, new zinc components have been created, which perhaps without this type of analysis would not be never born.

The impact of technology on new die casting processes

Even at the process level, zinc die casting has important innovations in store, especially in Bruschi, and all are related to the contribution of technology to operational needs.

To overcome the cavitation problem, for example, certain analyzes are currently being carried out to minimize its impact, but the use of fluid-dynamics simulations is currently being studied, again through software, in order to be able to modify the feeding channel and the flow system at the origin to prevent this phenomenon from damaging the mould.

With reference to the new die-casting techniques, on the other hand, the attempt to apply the hot runner injection process, typically used in plastic moulding, to the zinc alloy is under consideration. This technique would make it possible to avoid the generation of the so-called “sprue”, reducing the costs in the management of the process connected to its subsequent elimination. The amount of heat saved by the absence of sprue to eliminate would also bring with it important consequences from a green perspective such as the production of less CO2 and therefore greater respect for the environment.

Also as regards the machines, technological progress allows to have more and more sophisticated systems for the control of the main parameters of the die-casting process, also giving the possibility to deepen the correlations between those in input (speed, pressures and characteristics of the injection profile ) with the outgoing ones (weight, burrs, surface quality), through the aid of statistical process analysis software.

Finally, we point out the studies conducted for the production of new sustainable zinc alloys, which are made exclusively through the treatment and recycling of new zamak scrap deriving from the die-casting process. This type of product allows you to embrace the themes of the circular economy, zero waste and recycling which, until a few decades ago, seemed utopia, when compared to the world of foundries. For further information on this topic, we recommend that you contact Bruschi by filling out the form at the link: https://www.bruschitech.com/contact-us-bruschi.

The advantages of zinc die casting

The advantages of zinc die casting, compared to the use of other materials such as aluminium, are numerous.

The first advantage is the greater ease of management of the final surface treatment (chrome plating, painting…). This plus linked to the use of zinc is very useful for all those applications that must meet both aesthetic and functional requirements (for example, resistance to corrosion) and is increasingly in demand on the market.

In addition, zinc die casting has a lower process cost because the zinc alloy mould lasts up to five times that of aluminium, which deteriorates much more quickly as a result of the higher melting temperature (650°C than aluminium against about 400°C of the zamak).

Then, the cycle time of the process is much faster because zinc can be treated in a hot chamber, while aluminium can only be treated in a cold chamber. We refer to the blog post “Zinc Die Casting: A Look into the Future” for the technical explanation of the difference between the two processes. What should be emphasized here is that the hot chamber process, which has always been used in Bruschi for the production of zinc alloy components, allows for greater speed in the production process and an important reduction in mechanical processing subsequent to the die-casting phase.

In conclusion: the future of the zinc die casting market

Despite the current economic situation, the die casting market is showing some encouraging trends. From today to 2026, estimates speak of a global increase of 6%, to which the zamak market also seems to comply.

Surely the technological progress that zinc die casting is undergoing and that passes, as we have said, to the ever-increasing use of software and simulation technology, can help to shift the interest of those potential customers who usually turn to the plastic or aluminium market to the zamak market.

Everything lies in continuous innovation, which can lead to the creation of high-quality zinc alloy die-cast objects from an aesthetic and functional point of view and with an important saving from the point of view of production costs. Bruschi has the ambitious goal of being at the forefront of the die-casting market and is continuously receptive to new techniques and methodologies to be applied to everyday operations to help improve the sector.

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Cost reduction strategies in zinc die casting

Cost reduction in zinc die casting can be implemented in different ways. In fact, zinc is a versatile metal that, if manufactured with the right technologies, allows saving not only in absolute terms, because it allows the die caster to save the time, energy and raw material that are required in the process, but also compared to other metals.

In the production of die-casts it is possible to implement cost reduction by:

•  Choosing zinc instead of other metals or other metal alloys
•  Optimizing the productive process
• Designing processes and components together with the customer through co-design methods

  When it comes to save during die casting process it is also important to choose the right die caster, if you want to learn more on the matter read How companies can save while selecting the die caster.

