Circuit board factory: 6 decisive factors for purchasing reflow soldering

Circuit board factory: 6 decisive factors for purchasing reflow soldering

Reflow soldering is a key process in SMT process, and the role of reflow soldering equipment is self-evident. With the rapid development of China's electronic product processing industry, reflow soldering has also achieved rapid development. There are also many low-quality reflow soldering equipment in the market. How to select a high-quality reflow soldering equipment has become a puzzling problem for many manufacturers. So let me answer the six decisive factors for purchasing reflow soldering. 1、 When PCB is welded by reflow soldering, the longer the PCB stays in the reflow soldering, the better the welding effect will be. Therefore, the larger the volume of the reflow welder is, the longer the heating zone will be,

Reflow soldering is a key process in SMT process, and the role of reflow soldering equipment is self-evident. With the rapid development of China's electronic product processing industry, reflow soldering has also achieved rapid development. There are also many low-quality reflow soldering equipment in the market. How to select a high-quality reflow soldering equipment has become a puzzling problem for many manufacturers. So let me answer the six decisive factors for purchasing reflow soldering.

1、 Appearance

When PCB is soldered through reflow soldering, the longer the PCB stays in reflow soldering, the better the welding effect will be. Therefore, the larger the volume of the reflow welder is, the longer the heating area will be, and the better the heating effect will be. Nowadays, some pcb manufacturers want to cut corners and reduce the volume of reflow soldering in some six temperature zones, which is not up to the six temperature zone standard. Generally, 5-6 temperature zones are selected for medium and small batch production, and the reflow furnace with a heating zone length of about 1.8m can meet the requirements. Therefore, when purchasing a reflow welder, it is necessary to see how many temperature zones there are and how long it is heated.

2、 Temperature

1. The temperature control accuracy shall reach ± 1 ℃. The influence on the temperature control accuracy and the way of reflow welding heat generator is related to the heating and heat transfer way:

(1) The heating wire type heating element (usually the heating element is wound with imported nickel chromium wire) has a high exchange rate and a long service life.

(2) Infrared tube heating element (imported far-infrared heating tube), which is radiation type, has good uniformity, but will produce color difference with, and is mainly used for thermal compensation area, not for welding area.

(3) The heating tube type heating element has low heating efficiency. If it does not pass through the hot air, the uniformity of the heating surface is poor (generally less used).

Heating and heat transfer mode: full hot air circulation (good) and hot air circulation+infrared composite (good) and full red external (poor)

2. The maximum heating temperature is generally 300~350 ℃. If lead-free solder or metal substrate is considered, it should be above 350 ℃. The thermal insulation performance of different reflow soldering is different. Generally, the thermal insulation layer of low-grade products is not enough, and the maximum temperature is usually less than 300 degrees. Generally, the design temperature of reflow soldering can reach 300 degrees or above. The design temperature of reflow soldering is more than 320-350 degrees or above. If the reflow soldering is for radiator soldering, it can reach 400 degrees or above.

3. The transverse temperature difference of the transmission belt shall be below 5 ℃, otherwise it is difficult to ensure the welding quality. High quality reflow welding can generally be controlled at ± 2 ℃/± 3 ℃ (MCR series and ROHS series)

3、 Conveyor belt

1. The width of the conveyor belt shall meet the requirements of the maximum PCB size. Select the mesh belt width according to your PCB: select 300MM for PCB 200MM mesh belt application. Generally, select 300, 350, 400, 450, 500MM. The larger the width is, the greater the reflow power will be. Therefore, it is the most important to select the right one.

2. The conveyor belt shall operate stably. The vibration of the conveyor belt will cause displacement, suspension bridge, cold welding and other welding defects. For the reflow soldering of middle and low gears, the transmission mechanism is relatively simple, and there will be a little vibration. The front MCR ROHS series high stability synchronizer can generally solve the above problems.

4、 Temperature region

For standard lead-free production, we usually have 8 temperature zones, which can be divided into S series, M series, MCR series, ROHS series according to different production requirements. In terms of control, there are also instrument type touch type (optional) computer type. Control system: the computer system cooperates with Siemens system to select computer type reflow soldering to test whether the computer crash or removal will affect production. If the system board card of the industrial personal computer is not functional and does not have storage function, Once the computer system has a problem, the equipment can not be used. The cost of such systems is low. It is recommended not to purchase such models.

5、 Control circuit

The control circuit of good reflow soldering generally needs to be designed with anti-interference circuit. Its frequency converter and external impulse voltage will affect the stability of reflow soldering. If there is no relevant treatment, the manufacturer recommends not to purchase equipment.

6、 Temperature curve

It shall have the function of temperature curve test. If the equipment does not have this configuration, the temperature curve collector shall be purchased.

When purchasing reflow soldering, some people will win or lose by price. If they only pay attention to the price, they will be easily cheated by some electronic processing manufacturers and buy some products with high price and poor quality. Therefore, when they buy enough, they should focus on the quality of the equipment and choose their own reflow soldering equipment.

The circuit board manufacturer and circuit board designer explain the 6 decisive factors for purchasing reflow soldering.