The component in question is linked to the safety of the vehicle’s driver and passengers. Due to its very nature, it requires a maximum tolerance of a few thousandths compared to the required weight of 6 grams. Such a tight tolerance level is challenging to be respected 100% in producing die-cast parts.

Bruschi’s R&D team and technical office took the lead in developing a pioneering project in the sector. Leveraging software development and cutting-edge technologies, they overcame the common limitations of die-casting production and met the customer’s demand.

Therefore, the mass production of zinc pieces smaller than a €1 coin was guaranteed, respecting the tolerance specifications provided by the customer.

Bruschi designed and implemented a fully automated production process to ensure precision and quality. This process involves the use of robots equipped with precision grippers capable of extracting the die-cast components from the molds. A camera placed on the machine allows the robot to independently verify the presence of all the pieces inside the mold, dismantle them, and place them on a precision scale for quality assurance.

Any pieces that do not meet weight standards activate a reject system.

This is an example of how technological progress and engineering skills make it possible to satisfy the market’s needs, overcoming production limits that only a constantly evolving company can overcome.

The post Advanced Precision Automation: Bruschi and the Advantage for the Automotive Industry 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.

The post Mechanical strength: Breaking load test for zinc alloy components appeared first on Bruschi.

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.

The post What is zinc die casting? What will it be like in 2022? appeared first on Bruschi.

Products have been chosen on the basis of different principles: we privileged variety, selecting components that are produced for different sectors and complexity, in order to communicate our expertise and competence in satisfying the client’s requests.

Here the list of the videos:

• Die casting for household appliances: coffee machines
• Die casting for automotive: electronic steering wheel lock
• Die casting for automotive: sunroofs
• Die casting for building industry: windows and doors
• Die casting for household appliances: hinge for washing machines

Let’s give the floor to our experts.

Die casting for household appliances: coffee machines

In this video we show the production of a component for coffee machines and we describe the technical solutions implemented to obtain a perfect chrome finish.

This product is the bottom section of a coffee machine for the consumer market. It is an aesthetic component that comes into view and in contact with the end customer: for this reason there are specific technical and quality aspects to consider. During analysis stage, indeed, we have faced technical and process difficulties caused by the particular shape of the component, which could invalidate the requested standards thus reducing the quality of chrome finish.

It is exactly the particular geometry of the piece that does not allow the working of the internal surface and it is for this reason that, after careful analyses of the production process and considerations on the shape of the component, we decided to obtain a surface that was suitable for chroming process already after casting phase.

In order to reach this aim we have undertaken virtual and physical prototyping and simulation activities that have allowed the definition of optimal parameters for the production of the component. Thanks to simulation and prototyping we have identified two properties on which we have specifically focused our attention: roughness and surface quality. To achieve the expected result already during casting stage we tried to take the most out of production parameters. The lapping of the mold has been the chosen solution to obtain surface roughness already during casting phase; simulation and tests during production phase allowed us to modify the mold in order to obtain the requested surface quality and standards.

The adoption of these technical solutions and the modified parameters have therefore allowed us to obtain a product suitable for polishing and chroming treatments.

The polishing stage is carried out on still rough pieces, whose external surface is smoothed so that the subsequent chroming process has a good result. The next stage is indeed chroming phase. Chroming process is an aesthetic galvanic process that gives to the die cast a charming and protective aspect: the chrome surface, indeed, protects against corrosion. It is a process composed of various passages where the products are immersed in aligned tanks to receive sequentially processes of degreasing, copper plating, nickel plating and chromium plating. It is this final stage that gives, thanks to the extremely brilliant aspect, an important added value to the component, making it a distinctive element of coffee machines.

Die casting for automotive: electronic steering lock

In this video we present an automotive component whose mold has been designed in an unconventional way and on which it has been introduced an automatic threading system.

This component of the electronic steering lock has required an unconventional mold design because it is characterized by a complex shape. Indeed, the inner section of the product, which is designed to hold an electronic card and to contain sliding parts, has caused the main difficulties in mold design. Therefore, the structural complexity of the component, connected with the production process, has determined the necessity to obtain a considerable level of accuracy during mass production.

Considering that the product is designed to internally contain an electronic card and further functional elements, it is necessary the total lack of die casting defects (for example burrs) that could compromise the functionality of the product or of the elements inside the component. In order to achieve the requested precision and quality standards, mold has therefore been designed with an unconventional approach. The configuration with which it has been designed is indeed the opposite of the traditional one. The piece is picked up by its external part and not by the internal part as it usually happens: in this way we avoid both burrs and extractors in the internal part of the product.