Advantages of zinc: chemical and physical qualities and characteristics, melting temperature, circular economy

Zinc alloys usually employed in the die casting process have some properties that make them competitive if compared to other metals. These are chemical-physical properties that allow the reduction of costs related to productive processes and to the subsequent stages, such as, for example, those of disposal and recycling. Let’s analyze these characteristics in detail.

Chemical-physical qualities and properties

In the die casting process different zinc alloys are employed. The most common of those alloys are Alloy 2, 3 and 5, and they are chosen for the production of different components depending on their chemical-physical properties. In fact, according to the percentage and the relative values of the metals that are contained in them, the alloys have different characteristics that make them more or less appropriate to realize different typologies of products. For example, if the component is a safety product the alloy that guarantees the greatest resistance to wear, corrosion and pressure, yield strength and dimensional accuracy is to be chosen. In case of a technical component, for which it is often important to achieve details and thin ribs, the Zamak to be preferred will be the most fluid because it will be capable of spilling over the mold in the most uniform way. In this way it will be possible to obtain thin walls thickness that is essential to guarantee the functionality of products. Finally, for aesthetical products Zamak alloys able to ensure the best surface quality and the best performance if subject to subsequent processing and finishing, are to be preferred. Therefore it is very important to know the chemical-physical characteristics of the different zinc alloys in order to choose the most suitable for the production of a specific component. Only in this way, in fact, it is possible to make a winning choice and obtain, with reduced scrap rates, quality die casts that need a reduced number of finishing and further processing.

If you want to discover more about different zinc alloys and how to take advantage of their specific characteristics read the articles The best zinc alloys for hot chamber die casting and Zamak molding in hot chamber die casting: chemical composition.
To deepen your knowledge about the advantages of zinc in comparison to other metals read The importance of zinc die casting in automotive industry and Coating, plating and other kind of surface treatments.

Melting temperature

One chemical-physical property that has a great impact in terms of cost reduction is the melting temperature of Zamak. The melting point of Zamak, in fact, is low and this allows hot chamber die casting. Differently from aluminum, which has a higher melting point and that is cold chamber die cast, Zamak allows energy saving provided by the different technological process used to melt the material. There are further advantages related to time that are connected to hot chamber die casting: hot chamber die casting is a faster process than cold chamber die casting and, as a consequence, it has an increased productivity. Another saving factor related to melting temperature is that the mold, subjected to lower temperatures, is affected by less wear and, for this reason, has a longer lifetime, with beneficial effects especially in large scale production.

Circular economy

In this brief review of the qualities of zinc in comparison to other metals one last property has to be mentioned: recyclability. Zinc, in fact, fits in circular economy processes and therefore meets the recent trends toward environmental sustainability. Zinc recyclability is not only an advantage for the final consumer, who can recycle products and appliances, but it is also an important factor of cost reduction for the die caster. In fact, if the agreements with customer allows it, zinc can be re-melted and, in controlled percentages, it can be reintroduced in the productive process with evident consequences in terms of reduction of scrap rate and of optimization of the productive processes.

If you wish to learn more about the possibility of recycling Zamak click here.
If you look for insights on zinc circular economy we suggest you to read Zinc life cycle: how it contributes to circular economy.

Productive process optimization

In regards to cost reduction in die casting not only the properties of zinc are important but also the productive process with which the metal is manufactured. Die casting techniques and machineries have to be up to date with technological development in order to be efficient, for this reason constant research and innovation are necessary. It is also important to have effective supply chain and logistic managment, if you want to learn more click here.

For a general overview about these topics we suggest you to read the article Production process improvement in the die casting industry. If you wanto to deepen your knowledge on the  analysis necessary to optimize the productive process read the article How die casting companies can help you save time and budget.

