Check out this quick Environmental Webinar to learn about the advantages of using easily recyclable materials like aluminum, magnesium, or zinc instead of plastic.
energySMART Aluminum Furnace
Chicago White Metal is always looking for ways to improve the die casting process while decreasing energy usage. Back in 2014, CWM determined that one of the best ways to accomplish both of those goals was to replace our old reverberatory furnace from the 1970s with a modern central stackmelter aluminum furnace.
CWM worked with energySMART, a Nicor Gas program, to replace our underperforming furnace with a high-efficiency one. After much deliberation, CWM chose the StrikoMelter furnace from StrikoWestofen America because it offered the lowest energy consumption of any furnace in its class.
Energy Efficiency & Improved Performance
When CWM chose the StrikoWestofen energy-efficient aluminum melting furnace, we immediately received energySMART incentives in return for reducing our carbon footprint. With the new furnace, CWM cut the amount of natural gas we used in the melting process substantially. And even though the StikoMelter came with a smaller holding capacity, the melting capacity significantly increased to 4,400 lbs. per hour instead of 1,400 lbs. per hour with the old furnace.
By acquiring the modern furnace, CWM qualified for the Nicor Gas Energy Efficiency Program, an energy-purchase rebate program funded by Nicor Gas Company. The incentives from this program enabled CWM to make the investment, which saw immediate returns.
How it works:
The new furnace came with Striko’s patented ETAmax® system, which combines preheating, heating, and melting phases efficiently in a single melting shaft. While return material and ingots are melted quickly in the lower section, the material preheats in the shaft area above it.
The molten metal is then transferred to a holding bath, reducing waste and maintaining preset holding temperature. This simple but effective recuperative concept resulted in significant fuel consumption savings and a dramatic reduction in metal loss due to oxidation or dross. Other benefits of having a modern, energy-efficient furnace include:
- Easy to load: The furnace’s shaft is more expansive and can easily accept returns of up to 2.5m². Extra-large charging bins also mean there’s no need to “cut to fit,” saving precious time, resources, and money.
- Less energy wasted: Shortened metal melting, reduced natural gas consumption, and an improved material yield to increase efficiency.
- Cleaner metal: The design of the furnace limits the amount of dross and oxide production resulting in cleaner metal and less waste.
Looking back almost seven years to the date, we can say that it was well worth the investment when it comes to energy savings and improving CWM’s overall product. When asked about the furnace, Jim Reitenbach, Production Manager at CWM, said, “This was one of the best equipment investments CWM has ever made.”
Automakers are increasingly turning to die casting due to its combination of excellent mechanical and physical properties at an attractive cost. In addition to weight reduction, high-pressure die casting is also environmentally friendly. Plus, die casting offers built-in EMI/RFI shielding with high thermal conductivity, which is ideal for automotive electronic components.
Take a deep dive with CWM’s Jody Scollard in our latest Webinar! In it, you’ll find out which automotive electronic components make sense for die casting based on CWM-specific case studies. You’ll also learn about CWM’s history, our value-added operations, and whether or not die casting makes sense for your next project.
The key to a successful die casting is a good tool design, so it is vital that both the die caster and the customer are well-versed in die casting capabilities and how they fit with project requirements.
A die casting die is a custom-engineered, multi-part piece of equipment made from high quality, heat-treated steel. The tool is composed of two halves – a cover die (which is stationary) and the ejector die (which the die casting machine moves to meet the cover die). As soon as the two halves meet, the molten metal is injected into the tool, where it is held under pressure until it solidifies. After solidification, the metal is ejected, creating a nearly net shaped part within seconds.
Before a die is built, the customer first presents a concept or existing part to a die caster. A die cast engineer will assess the project from design to end product and work with the customer to optimize the part design for die casting. An initial discussion with the die caster may include topics such as: functional and cosmetic requirements, tolerances, annual and lifetime volume, alloy choice, mating parts, project timing, optimizing wall thickness, adding ribs, draft, and radius, etc. Download a checklist of common considerations from CWM’s Die Cast Design Center (DC²): NADCA Tooling Checklists for Die Casting Dies (2015).
Types of Die Casting Dies
A fully-featured, custom production die is a significant investment, so a prototype die is often used to make a small number of castings to test the part in several different scenarios (with the end product, dimensional accuracy, etc.). Prototyping strategies include 3D printed parts, machined hogouts, or gravity castings, but these involve tradeoffs on the design, tolerances, and properties. A high pressure die casting prototype die is the best approach if you want the same properties, alloy, geometry, and process that will be in place for production.
