High Density Metals Applications

CMW tungsten-based metals solve challenges across many different high density metals applications from die cast tooling to high-performance heat sinks for electronics packaging. Please review some of the most popular applications below:

Click on the links below to learn more about our applications.

Aircraft Counterbalances, Weights and Ballasts
Medical and Industrial Radiation Shielding
Die Cast Tooling
HIGH RELIABILITY Heat Sinks
Plastic Injection Molding / Extrusion Dies / Hot Runner Systems
HEAVY METAL Boring Bars & Grinding Quills
Rotating Inertia Members
Ordnance
Bucking Bars
Chassis Race Weights
EDM Electrodes

Aircraft Counterbalances, Weights and Ballasts:

CMW® 1000 and CMW® 2000 materials have long been specified for control surface aircraft counterbalances in both military and commercial aircraft. Large mass in a small space is required to balance and stabilize control surfaces which must operate at high speeds. A savings in total aircraft weight can result from the use of these materials because small, high density aircraft counterbalances require less surrounding material to enclose it. In addition, the high strength of the material permits the part to be located for the most efficient weight effect and therefore uses the minimum amount of material.

The CMW® 3000 series may be used when the application requires more ductility.

Medical and Industrial Radiation Shielding

Gamma radiation and X-rays are absorbed most effectively by high-density metals. CMW high-density materials are a family of tungsten-based materials with densities 50% greater than that of lead. The high-density, good mechanical strength and excellent machinability of CMW materials make them ideal for shielding applications. A variety of sizes and shapes are available.

Using CMW high density metals for your radiation shielding solutions will provide:

Thinner sections required vs. other materials
Non-toxic, environmentally friendly
Stronger structurally
Machines easily (similar to gray cast iron)
Stable at 1000° C
Does not require licensing
Good thermal conductivity
Low coefficient of thermal expansion

Click here to view a chart that details the gamma absorption characteristics of CMW® 1000 and other common shielding materials.

Medical

CMW® 1000 is often specified for syringe shields in place of lead. Because it is higher density, less material thickness is required to make the syringe shield, thus it is less bulky and therefore, easier for the technician or physician to transport and use.

Industrial
- CMW® 1000 is often used in industrial applications including collimators, isotope shipping containers, gamma cameras, cobalt teletherapy machines, geological equipment, nuclear reactors, satellites and more. CMW provides raw material or finish machined parts to your drawing and specifications.

Die Cast Tooling

Thermal fatigue is the #1 reason of tool end of life. Higher tensile strength and better thermal conductivity goes a long way to minimize thermal fatigue and thereby improve tool life. Anviloy® 1150 has a higher tensile strength at elevated temperatures than tool steel and has 5 times better thermal conductivity than tool steel. You can enjoy up to 10 times the die life with Anviloy® 1150.

Anviloy® 1150 should be considered a complimentary product to tool steel, not a replacement. Tool steel does a good job in many die casting applications, but its life decreases as casting temperatures increase. Anviloy® 1150 is perfect for these high temperature applications. It's typically used for core pins and rods which create the thru-holes, cavities, and indentations inside the castings.

Use Anviloy® Weld Rod for welding Anviloy® 1150 to other die materials, repairing cracked dies, and building up die erosion areas, thus extending the life of your investment.

With Anviloy® 1150, you will enjoy:

Decreased Costs: A longer die life means fewer replacement dies and less downtime changing them.
Improved Quality: An improved surface finish on the part means fewer rejects, less secondary machining, and also lower costs due to less scrap.
Increased Production: The potential to reduce cycle times due to the faster cooling rate provided by Anviloy® 1150.

Here's how it works:

