Basic requirements of PCB engineering.

- Feb 03, 2018-

Dose the receiving file conform to the rules set by the designer?Can meet PCB manufacturing process requirements?Is there a positioning tag?

Is the line layout reasonable?Line and line, wire and element welding disc, wire and through hole, element  welding disc and through hole, the distance between through hole and through hole is reasonable, can meet the production requirement.Is there any conflict between components in 2d and 3d space?

Is the printing plate size consistent with the processing drawing?The graphics in the PCB graphics, such as ICONS and marks, can cause a short circuit.

Edit and modify some undesired lines.

Is there any process line on PCB?Whether the resistance welding is in accordance with the requirements of the production process, whether the welding size is suitable, and whether the character sign is pressed on the device welding plate, so as to avoid affecting the quality of the electric equipment.And so on...

The generation of light - drawn data.

1, the puzzle

PCB design for PCB shape is too small, can not meet the requirement of the production process, or a product is composed of a few pieces of PCB, so you need to take a number of small plate together into a big plate area to meet the requirements of production, or to a multiple PCB products used together and facilitate production types.The former is similar to the stamp board, which can satisfy the PCB production process conditions and also facilitate the electrical installation of the components. It is very convenient to separate when used.The latter is to assemble several sets of PCB boards of a product together, so that it is easy to produce, and it is convenient for a product to be set up, clearly and clearly.

2. The generation of optical drawing data.

PCB board production is based on the film version.In the early production of the film version, the film should be produced first, and then the base map should be used for taking pictures or duplicates.The accuracy of the base map must be consistent with the requirements of the printing plate and should be considered to compensate for the deviation from the production process.The base map can be provided by the customer or produced by the manufacturer, but the two parties should cooperate and negotiate in close cooperation so as to meet the requirements of the users and adapt to the production conditions.In the case of the user to provide the base map, the manufacturer shall inspect and approve the base drawing, and the user can assess and approve the original or the first printed board product.The method of base drawing is manual drawing, mapping and CAD drawing.Along with the development of computer technology, PCB CAD technology gets great progress, also unceasingly to multilayer PCB production technology level, thin wire, small aperture, high density direction rapidly increase, the original film plate-making technology has been unable to meet the needs of the PCB design, so the light painting technology.The PCB graphic number of CAD can be directly designed by using the optical plotter.

According to the computer system of the optical plotter, the light drawing machine is controlled to draw the graph directly on the negative.Then the film was developed and the film was obtained.Use light painting technology making PCB film negatives, quick speed, high precision, good quality, but also avoid the textures or in artificial reproduction possible human error, greatly improving the work efficiency, shorten the PCB production cycle.Use my company's laser light painting machine, just can be completed in a very short period of time in the past, many people for a long time to finish the work, and its fine wire drawing, high-density blank is unmatched by manual operation.According to the structure of laser light drawing machine, it can be divided into plate type, Internal Drum and External Drum.The company's series of light - draw machine products are all international popular external roller type.

The standard data format used by the optical plotter is the gerber-rs274 format, which is also the standard data format for the printing plate design and production industry.The Gerber format is named after the pioneer in the design and production of the optical plotter -- American Gerber.

Optical mapping data, is the CAD software design of data conversion is called light painting data (mostly Gerber data), modified by CAM system, editing, complete light painting pretreatment (puzzle, mirror, etc.), so as to meet the requirement of PCB production process.Data is then processed into light painting machine, by the light painting machine of Raster image data processor (Raster) into Raster data, the Raster data sent via high power fast compression reduction algorithm to the laser light painting machine, complete the light painting.

3. Optical data format.

Light painting is based on vector data format type light painting machine developed on the basis of the data format Gerber data, and the data format of vector type light painting machine expanded, and compatible with the HPGL HP plotter format, Autocad DXF, TIFF and other special and general graphics data format.Some CAD and CAM developers have also extended the Gerber data.

Here is a brief introduction to Gerber data:

The official name for Gerber data is the Gerber rs-274 format.In the Gerber data, there is a corresponding D CODE (d-code) in the Gerber data.In this way, the drawing machine can control and select the code disk by D code, and draw the corresponding figure.Make a list of the shapes of symbols and sizes of D and D codes, and get a D code table.This D code table becomes a bridge from CAD design to light drawing machine using this data.The user must provide the corresponding D code table while providing Gerber light drawing data.In this way, the optical plotter can draw the correct figure according to the D code table to determine which symbol plate should be selected for exposure.

In a D code table, the D code should generally be included, and the shape, size, and exposure mode of the code plate corresponding to each D code.In the case of one of the most commonly used electronic CAD software Protel, the extension is.apt, which is an ACSII file, which can be edited with any non-text editing software.