Technologies

Brazing Copper Tube with Induction

Objective: To braze a copper tube ( 3/8″ OD by 2-4″ long) into a 3/8″ fitting in less than 10 seconds. Heating must take place in a channel type coil to allow for easy loading of parts.

Material Copper Tubing and Fitting with Braze and Stay Silv White Flux

Temperature 1300°F

Frequency 215 kHz

Equipment DW-UHF-10kw output solid state induction power supply equipped with a standard heat station containing eight 0.33 μF capacitors for a total of 0.66μF, a step down transformer, and a specifically designed induction heating coil.

Process DW-UHF-10kw solid state induction power supply was setup to achieve the following results: · 2.0 kW of power was directly loaded into the copper tube resulting in a heating time of 7.2 seconds to reach the necessary 13000F for brazing.

Results& Processing ease was achieved through the design of a unique channel type coil comprised of three turns of 1/8″ copper.

Induction Brazing Steel Tube

Objective: To heat an oil suction assembly (steel tubing and filter cap) to 1,850°F (1010°C) within 15 seconds for a brazing application.

Material 0.125″ (3.2mm) diameter steel tube and filter cap assembly, high temperature brazing flux, copper ring.

Temperature 1850°F(1010°C)

Frequency 500 kHz

Equipment • DW-UHF-6KW-I induction heating system equipped with a remote workhead containing 0.66 μF capacitors • An induction heating coil designed and developed specifically for this application.

Process A two-turn, specially-contoured helical induction coil is used to heat the tube assembly near the joint area. A copper ring and high temperature flux are then applied to the joint area. Power is applied for 15 seconds until the braze flows.

Results/Benefits Induction heating provides:

• Easy loading and unloading of parts

• Heat very precise areas within production tolerances

• Hands free heating that involves minimal operator skill for manufacturing

Induction Brazing Steel Pipe

Objective: To heat a stainless steel pipe, ferrule and elbow assembly to 1400°F (760°C) within 20 seconds for brazing.

Material 6″(152.4mm)long x 0.5″(12.7mm) diameter stainless steel conduit, 0.5″(12.7mm) long x 0.5″(12.7mm) diameter ferrule, 2″(50.8mm) elbow with 0.5″ (12.7mm) diameter

Temperature 1400°F (760°C)

Frequency 400 kHz

Equipment • DW-UHF-6KW-I induction heating system equipped with a remote workhead • An induction heating coil designed and developed specifically for this application.

Process: A specially designed, three-turn helical coil is used to provide heat to the assembly at the braze joint area. Two small silver solder braze rings are placed at each joint; the joints are coated with black flux to insure that the braze material flows cleanly. The assembly is placed inside the coil and power is applied for 15 seconds to cause the braze to flow.

Results/Benefits: Induction heating provides: • Consistent and repeatable results • No flame process • Faster process time

Induction Annealing Saw Blades

Objective: Induction Annealing saw blades used for cutting bread, prior to hole punching.

Material .38″ (9.6mm) wide and .51″ (12.9mm) wide continuous strips of 400 series stainless steel.

Temperature 600°C (315.6°F) for one second

Frequency 589kHz

Equipment • DW-UHF-6KW induction heating system equipped with a remote workhead containing one 1.00 μF capacitor. • An induction heating coil designed and developed specifically for this application.

Process A three turn helical coil at a 45º angle is used to anneal a 1.2″ (30.5mm) strip of saw blade prior to hole punching.

Results/Benefits Induction heating provides: • Improved quality of blades at hole punching location • Decreased scrap product • Easily incorporated into existing production lines

Induction Annealing Copper Wire

Objective: Induction Annealing a brazing copper wire for preform production.

Material: Copper Nickel Silver 2774 Alloy rod 0.070″ (1.8mm) diameter.

Temperature 650ºF(343.3ºC)

Frequency 580 kHz

Equipment: • DW-UHF-6kW-III induction heating system equipped with a remote workhead with one 1.0 μF capacitor, and a 4-20 mA input controller to aid in voltage ramping. • An induction heating coil designed and developed specifically for this application.