Minimizes Thermal Fatigue. Thermal fatigue (or heat checking) is the major reason for end of tool life. Heat checking is a thermo-mechanical fatigue process caused by thermal cycling, which creates cyclic stresses and strains in the cavity surface. Typical damage is the gradual growth of a network of cracks. Anviloy® 1150 has low thermal expansion and high thermal conductivity which are fundamental for heat checking resistance. The low thermal expansion allows for low thermal stress. A high thermal conductivity reduces the thermal gradients and thereby the thermal stress by cooling the casting faster.
Low Erosion. Erosion of the die is a problem. Anviloy® 1150 provides a low erosion rate due to its chemical resistance. This occurs because molten aluminum dissolves tool steel. Aluminum does NOT dissolve Anviloy® 1150, therefore you have a longer die life. This means you don't have to change the die or core rods as often which results in less downtime. Die life can be up to 10 times longer with Anviloy® 1150.
Reduces Soldering. Soldering (or sticking) of aluminum to the tool steel die as its being ejected is also a problem. Anviloy® 1150 can be a real problem solver for soldering because its high thermal conductivity allow increased cooling rates in difficult to cool areas of a die casting. When it's cooler it won't stick to the aluminum. The tool steel is still hot and may hold onto the aluminum.
Better Surface Finish. Poor surface finish can be a result of soldering (or sticking). As the tool steel heat checks and the surface of the die gets worse, soldering may occur which will cause surface finish problems with the part. This is a major issue where a functional or cosmetic finish is important.
Readily Machinable (similar to gray cast iron). It's easier to machine than heat treated tool steel. It also requires NO pre or post machine heat treatment as tool steel. You buy tool steel annealed and then you must heat treat it after you machine.
Easily Repairable. Cracked or chipped dies and core rods can be easily repaired by welding using Anviloy® Weld Rod.
Minimizes Shrinkage Porosity. Shrinkage Porosity is a void left in a solid casting due to the change in volume that takes place during the solidification of molten metal. Because Anviloy® 1150 has 5 times the Thermal Conductivity of tool steel, this higher level of thermal conductivity will pull the heat out faster (i.e. faster cooling rate) and thus reduce shrinkage porosity.

Nitriding Anviloy®

Nitriding is a heat treating process where nitrogen is diffused into the surface of a metal, most commonly steel, to case harden the surface. Anviloy® 1150 as produced has superior properties for die casting and does not require any heat treatment.

High Performance Heat Sinks for Electronics Packaging

Almost any heat sink material you specify involves a basic, unavoidable trade-off. Either you trade off high thermal conductivity for a low coefficient of thermal expansion or you sacrifice expansion for conductivity.

Either way, it does not make your job any easier. And it will not contribute to the overall reliability of your package as well as you would like.

Thermkon® high performance heat sink materials from CMW put an end to this trade-off. Because compared to the more limited heat sink materials such as copper, aluminum or Kovar®, Thermkon® offers a better matched rate of thermal expansion and a high thermal conductivity.

Its unique chemical composition is the reason. Thermkon® materials are fabricated from tungsten or molybdenum and copper in electronic grade powdered form. Tungsten or Molybdenum for strength, rigidity and low controlled coefficient of thermal expansion and copper for high thermal conductivity.

The result: A composite heat sink material that meets the increasingly complex demands of the electronics packaging industry. Without trade-offs. (Kovar® is a registered trademark of Carpenter Technology Corporation)

Benefits of Thermkon®
Benefits of Powder
Typical Uses
How it works

Benefits of Thermkon® materials include:

Hard solder, full contact brazes maximize thermal transfer
High electrical conductivity thanks to high copper content
Non-magnetic, will not interfere with system polarity
High-density tungsten-based Thermkon® materials enhance radiation shielding
Lower density Molybdenum base Thermkon® materials for weight control applications
High strength and modulus of elasticity due to high tungsten or molybdenum content. This increases the rigidity of your microsystem.
Can be supplied plated to facilitate solder attachment

Benefits of powder:

Most heat sinks are made from stamped metal. Thermkon® materials are not. It's a composite powdered metal material. That means the copper and tungsten or molybdenum in Thermkon® materials retain their own chemical characteristics instead of bonding together to form an alloy.

It is this unique chemical composition — made possible only through powder metallurgy — that endows Thermkon® materials with high thermal conductivity and low controlled rate of thermal expansion.

What's more, composite powder metals such as Thermkon® materials allow for intricacy of material design and consistency of parts over large production runs. Often Thermkon® materials will save you time and money because they are very machinable and often require less machining due to die design.

Plus, because heat is applied early in the powder metallurgy process, has no memory and will remain flat during later thermal cycling. Annealing is not necessary. Most stamped metal materials are heated later in the fabrication process and have memory… and thus lose their tolerances.

Typical Uses:

Because of exceptional performance characteristics, it is well-suited for almost any application requiring both high thermal conductivity and low thermal expansion.

Indeed, while other heat sink materials might exceed Thermkon® materials in one area or another, it is this unique balance of high conductivity and controlled expansion that makes ideal for such applications as:

Discrete flanges for NPN silicon bipolar power transistors
GaAs FET carriers
Flat Pack bases to match thermal and coefficient requirements of thick and thin film circuitry.
Machined housings for amplifiers and mixers

How does it work?

High Thermal Conductivity:

In today's advanced electronic packaging systems, heat dissipation requirements may rise as high as 10 watts… and perhaps higher in extreme and critical applications.

