PCB Assembly

Low cost PCB assembly

Publish Date:2020-11-06

The utility model relates to the technical field of PCB board, particularly to a low-cost PCB assembly with convenient assembly.
Background technology:
PCB board, also known as the printed circuit board, is the electrical connection of electronic components. The main advantage of using the circuit board is to greatly reduce wiring and assembly errors and improve automation and production labor rate. At present, according to the number of PCB layers, PCB can be divided into a single panel, double-sided board, four-layer board, six-layer board, and other multilayer circuit boards.
The PCB board structure is generally composed of a substrate layer and a conductive layer above the substrate layer, and the substrate layer is an insulating layer. In applying the PCB board, the corresponding electronic components will be welded on the electronic component pad on the PCB board’s conductive layer. In the existing technology, the connection between electronic components and the conductive layer is mostly by welding, which has the defects of a cumbersome process, inconvenient assembly, and high production cost. Moreover, the pins of electronic components are fixed on the pad by soldering tin. There may be false soldering.
Also, due to the poor thermal conductivity of the resin composite material of the insulating layer, the heat generated by the work of electronic components is mainly transmitted to the external air through the conductive layer’s copper foil. However, the thickness of the copper foil is minimal, and the thermal conductivity is limited. Therefore, it is usually necessary to set a heat dissipation layer at the insulation layer’s bottom. In the existing technology, the heat dissipation layer is generally connected with. However, these methods have the defects of inconvenient assembly.

Low cost PCB assembly

Technical implementation elements:
The utility model aims to provide a low-cost PCB assembly that is convenient to assemble and has the advantages of easy assembly and low cost. The PCB board with convenient assembly and low cost has good heat dissipation and has the advantages of easy assembly and low production cost.
To achieve the above purpose, the utility model is realized by the following technical scheme.
A convenient and low-cost PCB assembly is provided, which includes a substrate layer, a conductive layer arranged on the upper surface of the substrate layer, some electronic components arranged on the conductive layer, a heat absorbing and cooling material layer arranged on the lower surface of the substrate layer, and dissipation vias penetrating the conductive layer, the substrate layer and the heat absorbing and cooling material layer;
The conductive layer is provided with some socket slots for inserting the pins of the electronic components, and the notch of the socket is provided with some elastic conductive sheets for sealing the notch;

Low cost PCB assembly

Both sides of the heat absorbing and cooling material layer are provided with clasps, and the two ends of the base material layer are provided with clamping blocks for connecting with the buckle;
The plurality of heat dissipation via holes is inclined.
The longitudinal section of the inserting groove is set as U-shaped.
The slot of the socket is provided with four elastic conductive sheets for sealing the slot.
The inclination angle of the heat dissipation through-hole is set at 5 degrees to 10 degrees.
Preferably, the inclination angle of the heat dissipation through-hole is set as 8 degrees.
Both ends of the snap are provided with expanded shrapnel.
Two expanded shrapnel are relatively arranged at the two ends of the snap.

With the continuous development of science and technology, SMT processing gradually comes into our lives and is gradually known by more people. It belongs to a new type of electronic components, which is more common in the current society. So how can we reduce the production cost of PCBA and do a good job in quality control? The following is a brief introduction made by DEASPCB, a professional PCB assembly factory

Basic knowledge of low-cost PCB assembly

1、 Traditional patch
Brief introduction of SMT process
The traditional perforated electronic assembly process is to insert the components’ pins into the guide holes of the PCB and fix them, then use the wave soldering process to complete the whole welding process through the steps of flux coating, preheating, solder coating, detection, and cleaning.
2、 Introduction of SMT technology
With the development of the electronic industry, the products are designed to be short and light, making the volume and weight of various components smaller and smaller. The function density is also relatively improved to meet the trend of the times and customer needs. Under the influence of this change, surface adhesive components have become the main components of PCB, and its main feature is that it can greatly save space and reduce cost. Replace the traditional dip (dual inline package)
The surface adhesion assembly process mainly includes the following steps: solder paste printing, component placement, reflow soldering
The main steps of low-cost PCB assembly are summarized as follows:
Stencil printing: the solder paste is the bonding material between the surface adhesive assembly and PCB. First, the steel plate is etched or laser cut, and then the solder paste is printed on the PCB pad through the holes on the steel plate by the squeegee of the printer, so as to enter the next step.
Component placement: component placement is the key technology and focus of the whole SMT manufacturing process. In the process, high precision automatic placement equipment is used, and the surface adhesive components are accurately placed on the solder pad of printed solder paste PCB through computer programming. As the design of surface adhesive components becomes more and more precise, the distance between the pins becomes smaller, so the technical level of placement becomes more and more difficult.
Reflow soldering: reflow soldering is to preheat the PCB that has been placed with surface adhesive components in a reflow oven to activate the flux, then raise its temperature to 183 ℃ to melt the solder paste, connect the module foot with the PCB pad, and then cool down to solidify the solder, that is, to complete the bonding of surface adhesive components and PCB.
3、 Introduction of SMT equipment

