Tag Archives: pcb manufacturing process

Basic working principle of wave soldering

S-WS450 Wave Soldering machine

一、Wave soldering machine

Wave solderingis a kind of solder wave with a specific shape formed on the surface of molten liquid solder by means of pump pressure. When mounted components pass through the solder wave at a fixed angle, solder joints are formed in the lead solder zone. The component is preheated in the preheating zone of the welding machine (the preheating of the component and the temperature to be reached are still controlled by the predetermined temperature curve) in the process of conveyor belt conveyor. In actual welding, the preheating temperature of the assembly surface is usually controlled, so many devices have added corresponding temperature detection devices (such as infrared detectors). After preheating, the components enter the lead slot for welding. Tin trough contains molten liquid solder. The nozzle at the bottom of the trough determines the shape of the solder. Thus, the solder wave is heated when the welding surface of the component passes through the wave. At the same time, the solder wave wets the welding zone and expands and fills the welding process.

wave soldering process
wave soldering process

二、Basic working principle

Wave soldering is based on the principle of convection heat transfer to the welding area heating. The molten solder wave acts as a source of heat. On the one hand, it flows to wash out the pin welding area, on the other hand, it acts as a heat conduction. The pin welding area is heated under this effect. When the silver lead solder is used, the melting solder temperature is usually controlled at about 245 degrees Celsius. In order to ensure the temperature of the welding zone, the solder wave usually has a fixed width, so that when the welding surface of the component passes through the wave, there is sufficient time for heating and wetting. In traditional wave soldering, a wave is adopted and the wave is relatively flat. With the use of lead solder, double wave mode is adopted at present.

wave soldering pot

三、The welding spot

The pin of the component provides a way to immerse the liquid solder into the metal through hole. When the pin contacts the solder wave, the liquid solder climbs up along the pin and the hole wall with the help of the surface tension. The capillary action of metallized through-hole improves the climb of solder. When the solder reaches the PcB part, the surface tension of the pad is expanded. The rising solder discharges flux gas and air from the through hole, filling the through hole and forming a solder joint after cooling.

四、What’s the difference between wave soldering and reflow oven?


The mainly different are in heating source and solder supply mode.
In wave soldering, the solder is pre-heated and melted in the trough. The solder wave pumped by the pump plays a dual role of heat source and solder supply. The solder wave of solder solder solder causes the through holes, pads and component pins of the PcB to be heated, and also provides the solder needed to form solder joints. In reflow soldering, solder paste is pre-quantitatively assigned to the solder zone of PCB. The role of heat source in reflow is to re-melt the solder.

五、Main components and working principle of wave soldering

A wave soldering machine is mainly composed of conveyor belt, heater, tin trough, pump, flux foaming (or spraying) device, etc. It is mainly divided into flux adding area, preheating zone and welding area.

The solder in the solder tank, heated by a heater, gradually melts, and the molten liquid solder, under the action of a mechanical pump (or electromagnetic pump), forms a specific shape of solder wave on the surface of the solder tank, which becomes a wave. The PCB with mounted elements is placed on the conveyor and solder joints are welded by passing through the solder wave at a certain angle and at a certain immersion depth, so it is called wave soldering.

For a single wave, there is only one wave, called the advection wave. For double waves, the first wave is called the disturbing wave, and the second wave is called the advection wave (Ping Huabo).

The role of spoiler: SMT element welding and prevent leakage welding, it ensures the proper distribution of solder through the circuit board. The solder is penetrated through the slit at a relatively high speed, thus leading to narrow gap. The direction of the jet is the same as that of the circuit board. For SMT components, the disturbance wave can basically be welded. But for through-hole components, the spoiler wave itself can not properly weld the components, it leaves the weld unevenness and excess solder, so the need for a second wave – advection wave.

The role of advection wave is to eliminate burr and weld bridge generated by the disturbance wave. Advection wave is actually the wave used by the single wave soldering machine. Therefore, when the traditional through-hole components are welded on the dual-wave machine, the disturbing wave can be turned off and the soldering can be completed by advection wave. The entire wavefront of the advection wave is basically horizontal, like a mirror. At first glance, it looks as if the tin wave is static, but in fact the solder is flowing continuously, but the wave is very smooth.

六、Wave soldering machine welding spot molding

Solder Joint Forming: When PCB enters the front end of the wave, the substrate and pin are heated, and before leaving the wave, the whole PCB is immersed in the solder, that is, bridged by the solder, but at the moment of leaving the wave end, a small amount of solder is attached to the pad due to the effect of wetting force, and due to surface tension, it will come out. At present, the shrinkage of the lead wire is small, and the wetting force between the solder and the pad is greater than the cohesion of the solder between the two pads. Therefore, a full, round solder joint will be formed, leaving the excess solder at the end of the wave, and due to gravity, it will fall back into the tin bath.

