Induction Brazing & Soldering

Induction Brazing & Soldering - Overview

Brazing and soldering soldering refers to the joining of two or more components using a special filler material and heat. Although very similar in nature there are fundamental differences in the two processes defined by the temperature and the metallurgical reaction between the filler and base metals.

In soldering the metal filler will typically have a melting temperature of less than 450°C and an intermetallic phase is formed in the joint area. In the brazing process the metal filler has a melting temperature in excess of 450°C and solid solutions are formed in the joint area.

Induction Brazing

The principle advantages of Induction Heating in Brazing applications are as follows:

  • Precise control over the position and temperature of the joint zone leading to more predictable results. An added benefit is that only a very localised area of the component is affected by heat.
  • Significantly reduced energy costs due to the efficiency of the induction heating process.
  • Health and safety benefits due to the removal of naked flames and pressurised gas storage systems from the process.
  • Easily repeated results and de-skilled setting and operating procedures no torch skills required.
  • Reduced scrap due to reliability and repeatability of process.
  • Ease of incorporation of the process into a vacuum system.
  • Improved working environment due to reduced noise and heat produced in the surrounding atmosphere.

All Induction Brazing systems feature the same principle elements as follows:

  • An Induction Power Unit - The power and frequency of this unit is selected based on a variety of parameters including throughput, component thickness and the desired hardness pattern.
  • A Mechanical Handling System - The type of handling system will be dictated by the components to be processed, the throughput required and customer preferences and requirements. The purpose of the handling system is to position the work-piece accurately in the induction coil for the heat cycle to take place. However fully automated systems can be used to also assemble the individual parts and apply solder and flux to the correct positions.
  • A Filler Material - Literally hundreds of soldering and brazing alloys are available in sheet form, pre form or paste. Inductelec have formed technical partnerships with all the main manufacturers and suppliers of these alloys and as such can help advise on specific applications.
  • Cooling System - The cooling system will normally be a split type where the cooling water for the generator is on one circuit and the quench is cooled on a separate circuit. Typically air blast coolers, refrigeration chillers and water to water cooler are utilised subject to climatic conditions and local requirements.
  • A fume Extraction System - designed to remove metal fume and flux fumes.
  • In some cases Temperature Control or Monitoring - is used utilising infra-red type pyrometers.

In its simplest form the induction brazing system will be a generator a coil and a cooler. The system is manually fed and the operator assembles all the component parts places them in the coil and initials the braze cycle. However in order to maximise throughput a variety of techniques and systems can be employed.

Mutiple Head Systems

In the multi head system the power unit is equipped with more than one work-head and a power changeover system to switch the generator power to either work-head in turn. This allows load unload to take place at the station which is not being heated whilst brazing takes place at the other station often removing the load unload time from the process.

Conveyor Systems

In line conveyors are often utilised in high volume situations where a skid coil can be used the conveyor can be either an indexing type or run at a constant speed subject to the application.

Rotary Table

As with the conveyor the rotary table can be used for many brazing applications and can be either an indexing type or a constant speed version subject to coil geometry and other application based criteria.

Both the rotary table and the conveyor based units can be equipped with a variety of ancillary equipment including bowl feeders, pick and place units, quality monitoring devices and solder and flux dispensers to increase the level of automation.

Induction Brazing - Case Study Multi Head System

Application - Confidential.
Component Details - 5mm brass to 3mm Copper.
Process Requirement - Braze copper wire to bore of Brass Tube.
Induction Equipment - UT 111 200 12kW 200kHz Ultra-Tec power unit with twin low impedance safe-braze work-heads and auto changeover system.
Feed System - IHG 571 TSBS Twin head brazing system, featuring specially designed low pressure pneumatic clamp tooling for accurate positioning of the component to be brazed. Input to the system was manual using a pre-assembled component and a pre-formed solder ring. The system featured PLC control with a recipe based setting system utilising a Mitsubishi HMI with error trapping on all critical parameters. Work coils, IWC 12 air-blast cooler & Extraction system.

Induction Brazing - Case Study Rotary System

Application - Induction Brazing.
Component Details - Electrical contacts.
Process Requirement - Join Silver tip to Brass or Copper sub component.
Induction Equipment - 2XUT 111 50 5kW 100kHz Ultra-Tec power units.
Feed System - IHG2534 MPRT Multi station rotary table based brazing system. The system features an 8 position rotary table complete with automatic braze paste dispenser, pick and place component assembly, twin braze station and QC station. Operator protection was via a light guard and fume extraction was provided at the braze station. The system featured PLC control with a recipe based setting system utilising a Mitsubishi HMI with error trapping on all critical parameters. Work coils, IWC 10 air-blast cooling systems.

Please browse our website for more information about Induction Brazing then contact us on 0114 272 3369 to speak to a member of our team or e-mail us on info@inductelec.co.uk.