ClassifICation of red patch adhesives and mounters
What is the difference between red rubber wire mesh and solder paste wire mesh? Is the process different? Price not used? Still different? In fact, the difference between the two is When opening the wire mesh, open the solder paste mesh in the original pad, and then open the red plastic mesh in the center of the two pads. The hole can be extended to double points and bone shape
1. The thickness and opening of the template shall be made of red surface mounted patch plastic.
(1) The thickness of red rubber mesh is usually 0.18mm, 0.2mm, 0.25mm, etc.
(2) The opening requirements of the red plastic template: the opening width of the IC is 1/2 of the width of the two pads, and multiple SMAll round holes can be opened.
2. Red plastic equipment patch design requirements:
(1) The long axis of the chip assembly must be perpendicular to the transmission direction of the wave soldering machine; The long axis of the IC equipment must be parallel to the conveying direction of the wave soldering machine.
(2) In order to avoid the shadow effect, the ends of components with the same size are arranged in parallel with the direction of the welding wave; Parts of different sizes must be staggered; Small parts shall be arranged in front of large parts; The body can protect the welding head and welding nail. When it is not possible to arrange according to the above requirements, there must be a gap of 3 to 5 mm between the components.
(3) The feature directions of components must be consistent. For example, the polarity of the electrolytic capacitor, the anode of the diode and the single pin end of the transistor should be perpendicular to the transmission direction, the first stage of the integrated circuit, etc.
3. Red plastic opening and pad design surface mount patch assembly:
(1) Assembly holes must be arranged in the basic grid, 1/2 basic grid and 1/4 basic grid. The clearance between the plug hole and the pin diameter of the inserted part facilitates wetting the solder.
(2) For wiring of high-density components, oval grounding mode shall be used to reduce tin connection.
Basic requirements for components and printed circuit boards in wave soldering process.
(1) Three layers of surface mounted components shall be selected. The main body of the component and the welding point can withstand the temperature impact of more than twice welding every 260 ℃ wave. After welding, the main body of the device is not damaged or deformed, and the end of the chip assembly is not coated.
(2) The surface mount substrate must be able to withstand heat resistance of 260 ° C/50 seconds. Copper foil has good peel strength, and the welding resistant layer still has sufficient adhesion at high temperature, and the welding resistant layer will not wrinkle after welding.
Classification and maintenance knowLEDge of surface mount mounters
Classification of SMT tape: steel wire T-shaped track, main belt, motor belt, X-axis belt, Y-axis belt, RN axis synchronous belt: input plate drive belt, CP33L conveyor belt, CP40L conveyor belt, CP45FV/NEO conveyor belt, R-axis belt, SM321 conveyor belt, toothed belt, Z-axis belt, JUKI2050 T-axis belt, wide belt, conveyor belt.
Specification of surface mounted patch tape: (thickness: 0.6mm 0.8mm 0.9mm 1.0mm 1.1mm 1.2mm 1.3mm 1.5mm 2.0mm)
How to fix the SMT tape:
1. Turn off the power, remove the protective cover, loosen the mounting bolts on the motor base, and move the motor forward and backward.
2. Shake the motor to make the belt loose enough for disassembly. Do not use tools to slide the surface mounting tape.
3. Remove the old belt and check for abnormal wear. Excessive wear may indicate a problem with the transmission design or maintenance.
4. Clean the surface mount patch belt and pulley: Clean the cloth with a small amount of non-volatile liquid. Do not soak in detergent or rub the belt with detergent. Do not scratch the belt with sandpaper or sharp objects. The belt must be dry before installation.
5. The SIMplest way to check whether the belt is broken or worn is to use a pulley groove gauge. If excessive wear occurs, replace the pulley.
6. Check the symmetry, durability and lubrication of the remaining drive components, such as bearings and bushings.
Surface mount patch has a high demand on the conveyor belt, especially the anti-static requirement In the manufacturing process of electronic products, electrostatic discharge can change the characteristics of semiconductor devices, causing damage or unstable performance, resulting in damage to the final product or improper use
The above is the explanation given by the editor of PCB circuit board company.
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