Difference between vacuum vapor reflow welding and hot air reflow welding

The difference between gas phase reflow welding and hot air reflow welding is that gas phase reflow welding USES vapor phase liquid to heat the key.

Vapor phase reflow welding process has many advantages over other reflow welding methods, mainly in the following aspects: high temperature control accuracy, high temperature uniformity, and relatively low oxygen content control, can be used in a low oxygen environment for welding.

(1) high accuracy of temperature control.

In welding, the temperature of the welds depends on the boiling temperature of the fluid because the heat is applied to them by boiling the vapor.

Due to the narrow boiling range of vapor phase fluid, the welding temperature can be precisely controlled.

This is very advantageous for welding temperature-sensitive components, as various gases with different boiling temperatures can be obtained.

Therefore, in the welding of complex components, a series of solder with lower melting point can be used.

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(2) high temperature uniformity.

Vapor phase liquid fluid has a high heat transfer coefficient, because condensation is generated on all exposed surfaces, the temperature of the whole circuit board welding temperature on the surface of the circuit board temperature uniformity is very good.

(3) low oxygen welding.

Since the initial vapor is about 20 times denser than air, oxygen is sufficiently removed from the system.

In fact, trace amounts of oxygen are always present in steam.

This is probably due to the inherent solubility of the oxygen in the steam and to the fact that the oxygen sent to the steam is added, the total amount is usually ignored.

(4) geometric correlation.

Because condensation occurs on the entire surface, the geometry of the assembly has little effect on the process, and the steam seeps into parts of the device that are invisible from the outside of the weld.

Especially for large size BGA, transformers, shielding cover and other workpiece welding is very advantageous.

(5) welding quality.

Because the real air welding system is in a relatively closed and a vacuum auxiliary under the condition of welding, this condition is one of the traditional hot air reflow soldering does not have, so under the condition of the vapor phase welding is able to put the solder flux volatile bubble from effective eduction, greatly reduces the welding the hollow ratio, effectively improve the welding quality.

Of course, the real air phase reflow also has a great shortage, many companies to the real air phase welding god.

It seems like it's perfect.

Actually because the boiling point of the real air phase itself is not high.

Can only weld low - temperature solder.

If there are high temperature welding requirements.

In fact, true air phase reflow welding is not weldable.

Such as gold, tin, silicon, or germanium, even some high lead solders are not weldable.

If you need a wide range of welds, consider using a standard vacuum welding oven.

TORCH comrade customer vacuum reflow welding, there are many industries in use.

Can use solder paste welding technology, welding technology, eutectic welding technology, wide range of use.

At present, real air phase welding is rarely used in the enterprise market.

They are mostly used in military research institutes where there is no shortage of money.

If you are interested in our products, please visit our website（www.torch.cc） or search Vacuum reflow oven on baidu to learn about our products.