Automation and cycle time

An important step to achieve cost reduction is, for example, the introduction of automation in the productive process. In fact, automation makes the system more efficient by diminishing the percentage of scrap and allowing the operators to deal with activities with a greater added value.

Moreover, the acquisition of automation is closely related to the capability of updating and implementing the productive machineries. Thanks to the purchase of new machineries activities that used to be manual become automatic with a resulting diminishing in lead time, cycle time and scrap rate and a noticeable increase in productivity. Cycle time, in particular, is very important in relation to cost reduction strategies: in fact diminishing cycle time means increasing OEE, the productive performance index of a plant, and, consequently, the production. In the specific field of hot chamber die casting the reduction of cycle time represents a further saving opportunity because, in a reduced cycle time, the thermal power that the melted material provides to the mold is increased with a resulting decrease of cold fronts and related defects.

If you want to learn more about automation and its importance for the production process read How automation helps improving the production process; if you want to discover more about cycle time and its optimization we suggest you to read How die casting cycle time optimization can help to reduce costs.

Simulation

Another strategy to optimize the productive process is to use simulation software that allow designers to forecast what is going to happen during the die casting process. Simulation is a useful instrument to prevent problems, errors and defects during the production of the die casts and it is, moreover, a fundamental aid during design, prototyping and testing phases.

You can find a study about the advantages of simulation in zinc die casting clicking here.

Quality certifications

A guarantee of optimization of the productive process and of the subsequent cost reduction is the achievement of quality certifications. Smeta 4 Pillars, for example, is a certification of qualitative standards, environmental management, company integrity, health and safety with a noticeable impact in terms of cost reduction. In fact, Smeta 4 Pillars through the sharing of standardized approaches improves and aligns the productive process safeguarding brand reputation and guaranteeing an ethical supply chain.

Co-design

Co-design consists in a series of activities aimed at increasing the value of the product and at improving it in terms of quality and efficiency. Often these activities do not result in an increase in production costs but, on the contrary, they result in a decrease in costs. Through co-design, if already implemented during designing phase, it is possible to agree with the customer on weight reduction, elimination of secondary operations, optimization of the mold and a number of other actions that directly lead to a noticeable cost reduction. Obtaining a drawing that is already optimized for mass production allows the customer to have a final product that is in line with expectations and with less risks and scraps. As a further assurance of cost reduction, already during co-design phase, it is possible to undertake a VA/VE value analysis and to optimize the process through the DFM. VA/VE value analysis is a method of problem solving that allows the effective identification of unnecessary costs making it possible to reduce them. DFM, Design for Manufacturability, is a feasibility study in which the design of the product is evaluated and in which adjustments, special treatments and structural modifications are proposed in order to make the optimization of the production possible.

For a deeper insight on co-design we suggest you to read the article Product design for die casting, if you want to deepen your knowledge on VA/VE read The zinc die caster impact on production costs reduction. 

The methods to implement cost reduction in zinc die casting and to optimize processes and products do not end here. However, by reading this article you should have had evidence of some important benefits of cost reduction.

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The case study concerns a component produced for the building industry and the related mold, which was built 10 years ago. Over the years the mold began to cause problems due to its wear condition: it was therefore necessary to study and examine mold design and to introduce significant changes, in order to reduce casting defects that emerged on the component.

In accordance with the lesson learned approach, Bruschi engineers have analyzed production performances of the component and defined new parameters on the basis of the knowledge they assimilated through the years. Furthermore, cutting edge technology, such as simulation software, has allowed Bruschi design department to foresee material reactions and to make accurate changes to mold design, in order to reduce casting defects. In this way, they have figured out new solutions with the aim of achieving a component that could meet the requested quality standards.

