SMT Component Placement Process Of Parts : Manual Placement, China SMT PCBA factory_

SMT Component Placement Process Of Parts : Manual Placement

(1) Manual mounting process requirement

1. Improve the production efficiency as much as possible, under the condition of certain human and material resources, achieve the purpose through reasonable arrangement work procedure and adopt the best operation method.

2. Ensure the excellent and stability of product quality. This is reflected in the production process of the product components, semi-finished products in the production line of the high rate of straight-through, the finished product inspection pass rate is high, good consistency of technical indicators; finished products in the unqualified products in the return of failure causes no instability factors or abnormal failure.

3. Ensure that each component can work normally in the whole machine with its original performance after installation. The performance of the components should not be reduced or the parameters should not be changed due to improper installation process.

4. Develop detailed operating specifications. For those installation processes that directly affect the performance of the machine, as far as possible, the use of special tools to reduce the arbitrariness of manual operation.

5. The arrangement of the work sequence to facilitate the operation, in order to maintain the orderly arrangement and transfer of work between. In the installation process, to install large components, auxiliary parts, combined parts on the frame or base plate, when installing, inside and outside, up and down, left and right should have certain regularity, also pay attention to the shape symbol and mark position of each installed device, easy to observe when checking and also pay attention to the sequence order when combining.

(2) The application scope of manual mounting.
1、Because individual components are loose parts, special components don't have corresponding feeder, or because of the device's pin deformation and so on various reasons cause can't realize on the pick& place machine to mount, as the machine mount after the supplementary mount.
2、A small amount of new product development stage or small batch production;
3、Because of the financial shortage, has not introduced the mounting machine, at the same time the product assembly density and difficulty is not very big. (3) the process flow of manual patching.

A. Application of solder paste: can use simple printing tool manual printing solder paste process or manual dispensing machine drop coating solder paste process.

Second, manual mounting: 1. Manual mounting tools (1) stainless steel tweezers (2) suction pen (3) anti-static workbench (4) anti-static wrist strap

2、Placement order 
1), first place small components, then place big components. 
2), first place short component, after place high component. 
3), First light and then heavy. The installation process, first installs the light component, after installs the heavy device. 
4), first after the example installed. Installation process, while using the example, screwing, welding and other processes, should first example, then screwing, and finally welding. 
5), first inside and then outside. In the combination of parts to connect the whole machine, first from the combination of the rack for installation, and then gradually installed to the outside. 
6), Generally arrange the assembly line mounting station according to the kind of components. Each person pastes one kind or several kinds of components; The components with more quantity can also arrange several pasting stations. 
7), Can set up an inspection station behind each mounting station, also can set up an inspection station after several stations, also can complete the whole version inspection after mounting. To set according to the density of the assembly board. 
8), first load conventional, common components, after loading fragile components, can prevent damage in installation. 
9), Keep the work site neat and orderly, effectively control the harm caused by the production residue. 
10), Installers should be responsible and develop good working habits. 
11), The strict operation procedure, the complete protection measure, the perfect fire prevention and the safe use point regulation system etc. are the factors that cannot be ignored in the production.

(3) Manual mounting method 
1) Momentary type, cylindrical Chip component mounting method. Hold the component with tweezers, align the component solder end with the pad at both ends, put it on the pad solder paste centrally, the polar component mounting direction should conform to the requirement of the drawing, after confirming the accuracy, press it gently with tweezers, make the component solder end invade the solder paste. 
2) SOT mounting method Hold the component with tweezers, align the solder end of the component with the pads at both ends, and put it on the pad solder paste centrally, and gently press the component with tweezers after confirming the accuracy, so that the pin of the component is not less than 1/2 thickness into the solder paste, and all the pins of the component are located on the pad. 
3) SOP, QFP mounting method Device 1 pin or front mark align with the front mark of the printed character, hold or suck the device with tweezers or suction pen, align with the mark, align with the pads on both sides or four sides, center the device, and gently press the top surface of the device body with tweezers so that the component pins are not less than 1/2 thickness into the solder paste, requiring all the component pins to be located on the pad. Pin pitch 0.65mm below the narrow pitch device should be mounted under 3~20 times microscope. 
4) SOJ, PLCC mounting method SOJ, PLCC mounting method is similar to SOP, QFP, because the pins of SOJ, PLCC are at the bottom of the device, so when aligning, it is necessary to check whether the pins and pads are aligned by eye from the side of the device and the PCB board into 45 degree angle.