Equipment Highlight: Investment in Energy-Efficient Furnace Pays Off

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.”

Inside CWM: Winter 2020 – Vol. 16 No. 3

In the Winter 2020 edition of Inside CWM you can learn about:

  • A look back over the last 60+ years in the Die Cast industry by CWM Chairman, Walter Treiber
  • Recognition of CWM’s Outstanding Performers of the Month & Year
  • CWM Pet Superlatives
  • CWM employee service awards from 2020
  • “Employee Bragging Rights” – an update on some CWM’ers and their families
  • “CWM Gives Back” – Toys-for-Tots and CWM
  • CWM does #TBT
  • CWM Word search
  • Health Fair 2020

Click here to read Inside CWM: Winter 2020

Die Cast Prototyping – Benefits and Types

In addition to Chicago White Metal’s advanced part design and DFM assistance, CWM offers various prototyping options to bridge the gap between design and production tooled high pressure die casting. CWM’s prototyping process offerings include:

  • 3D printing (resin)
  • CNC machining
  • Gravity casting via the sand, rubber-plaster mold, or investment casting processes
  • Prototype die casting

Reasons to Use Prototyping

Prototyping offers the opportunity for design verification – a chance to identify design flaws before committing to production level tooling. And while it is not necessary to prototype every design, sometimes doing so saves time and money. Generally, the further along in the developmental cycle a design error is discovered, the greater its cost.

When tooling needs to be scrapped or reworked, the impact is evident in terms of costs and delays. However, reworking a die cast die also adds cost in decreased die life and potential negative quality impacts. Using today’s prototyping technologies can help manufacturers avoid these stressful situations.

There are several prototype methods from which to choose. Selecting the best option for your application comes down to tradeoffs. For example, some options, such as 3D printing of a plastic model or machining from billet, are relatively inexpensive for low quantities because no tooling is required. But the mechanical properties of a plastic or machined part are quite different than the properties of a die casting. Assessing what prototype process is best for your needs requires consideration of quantity, timing, mechanical properties, dimensional accuracy, surface finish, wall thickness, cosmetic requirements, etc. A good high pressure die casting supplier should be able to guide you toward the appropriate option.

Prototype Methods

(click image to enlarge)

3D Printed Prototypes

3D printing enables the production of rapid prototypes in many types of plastic, directly from STL design files. Fused Deposit Modeling (FDM) is one form of 3D printing that builds parts layer-by-layer, from resin, directly from 3D computer data. An FDM machine can produce geometrically complex shapes to tolerances of +0.005 in (+.127 mm).

At CWM, we use FDM prototypes for every new die casting project to expedite production and shorten total lead-times. These prototypes give our suppliers and our engineering, production, and quality teams a chance to see parts in advance, ensuring that the part and die cast design is robust. They are also used to develop fixtures, tools, racks, etc., for inspection, machining, assembly, painting, plating, etc. FDM models ensure that the part design results in an efficient manufacturing process and helps reduce overall project lead-time by allowing simultaneous construction of downstream process tooling.

Machined Prototypes

Machined prototypes are widely used because they offer product designers a good combination of physical and mechanical properties, generally short lead-time, and zero to minimal tooling investment. Prototype parts can be machined from billet via CNC machining by working directly from customer CAD files. After transferring a machined prototype to a CAM program interfacing with CNC workstations, we can produce these prototypes in just a couple of days.

CNC machining can produce parts to almost identical part weights and hold exceptional tolerances such that validation of form and fit is assured; we can then perform many functional tests. However, properties are not identical to die castings and parting line conditions, and sometimes the draft required in a die casting is not represented in a machined prototype.

Gravity Cast Prototypes

Sand casting, investment casting, and rubber plaster-mold castings are some of the gravity cast processes used for prototyping. Because of longer solidification times and alloys specific to those processes, various heat treatments are used to approximate a high pressure die casting alloy’s properties.

Compared to high-pressure die casting, sand cast prototypes require thicker walls and larger tolerances, so features that might be “as-cast” in a die casting may need to be machined in a sand casting. These processes utilize lower-cost tooling than high-pressure die casting but have much higher piece prices. These design, property, and cost tradeoffs have to be considered when evaluating the best prototype approach.