Process A unique helical coil consisting of four consecutive coils connected in parallel with a quartz tube lining is used to heat the wire to 650ºF (343.3ºC) for annealing.

Results/Benefits Induction heating provides: • Higher productivity of 27′ (8.2m) per minute • Reduction in surface oxidation & scaling • Consistent, repeatable results

High Frequency Induction Brazing Diamond Inserts

Objective: Induction Brazing diamond inserts to a steel drilling ring

Material : • steel ring and diamond inserts • Braze shim preform • Flux

Temperature :1300 – 1350 (700 – 730) °F (°C)

Frequency :78 kHz

Equipment: DW-HF-15kW, induction heating system, equipped with a remote heat station containing two 0.5 μF capacitors (total 0.25 μF) An induction heating coil designed and developed specifically for this application.

Process: A multi-turn, internal-external helical coil (A) is used to generate the required heating pattern. Initial tests on the ring alone determine system tuning. Flux is applied to the part and the braze shims are inserted into the counter-bored holes (B). This is followed by the synthetic diamonds. The part is loaded into the coil and weight is placed onto the diamonds (C). RF Induction Heating power is applied until the braze flows. The power is turned off and the part air cools to room temperature.

Results/Benefits • reduced ring warping compared to furnace induction heating • decreased cycle time due to reduced ramp-up and cooldown times

Induction Brazing Carbide File

Objective: Induction Brazing carbide rotary file assemblies with uniform concentricity in an aerospace application

Material • Carbide blank • High speed steel shank • Temperature indicating paint • Braze shim and black flux

Temperature 1400°F (760°C)

Frequency 550 kHz

Equipment: DW-UHF-4.5kw induction heating system, equipped with a remote heat station containing two 0.33 μF capacitors (total 0.66 μF) An induction heating coil designed and developed specifically for this application.

Process A multi-turn helical coil is used. The part is heated to determine the time required to reach the desired temperature and required heat pattern. It takes approximately 30 – 45 seconds to reach 1400°F (760°C) depending on the various part sizes. Flux is applied to the entire part. A braze shim is sandwiched between the steel shank and carbide. Induction heating power is applied until the braze flows. With proper fixturing, concentricity of the part can be achieved.

Results/Benefits • Repeatable, consistent precise heat.

 

Induction Brazing Copper Fittings
Objective: Copper ‘tees’ and ‘ells’ are to be brazed to the aluminum body of a refrigeration valve

Material: customer’s valve copper fittings braze

Temperature: 2550 ºF (1400°C)

Frequency: 585 kHz

Equipment: DW-UHF-10kw induction heating system including a workhead containing two 1.5μF capacitors (total 0.75μF) and a three-turn helical coil

Process: The valve is placed inside the coil and RF induction heating power is applied until the part is heated to the required temperature and the braze is seen to flow into the joint. Two tube sizes were run using the same induction heating system settings with differing cycle times.

Results/Benefits • energy is applied only to the zone to be heated • heating of the joint/braze is uniform and repeatable

Annealing Metal Stamp With Induction

Objective: Induction Heating the opposite end of a metal stamp so that it mushrooms instead of cracks/splits when struck by a hammer.

Material S-7 steel of varying rectangular cross sectional sizes

Temperature 1400-1800 ºF (760-982) ºC

Frequency 300 kHz

Equipment DW-UHF-10KW, induction heating system, equipped with a remote heat station containing two 1.5 μF capacitors for a total of 0.75 μF and three different induction heating coils designed and developed specifically for this application.

Process One five-turn and two four-turn helical coils are used to heat the end of stamps to the required temperature. Two part sizes can be run in each of coils, using the same machine settings except for cycle time. Cycle rates dependent upon the crosssection size. The 3/8″ (0.9525 cm) square size is has a rate of below 10 seconds. The rate for the middle size, ½” – 1 ½ ” (1.27 – 3.81 cm) is 30 to 60 seconds. A 1″ (2.54 cm) square part takes approximately two minutes. Fixturing can influence the length of the cycle time required. For shorter heat times a larger power supply may be used.

Results/Benefits Precise heat only to the area that needs annealing is more efficient and repeatable than heating with a torch.