As you can see from the Thermal Conductivity figure below, all Thermkon® composite materials provide the high thermal conductivity needed for excellent heat dissipation. The greater the copper content in each Thermkon® grade, the higher level of heat dissipation. To assure not only a high but also a uniform level of heat dissipation across the heat sink's surface, CMW uses a special 1200° C infiltration process to fabricate Thermkon® materials. This process allows Thermkon®'s high grade copper to permeate the porous sintered tungsten or molybdenum base skeleton. This results in an even distribution of copper throughout the heat sink.

To protect your system from the thermal mismatch problems that often occur with overheating, Thermkon® composite materials maintain a controlled rate of thermal expansion as they dissipate heat, even in superheated conditions.

In turn, this even distribution of copper promotes uniform heat dissipation across the entire surface of the heat sink. This reduces thermal stress on the chip and components and helps keep your system from falling prey to overheating — the number one cause of microsystem failure.

Controlled Thermal Expansion Rate:

Any significant difference in the thermal coefficient of expansion between the heat sink and the chip — and many of the substrate materials in your package — may cause the solder joints attaching the materials, the leads, the substrates or the chips to break. And your system fails.

To help prevent this. All Thermkon® composite materials offer controlled coefficients of thermal expansion closely matching those of semiconductor materials and alumina ceramics. The more tungsten or molybdenum content each Thermkon® material has, the lower it's coefficient of thermal expansion.

Field tests show that Thermkon® materials maintain an acceptable, controlled expansion rate even in temperature extremes such as -100° C to + 500° C … where many other low thermal expansion materials experience severe problems.

Thermal Conductivity & CTE of Various Metals Chart

Recreation:

CMW high-density materials can provide such diverse solutions as giving a golf ball more drive or the tennis racket the right feel. The engineer's imagination is the only limitation!

Plastic Injection Molding, Extrusion Dies and Hot Runner Nozzles

Anviloy® 1150 and Anviloy® Weld Rod are tungsten-based high density metals that have been developed for plastic injection molding, difficult extrusions and hot runner nozzles as an alternative to P-20 tool steel and Copper Beryllium to save you time and money.

With this material as the base for your dies, molds, and hot runner nozzle tips, you will be pleasantly surprised with:

Longer mold and core life
Less production downtime
Better surface finishes on products
Fewer rejects
Lower cost per piece
Less porosity (or sink) in heavy sections
Faster cycle times

Benefits/Advantages:

Removes heat four times faster than traditional tool steel
Reduces sticking
Low erosion rate
Readily machinable (similar to gray cast iron)
Requires no pre or post machining heat treatment
Easily welded and repaired with Anviloy® Weld Rod
Environmentally Friendly (contains no Beryllium)

Here's how it works: Anviloy® 1150 is a tungsten-based material made using special high temperature powder metallurgy techniques. Anviloy® 1150 material has a low coefficient of thermal expansion, excellent thermal conductivity and good material properties at elevated temperatures. Tungsten is used as a base due to its high melting point and low coefficient of thermal expansion. Elements added to the tungsten enhance machinability, ductility and welding. The excellent thermal conductivity provides an additional benefit to increase cooling in difficult to cool areas and thus potentially increases production rates. Material properties are established during the manufacturing of Anviloy® 1150 which eliminates the problems associated with heat treatment of other tool materials.

Heavy Metal Boring Bars & Grinding Quills

NO-CHAT® and NO-CHAT® Max tungsten-based materials were developed as an alternative to tungsten-carbide heavy metal boring bars and grinding quills for better performance and longer tool life. This material is also used for Arbors, Spindles, Tool Holders and Shanks to reduce vibrations and chatter.

With this material as the base for your heavy metal boring bars, grinding quills, arbors, spindles, tool holders and shanks, you will be pleasantly surprised with:

Reduced Vibration and Chatter
Extended Tool Life
Reduction in machining and finishing costs because the material machines similar to gray cast iron
Less chipping and breakage versus tungsten-carbide

Here's how it works:
These materials have an inherently high mass and modulus of rigidity and these properties make it ideally suited as tool support material where less rigid and less massive materials will chatter or vibrate, thus the name NO-CHAT® and NO-CHAT® Max.

Actual Tests using an oscilloscope show the comparative tool vibration between No-Chat® and Steel when machining a 1% CrCu material, feed 0.008 IPR, and speed 375 FPM, cut 0.020 inches, Style C-8 Lathe Tools (using identical non-ferrous grade carbide tips).

As a result of High Thermal Conductivity (5 times that of tool steels) the material provides an additional benefit in allowing tools to run cooler, extending tool life.

Rotating Inertia Members

CMW high-density metals materials are used in inertial guidance systems, navigation devices and similar equipment. Typically, CMW® 1000, 2000, and 2925 are used for these applications. These materials possess a high elastic modulus, high strength and density, low magnetism, and good machinability. The design engineer may also select the most desirable combination of properties from the broad list of CMW Materials. In addition, Anviloy® 1150 and Elkonite® Copper Tungsten selections have solved miniaturization problems in guidance systems.

