Why does PCB production require panelization and board edges?

Why does PCB production require panelization and edges?

1.PCB paneling improves placement efficiency

In the SMT industry, we often see panelization in SMT production lines, which are generally called two-in-one and four-in-one. This is because the patch line has many processes. The core equipment from the front end to the end is the printing machine and the patch panel. chip machine, reflow soldering;

Generally, the front-end printing machine takes about 10-25 seconds to print a board, while the back-end high-speed placement machine may only need a few seconds to attach all the electronic components to a board, so the placement machine may be idle. The phenomenon of boards will reduce the production efficiency of the entire SMT production line. Therefore, PCB boards need to be assembled into panels in order to achieve a balance of production efficiency in each process of the SMT production line. There will be no accumulation and empty waiting, so that Each process equipment is fully efficient.

2. PCB panel production improves PCB board utilization

The circuit board designs of many electronic products have irregular shapes, such as L-shaped PCB boards or round PCB boards. If it is a two-in-one, it will be wasted. However, a four-in-one can improve the utilization rate of PCB boards and reduce PCB board waste. ,

3.The purpose of PCB edge production

(1). The main purpose of PCB board edge design is to assist PCBA production. Today’s SMT production lines are very automated. PCB boards are transported by belts and chains. The main purpose of the board edge is to provide these belts and chains. Chains are used to transport boards.

(2). The edge of the PCB is used to position the board during ICT or FVT testing after SMT to prevent the needle bed from moving away from the test points. It is used as a sensor in SMT production lines to detect the position of circuit boards.
PCB paneling improves placement efficiency

4. PCB panel production improves PCB board utilization

The circuit board designs of many electronic products have irregular shapes, such as L-shaped PCB boards or round PCB boards. If it is a two-in-one, it will be wasted. However, a four-in-one can improve the utilization rate of PCB boards and reduce PCB board waste. ,

The five holes can be clearly seen, indicating that after attaching the piece, the craft edge can be broken off by hand.

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5. Things to note when PCB assembly

In order to facilitate production, PCB circuit board imposition generally requires the design of Mark points, V-shaped grooves, and process edges.

(1)imposition appearance

a. The outer frame (clamping edge) of the PCB panel should adopt a closed-loop design to ensure that the PCB panel will not deform after being fixed on the fixture.

b. PCB panel width ≤ 260mm (SIEMENS line) or ≤ 300mm (FUJI line); if automatic dispensing is required, PCB panel width &TImes; length ≤ 125 mm &TImes; 180 mm.

c. The shape of the PCB panel should be as close to a square as possible. It is recommended to use 2&TImes;2, 3&TImes;3,… panels; but do not form a yin and yang board;

(2) V-shaped groove

a. After opening the V-groove, the remaining thickness X should be (1/4~1/3) of the plate thickness L, but the minimum thickness The upper limit can be used for boards with heavier load-bearing capacity, and the lower limit can be used for boards with lighter load-bearing capacity.

b. The misalignment S of the upper and lower incisions of the V-shaped groove should be less than 0.1mm; due to the limitation of the minimum effective thickness, it is not suitable to use the V-groove paneling method for boards with a thickness less than 1.2mm.

(3)Mark point

a. When setting the reference positioning point, usually leave a solder mask-free area 1.5 mm larger than the positioning point.

b. Used to help the optical positioning of the placement machine. There are at least two asymmetric reference points at the opposite corners of the PCB board with placement devices. (http://www.dgzj.com/ All Rights Reserved) Reference for optical positioning of the entire PCB The points are generally at the corresponding diagonal positions of the entire PCB; the reference points for optical positioning of segmented PCBs are generally at the corresponding diagonal positions of the segmented PCB circuit boards.

c. For QFP (Quad Flat Package) devices with lead spacing ≤ 0.5mm and BGA (Ball Grid Array Package) devices with ball spacing ≤ 0.8mm, in order to improve placement accuracy, it is required to set reference points at the two opposite corners of the IC.

