Some standard content:
1 General Principles
National Standard of the People's Republic of China
Printed board drawing
Printed board rawlng
UDC 621.3
GB S489--85
1.1 This standard specifies the rules for drawing printed board parts drawings and printed board assembly drawings (hereinafter referred to as printed board assembly drawings) by manual, automatic and manual methods.
This standard does not specify the drawing rules for microcircuits, microcomponents and similar products. 1.2 The drawings of printed board parts drawings and printed board assembly drawings shall be drawn by orthographic projection and symbol method, and marked by inch line and grid method. The drawing requirements: In addition to the provisions of this standard, they shall also comply with the provisions of relevant standards. 2 Printed board parts drawings
Printed board parts drawings are drawings that represent electrical diagrams, structural requirements, marking symbols, technical requirements and related instructions. 2.1 Dimensioning method
The position and size of the conductive pattern, lead hole and other structural elements of the printed circuit board are generally determined by the following methods. 2.1.1 Dimensioning method
Dimensions are marked in accordance with the relevant provisions of CB445884 "Mechanical Dimensioning Method". 2.1.2 Grid method of rectangular coordinate system (hereinafter referred to as rectangular coordinate grid method). 2.1.2.1 The use of rectangular coordinate grid shall be in accordance with GB136-78 "Printed Circuit Grid". 2.1.2.2 When using the rectangular coordinate grid method to mark dimensions, the grid line number and the number of grid points shall be marked! The designer shall determine according to the density and proportion of the graphics (Figure 1).
National Bureau of Standards Issued on November 1, 1985
Implementation on May 1, 1986
GB5489-85
2.1. Polar coordinate grid method (hereinafter referred to as polar coordinate grid method) Polar grid spacing is determined by angle (degrees or arc) and diameter (or radius), and is selected based on the configuration of the conductive pattern of the printed circuit board (Figure 2, 3).
18' ± 30
# × 36 - 324
45u.5±0.24
2.1.4: Mixed method
GB5489-85
Dimension line method and polar grid method can be used to mark dimensions on a drawing at the same time (Figure 4). In the following forms, the following forms can be used to mark dimensions using the coordinate grid method: a. Mark the grid on the entire drawing 1 (Figure 5: b in ooobe1
① ~ $2.2H13
+8-41.iH18
string 35 -41H13
GB 5489—B5
Mark the grid on the drawing of the printed board (Figure 3) and mark the grid position with the dimension marking lines around the printed board (Figure 6), 80
d. Use the coordinate numbers to mark the main scale. The marking method is: first mark the origin of the coordinates, then mark the values, the axis values parallel to the axis: the radial values are in line.
2.1.6 In the printed view, the origin of the marking system can be selected according to the following methods: a: the center of the hole closest to the south pole (other than the art hole) is the origin (Figure 6); h, the intersection of the most exposed outer circle line is the origin (Figure 1, 5); e, the center point of the solid pole is the origin (2, 3). 2.2 Guide drawing
CB5489—85
2. 2.1 Conductive graphics: Generally drawn with a double-line wheel (Figure 8a), you can also color the double-line wheel (Figure 8b), or use a single line (Figure 8c). When the width of the printed conductor is less than 1m1 or the width is basically the same, the conductive pattern can be drawn with a single line. At this time, the conductor width and the minimum required connection plate size value should be indicated (Figure 8d). There are
: -400 leads, 8+4 holes are 2.3.4 The straightness of the connection plate is 1.5. The width of the printed line is 0.5, and the distance between the two conductors is not less than 0.7. Figure 8
2.2.2 When it is necessary to point out that a certain area of the printed board is not allowed to be laid out with conductive graphics, its boundaries should be marked with a thin solid line on the drawing (Figure 9).
2 Hole dimension
GB 5489—85bZxz.net
2.3.1 The center of the hole must be at the intersection of the coordinate grid lines. 2.3.2 The common center point of a circularly arranged hole group must be at the intersection of the coordinate grid lines, and the center of at least one hole in the other holes must be located on the coordinate grid line of the above intersection (Figure 10a). 2.3.3 For holes in a non-circularly arranged hole group, at least one hole must have its center at the intersection of the coordinate grid lines, and the center of at least one hole in the other holes must be located on the same coordinate grid line of the above intersection (Figure 10b). a
2.3.4 Metallized holes are generally indicated by text descriptions and marks. b
2.4 Simplified drawing method
GB 5489-85
2.4.1 Conductive patterns and structural elements specified in the technical requirements of the drawings may be represented by symbols (Figure 8d). 2.4.2 Conductive patterns that appear regularly and repeatedly on a printed board may not be drawn in full, and the distribution pattern of these conductive patterns must be pointed out.