After the optimization of mold design we also introduced during production cycle an automatic system for threading. This system, integrated into casting area, allows both the cutting of sprue runners and the simultaneous threading of two M8 holes. There are two important benefits that result from the implementation of this system: first of all we avoid manual operations (so the operator is free to deal with activities with greater added value) and, moreover, we obtain productive efficiency and continuity, with a resulting cost and time saving. Die casting technology, in particular die casting for electronic steering lock, thanks to our innovative approach and to the technical expertise of our engineers, constitutes a great choice for the production of automotive components because it ensures production accuracy also for the most complex products.

Die casting for automotive: sunroofs

In this video we present a component for automotive industry characterized by very close tolerances and complex geometries.

This part is a component for car sunroofs that has a complex shape and is characterized by very thin areas. Therefore it requires a high level of detail and accuracy. To meet the requests of the costumer we have adopted specific technical solutions that have assured the functionality of the piece and, at the same time, have allowed us to obtain a product free of every minimal deformation.

These solutions have been implemented in mold design phase and during the simulation of the filling flow, while the implementation of the injection channel, tilted sliders and ejectors has been managed in every detail to achieve complex shapes. For the simulation we have used Magmasoft software, which has allowed us to optimize filling flows in the entire die cast and in particular in the thinnest areas. The outcome has been a uniform and homogeneous filling. In addition, to increase even more the accuracy of the result, we have employed the vacuum technology, a tool designed and realized here in Bruschi to guarantee dimensional stability.

The technical solutions devised by the engineers have allowed us to achieve a product that has excellent technical features, compliant with our production process and that meets the complete satisfaction of the costumer. For the automotive industry, in this case for the production of sunroofs components, die casting technology allows the achievement of products with close tolerances and complex shapes that fully meet strict standards of the sector.

Die casting for building industry: windows and doors

In this video we show the production of the cover of the opening and closing system for windows and doors.

The component is part of the opening system for windows and doors: so it is characterized by functional and aesthetic properties. On the one hand, the functional properties are determined by the fact that the component contains in its inside other elements of the opening system. The aesthetic properties, on the other hand, derive from its nature of external element that comes in contact with the end costumer. For this reason the piece must have an optimal surface quality.

Therefore, to design and produce this component, we have considered various different aspects and we have found solutions able to ensure aesthetics and functionality. As regards aesthetics we focused on avoiding the formation of air entrapments in the die cast to obtain a surface suitable for powder painting. To obtain this kind of surface quality we used simulation software and the vacuum valve: these solutions permitted us to reduce painting scrap from 30% to about 0%. Concerning the functionality, instead, we have developed in collaboration with the costumer a re-design activity of the internal part of the component, aimed at reaching thin wall thickness that would maintain the properties of the product unchanged. Thin wall thickness, in windows and doors opening system, are important because the component has in its inside the fixing and the sliding system of opening mechanism and the reduction of thickness improves its functionality. The benefits provided by the reduction of thickness are considerable and concern less quantity of raw material and cycle time reduction. However, the production of the component does not confine itself to casting process. Indeed we have designed and realized an automation for the threading of 6 M5 holes. The threading phase is immediately after casting stage: the product passes through a vibrating device and after on a rotating table with three threading stations. The implementation of this automatic threading system has resulted in a considerable reduction of timing of the secondary processes.

Years of experience in die casting for windows and doors, technical skills and know how, have made it possible to produce a component characterized by specific aesthetic and functional properties and able to satisfy the costumer’s requests.

Die casting for household appliances: hinge for washing machines

In this video we show the production of the hinge for washing machine and the technical solutions adopted to guarantee the functionality of the product.

The post 5 Case Studies: watch Bruschi die casting videos appeared first on Bruschi.

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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The post How to reduce casting defects through mold design appeared first on Bruschi.

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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VA/VE Analysis History

In 1961, in his book “Techniques of Value Analysis and Engineering”, American engineer Lawrence D. Miles stated:

 “Value analysis is a problem-solving system implemented by the use of a specific set of techniques, a body of knowledge, and a group of learned skills. It is an organized creative approach whose purpose is the efficient identification of unnecessary costs, i.e. cost that provides neither quality nor use nor tool life nor appearance nor customer features.”

The term Value Analysis / Value Engineering originated in the early days of technique development and its first approach was to increase value, rather than to reduce costs. Therefore there was a need to analyze value.