Elements that influence superficial quality of the diecast

Superficial quality of a component produced with die casting technology can, indeed, be determined by multiple factors, such as mold thermoregulation and temperature of the material injected in the cavity, but it mainly depends on the filling method of the feeder. The design of an appropriate feeder, which allows a symmetrical filling of the cavities, is therefore a fundamental requirement to avoid superficial defects on the product. On the contrary, an asymmetric or divergent feeder can cause air entrapment in the die cast, as well as areas with evident cold laps caused by irregular filling.

Case study

This case study is about a component that is part of a hinge for a door. After several years of component production with the first mold, the latter was worn out and it caused superficial defects on the product, such as cold laps, lack of material and porosity. Bruschi engineers have conducted an analysis of the parameters and of the geometry of the mold, after that they have identified the leading cause of the defects: the incorrect filling of the cavities. In order to solve this problem they have thus decided to design and build a new mold. With a view to reduce casting defects the design department has therefore modified mold design, more specifically feeder design.

Phase 1 – Simulation

The first phase of mold design project concerned simulation of the filling of the cavities with thermofluidodynamic simulation software Magmasoft, which allows foreseeing to a good approximation the behavior of the material during filling phase. With Magmasoft it is indeed possible to examine different parameters, such as temperature of the metal in every stage of the filling, air pressure in the cavity, material speed and presence of areas with air entrapments. For further information on simulation, here are some previous posts:

• Simulation for HPDC: surface aesthetical quality in automotive
• Simulation for HPDC: shrinkage porosity case study
• Simulation for HPDC: die maintenance and optimization of set up

Simulation has highlighted three main problems:

• Asymmetrical filling
• Divergent feeder
• Lack of homogeneity in the material temperature

To best define the corrective actions to implement engineers had to carefully observe product’s shape: the component has, indeed, a thicker upper section and a thinner lower section. The product’s geometry has thus requested a specific care during the design of the feeder because, in order to achieve a symmetrical and regular filling, it was necessary to add further elements that could facilitate the dynamic behavior of the filling fluid.

Phase 2 – Upper section design

Simulation phase has revealed that the filling of the upper section was asymmetrical and therefore caused air entrapment in the die cast, with consequent air bubbles presence on the component’s surface. The cause of the asymmetrical filling was ascribed to the different speeds at which the material started to fill the cavity. As a matter of fact, the fluid entered from the injection point with a high kinetic energy and continued its way by following the cavity geometry, which drove the material to fill specific areas that were thus quickly and more filled, reaching instead only at a later stage those areas that were not in the direction of the main flow.

The first problem to solve was therefore related to the asymmetrical entrance of the material in the gate: in order to symmetrize material entry in the cavity, designers have added a damper at the end of the main feeder. With the new configuration the flow, before dividing, fills the damper while losing kinetic energy and continues its way towards the cavity at a constant speed.

The second problem, still concerning the upper section of the die cast, was related to the divergence of the feeder in specific sections, thus causing the appearance of turbulences. Consequently, engineers have designed a convergent feeder, which has helped to better channel the material and to facilitate the filling of the cavity, thus reducing boundary layer separation.

Phase 3 – Lower section design

The lower section of the product is visibly different from the upper section. Indeed, it is a thinner part that, with the first mold, was filled by material at low temperatures thus causing the presence of cold laps and lack of material. By observing the component’s shape, it was indeed clear that a uniform filling was difficult to obtain, particularly in the lower section: the material filled in the first place the whole upper section, which is characterized by an important dimension, while it reached only at a later stage the lower section. Consequently, the material started to fill the lower section at a too cold temperature, such as not to guarantee an appropriate level of superficial quality.

With the aim of solving this problem, Bruschi team has designed a devoted feeding system through the addition of two auxiliary runners. The runners have been added to the lower section of the component in order to achieve a regular filling, by maintaining a stable material temperature in the entire die cast. The two auxiliary runners, as well as the main feeder, have been designed in order to obtain a symmetrical flow: to achieve this result engineers have added two further dampers to the auxiliary runners.

