Vacuum Brazing Technology is developed by SLRI’s engineering team (Petty patent of invention no. 1703001736).



Samrerng Duangnil
Synchrotron Light Research Institute (Public Organization)

With small amount of wiggler, this brazing technique is advanced in accuracy control and multiple brazing on different metals. Capacity to develop such technology domestically helped to reduce import expense of more than 18 million Thai baht. Various applications are developed in consequence, such as, Heat Treatment, Air Conditioning System, and Catalytic Converter.

Detail concept was inititally designed for vacuum brazing under 10-Torr with a 300x300x500 mm. cubic shelf, an accessible space to load a work piece from the front portal. The brazing can produce heat up to 1,200 C° through a Heating Element. Temperature degree can rise up to 0.5-30 C° per minute while controling Temperature Ripple to under ±2-5 C° and stabilising internal temperture to ±5 C°.


SLRI’s Brazing was designed and developed as demonstrated in Figure 1 with 6 components:

1. Vacuum Chamber

2. Hot zone.

3. Heat Exchanger

4. Gas quenching using nitrogen

5. Vacuum System

6. Control System

Figure 1 Components of Brazing


Figure 2 Brazing at Synchrotron Light Research Institute, Nakhon Ratchasima

Vacuum brazing procedure is based on two or more brazing metals. These metal can be the same or different type including silver wire or alloy such as, brass wire, copper & phophorus metal. Melting point of supplement metal must be over 450 C°; however, temperature must be less than a brazing metal. This supplement metal will be heated to joint the work piece with Capillary technique.

System activation is the first step before loading the work piece into brazing chamber. In starting the brazing procedure, vacuum system must be set to at least 5 x 10-4 Torr and boosted to the melting point of Filler Metal. Power supply of heated zome will be turned off at the finish of the brazing procedure. Until internal temperature is cool down to less than melting point of joint metal, nitrogen will be a cooling inlet in the heated zone and coolant system to the heat exchange. system, Heat will then be propelled from the brazing until temperature reached to less than 100 C° before unloading a work piece (Procedure is as shown in Figure 3)


Figure 3 Procedure of vacuum brazing

Such domestic development of Vacuum Brazing helps in saving up to 18 Million Thai Baht from import of products and tools.. Essentially, this technology demonstrated the true efficiency of Thai people to the world. Brazing technique can be applied to various metal brazing as shown in Figure 4 and 5.

Sample of work pieces

Figure 4 Sample of work pieces by brazing technique to be using in vacuum system and particle accelerator at SLRI

Brazing of grip and cutty edge material Brazing to improve mechanical properties
Joint of compressor point in air system Joint of catalytic converter parts.

Figure 5 Sample of industrial applications from brazing technology

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