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SMT production line equipment selection basis
PCBA Tech
SMT production line equipment selection basis

SMT production line equipment selection basis

2021-11-07
View:39
Author:Downs

(1) Existing product types, devices, production capacity, and line construction requirements.

At present, the annual output of intercom products SMT circuit boards is about 4,000 pieces, with 28 varieties, and the annual output of the largest variety of circuit boards is 2,000 pieces.

The maximum size of the circuit board is 320mm*260mm*3mm; the minimum size is 120mm*80mm*3mm, and the maximum height of the device is 10mm.

DUB user board with the largest number of single types of devices: chip resistors, 24 types of capacitors, 10 types of SOP, 2 types of PFP packages, 0.3 mm pitch PLCC package 44 pins 55mm*55mm, 3 types of QFP packages, 80, 160, 208 pins , Pitch 0.3 mm;

IP intercom production requires the use of CSP, BGA, PGA, LBGA, connectors, shields, crystal oscillators and other new SMT packaged devices;

The production line can produce smart instrument SMT circuit boards;

The next step is to process and produce PCBAOEM.

pcb board

With the increasing density of circuit board assembly devices, more new packages with extremely narrow pitches, small size, and high placement accuracy requirements, production is becoming more and more difficult. The precision and production speed of manual placement cannot meet the requirements of high-yield, high-precision, and high-quality circuit board manufacturing in the industrial intercom manufacturing base.

The two existing platform pipelines are required to be relocated to the industrial park to realize THT plug-in and extension assembly, saving investment. Ready to build a new automated SMT production line.

(2) Intercom SMT circuit board mounting defects and process flow.

Manual SMT placement defects:

a. CHIP component placement offset, manual pressure inconsistency, visual inspection can not detect subtle placement gaps, QFP manual placement is inaccurate, cannot be placed in place at one time, and needs to be placed twice, resulting in solder paste adhesion. Bridging.

b. Manual solder paste printing speed is slow, forming a bottleneck restricting the production speed of the whole line.

c. Optimized reflow soldering curve and improper cooling zone, resulting in poor soldering and warpage.

SMT production of digital intercom circuit boards currently uses semi-automatic printing machines, platform production lines, manual placement of vacuum suction pens or tweezers, and reflow soldering processes.

After moving to the industrial park, the circuit board SMT assembly process is single-sided mixed assembly. The optimized process flow is: PCB inspection→Automatic printing of solder paste on side A→automatic placement of SMT and SMD components on side A→reflow soldering→AOI inspection→in-line THT on side B→hand soldering of THT pins on side B→cleaning→function Test → enter the semi-finished product warehouse. Need to configure printers, placement machines and reflow soldering equipment.

(3) According to the existing product assembly density, narrow-pitch QFP, large-size SMD, and special-shaped components, it is determined that the IC special-shaped placement equipment is equipped with a full-vision high-precision multi-function placement machine. Taking into account the high-speed production needs to be equipped with a high-speed CHIP component placement machine.

3. Equipment selection steps (capacity calculation).

(1) Calculate the maximum output in 2009 and calculate that the total number of SMD components for the year is 583,840 points. We calculate it at 600,000 points.

(2) Theoretical capacity calculation:

a. Manual patch

Each station has 1,000 points per shift, five stations, 5,000 points in eight hours (shift production), and 600,000 points are placed in 120 shifts.

b. Automatic placement machine

The placement speed of a combination of a high-speed machine and a multi-function machine is between 10,000 points and more than 100,000 points per hour. We calculate it at 10,000 points per hour. Regardless of line change, single species: 8 hours (shift production) 80,000 points, 8 shifts are required to complete 600,000 points placement. Consider multi-variety, small batch, frequent line change, and relax 1 times the working hours.

(3) SMT whole line configuration methods are divided into two types: "multi-variety, small batch" and "small-variety, large batch".

The configuration principle of "multi-variety and small-batch" is to be flexible, expand and save resources.

The configuration principle of "small variety, large batch" is: flexibility, high speed, reliability, and creativity. In mass configuration, it is necessary to be as high as possible to increase productivity and reduce costs. At the same time, high-speed requires good reliability, strong consistency, high flexibility and stability, in order to have higher profits and higher return on investment.