In addition to that, considering the particular shape of the product, in order to further facilitate the filling in the whole cavity, engineers have designed a partially tangential in-gate capable of channel the material in critical areas. The lower section presents, indeed, some inserts that, without this type of gate, could potentially obstruct the material flow, thus impacting on filling uniformity. This kind of solution therefore determines a better material distribution, by facilitating its entrance in the cavities and the reaching of the most critical areas.

Achievements

After having modified mold design engineers have conducted the simulation of the filling of the cavities with the software Magmasoft and have obtained excellent results: the previously observed critical issues have indeed remarkably decreased. Specifically, through the design of a new feeder, designers have achieved a higher filling uniformity, which has consequently determined the reduction of casting defects on the component’s surface.

This case study therefore confirms the importance of knowing how to draw on previous experiences for the resolution of new problems, by combining know how and technology in order to achieve increasingly outstanding results. Mold design and Magmasoft have allowed designers to test various solutions before proceeding with the actual production of the component, thus obtaining relevant benefits in terms of quality, time and costs.

To get updates on trends and innovations in the Zinc Die Casting industry, you are welcome to subscribe to our blog.

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Productivity enhancement represents, indeed, an advantage both for the supplier and the client: on the one hand the supplier benefits from costs savings, while on the other hand the client can rely on a partner that offers quality performances in short times. Bruschi has always considered this subject a core aspect, as a matter of fact through the years Bruschi has taken several measures in order to achieve an ever-increasing process improvement.

How to reach process improvement

Process improvement can be developed through a well-defined action plan, which takes into consideration the complexity of elements that characterizes the production department. Production is indeed composed not only of machinery, but also of product design, technologies, operators and planning activities, to mention some of the most important components of this structured system. To improve the production process it is therefore crucial to have a comprehensive view of all these elements, in order to implement a strategy that is functional on multiple aspects.

As a consequence, the first step to take is the setting of the tools and of the adjustment actions that can impact on the improvement of the different stages of the production. In Bruschi the process improvement plan is composed of four central elements:

1. Automation

2. Simulation

3. Scrap reduction

4. Cycle time

1. Automation

The introduction in a production system of automated machinery equipped with state-of-the-art technologies generates relevant benefits in terms of reduced lead time, costs reduction and achievement of quality standards requested by clients. The replacement of workforce with automated systems allows, indeed, to obtain a faster process, consequently enhancing the whole lead time. In addition to that, automation leads to a reduced likelihood of error compared to manual operations. This translates into a relevant production costs reduction, which is further increased thanks to energy and material saving that automation generates. The introduction of automated machinery in the production department produces another significant advantage that allows quality control improvement, too. As a matter of fact, operators that previously dealt with manual operations on the component thanks to automation can take responsibility for other activities with a higher added-value, such as quality control.

A process improvement project of a specific component, for a client of the sector of small appliances, has obtained excellent results in terms of increased productivity and decrease of manual activities of operators. Process improvement project has been developed in order to solve a situation of misalignment between production capacity and client’s demand. Through the introduction of automated systems this gap has been narrowed, thus achieving an optimized cycle time. After several studies and researches it has been possible to apply some changes to the process, which have brought to significant benefits: an increase of 33% of production capacity and a decrease of -95% of manual activities made by operators.

For more detailed information on automation consult the post below:

• How automation helps improving the production process
• The Importance Of Automation Optimize The Production Time

2. Simulation

Simulation of the die casting process represents another essential element that impacts on process improvement: with simulation software engineers can indeed foresee material reactions inside the mold. This process is feasible thanks to a thermos-fluid dynamic analysis of the mold, known as CFD simulation (Computational Fluid Dynamics), which allows the engineer to detect potential defects, such as cold laps and hot spots, on the die cast. The simulation stage proves especially helpful to obtain an optimized mold design before starting with the production process. During this stage it is indeed possible to select the best mold design parameters to apply, so that potential defects on the piece are previously detected and, consequently, production costs and further mechanical operations are reduced.