S-WS250 Wave Soldering machine

How to choose laser marking machine in SMT production line

The most important choice of laser marking machine is its laser.So today I’m gonna to tell  you something about four most common lasers.

 

S-UV-300 laser marking machine for PCB
laser marking machine for PCB

1. CO2 laser /(CO2 laser marking machine)

1)Principle

CO2 laser marking machine principle: CO2 laser marking machine, or carbon dioxide laser marking machine (CO2 is carbon dioxide). It is a laser galvanometer marking machine using CO2 gas as working medium. CO2 laser marking machine is a CO2 laser with CO2 gas as the medium, CO2 and other auxiliary gases are charged into the discharge tube on the electrode to add high voltage, the discharge tube produces glow discharge, so that the gas emits a wavelength of 10.64um laser, laser energy amplified, after the galvanometer scanning and F-Theta mirror focusing, under the control of computer and laser marking control card. The marking of images, words, numbers and lines can be carried out on the workpiece according to the requirements of users.

2)Constitution

CO2 laser marking machine consists of CO2 laser, 10.64 field mirror, 10.64 beam expander, CO2 laser power supply, scanning galvanometer, control computer, laser control card, laser control software, laser frame, laser circulating water system, circuit control system and other parts.

3)Advantages and application areas

The main features of CO2 laser marking machine are: using carbon dioxide laser, belonging to the general model, post-focusing mode, small size, high integration.

This machine is suitable for marking most non-metallic materials, such as paper packaging, plastic products, label paper, leather cloth, glass and ceramics, resin and plastic, bamboo and wood products, PCB board, etc. CO2 laser is a gas laser with a wavelength of 10.64 um in the far infrared optical band. CO2 gas filled discharge tube is used as the medium to produce laser. When high voltage is applied to the electrode, glow discharge is produced in the discharge tube. The gas molecule can release the laser, and the laser beam is formed after amplifying the laser energy.

Auto-Laser marking machine
Auto-Laser marking machine

2.Green laser /(Green laser marking machine)

1)Principle

Green laser marking machine uses high-power multi-mode laser diode pumped to produce green laser beam after laser frequency doubling, and then through computer control of high-speed scanning galvanometer deflection marking or cutting. Two laser beams are projected from different angles into transparent objects (such as glass, crystal, etc.), accurately intersecting at a point. Because two laser beams interfere and cancel at the intersection point, their energy is converted from light energy to internal energy, releasing a lot of heat, melting the point into a tiny hole. The machine accurately controls the intersection of two laser beams at different locations, creating a large number of tiny holes that eventually form the desired pattern.

 

2)Advantages and application areas

The green laser with 532 nm wavelength has obvious advantages: smaller spot diameter, more concentrated energy, high electro-optic conversion efficiency, good beam quality, marking accuracy below 10 micron level, neat marking frame, no explosion point, no thermal deformation. Mainly used in glass, crystal products, surface and internal marking, ceramics, metals, electronics, plastics and other products. It belongs to the category of cold light. It is also suitable for some products with high heat reaction and high precision.

3.Ultraviolet laser/(Ultraviolet laser marking machine)

1)Principle

Through photochemical ablation, that is, by laser energy to break the bonding between atoms or molecules, making it into small molecules gasification, evaporation. The focus spot is very small and the heat affected zone is very small, so it can be used for superfine marking and special material marking.

2)Constitution

The main components of UV laser marking machine are: focusing system, trigger type, computer control system, laser power supply, laser, galvanometer field mirror scanning system, marking control software.

3)Advantages and application areas

Ultraviolet laser marking machine with its unique low-power laser beam, especially suitable for ultra-fine processing of the high-end market.iPhone, cosmetics, pharmaceuticals, food and other polymer packaging bottle surface marking; flexible PCB board; silicon wafer micro-hole, blind hole processing; LCD liquid crystal glass, glassware surface, metal surface coating, plastic buttons, electronic components, Communications Equipment,  and other fields.

Laser marking machine
Laser marking machine

4.Optical fiber laser/(Optical fiber laser marking machine)

1)Principle

Optical fiber laser marking machine principle: Optical fiber laser marking machine is the use of laser beams in a variety of different substances on the surface of permanent marking. Marking effect is through the evaporation of the surface material to expose the deep material, or through the light energy causes the chemical and physical changes of the surface material to “engrave” out the trace, or through the light energy burns off part of the material, showing the desired etched patterns, text, bar code and other graphics. The so-called fiber laser marking machine refers to the use of fiber laser marking machine, fiber laser with small size (no water-cooled device, using air-cooled), light is good quality (base mode), maintenance-free and so on.

