TUCOMET®
Tungsten-Copper
TUCOMET® is the brand name of a product group which is made from tungsten and copper.
Tucomet® tungsten-copper products are available in a broad range of formulas for applications in resistance welding, EDM, heat sinks, and electrical contacts.
TUCOMET® materials are typically made by infiltration of pressed or pre-sintered tungsten blanks. This material can be called a tungsten alloy. The infiltrated material can then be easily machined.
TUCOMET®
Tungsten-Copper Applications
Resistance Welding
Resistance welding is a method for joining materials by using heat and pressure. The work piece is heated by electrical current using conductive electrodes. The welding arrangement consists of individual series-connected contact and material resistances, which convert electrical power into heat in proportion to their size.
For process variations we recommend the following materials:
Resistance spot welding - TUCOMET® 80, W, WCu-composite, CuCrZr, CuCoBe
Resistance projection welding - TUCOMET® 80
Resistance seam welding - Mo, TZM, TUCOMET® 80, TUCOMET® 75
Resistance butt welding - Anviloy® 180F, ANVILOY® 173M, TUCOMET® 80, TUCOMET® 90
Discharge welding - TUCOMET® 80, TUCOMET® 90
Resistance stud welding - TUCOMET® 80, TUCOMET® 90
Flash butt welding - TUCOMET® 80, ANVILOY® 180F, ANVILOY® 173M
Electrical Discharge Machining (EDM)
Electrical discharge machining for high-precision material processing is called “erosion” or “spark erosion”. Here, numerous small discharges between the electrode and work piece, inside the dielectric, erode small pieces of an electrically conductive work piece. For example, a hole can be drilled (drill EDM) or a work piece can be cut by a wire (wire EDM). Thus, a complex tool contour can be negatively reflected (imaged) on a work piece (die sinking EDM). An application that is gaining in popularity is disc eroding which is used for sharpening PCD (poly crystal diamonds) or hard metal saw blades and wood cutting tools. In this application a rotating disk serves as an electrode. The accuracy of these processes depends on the stability of the tool electrode, because the spark also removes electrode material even if it is at a much lower extent. This is why the electrode material from which the electrodes are made is of particular importance. The electrode material determines critical process parameters such as removal rate, wear, burrs, thermal expansion and requirements regarding rinsing.
We recommend the materials:
TUCOMET® 60
TUCOMET® 75
TUCOMET® 80
TUCOMET® 90
Tungsten
Molybdenum
Heat Sinks
The requirements of computing power and microelectronics in computer and communication technology, as well as power electronics in laser, aviation and aerospace technology are demanding. Chip development is being characterized by increasing energy density and high heat losses, while at the same time reducing the structures size. Therefore these systems are in principle more sensitive to degradation and must be protected from overheating by an effective thermal management. That is why Si and GaAs semiconductors must be mounted on substrates or floor panels, which function simultaneously as a heat sink. In order to avoid thermal stresses, materials of the same thermal expansion rate and high thermal conductivity are required. Materials made of TUCOMET® alloys meet these characteristics perfectly.
Weldstone supplies plates and heat sinks according to customer specifications in the computer industry, optoelectronics, telecommunications, aviation and aerospace.
Base plates (heat-slugs) for IC Packages
Heat sinks for optoelectronics and lasers
Heat sinks for microwave applications and optical fiber for packages
Heat sinks for high-performance chips
Electrical Contacts
Electrical contacts build electrical connections between components in overvoltage protections, relays and switches. The requirements for the switch contacts are different depending on the switching power, switching voltage, switching frequency, continuous current, and the starting and breaking current. Accordingly, the requirements for the contacts and the methods to ensure their safe function vary.
To prevent oxidation, the contacts can be made corrosion resistant by coatings with precious metals or by operating the contacts in a vacuum, inert gas or oil. Other problems include contact erosion, erosion by spark flashover, or arcing and welding at high power. These problems can be solved by using refractory metals like tungsten.
There are different materials for choice:
Tungsten/Silver W50Ag, W60Ag, W70Ag, W80Ag
Tungsten/Copper TUCOMET®50, TUCOMET® 60, TUCOMET® 70, TUCOMET® 80, TUCOMET® 90
Tungsten
Composite material W/Cu, WLa/Cu, W/WCu, W/CuCrZr
Machining
Turning
All turning operations - inside and outside - can be accomplished with common tools made from tungsten carbide listed in the ISO groups of machine cuttings K 05 to K 20. Using tungsten carbide turning tools, cuts without chamfer, with a setting angle of 6°, and a face angle of 6°- 12° should be selected. For cutting, positive rakes are preferred with a chip breaker and without chamfers. Cutting speeds of 80 - 120 m/min can be achieved. Also High Speed Turning is possible. Cooling agents are not required.
Drilling
Drilling requires drills made from high-speed steel (preferably material NR. 1.3342 or 1,3343) or tungsten carbide of the ISO group of machine cuttings K 10 suitably. The tip angle of the drill should be 120°. Depending on the choice of the tool material cutting speeds from 20 to 80 m/min are possible. Since no cooling agent is used, the drilling made of high-speed steel needs often to be ventilated, in order not to let cutting edge of the drill rise to a temperature over 550°C.
Milling
Face Mills with positive indexing inserts, made from tungsten carbide of the ISO machine cutting groups K 10 / K 20 or P 20 to P 30, have proven to work well. With an angle of the major cutting edge of 80°, the face angle of the indexing insert should be 6° - 10°. Likewise the angles of inclination should be 6°, and the setting angle 6°. A cutting speed 80- 120 m/min is recommended. High Speed Milling is possible. No cooling agent is needed.
Grinding
For sharpening Tungsten alloys, ceramic bound grinding wheels made of silicon carbide can be used. With a granulation of 50- 120 the degree of hardness of the disk should be H to K. For cooling of the disk and reliable clearing of the splinters, the grinding area must be rinsed with a strong cooling agent jet. The cooling agent can be a mixture of water and a commonly used additive.
Bonding
All Tungsten alloys can be well hard brazed. As solder, the silver solder 8427 at 840°C and 8449 at 690°C working temperature perform satisfactorily. In special cases Tungsten alloys can be connected also by friction welding with steel, copper, aluminum and their alloys.
Electrical Discharge Machining
Tungsten heavy metal alloys can be processed by Electrical Discharge Machining (EDM). The high melting refractory metals contained in the alloys require high-melting electrode materials. Therefore we recommend TUCOMET® 80 and ANVILOY® 170C which you can also order from us. It has to be ensured that the electrode is used as cathode.