If you are interested in simulation, here are additional posts on this topic:

• The Benefits Of Simulation In Die Casting Design
• Die Casting Simulation For Shrinkage Porosity Prediction
• How To Use Die Casting Simulation For Cost Reduction
• Hpdc Simulation For Die Casting Process Optimization
• Die Casting Simulation A Casting Process Optimization
• Hpdc Simulation Benefits For Die Casting
• Simulation For Hpdc Surface Aesthetical Quality In Automotive Case Study
• Simulation For Hpdc Shrinkage Porosity Case Study
• Simulation For Hpdc Die Maintenance And Optimization Of Set Up

3. Scrap reduction

Scrap reduction can be achieved through an accurate planning of the whole production process of a component. First of all it is necessary to carry out a product and process analysis that focuses on the causes of scrap. To identify these causes engineers must use simulation software to foresee every stage of the production, from design to finishing operations. Once again simulation proves to be an indispensable tool for zinc die casting process improvement, because it allows engineers to avoid defects and to check technical properties before starting with the component production, thus producing a consistent costs and lead time reduction. Once scrap causes have been figured out it is possible to proceed to the outlining of potential solutions to apply, identifying the most relevant steps in the production process and constantly checking them.

To know more about scrap reduction, here are extra posts on the topic:

• How To Reduce Scrap In Die Casting Process
• Simulation For HPDC Scrap Reduction Case Study

4. Cycle time

The expression cycle time defines the period of time required to produce a product. Cycle time represents a central variable in the production of a component because a reduced cycle time results in a reduced lead time, which is the period of time needed to accomplish a customer’s request in terms of supply. An optimized lead time generates an increase in the client’s satisfaction, because it allows the supplier to meet deadlines and standards demanded by the client. As a consequence, in order to guarantee a rapid and efficient service, cycle and lead time have to be enhanced to the maximum extent possible. Cycle time can be shortened paying attention to different aspects of the production process, especially to simulation stage and to technological systems of the production department. First of all, as already mentioned, it is important to simulate production and defining the best process parameters to apply for the production process. In this way potential defects will be avoided from the very beginning and, consequently, it will be possible to eliminate further mechanical operations. Another core element for cycle time shortening is the technological system of the foundry, whose technological innovation level can generate relevant time reduction during the production process. As a matter of fact, automated machines lead to optimized cycle times and to more accurate operations, discriminating factors for the achieving of performances requested by customers. Furthermore, periodical checks on machinery help understanding how cycle time can be further improved.

Check the posts below to learn more about cycle time:

• Process Optimization For Die Casting Cycle Time Reduction
• How Die Casting Cycle Time Optimization Can Help To Reduce Costs

Why process improvement is crucial for a business

Process improvement is a crucial element in the management of a business because it leads to production costs reduction and faster productive processes. With the aim of reaching these benefits it is therefore necessary to introduce automated technology and simulation software in the production process, and to optimize scrap reduction and cycle time. With the outlining of a precise process improvement plan lead time can be shortened and, as a result, client’s satisfaction will be increased.

To get updates on trends and innovations in the Zinc Die Casting industry, you are welcome to subscribe to our blog.

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You can find a full list of discussed topics in our first post on the subject, by clicking here.

CASE STUDIES AUTOMOTIVE: Surface aesthetical quality

The subjects of this case study are the thin plates in car vents that direct and control air flow in the car’s passenger compartment.

The vents for air flow control are usually made of plastic, but the object of our case-study is the central plate, used by the driver to direct the other air ducts and therefore made in alloy.

This product poses challenges especially for the surface aesthetical quality, because of its exposed position in plain sight inside the passenger compartment, the high-end car on which the vent will be installed and possibly the criticalities of surface treatment after die casting.

OBJECTIVE AND PHASES OF THE SIMULATION

The simulation analysis will thus focus on engineering an optimal flow through the feeders to avoid defects such as flow marks and blisters in the product.