(4) process edge

There should be no large components or protruding components near the connection points between the outer frame of the panel and the internal small boards, or between small boards, and there should be a space of more than 0.5mm between the components and the edge of the PCB circuit board. , to ensure the normal operation of the cutting tool.

(5) Positioning holes on the board

a. The reference symbols used for the positioning of the entire PCB circuit board and the positioning of fine-pitch devices. In principle, QFPs with a pitch less than 0.65mm should be set at their diagonal positions; the reference symbols used for positioning PCB sub-boards should be Use in pairs and place them at the opposite corners of the positioning elements.

b. Positioning posts or holes should be left for large components, such as I/O interfaces, microphones, battery interfaces, micro switches, headphone interfaces, motors, etc.

A good PCB designer must consider production factors when performing imposition design to facilitate processing, improve production efficiency, and reduce production costs.

PCB circuit board component layout requirements

Reasonable arrangement of PCB circuit board components in patch processing is the basic prerequisite for designing high-quality PCB diagrams. The requirements for component layout mainly include five aspects: installation, stress, heating, signal, and appearance.

1. Installation

Refers to a series of basic principles proposed in specific application situations in order to smoothly install circuit boards into chassis, shells, and slots without causing spatial interference, short circuits, and other accidents, and to keep the designated connectors at designated positions on the chassis or shell. Require.

2. Force

The circuit board used in patch processing should be able to withstand various external forces and vibrations during installation and work. For this reason, the circuit board should have a reasonable shape, and the positions of various holes (screw holes, special-shaped holes) on the board should be arranged reasonably. Generally, the distance between the hole and the edge of the plate must be at least greater than the diameter of the hole. At the same time, it should also be noted that the weakest section of the plate caused by the special-shaped hole should also have sufficient bending strength. The connectors on the board that “extend” directly out of the equipment shell must be properly fixed to ensure long-term reliability.

3. Heating

For high-power devices that generate serious heat, in addition to ensuring heat dissipation conditions, attention should also be paid to placing them in appropriate locations. Especially in precision analog systems, special attention should be paid to the adverse effects of the temperature field generated by these devices on the fragile preamplifier circuit. Generally, the very high-power part should be made into a separate module, and certain thermal isolation measures should be taken between it and the signal processing circuit.

4. Signal

Signal interference is the most important factor to be considered in PCB circuit board layout design. The most basic aspects are: separate or even isolate weak signal circuits from strong signal circuits; separate AC parts from DC parts; separate high frequency parts from low frequency parts; pay attention to the direction of signal lines; layout of ground wires; appropriate shielding and filtering and other measures.

5. Beautiful

Not only should the components be placed neatly and orderly, but also the routing should be smooth and graceful. Since ordinary laymen sometimes emphasize the former to one-sidedly evaluate the merits of circuit design, for the sake of product image, the former should be given priority when performance requirements are not stringent. However, in high-performance situations, if double-sided panels have to be used and the circuit board is also packaged inside and cannot be seen at ordinary times, priority should be given to the beauty of the wiring.

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In addition to DXP, what other software can be used to draw PCB?

ZentiPCB

First on our list is the ZentiPCB platform from Mirko Bruno Sortini, which provides a range of free software to help users design their own PCBs. ZentiCapture allows users to quickly and easily design schematics using a simple toolset that allows users to place parts (component symbols) through orthogonal locking and pin snapping. Once the schematics (in diagram form) are complete, they can be ported to ZentiPCb.

ZentiPCB is a CAD-based program that allows users to import netlist files and visualize their diagrams. The layout editor provides the ability to import components directly from the library using cursors, supporting single-sided and double-sided panels depending on needs.

TinyCAD

TinyCAD comes from SourceForge users beischer, don_lucas and mattpyne. Don’t underestimate this software just because of its name. This software provides all functions of PCB design and wiring design. The software contains 42 libraries with a total of 755 symbols, including digital logic gates, electromechanical components and even microcontrollers. And each component can be edited, and users can even add their own component symbols. TinyCAD supports multiple netlist formats (Eagle SCR, PADS-PCB, XML, etc.) and can also generate SPICE netlists.

