Lead-free flux is auxiliary substances that we use for brazing and welding metals. The range of a reliable company includes products used in the radio engineering industry - fluxes on various bases.
Operating principle of lead-free flux
Heating of the metal is essential to facilitate the connection of parts and the printed circuit board. At the same time, an oxide film forms on its surface. Moreover, it reduces the ability of the solder to bond with metal parts.
Lead-free flux allows you to solve the problem. At room temperature, this chemical compound remains inert, and intense heating is necessary to obtain useful properties. Moreover, you can also add fluxes to the solder or can directly apply them to metal surfaces to prevent unnecessary oxidation.
Thus, you can easily perform three tasks at once:
- dissolution of the oxide film formed on the surface of the metal being processed;
- the role of the oxygen barrier to prevent further oxidation;
- improving the wetting of surfaces to be soldered.
One of the main requirements for fluxes is the ability to withstand high temperatures while maintaining all the useful performance properties.
Types of soldering fluxes
Fluxes can be organic or inorganic compounds. The choice of a particular option depends on the intended application. Most organic fluxes are non-corrosive. However, some varieties, especially acidic ones, can be corrosive.
Therefore, the use of the lead-free flux requires special attention. It should also be in mind that non-compliance with the manufacturer's recommendations may lead to deterioration in the electrical properties of finished printed circuit boards.
Organic fluxes are based on the following components:
- solvents to maintain optimal consistency;
- various additives
You can classify inorganic fluxes into two types:
- rosin and
According to the consistency and the method of packing, the following varieties can distinguish - liquids, pastes, and water-soluble powders.
Why lead free soldering is important for metal?
Soldering fluxes using soft solders are necessary to clean oxidized metal surfaces. And it improves the activation and wettability of already welded surfaces. Moreover, it minimizes defects, and protects the soft solder and solder site from oxidation.
Preheating is necessary when removing the base of the lead-free flux when reducing and activating thermal shock on printed circuit boards and components made of various materials.
When we can use liquid flux?
You can use liquid fluxes for wave and double wave soldering, which are common in hole-mount or mixed-mount technologies. Further, you can also actively use some types for manual soldering in pilot production and for repairs.
During brazing, fluxes are dissolved with oxides and sulfides, protecting the surfaces from oxidation, and also reducing the surface tension of the solder.
Varieties of lead-free flux composition
In those cases when you solder copper parts, lead-free flux is common to evenly distribute the solder at the place of the proposed joint, as well as to clean the metal surface from zinc chloride, hydrochloric and boric acid, dirt, dust. Thanks to this, protection against oxygen molecules in the air appears. You can also use materials rich in wax, resin, rosin as a flux.
It is very important to choose the right flux. To do this, it is necessary to take into account the types of metal composition, solders, temperature regime of heating. There are three main types of fluxes.
- Anti-corrosion flux. This is a substance that contains phosphorus and special solvents. Through interaction, these substances give an organic compound. Moreover, the advantage of this flux is that there is no need for additional cleaners after soldering.
- Gold flux. The composition of this substance includes a large number of components. Manufacturers prepare the composition from salicylic acid, gold, ethyl alcohol, petroleum jelly. The seam when soldering using such a composition, you can characterize by an even and neat shape.
- Activating flux. You can add borax and rosin here. The borax melting point is 700 ° C. In addition, no harmful substances are released into the air during soldering. You can prepare these fluxes yourself. For this purpose, you can mix parts between rosin, aniline, salicylic acid, anhydride, diethylamine.
FEATURES OF SOLDER JOINTS USING FLUX
If we compare the connection of copper material using flux with welding by hand, then the first option increases the efficiency of the workflow by five. Why is this happening? When lead-free flux soldering is good to use, electric currents applies through the electrode wire element to the overhang.
When you are using a flux, it allows using a higher density of welding currents. Thanks to this, there will be no risk of overheating of the electrode element in the protrusion and detachment of the coating. Further, if higher welding currents are good to use, the base metal is melted to a considerable depth. Thanks to this, soldering is performed without separating the thickened edges.
HOW TO CHOOSE A FLUX?
In order to correctly choose the type of flux for a particular case, you should take into account several important factors. If you want to avoid the formation of an oxide film on the seam, you need to control the temperature conditions of the solder and the metal composition, they must be the same.
Therefore, when choosing a flux, you need to focus on the type of solder. But if the temperatures of the metal and solder composition are the same, then the flux can serve as a temperature indicator and avoid damage to parts.
Lead-free flux can be of three types of consistency: paste, powder, liquid. Mostly we make use of liquid flux when using soft solder. Moreover, you can store them in tubes. The powder version is sometimes inconvenient to use. You should apply the paste evenly, store conveniently, and should apply without prior preparation.
QUALITY FLUX FACTORS
- The flux should create an even coating.
- The density and toughness must match the solder, which eventually takes the place of the flux.
- The flux must completely remove oxide compounds and prevent them from interacting with the material.
- The chemical composition of the flux must be stable.
- During the soldering process, the seam should be clearly visible.
- The flux must be capable of vertical connections.
- After the working process, you can easily remove the dirt from the surface.
After finishing the work, it is necessary to remove all the remaining flux. For this, special solutions are applicable.
Metal milling is one of the new metalworking services which you can get from a good company.
There are several methods of metal processing using lead-free flux, among which milling is the most common. The technique owes its name to the main tool - a milling cutter. Furthermore, it is good to use in the manufacture of metal products and blanks. Its cutter actually has been equipped with several blades (teeth), through which milling is carried out.
TYPES OF MILLING WORK ON METAL
The model and purpose of the milling machine, dimensions, weight, and shape of parts are the main elements that determine the type of milling work. In fact, there are two main types:
- Vertical milling.
- Horizontal milling.
On a horizontal machine, a milling cutter is engaged in facing the length and width for specified volumes. Moreover, it makes a product or cuts using disk cutters, cuts splines, gear wheels, and also other works.
Vertical machines allow more precise work. It uses 2 mechanical feeds at the same time.