  1. Stencil Printing: MP0 / MPM2000 / PVⅡ
  2. Component Placement: FUJI ( CP643E / CP742ME & QP242E / QP341E )
  3. Reflow Soldering: FURUKAWA( XN-425PHG / XN-445PZ / XNⅡ-651PZ ) ET10, ET11.
    4、 Explanation of SMT common names
    SMT: Surface Mounted Technology (SMT): the assembly technology of directly mounting components on the surface and welding them to the specified position on the surface of the printed circuit board
    SMD: surface mounted devices (SMD): the shape of SMD is a rectangular sheet, cylindrical line, or special-shaped, and its welding end or pin is made in the same plane, which is suitable for surface adhesive electronic components
    Reflow soldering: by remelting the paste solder paste pre-distributed on the PCB pad, the mechanical and electrical connection between the surface adhesive module terminals or pins and the PCB pad can be realized
    Chip: rectangular chip component: there is no lead at both ends, with solder end, and the surface of the chip is rectangular
    SOP: Small Outline Package: small molded plastic package with wing or J-shaped short pins on both sides
    QFP: Quad Flat Pack: thin surface assembled collective circuit with wing short pins on four sides and pin spacing of 1.00, 0.80, 0.65, 0.50, 0.40, 0.30mm
    BGA: Ball grid array: packaging form of the integrated circuit, whose input and output points are tin balls arranged in a grid pattern on the module’s bottom surface.
Low cost PCB assembly

5、 Packaging method of low-cost PCB assembly
Ribbon/stick (shipping tube) – main component container: the ribbon is made of transparent or translucent polyethylene (PVC) material and extruded into a standard shape that meets the current industrial standards. The strip size provides appropriate component orientation and orientation for industry-standard automatic assembly equipment. Strips are packaged and transported in the form of a combination of the number of individual strips.
Tray – main component container: the tray is made of carbon powder or fiber materials selected based on the special tray’s temperature rate. Trays designed for components requiring exposure to high temperatures (moisture sensitive components) have a temperature resistance of usually 150 ° C or higher. The tray is cast into a rectangular standard shape, which contains a uniform alternate cavity matrix. Cavities hold the assembly and protect during transportation and handling.
The bay provides an accurate component location for standard industrial automation assembly equipment used for mounting during PCB assembly. Pallets are packaged and transported in the form of a single pallet, then stacked and bundled together with a certain rigidity degree. An empty cover tray is placed on the loaded components and stacked trays.
Tape and reel – main component container: typical tape and reel structures are designed to meet modern industrial standards. There are two generally accepted standards for the construction of covered coil packaging. EIA-481 is used for embossed structures, while eia-468 is used for radial LED components. So far, the structure of active IC is embossed tape
6、 Why is the cleaning free process applied in low-cost PCB assembly processing technology?

  1. The wastewater discharged from the product cleaning in the production process will bring pollution to the water quality, the earth, and even animals and plants.
  2. In addition to water cleaning, the use of CFC & HCFC for cleaning also pollutes and destroys the air and atmosphere.
  3. The cleaning agent remains on the machine plate and causes corrosion, which seriously affects the product quality.
  4. Reduce the cost of cleaning operation and machine maintenance.
  5. No cleaning can reduce the damage caused by PCBA in the process of moving and cleaning. There are still some components that cannot clean.
  6. The residual flux has been controlled and can be used by the product appearance requirements to avoid visual inspection of the cleaning state.
  7. The residual flux has continuously improved its electrical performance to avoid leakage of the finished product and any injury.
  8. The wash free process has passed several international safety tests, proving that the chemical substances in the flux are stable and non-corrosive.
Switch knowledge of low-cost PCB assembly

SMT processing is a kind of technology and process in the current electronic assembly industry. It compresses the traditional electronic components into only one-tenth of the device’s volume to realize the degree of electronic product assembly, high reliability, miniaturization, low cost, and production automation. Its related assembly equipment is called SMT equipment. As the key equipment in SMT, SMT processing, and placement machine, You need to know a lot about it. Ideaspcb to talk about SMT Mounter switch knowledge.
The switches of low-cost PCB assembly machines are divided into emergency switches and general stop switches. They are different and cannot be used casually.
The emergency switch is used in emergencies, such as life-threatening or the risk of crashing the machine, we need to use the emergency switch. If you also use the emergency switch when the machine is running normally, What will immediately cut off all servo power of the machine, and the machine will stop running immediately. If you choose the general stop switch, the machine will stop after completing its steps.
Let’s take an example. If the machine is sucking material, the machine must stop after it is pasted. At this time, if you press the emergency switch, the machine will stop sucking material immediately, which obviously can’t achieve our goal. Therefore, when we use SMT to process SMT, we can’t ignore its switching problem.