In the first phase of the process we studied the effect of various runner configurations, one by one, to identify the runner with the best characteristics. Then we improved the shape of the runners, especially at the entry of the die.

The objectives sought in the various phases of the simulations were:

• Filling consistency of the die according to a main flow direction
• Decrease of the probability of cavitation to increase the speed of flow
• Reducing the filling time and keeping the alloy at a high temperature during this phase
• Absence of air bubbles in the product

RESULTS

In the study of product surface quality, the main parameter to consider is temperature. The temperature must be maintained the highest and the most consistent possible throughout the duration of die filling up to the end of filling process, especially in parts of the product that will be in full sight.

The images portray the analysis results at filling cycle end: the temperature is sufficiently high and homogeneous, with even better characteristics in the top surface, which requires a higher level of quality since it will be visible in the compartment of the car it will be installed in.

From the velocity field analysis it is possible to observe the feed direction and the speed modulus at the die entry point: a particularly critical point because it is often subject to cavitation phenomena, causing die wear.

By looking at the picture, we can notice filling consistency and that the last volumes to be filled are close to the overflows, allowing the exit of the first alloy arrived in the die, because the temperature will be lower.

The velocity field, depending not only on the runner geometry but also on boundary conditions at die entry level, has been obtained by using process parameters common for die casting this kind of product. The speed pattern is sufficiently low even in the vicinity of the gates. This has a positive effect on manufacturing because it will allow to apply higher filling parameters without the risk of premature wear of the die.

The next image shows that the impact of the runners is well balanced: the two runners, identified by red and blue colorings, fill the die in a consistent manner. Proper functioning of the small runner on the left is confirmed: the presence of the orange color, as small as it is, is necessary to avoid flow marks.

The influence of runners (orange liquid) should be reduced but not zero: it’s presence may be necessary in order to avoid flow- marks in the entry zone.

And finally, the field that shows trapped air indicates a favorable situation: the air contained in the casting is not an issue because it distributed evenly across the volume and concentrated only at the sprues, granting the achievement of requested surface aesthetical quality.

All of these analysis confirm that the design and the filling system are optimized to obtain the best esthetic quality, granting a smooth surface that can undergo the required coating and contribute to the perceived value of car interior.

In conclusion, the simulation study allowed us to assure the best surface aesthetical quality for air flow vents, by analyzing four main factors: main flow direction, speed of flow, filling time and temperature, absence of air trappings. Thanks to the analysis of these factors, it was possible to optimize the casting process by redesigning the shape of the runners and thus to fulfill the requested levels of esthetic quality.

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This post is part of a series in which we explain the importance of simulation for HPDC (High Pressure Die Casting) through the presentation of real life cases.

You can find a full list of discussed topics in our first post on the subject, by clicking here.

CASE STUDY DIE MAINTENANCE: automotive industry

The product we are going to analyze in this post is a steering lock housing assembly for automotive industry.

The critical part was the upper cover of the steering block assembly, containing an electronic card. The part itself was not flawed at first, but soon the signs of mold erosion started to show up. The erosion of the mold left distinctive marks on the surface of the component: these irregular dark spots were the sign of die wear.

The identified die wear was caused by the high speed of flow during the filling phase and by the specific geometry of the part. The consequences of poor die maintenance are rather severe as they can bring on a malfunctioning of the part, caused by surface spurs resulting from die wear, in addition to increasing the need for maintenance work. In order to solve the problem, a simulation of the filling process was run.

OBJECTIVE AND PHASES OF THE SIMULATION

The objective of the simulation was to identify opportunities for slowing down or eliminating erosion on an existing die: to achieve the wanted result, our engineering department run an analysis of alternative feeder solutions.

The first step was to identify the cause of erosion: erosion is caused by the development and non-stationary implosion of alloy bubbles against the surface of the die. Due to high speeds of the flow through the narrow ducts in proximity of feeder, the pressure falls below the vapor pressure of the alloy, causing it to evaporate instantaneously.