Lawrence D. Miles continues:

“Value analysis approaches may assist all branches of an enterprise-engineering – manufacturing, procurement, marketing, and management – by securing better answers to their specific problems in supplying what the customer wants at lower production costs. Quite commonly, 15 to 25 per cent and often more of manufacturing costs can be made unnecessary without any reduction in customer values by the use of this problem-solving system in significant decisional areas.”

VA/VE is an extremely powerful approach with over a century of worldwide application and it can be applied to any cost generating areas with equal success.

Il VA/VE è un approccio estremamente efficace con oltre un secolo di applicazioni in tutto il mondo e può essere applicato ad ogni area che genera costi con lo stesso successo.

Value Analysis / Value Engineering Definitions

Value Analysis – VA

What is value?

Different customers will answer to that question in different ways. The value of a product can be the performance of its functions or its aesthetic beauty, when applicable and needed. As a general statement high level performances, capabilities, emotional appeal, style, all compared to cost is commonly what we consider as value.

Therefore Value = Function / Cost

Value Analysis is a standardized, multi-skilled team approach which aims at identifying the lowest cost way and ensuring the highest worth to accomplish the functions of a product, process or service. Value analysis means to assess product functions and value-to-cost ratios, and to find opportunities for costs reduction.

Value Engineering – VE

As we said above, Value Analysis is the application of several techniques to identify the functions of a product (or service) and provide them at the lowest cost.

Value Engineering refers instead to the design stage. This approach is generally used for new products, therefore the same principles and techniques to pre-manufacturing stages such as concept development, design and prototyping are applied.

To sum up, VA / VE is an orderly and systemic method to increase the value of an item, which can be a product, system, process, procedure, plan, machine, equipment , tool, service or working method. Function analysis is part of VA as its purpose is to identify product functions compared to cost and price; design and construction assessment is done through VE with the goal of  eliminating elements which are not contributing to function.

Product’s function should not be conceived solely as its application and practical uses: it can also include aesthetic factors, or the union of the two following dictates of functional beauty philosophy: this theory is based on the coexistence of aesthetics and performance. What matters the most in drafting a VA / VE is that the function is clearly defined, so that it can be analyzed in detail and sub-segmented to make the analysis easier.

If you are interested in functional beauty, Bruschi is going to give a lecture on the topic: click here to learn more.

In VA/VE the function of a product or service, defined by customers to meet their requirements, is identified, the monetary value for that function is established, the specified performance and requested reliability provided at the lowest Iife-cycle cost.

Following a VA/VE approach it is possible to increase customer satisfaction and add value to the investment.

Even the best and most innovative designs can age and become uncompetitive: in these cases VA/VE can support both customers and suppliers in finding and optimizing any value mismatches in products, components, processes, projects or low performing functions.

A correct segregation between necessary and unnecessary functions of products leads to a creative development of alternative ways of accomplishing them – as requested by customers – at lower cost.

VA/VE enables a company to highlight areas that need to be analyzed and improved, with a standardized method which generates ideas and alternatives, considerably increasing the value of goods and services.

A project completed with VA/VE technology is more successful and efficient than a project developed without that approach, because goals and requirements are pursued in a customer centric way. VA/VE is almost unlimited in identifying area of potential savings, as it can be used to reach quality, improve efficiency and reduce risks, in a cost saving way.

VA/VE Approach & Main Steps

According to the principles of “Techniques of Value Analysis Engineering” there are different phases of VA/VE:

• Exhaustive accumulation of information and identification and improvement of assumptions.

• Penetrating analysis. What senses of direction does this informative provide us with? What specific problems will, when solved, bring important cost benefits?

• Creative mental activity, in which all judgement is temporarily deferred to form the roots of a variety of different solutions to each of the specific problems developed in the preceding analysis.

• Judgment-type mental activity, in which what results from creative thought is searched for ideas roots to minimize disadvantages and maximize advantages sufficiently to meet the need for cost and/or operation improvement.

During the information phase, the project and its requirements are analyzed, and then the function analysis studies the possible room for improvement. In the creative stage ideas to increase performances are developed: from the resulting list of ideas only a short set is evaluated in order to find the ones with best potential to reach the goal. The following step is development of alternatives and their presentation to decision makers and, eventually, implementation.

VA/VE tools are extremely powerful and fundamental to reach objectives such as decreasing costs, improving quality and shortening time-to-market.

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The connection between the injection system and the shot entry is composed of two main elements: the feed and the runner. Their structure and size have a crucial impact on the casting flow, since different shape can bring about different results and help in reducing the risk of defects in the die casted product.