Precision machined homogeneous structural members of CMW high-density materials can provide more momentum in a limited space.

Ordnance

CMW high-density metals are often specified for military use. Their density, hardness, strength, ductility, non-magnetic and heat resistance properties make them an excellent choice for ordnance applications.

Please review our list of Materials to see which best fits your application need, or feel free to contact us directly at metals@cmwinc.com.

Bucking Bars

This is the Ultimate Bucking bar material - you will never use steel bars again! Because of the density, you can create the best shape for your space so it's just right for getting inside the ribs and spars gaps on wings, flight controls, etc. The weight and the density of the metal make for the best rivet bucking in the industry. With tungsten-based bars, just a few taps with a 3X rivet gun and a 1/4 rivet is complete. This saves possible damage to the aircraft skin and frames due to less repeat riveting and it also saves time allowing you to move on to the next rivet.

Tungsten-based bucking bars are also ergonomically better than steel. Studies show that tungsten-based bucking bars reduce the amount of vibration the user experiences and therefore reduces the chance for white finger or carpal tunnel syndrome.

CMW materials used for this application include CMW® 1000 and Anviloy® 1150.

Please review the following paper "Ergonomic Field Assessment of Bucking Bars During Riveting Tasks" written by Michael J. Jorgensen and Muthukurappan Viswanathan in the Industrial and Manufacturing Engineering Department at Wichita State University, Wichita, KS.

Reprinted with permission from Proceedings of the Human Factors and Ergonomics Society 49th Annual Meeting. Copyright 2005 by the Human Factors and Ergonomics Society. All rights reserved. HFES does not endorse individuals, products, or services mentioned in this article. Ergonomic Field Assessment Bucking Bars

How does it work?
The tungsten-based bucking bar has one or more smooth surface which is held up against the back of a rivet while it is being shot. The energy gets transferred from the source (the rivet gun) through a medium (the rivet) to the receiver (the bucking bar). The gun is on one end, and the bucking bar is on the other. The gun impacts the rivet, which sends the impulse to the bucking bar, which actually bounces off the rivet and "swings" back at it (by virtue of the person holding it firmly in place), smashing the rivet in turn. This happens many times per second - depending on air pressure and trigger operation. The primary skill required when bucking rivets is to hold the bucking bar stable and square to the rivet. Other than that, just let physics do the work. You don't have to push on the rivet, just hold it steady.

Helpful Hint: Applying duct tape on the bucking bars is a way of keeping parts from getting scratched. For example, if you're bucking rivets along a wing rib that's been primed, just wrap the corners of your bucking bar with duct tape and you won't gouge the rib or scrape away the primer.

Availability:
CMW supplies both raw material and finish machined parts to your specification. Please contact us directly at metals@cmwinc.com or Submit a RFQ with your request.

Chassis Race Weights

In confined spaces where mass is required for balance, CMW® 1700 Chassis Race Weights are often specified. Race cars can be given just the right "feel" or balance to maximize performance. CMW® 1700 Chassis Race Weights are twice the density of steel and 50% heavier than lead.

CMW® 1700 Chassis Race Weights will:

Lower your center of gravity
Adjust balance between front & rear
Machined to fit easily into chassis frame rail
Threaded holes on both ends for easy movement
Standard block is 2 5/8" x 3 5/8" x 6" and weighs 35 lbs
Other sizes available

Availability:
Our standard block is CMW® 1700 material with dimension of 2 5/8" x 3 5/8" x 6" and weighs 35 lbs, but we will precision engineer and manufacture tungsten-based racing weights to your specification. Just contact us directly at metals@cmwinc.com or Submit a RFQ with your requirement.

Properties & Comparison to Lead:

Physical Properties	CMW®1700	Lead
Density (minimum) Gms/cc	17	11.3
Density (minimum) Lbs/Cu. In.	0.614	0.402
Tensile Strength (minimum) KSI	110	2.2
Yield Strength .02% offset (min.) KSI	75	1
Creep Rate	0	3

EDM / ECM Machining

Elkonite® Copper Tungsten is a standard for production of long lasting electrodes for EDM and ECM applications. Usually the less dense and more electrically conductive Elkonite® Copper Tungsten's are used for EDM applications and Elkonite® Silver Tungstens are used for ECM applications, but where maximum wear resistance is mandatory, the high-density grades of Elkonite® 40W3 and Elkonite® 50W3 Copper Tungsten are better solutions.

Elkonite Info Sheet