Subsequently, the alloy enters the die with a larger cross section than the feeders, causing an expansion that reduces the speed of the flow. The pressure rises rapidly causing the implosion of vapor bubbles and freeing up energy. This entire process is called cavitation and is the main cause of wear to the internal surface of the die.

RESULTS

The filling velocity field represents the speed of the flow when it initially enters the control volume.

Since cavitation is a non-stationary process that takes place in the first phase of filling, which is also the phase of highest instability, the study of filling velocity field represent the highest opportunity to identify the critical areas.

As the following images show, the new geometry positively influences the expansion of the flow, mitigating the velocity gradients along the green line.

Internal part of the housing

The area with largest cavitation is in the center of the field, where the green line demarcates the separation between two areas with different speeds. Exactly in this area, because the flow slows down and pressure increases, the alloy bubbles implode and damage the die.

With the new feeder duct the green line is moved generating a broadening of flow diffusion. This broadening should shift the cavitation area and reduce the risk of cavitation because of the lower speed gradient in the critical area of the die.

External part of the housing

The green line moved on the fixed side of the die as well, broadening the diffusion and diminishing the transversal speed gradient.

In conclusion, the use of simulation allowed to identify the critical area in which cavitation was occurring and to design a broaden flow to shift cavitation, preventing wear of the die and reducing the need of die maintenance.

We will now move on with the next case study, which focuses on small domestic appliances and set up parameters optimization.

CASE STUDY OPTIMIZATION OF SET UP PARAMETERS: small domestic appliances

The subject of our second case study is a chrome plated handle. The product is a component for a pad type coffee machine: in this case there was not a problem to fix, but it was necessary to identify the correct filling of the die to optimize the production.

In order to achieve a high level of esthetical quality, the die has to be maintained at very high temperatures: high temperature in the die reduces alloy cooling during the filling phase, reducing flow marks. However, high temperatures implies longer cooling time: as a consequence, the cycle time expands because of the prolonged solidifying phase of the part. Therefore, it is necessary to establish an operating temperature range that allows a high quality level while keeping the cycle time as low as possible, to increase productivity.

Once identified, the die casting conditioning parameters can be set to keep the die within the range. These conditioning parameters are entry temperature and the type of coolant.

OBJECTIVES AND PHASES OF THE SIMULATION

The objective of the simulation is to estimate the change in surface quality and cycle time at the varying of die temperatures.

Die temperature depends on two factors: the geometry of the conditioning circuit, defined in engineering phase, and the temperature and nature of the coolant applied in production phase.

In the simulation, a homogeneous die temperature was imposed in proximity of the cavity. Surface quality has been determined by the average value of the alloy temperature at the end of the filling phase, whereas the production cycle has been derived from the necessary time for the component to solidify and cool to a temperature of 340°C.

The evolution of the two quantities has been calculated across a series of simulations in which the temperature was made variable.

RESULTS

The following graph clearly indicates the results of the series of simulations. Technically, this is not an optimization analysis because the two monotonously increasing curves do not allow to find an absolute minimum or maximum: it can be considered as a tradeoff analysis to define the optimal temperature range.

The 180 – 228°C temperature range is where the surface quality curve grows most significantly, while the product cycle time stays fairly constant before increasing almost exponentially.

For these reasons we choose the range within bandwidth of about 10°C, placed at the extreme right of the interval (218°C < T < 228°C).

In this case, simulation of the component has helped determine the ideal die temperature range to obtain the required surface quality, guiding the setting of entry temperature and the choice of the coolant.

In conclusion, throughout this series of post we have seen different applications of simulation for die casting: scrap reduction, optimization of esthetical quality, improvement of mechanical characteristics, improved die maintenance and optimization of set up parameters are only some of the many advantages offered by the use of this technology.

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