Runner positioning

To define the ideal position of the runner it is necessary to keep in mind that molten metal should cover the shortest distance possible to avoid premature cooling. Because of this, it is usually suggested to direct the flow towards the smallest side of the cavity, or to take advantage of ribs and branches to ease cavity filling. When dealing with more than one shot entry, it is important that flows are not convergent, since that would cause an energy loss and the formation of turbulences and air trappings: therefore, it is best to design the runner to obtain parallel or divergent flows.

Runners position it is also crucial to keep under control the distribution of shrinkage porosity. It is impossible to avoid porosity, but it is possible to manage it. In fact, in order to obtain a disperse and uniform porosity the shot entry should be placed in correspondence to the thinner parts of the casting, while in order to obtain a reduction of the porosity in a massive zone the shot should be placed next to the thicker parts of the casting.

Moreover, the flow should be directed towards those zone with high quality requirements: to obtain a high surface quality it is needed that the cast should be as direct as possible. These precautions lead to a better control of shrinkage porosity and thus to a casting process optimization.

Design and dimension of runners

Another important element to consider is the shape of the runners. Normally the most used shape is trapezium, but for some high tolerance alloys, such as Zamak, runners with circular cross-sections can be used: this reduces energy dissipation, thus preserving flow’s temperature.

During the designing phase, the ratio between the runner’s section and the shot entry should be kept in mind, but there is no universal rule: the choice depends on the wanted result. Smaller runners allow for a saving of both material and energy, but require more power from the injection system and are more subjected to premature solidification. On the other hand, larger runners require more material and energy, but have higher hydraulic efficiency and increase the thermic value of the mold. Therefore, they require also a longer cooling time which could have a negative impact on the cycle time.

Moreover, the cross-section of the runner should be decreasing in size through their whole length, and this applies also to branches:  the entering section should be equal or larger than the exiting one. If the main branch splits to two runners with the same cross-section, the resulting runners should also be of the same size, and their sum should be equal or smaller than the main branch.

Another issue regarding the design of the runner could be the presence of sharp edges and the discontinuity of flow deviations, the most critical points in the design of the runners. They should be avoided to prevent the formation of turbulences. When working with compound dies a particular attention should be given to construction and assembly errors, because the formation of bottlenecks and bulges could damage the metal flow. This kind of mistakes can be fixed in the tool shop, allowing for a recovery of the original functionality of the mold.

Finally, it is important that the volume of the runners will let the metal flow in the cavities at the same time, and that is why their length must be constant.

To allow the casting to be evenly distributed in all the cavities, it is necessary to attach the main runner to the injector with a feed.

The feed

The feed is a junction needed to pass from the squared section of the injection channel to the thin one of the shot entry. There are many different types of feeds and each one has different advantages, but all have the same main functions: to make the passage between the channel and the entry more gradual, so as to contrast metal tendency to withdraw from walls, and to direct metal flow.

The most common models of feed are the fan feed and the double tangent feed:

• The fan feed creates a narrow flow with a higher speed in the middle. Because of this, it is more suitable for short and thick shot entries, and it is ideal for small angles;
• The double tangent feed produces a larger flow, with higher speed at the sides. Because of this, it is more fitting for long and thin shot entries and offers larger angles;

Independently form the chosen type of feed, the section should be linearly decreasing from the channel to the shot entry. This means that it is not enough to use a trapezium-based feed, but it will be necessary to curve either the base surface or the side’s surface.

Pro and Cons of a straight feed

The term “Straight feed” identifies those feeds with a straight trapezium base and curved sides. The main advantage of this kind of feed is that the opening angle is the same as the half-opening of the feed, making it easier to remove the runners, while the main disadvantage is the tendency to work with a cold shot entry. Moreover, the flow generated by this feed has a narrower leading front and thus the metal has a tendency to withdraw from the walls.

Pro and Cons of a curved feed

The curved feed is a feed characterized by straight sides and a curved base. It is ideal when it is necessary to have a stronger flow to the sides, but the opening angle is harder to calculate and it causes the formation of small parts that require removal. The flow created by this kind of feed has an higher speed in the middle and metal tends to stick to the walls.

After learning about their strengths and weaknesses, it should be clear that, just like the runners, the type of feed should be chosen depending on the wanted result, on the power of the injection machines and on other secondary conditions. By allowing a better control of the casting flow and reducing the risk of air trapping formations, the feed is a fundamental tool for casting process optimization.

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