Prototype die casting dies can be produced in shorter lead times and at less cost because they can utilize standardized components (such as an existing die base and other components), and pre-hardened, uncoated tool steels. They also require less engineering and may employ less efficient cooling or ejection techniques compared to other production methods. The tool will not last as long and the die will not run as efficiently as a typical production die, but this is a non-issue when you only need a small quantity of parts (1,000 or less). Design changes can be made faster and at less cost with a prototype die than would be the case on a custom, hardened/coated steel production die. Parts made from a prototype die are generally hand cleaned of flash, avoiding the lead time and cost of a trim die.
Production dies are used when all designs are finalized, approved, and the program is ready to “launch” into an actual run. These dies can have single or multiple cavities and the option of slides, depending on the design. Read more about slides below, under “Casting Features and Die Considerations”.
Trim dies: In addition to the production die cast die, CWM employs trim dies for high volume production. The trim die “trims” off the runner, overflows, and flash from the part, immediately after it is cast. Some trim dies only require an open/close function, and others need multiple stations, cam, or hydraulically-operated motions to successfully remove all of the flash. Occasionally, part geometry precludes the ability to completely remove flash with a trim die. In that case, custom trimming devices, mechanical or hand de-flashing strategies will be employed.
A unit die is a special type of production die. A common die-caster owned unit holder keeps the customer-owned cavity block or unit die with cavity insert intact. Single and double unit holders are common and come in a variety of sizes. Typical sizes of the cavity blocks that they hold are 8”x10”; 10”x12”; 12”x15”; or 15”x18”. Since unit dies employ generic components, they are often used for smaller, less complex parts with lower volume. Larger, multiple slide, complex geometry, and higher volume parts are generally better served with a complete custom die that is engineered specifically for that part and allows for maximum efficiency and control.
Die Components and Terms
Some of the more common die components and terms include cavities (or cavity inserts), parting lines, cores or core pins, slides or slide cores, ejector plates and ejector pins. A brief description of each follows:
Cavity Blocks or Cavity Inserts
These are the portions of the die casting die into which the part geometry is formed. There is the ejector cavity (sometimes called the core cavity) and the cover cavity. The cavity blocks are made of premium grade tool steel and are normally heat-treated to a very high hardness, then coated for lubricity and long life. Water cooling lines pass through the cavity blocks as do the ejector pins that are used to push the part off of the die. The cavity blocks are where most of the cost comes from, as generally this is where most of the custom design, engineering, and detailed machining is done.
When the two die halves close, metal is injected into the cavity blocks and cooled in order to create the part. There is a line that forms on the part where the cover half and the ejector half meet called the “parting line.”
More information on the parting line can be found in the following blog, “Read Between the Lines: Parting Line Placement in Metal Die Casting Design”.
Cores or Core Pins
A “core” is the separate and replaceable part of the die that forms an internal feature of the casting. A core can be any shape, though circular is the most common (usually referred to as a “core pin”). A core may be fixed to the die cavity or to a slide, actuated through the mechanical opening/closing of the die, or by hydraulic cylinder or other means.
Slides or Slide Cores
A slide (or slide core) is the portion of the die that forms a feature of the casting, that cannot be made with the normal opening and closing of the die, but is required to move at some angle relative to the parting line (with the most common orientation being parallel to the parting line). The “slide” is the general term for the entire moving section, but a slide consists of multiple pieces (such as the slide front or tip, the wear plates, gibs, locks, carriers, etc.) and is generally water cooled. Slide core is the general term used for either a simple core pin that is moving in and out on some angle to the parting line or a pin within the larger slide mechanism (for example: a replaceable “slide pin” can be mounted in the slide to form a specific hole, where the rest of the slide face forms the outside surface of the part).
Angle pins and hydraulic cylinders are the most common motion sources that activate slides. Both sources of motion need to be designed into the tooling to avoid interference with part ejection/removal.
Angle pins are the more economical option because it is activated by the opening and closing of the die, and does not require hydraulics or switches, but is limited to shorter movements. The hydraulic method offers a wider range of options including pull direction, timing of the pulling, and length of pull. A die cast engineer can recommend the appropriate option based on the project.
