What technical parameters should be considered when purchasing reflow soldering equipment

In addition to the price factors, the technical parameters of reflow soldering equipment are very important in the purchase of reflow soldering equipment. They should be taken as the core of the purchase, including the heating mode of reflow soldering equipment, the application scope of solderable PCB, transmission system (including transmission mode, transmission direction and speed regulation range), the temperature characteristics of reflow soldering equipment, the configuration of temperature control system and power, appearance structure Nitrogen supply system and nitrogen consumption, etc. Overall, the main technical parameters of reflow soldering equipment are as follows:

1、 Heating system parameters of reflow soldering equipment

The heating system parameters of reflow soldering equipment mainly include the number of heating temperature zones, temperature characteristic parameters, power consumption parameters, etc.

1. Number of heating temperature zones of reflow soldering equipment:

Reflow soldering equipment shall have at least three heating sections with independent temperature control. The more heating sections, the more flexible the adjustment of process parameters. The number of heating sections is directly related to the heating length. The heating length is determined according to the specification of the printed board to be welded, the size of equipment load factor, the level of production efficiency and the requirements of product manufacturability. Generally, 4 ~ 5 temperature zones are selected for medium and small batch production, The length of the heating zone is about 1.8m, which can meet the requirements.

2. Temperature characteristic parameters of reflow soldering equipment

Temperature characteristic is a comprehensive reflection of the design quality of reflow soldering equipment, including four important indexes: temperature control accuracy, temperature non-uniformity, repeatability of temperature curve and maximum heating temperature.

(1) Temperature control accuracy directly reflects the stability of temperature field of reflow soldering equipment, and its index range is mostly ± L ℃ ~ 2 ℃, which requires sensitive temperature sensor.

(2) Temperature unevenness, also known as the transverse temperature difference of the transmission belt, is an important index to characterize the performance of reflow soldering equipment. It refers to the temperature difference at the working part on any section perpendicular to the PCB transmission direction in the furnace. Generally, the bare PCB with the maximum width that can be soldered by the reflow soldering furnace is tested, which is expressed by the maximum difference of the welding peak temperature of the three test points. This index reflects the real temperature on the printed board and directly affects the welding quality of products. The current advanced index is less than ± 2 ℃.

(3) The repeatability of temperature curve directly affects the consistency of welding quality of es2818 printed board, which should be paid great attention to. Generally speaking, the index shall not be greater than 2 ℃, that is, the temperature difference between different detection time periods at the same point shall be measured for many times.

(4) Temperature curve built-in test function.

(5) Maximum heating temperature: generally 300 ℃ ~ 350 ℃. If lead-free solder or metal substrate is considered, more than 350 ℃ shall be selected, and the upper and lower heaters shall have independent temperature control system.

3. Power consumption parameters of reflow soldering equipment

The size of power is often ignored when users buy. In fact, as far as the equipment manufacturer guangshengde is concerned, the determination of power is obtained through calculation, comparison and even test during design and development. In fact, the power not only affects the distribution load of users, but also has a great impact on the heating rate of equipment and the rapid response ability of product load changes. Since different manufacturers have different fixed values for the maximum product load factor of the equipment, usually 0.5 ~ 0.9, generally speaking, the heating time of the equipment does not exceed 30min, so the power of similar models is also quite different, which should be paid attention to when purchasing. Generally speaking, the temperature rise time of the equipment shall not exceed 30min. When the equipment works continuously, the furnace temperature shall be stable and its fluctuation shall be less than ± 5 ℃.

2、 Parameters of transmission system of reflow soldering equipment

Transmission system equipment parameters mainly include solderable PCB specification, transmission speed and conveyor belt stability.

1) Solderable PCB specification

The specification of solderable PCB refers to the size range of PCB that can be soldered by reflow furnace. At present, the maximum width of solderable PCB of most reflow furnaces has reached 600mm, and the equipment of different specifications has been serialized, so there is a large choice.

Due to different printed boards, the requirements for equipment transmission system are also different, so consideration should be given to it.

2) Transmission speed

The transmission system mainly includes transmission mode, transmission direction and speed regulation range. The speed regulation range of transmission speed is generally 0.1 n/min~1/2. N / min, stepless speed regulation mode is adopted. Adopt chain transmission or network transmission, or both, and strive to achieve stable PCB delivery.

3、 Outline structural parameters and other characteristic parameters of reflow soldering equipment

For the appearance of reflow equipment, the reflow equipment mainly considers the overall dimensions of equipment, plant design, equipment color matching and coordination, modeling, etc. It is generally expressed by the length, width, height, front and rear installation clearance and other parameters of reflow welding equipment.

4、 Other special requirements and parameters of reflow soldering equipment

Reflow soldering equipment also includes many characteristic parameters, which are not available in every reflow furnace, but now many high-grade reflow soldering equipment have relevant functions, including the following characteristic parameters:

(1) Nitrogen welding environment capability. Purity ppm, consumption, measurement function.

(2) Exhaust air volume and allowable variation range.

(3) Removal method of flux residue (simple, low cost) and recycling rate.

(4) Internal wind speed control.

(5) Built in temperature detection and monitoring.

(6) Power failure treatment.

(7) Overtemperature alarm and protection function.

(8) Cooling efficiency. It shall be determined according to the complexity and reliability requirements of products. For products with complex and high reliability requirements, high cooling efficiency, such as water cooling, shall be selected.