2)Constitution

Fiber laser marking machine is mainly composed of fiber laser, high-speed scanning mirror, marking software, industrial computer and cabinet. Fiber laser is the core part.

3)Advantages and application areas

Mainly used in: plastics, electronics, metals, ceramics, tobacco and other materials marked out the required text, pattern, bar code and other graphics. Optical fiber laser marking machine easy to operate, fast marking, clear and other advantages, making the production efficiency of enterprises more efficient. Our commonly used pulsed lasers are 10W, 20W, 30W and 50W.

laser marking machine sample1
laser marking machine sample 1

Summary

We design and manufacture automatic machine for the PCB/SMT and Thru-hole industries in Shenzhen China. We help companies looking to low cost equipment with smart, ROI-driven assembly equipment solutions.Contact us today to learn how we can help you。

S-UV-300 laser marking machine for PCB

Product overview and industry application of laser marking machine

Abstract: The laser marking machine is means it use of  laser.  laser has the advantages of small volume (without water cooling, air cooling), good beam quality (fundamental mode), free maintenance etc, is mainly composed of laser, vibration lens, marking card three parts.

Guide: all you want to know about  laser machine knowledge is here!

S-UV-300 laser marking machine for PCB
S-UV-300 laser marking machine for PCB

In recent years, laser marking has become a hot topic in the study of laser physics. It is considered to be a new generation of products that may replace manual marking in an all-round way. The laser marking machine is a permanent mark on the surface of a variety of materials using a laser beam. The principle of marking is to expose deep matter through the evaporation of surface matter, or to engrave traces through the physical change of surface material caused by light energy, or to burn out some substances by optical energy to etch all kinds of graphics、patterns、characters、barcodes etc,.

The laser marking machine is means it use of laser. It has the advantages of small volume (without water cooling, air cooling), good beam quality (fundamental mode), free maintenance etc, is mainly composed of laser, vibration lens, marking card three parts.
Laser marking machine and its laser beam quality was good and with 1064 nm output center,it’s whole life is about 100 thousand hours,Laser compared with other types of markers for longer life. The efficiency of electro-optic conversion is above 28%, and the conversion efficiency of 2%-10% have a great advantage for other type of marking machine. It has excellent performance in energy saving and environmental protection.

Equipment features
1. A variety of metal and nonmetal materials can be processed. Especially for high hardness, high melting point and brittle material, it is more advantageous to mark the brittle material.
2. It belongs to non – contact processing, no damage to products, no tool wear and good marking quality.
3, the laser beam is fine, the processing material consumption is very small, and the processing heat affected zone is small.
4. The processing efficiency is high, the computer is controlled, and the automation is easy to be realized.

Application fields
Markers are widely used in many fields of graphics and text of integrated circuit chip, computer accessories, industrial bearings, watches, electronic and telecommunication products, aerospace devices, auto parts, household appliances, hardware tools, moulds, food packaging, jewelry, tobacco and military things, and mass production line.

Main features
Laser is divided into three kinds of types: CO2 laser/Green laser/UV laser. The following is a detailed introduction.
1, CO2 laser:10~20W, (laser wave is about 1064nm)
2, Green laser:7~10W(laser wave is about 532nm)
3,UV laser:3~5W(laser wave is about 355nm)
Laser marking machine is the most advanced marking equipment in the world. It has many advantages, such as good beam quality, small volume, fast speed, long service life, flexible and convenient installation, and low maintenance.Laser is the latest international, the most reliable structure, small volume, low power consumption.close to the ideal beam, the USB interface output control, optical scanner, laser with high repetition rate, high speed without distortion.

Future advantage
(1) low cost of manufacturing, mature technology and the availability.
(2) the light source has a very small volume area ratio, fast heat dissipation and low loss, so the up conversion efficiency is high and the laser threshold is low.
(3) the output of laser wavelengths is more.
(4)tunability: because of the wide fluorescence spectrum.
(5) the laser easy to apply to various multi-dimensional and arbitrary space processing applications, making the design of the mechanical system very simple.
(6) no thermoelectric refrigeration and water cooling are needed, only a simple air cooling is needed.
(7) high electro-optic efficiency: the integrated electro-optical efficiency is as high as 20%, saving the power consumption of the work and saving the operation cost.

S-UV-30A laser marking machine
S-UV-30A laser marking machine