Ejector Plates and Ejector Pins
Once a part has been cast and cooled, the halves open up and reveal the cast part. The part typically shrinks in size as it cools, remaining in the ejector half of the die. Ejector pins that are driven by a moving ejector plate are activated and used to push the casting off the die.
The ejector pin leaves a slight imprint on the casting, which indicates the placement of the pin should be in a non-cosmetic surface area of the casting that is not critical to the design (overflow, boss, bottom of a deep pocket, bottom of a rib, etc.). Ultimately, the number of pins, pin locations, and pin sizes are dependent on the configuration and size of the part, along with other requirements.
Contact a CWM Die Cast Engineer.
Our engineering team is prepared to answer any questions you may have about the die casting process, as it pertains to your project. Feel free to contact us directly at 630-595-4424, or e-mail us at email@example.com in order to get in touch with the appropriate specialist.
Robots have many applications; they can manufacture cars, electronics, medical devices, and they can even be used to automate some aspects of Chicago White Metal’s die casting process. Robots are here to stay, and one of the main reasons for that is the fact that they can perform high-risk tasks that take humans out of potential harm. A good example of this is the act of extracting a hot casting from a steel die casting mold. They can also perform repetitive pick-and-place tasks, enhancing productivity, and minimizing room for error.
Last year, Chicago White Metal integrated several more robotic work cells throughout the plant to assist with die casting, CNC machining, and other operations. CWM employs both traditional and collaborative robots. The CWM team recognized the advances in robotics technology and used it to provide the best possible products and services to its growing list of clients.
Chicago White Metal has employed traditional robots for many years. The advantage of a traditional robot is that they are very robust and can handle a heavier payload. They can also work more quickly and precisely in harsh environments than collaborative robots. They are ideal for high volume processes. Chicago White Metal uses traditional robots in larger die casting machine cells and in high volume dedicated machining cells where additional processes, such as leak testing and visual inspection are incorporated.
Chicago White Metal’s R&D team researched the advantages of collaborative robots (also known as co-bots), and since most of CWM’s parts do not require a large payload, collaborative robots make sense for many of our processes. These robots are less expensive and easier to program than traditional robots. They can be deployed alongside humans to drive efficiency. They can also work autonomously in environments that may be less safe or less hospitable than other areas (e.g., CNC machine areas).
CWM employs co-bots to load/unload CNC machines, perform light duty filing, and other processing, along with air gaging and other inspection.
Robotics Manufacturing & Die Casting
Not only does CWM use robots to manufacture cast and machined components, several of the components CWM manufactures are themselves components to a robot. CWM’s die castings are used as internal or external structural components. The exterior housings protect the sensitive electronics within a robot and provide a beautiful cosmetic appearance. Internal components might hold together different CPUs, motherboards, and other vital electronics, as well as gearing and other mechanical controls. Die cast components can be used as sensors, actuators, power supply units encasements, control systems, wheels, and end effectors (this can range from universal grippers to mimic human hand functionality, or interchangeable tools such as drills).
CWM produces components in Al, Mg, and Zn.
Robotics require components with excellent physical and mechanical properties. Some of the components are heavily loaded and need maximum strength and stiffness. Others are at the end of the arm where a lighter weight alloy, such as aluminum or magnesium, can improve the robot’s capabilities. Some small parts can be cast in high volume using zinc, which is excellent for lower tooling costs, and longer tool life. Chicago White Metal Casting is unique in that we can cast components of all three alloys within our plant. In general, the following is true:
- Using a magnesium alloy would create a lighter weight part with stiffness equal to aluminum.
- Using a zinc alloy would work best for thin wall or tight tolerance parts or small parts with high volume.
- Using an aluminum alloy provides an excellent overall value when weight, tolerances, corrosion resistance, and finishing options are considered.
Robotics Case Studies
Collaborative Robot Components
Processes: Initial Processes: Die cast, de-gated, polished, vibratory deburred, acid-etched, CNC machined, Trivalent Chromated (TCP), highly cosmetic powder coated in the customer’s proprietary red color.
The CWM Difference: Chicago White Metal cast eight parts on the robot (seven are visible, one is in the interior), working closely with the customer’s engineering team throughout the prototyping and the entire design-for-manufacturing (DFM) process to create the family of parts. Certain parts required a more complex tooling design due to the odd shape of the parts, such as one of the parts requiring the part to be sawed off at the gate to prevent breakout, and other trimming defects. The result was only one minimal area of the die casting requiring hand cleaning.