Die Cast Prototypes

For those who want a prototype with the same properties, alloy, and geometry designated for production and larger quantities, a high pressure die cast prototype is often the best approach. Prototype die casting dies can be produced in shorter lead-times and at less cost because they utilize standardized components – like an existing die base – and pre-hardened, uncoated tool steels that do not require post machining heat treatment.

The tool will not run as efficiently as a typical production die, and flash will need to be removed by hand instead of with a production trim die, but part costs will be much less than machined or gravity cast prototypes. A prototype tool can provide 1000 or more high-quality pieces that can be used for prototype or even initial production.  

The CWM Difference

Chicago White Metal offers all of these prototype options that you read about today. If you are interested in more information about prototyping or if you would like to speak with one of our team members, email sales@cwmtl.com or call (630) 595-4424.

Die Cast Tooling 101

Die Cast Tooling 101

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

Prototyping Dies

CWM Prototype Die Casts

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

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.

Unit Dies

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.

Parting Lines

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 sales@cwmtl.com in order to get in touch with the appropriate specialist.

CWM Adds New Idra Die Casting Machine, Full Implementation Planned for Q4 of 2020

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. 

CWM Update: New Website Design and Subscription-Free DC2

Chicago White Metal Homepage

We are proud to announce the re-launch of our company website, www.cwmdiecast.com! In an effort to create a better, more user-friendly experience for our visitors, we made some significant upgrades. The website is now fully responsive and features a much more modern look and feel to better showcase our products and educational content.

Now that the website is responsive, it’s compatible with any device, i.e. desktops, laptops, tablets, and all mobile devices. We always strive to stay ahead of the curve and offer not only the most innovative die cast solutions to our customers, but a great user experience online for anyone who visits our website too.

Last but not least, we want to provide you with easily accessible, valuable resources so you can learn more about our products and company. That’s why we removed the need to subscribe to our Die Cast Design Center and added educational materials from the DC2 to their corresponding pages (see the bottom of the Die Casting page for example). You can now view CWM’s Design Guides, Case Studies, Webinars, and much more at the click of a button! The Design Center and Blog will be updated consistently, so be sure to check back regularly for the latest in CWM news!

Feel free to browse the new design and contact us by filling out one of the forms throughout the website or by calling (630) 595-4424.

CWM and Aerosonic Take Flight with NADCA Award

Eric Treiber, CWM President and CEO, accepts NADCA Award

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!

NADCA Die Casting Submission

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.

Aircraft Altimeter housing

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 Invests in Robotics and Automation

FANUC CNC Robot die casting
FANUC CNC Robot die casting

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.

CWM Takes Recycling to New Levels

CWM Recycles AL, ZN, and MG
CWM Recycles

As a further refinement to our environmentally responsible culture, CWM has launched a new Recycling Initiative to help take our focus on environmentally friendly manufacturing and overall stewardship to a new level. One of our key objectives is to encourage similar programs with our suppliers, neighbors, and customers.

CWM Recycles Magnesium Scrap

CWM’s recycled materials, such as plastic, steel, cardboard, electronics, etc. are typically sent to a certified recycling vendor. CWM, however, as part of our new Recycling Initiative, is taking the extraordinary step of requiring our recycling vendors to provide a full manifest/certification and/or a detailed process map that illustrates exactly how recyclables are processed. We are finding that not everything is being recycled as we thought. Plans are underway to deal with this issue transparently, and to determine what improvements can be made.

We are also asking our suppliers to provide the recycled content of products sold to CWM. As an example, we asked our food/beverage provider to see if plastic stirrers, lids, utensils, and containers can be replaced with something more environmentally friendly. That effort resulted in eliminating plastic soda bottles (cans and cartons only), changing coffee stirrers from plastic to wood, and replacing foam coffee cups with biodegradable ones.

CWM takes environmental stewardship seriously. We’ve been a leader in our industry in this regard, having had recycling programs in place for more than 30 years. And though we can’t completely overhaul the entire recycling industry on our own, our team will do what we can to initiate changes. We are confident that this renewed Recycling Initiative will have a very positive impact on CWM and our community of suppliers, customers, and neighbors. Stay tuned for more information in the coming months!