CometCAD

CometCAD is another great example of a free software platform that provides an electronic circuit schematic editor and a PCB layout editor. It’s just that this software only supports Windows platform. CometCAD electronic circuit schematic editor supports multi-page schematics, symbol rotation, parts list and netlist schematic output. The PCB wiring editor provides almost all the functions mentioned above (component library, double-sided PCB, etc.), and also has the function of outputting CAM files. It can also be used to design rectangular multi-PCB boards.

BSch3V

Those who don’t want unnecessary features and only need the most basic functions can try Suigyodo’s BSch3V schematic capture package (where BSch stands for Basic Schematic basic schematic). The PCB editor allows users to design single-layer, double-layer, or even four-layer PCB boards with a design area of 30 square millimeters. It also features a component library, component list generator and a netlist generator. Users can also use two other software to enhance the functions of BSch3V, including SmdICpad (used to obtain QFP, PLCC, SOP data) and POLYGON (area for placing copper).

Designer

PCWeb’s Designer is one of the most feature-rich editors on the Internet, and it’s free to use. The software has an impressive lineup of tools, including Schematic Capture (place components, routing/nets, annotations, etc.), PCB (place components, routing, design rule checks, etc.) and Part Editor (create/define components, add symbols, etc.), in addition, it also includes the BOM table function. The BOM manager integrates Digi-Key, allowing users to assign a number to each individual component on its PCB. This number will be displayed through the BOM table to facilitate procurement. . This software is a software that is conducive to efficient production.

Fritzing

The Fritzing platform is more than just a simple PCB editor, but is designed to give makers and hackers the ability to actually create their own designs. It is designed so that users can implement their own Arduino microcontroller-based designs and create production-ready PCB layouts. Once the user has designed an actual circuit on the breadboard, it can then be transferred to the editor, which contains three different project views. The breadboard view allows users to drag and place virtual electronic components on a virtual breadboard. The schematic view is the formal expression of the schematic, which corresponds to the circuit on the virtual breadboard, but users can also edit it as needed. Finally, the PCB view allows users to place components on a virtual printed circuit board that can then be used for production.

​KiCAD

The most popular free PCB editor on the Internet can be said to be KiCAD, which is an EDA tool similar to the above-mentioned Fritzing. This software provides virtual environment capabilities at every stage of the design process. Components included are Eeschema (schematic editor), Pcbnew (printed circuit board editor), Gerbview (Gerber file viewer), and Cvpcb (path selector for component associations). In addition, there is a built-in BOM manager, allowing users to mark the bill of materials and calculate costs easily.

DesignSpark

DesignSpark’s PCB platform is another widely used PCB editing tool for EDA applications. Similar to the two tools mentioned earlier, DesignSpark PCB provides schematic editing functions, while PCB Wizard is used to improve schematics, and Autorouter can complete automatic routing between components. However, this software does have some things that need attention. For example, this software consumes a lot of resources. If the project does not exist on the same computer, problems may occur. In addition, some functions must be registered by the user before they can be unlocked. The worst thing is The software also displays ads.

gEDA

Despite the fact that most PCB software runs on Windows-based computers, there are some designed specifically for Linux users, including Ales Hvezda’s gEDA project, which provides a collaborative open source EDA tool. The collaborative component refers to the ongoing efforts of collaborating developers to develop and update the gEDA toolkit, which includes gEDA’s schematic capture and netlist platform for circuit design, PCB layout design and optimization, and Icarus Verilog, a tool for simulation Hardware description language for electronic systems). In addition, it also includes ngspice/ngucap SPICE/analog emulator, gerbv Gerber viewer and GTKWave digital waveform viewer.

Osmand PCB

A PCB editor for Mac comes from Osmand PCB, which allows users to make PCB designs of almost any size and shape, and can create as many layers as they want. The software can design routing with spatial resolution down to 10 nanometers and routing at any angle, and supports both imperial and metric units. Osmand also allows users to move and reposition components, connect/route/modify paths, and design PCB labels using its included libraries. This software also supports Lua language script support and can generate Gerber (RS-274X) files and Excellon demonstration files. This is a luxurious configuration for a free software.

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