Three Spoke Wheel Hub for Automated Warehouse Robot
Processes: Die cast, de-gated, vibratory deburred, machined
The CWM Difference: Chicago White Metal cast a custom aluminum, three-spoked wheel hub which would allow the robot to move to various areas quickly. CWM worked with the customer’s engineering team on design, making the DFM process relatively smooth and straightforward when moving into production.
Click here to view the .PDF: Industry Spotlight – Robotics
Chicago White Metal is extremely proactive in the research of advanced technology and innovation, and their implementation into the die casting process. These efforts are put forth by the company in order to improve and enhance quality, efficiency, measurability, and overall cost savings for existing and future projects.
CWM leadership encourages an environment of cultivating innovative ideas where process improvement is concerned, granting members of the team an opportunity to take an active role in examining and suggesting alternatives to either modify or drastically change current techniques. The team is excited to implement these innovations into the workflow in both traditional and non-traditional ways.
New Idra Die Casting Machine (2019)
A new Idra Die Casting machine was purchased last year. Extensive planning by the Chicago White Metal team was thoughtfully executed, with full implementation planned for the beginning of Q4 in 2020. This new die casting machine has a 900-ton capacity, which gives Chicago White Metal the opportunity to accommodate substantially larger applications. Although the machine is being installed into the magnesium department, it will initially be used to cast aluminum parts.
The automobile industry is the largest market for high pressure die casting components. The demand for electric vehicles has been rapidly growing thanks in large part to changes in emission norms worldwide and a shift in consumer preferences. These changes have pushed automakers to replace heavier components with lightweight, environmentally-friendly options made from alloys like Magnesium or Aluminum.
Reducing weight is significant for hybrid electric, plug-in hybrid electric, and electric vehicles, where battery efficiency is critical. Aluminum and Magnesium die cast components can dramatically reduce vehicle weight, which improves overall vehicle performance, increases fuel or battery efficiency, and extends driving range. Chicago White Metal is helping to fuel this evolution by casting complex shapes at near-net shape in high volumes and within tight tolerances using lightweight alloys.
Automakers who make electric or hybrid cars are increasingly turning to Aluminum due to its combination of excellent mechanical and physical properties at an attractive cost. In addition to weight reduction, high-pressure die cast aluminum alloys have added dimensional accuracy and stability – not to mention the added strength and high-speed production capabilities.
Lighter Weight and Good Malleability
While not as light as Magnesium, Aluminum is still 1/3 the weight of steel, which goes a long way when it comes to reducing the weight of a vehicle. That’s why Aluminum die castings are replacing steel in structural and cosmetic body parts (i.e., vehicle bodies, hoods, doors, bumpers, crash boxes) in modern vehicles.
Malleability is also a significant factor as to why automakers are turning to Aluminum. It can be easily rolled into a sheet, formed as a stamping or extrusion, or welded. And it can be a high-pressure die cast, which allows for the rapid conversion of molten metal to a net shape 3-dimensional complex shape.
Aluminum is excellent for automotive applications when there’s a need for high visibility and structural integrity, such as in A-B-C pillars. While Aluminum is lighter than steel, it absorbs more energy, providing an extra layer of safety for the vehicle as well. Utilizing aluminum components can help reduce vehicle weight by as much as 40% without compromising the safety of the vehicle.
Magnesium was initially used in race cars in the 1920s to gain a competitive edge because of how lightweight it is. Now automakers use this lightweight alloy for applications like mirror housings, steering columns, driver’s airbag casings, seat frames, and dash encasings.
The auto industry’s quest for greater battery and fuel efficiency, along with demand for improved performance, has driven an increased interest in high-pressure die cast Magnesium alloys. These alloys include AZ91D with its excellent combination of mechanical properties and the highest strength to weight ratio of any structural metal.
Mg is 75% Lighter than Steel, 33% Lighter than Aluminum
Magnesium provides a drastic weight difference that supports its use as a durable metal alternative to steel and plastic. Unlike plastic, Magnesium’s properties do not degrade with temperature and UV light, and Magnesium is 100% recyclable. With its superior dampening capacity and low-mass inertia, Magnesium is well suited for parts designed for frequent and sudden changes in motion direction – making it ideal for car part design. Many part designers also prefer working with Magnesium because they can produce parts that are more complex than steel, without sacrificing strength.
Although Zinc products are heavier than their Aluminum and Magnesium-based counterparts, they do have the highest yield strength of all three alloys. Zinc can also be cast thinner than any other metal and can hold extremely tight tolerance requirements. While Zinc might not be the best option when it comes to the light-weighting strategy, several Zinc-made applications are ideal for automotive design and structure.
The CWM Difference
Chicago White Metal Casting can cast all three families of alloys; Aluminum, Magnesium, and Zinc. Our technical expertise, combined with full-service capabilities and engineer design services, can provide automakers or part designers with die casting solutions that meet the challenges of their hybrid electric, plug-in hybrid electric, and electric vehicle part design.
Contact us today by filling out the form on this page or call +1 630-595-4424 to speak with a member of our team.
Congratulations to the Chicago White Metal Casting and Aerosonic Engineering teams for winning yet another North American Die Casting Association (NADCA) award for design excellence in 2019!
The NADCA Award for Design Excellence is a prestigious die cast engineering award which enlists a committee chosen by NADCA to review hundreds of submissions from various die casters and then carefully select the best of the best in the industry.
Chicago White Metal and Aerosonic worked on an Aircraft Altimeter housing, which is a die cast housing that attaches to another cup-shaped housing, protecting the gears and mechanics of the altimeter. The “serrated” edge of the circular part of the component works in conjunction with the gears, with all parts responding to the barometric pressure of the atmosphere.
The design came to Chicago White Metal as a concept – this was a new part which was collaboratively designed by both engineering teams.
The high pressure die casting process was used to create a net shape product with the gears included in the as-cast design. This process allowed Chicago White Metal to produce parts at a rate of 130 casting per hour, which is faster and therefore less costly than any other process that could have been chosen for this project.
Chicago White Metal remains very proactive in the research and implementation of advanced technology into the die casting process, added value and finishing operations. CWM leadership encourages an environment where team members can examine and suggest alternatives to current techniques in order to improve and enhance quality, efficiency and measurability. This ultimately leads to an overall efficiency for existing and future projects. The team is always excited at the prospect of taking an original idea and watching it grow into a reality.
One idea that came to life in 2018 is the implementation of robotics and automation technology in the CNC department. There are currently 6 active robot implementations: 4 Universal Co-bots and 2 Fanuc Robot Cells. These robots were commissioned quickly in the past 12 months, calling for the promotion of Daniel Lechuga to Automation Specialist in order to keep up with the equipment maintenance and wiring.
The Fanuc Robot Cells are dedicated to several tasks such as facilitating added value and finishing operation checks, leak testing several parts at a time, and tending to CNC machinery. This allows team members to tend to other machines and focus on performing more critical tasks. The Fanuc robots were the first to be integrated into the CNC department and can be seen on the shop floor with cages around them. They are currently facilitating parts for an archery riser and an automotive ECU housing.
The Universal Co-bots are collaborative robots that work safely alongside humans. The robots themselves have sensors that detect when someone is near or approaching the robot, triggering the mechanism which slows down and stops the machine. Chicago White Metal implemented four co-bots, which are currently handling parts for two different models of portable oxygen concentrators, a crossbow riser, an electronic housing, and a medical device handle.
Chicago White Metal collaborated with a crossbow maker to get a bullseye win for a riser part! Eric Treiber accepted the award on behalf of CWM for the 2018 North American Die Casting Association (NADCA) Excellence in Design Award, winning the “Aluminum 1 to 10 lbs.” category.
The crossbow manufacturing company was focused primarily on two things: safety and quality. The riser is a safety-critical part that is the “heart” of the crossbow, so the strength of the part was vital to the success of the end product. The crossbow was designed to be narrow and made for pinpoint accuracy. It is one of the lightest crossbows on the market, weighing in at only 6.3 lbs.
This was the manufacturer’s very first die cast part, which enabled them to convert the “machined from extrusion” approach that they typically do for crossbow risers to a high pressure die casting process. The design was modified to incorporate as-cast pockets in order to eliminate additional assembly. Ultimately, the cost was reduced by 1/3 simply by converting to the high-pressure die casting process.
“The Aluminum 1 to 10 lbs category is typically a more competitive category. That makes the win even more of an honor,” Marketing Coordinator Roseann Rimocal says.
CWM’s internal marketing showcase will display the parts, the end product, and the award for a couple weeks. The plaque will then be transferred to its new home in the Research & Development wing, along with a number of other design awards Chicago White Metal has taken home over the course of many years.