2.5 Marking symbols and marking symbol diagrams
Marking symbols refer to the graphic symbols, simplified shapes and position numbers of components and devices on the printed board parts drawing, components and devices in the schematic diagram and logic diagram, and component and device mounting position marks.
Marking symbol diagrams are drawn according to the component and device mounting positions and are represented by the position numbers in the logic diagram (Figures 11a and 11b). Ce
Generally, the graphic symbols, simplified shapes and position numbers of components and devices in the electrical schematic diagram and logic diagram can also be used to represent the component and device mounting position marks and their position numbers in the electrical schematic diagram and logic diagram (Figure 11c). z
SR105R13
2.6 Single-sided printed board parts drawing
GB5489-85
Continued Figure 11
The drawing of a single-sided printed board is generally represented by two views. If necessary, the structural elements and marking symbols can be drawn separately. In this case, the technical requirements and relevant instructions should be written on the first sheet. If necessary, several printed boards can be assembled into one board for drawing. 2.7 Double-sided printed board parts drawing
The drawing of a double-sided printed board is generally represented by two views (front view and rear view). When the conductive pattern on the rear view can be clearly represented in the front view, a view can also be drawn. If necessary, the structural elements and marking symbols can also be drawn separately. In this case, the technical requirements and relevant instructions should be written on the first sheet.
2.8 Multilayer printed circuit board parts drawing
Each conductor layer of a multilayer printed circuit board should be drawn with a view, and the layer number should be marked on the view. The numbering method is: starting from the component side, each conductor layer is numbered in sequence. When the view is a rear view, the words "quality view" should be marked above the view. Other structural elements and marking symbols can also be drawn separately. At this time, technical requirements and relevant instructions should be written on the first sheet. 2.9 Automated or semi-automated drawing
When using automated or semi-automated methods to draw printed circuit board drawings, positive image photographic film images with a ratio of 1:1 can be used as continuation pages of the drawings. The size of the photographic film is determined by the printed circuit board drawing, and the drawing number, frame sequence number and total page number are marked on the film. Other data required for manufacturing printed circuit boards (such as perforated tapes, tape numbers, etc.) should be placed on the first sheet of the drawing. 3 Assembly drawings of printed circuit board assemblies (commercially known as printed circuit board assembly drawings) The printed circuit board assembly drawing is a drawing that shows the connection relationship between various components, devices, structural parts, etc. and the printed circuit board. 3.1
-General requirements
3.1.1 When drawing the printed circuit board assembly drawing, the convenience of viewing should be considered first, and the appropriate representation method should be selected according to the characteristics of the installed components, devices and structures. On the premise of neatly and clearly expressing the connection relationship between components, devices, structural parts, etc. and the printed circuit board, strive to make the drawing simple. 3.1.2 The drawing should have necessary external dimensions, installation dimensions, and connection positions and dimensions with other products. 3.1.8 The polarity of various components and devices with polarity should be marked on the drawing. 8.1.4 There must be necessary technical requirements and instructions. GB 54B8-85
3.1.5 Rules for selecting views
: When there are components, devices and structural parts on one side of the printed board, generally only one view is drawn, and the side with components and devices is the main view. : When there are components and devices on both sides of the printed board, generally two views should be drawn, with the side with more components, devices and structural parts as the main view and the side with fewer components as the rear view. When one view can express clearly, one view can also be drawn. At this time, the components and structural parts on the back side should be drawn with dotted lines. When the components and devices are drawn with graphic symbols, only the leads are drawn with dotted lines (Figure 12). 8
3.2 Methods for drawing components, devices and structural parts
3.2.1 On the premise of clearly indicating the assembly relationship, the components and devices in the printed board assembly drawing generally adopt simplified shapes or draw graphic symbols according to GB4728 "Special Graphics for Electrical Drawings" (Figure 13). When the components and devices have direction requirements in the assembly drawing, the positioning feature marks must be marked (Figure 14). 3.2.2 When it is necessary to fully and detailedly express the assembly relationship, the structural parts and components and devices in the printed board assembly drawing shall be drawn according to the provisions of GB4458-84 "Mechanical Drawing Drawing Method". GB 5489-85
3.8 Serial numbers and position numbers of components, devices and structural parts in the printed board assembly drawing 3.3.1 The structural parts and components and devices drawn according to GB 4458 in the printed board assembly drawing should be marked with (beside) serial numbers. Other components and devices can be marked with their position numbers in the electrical schematic diagram and logic diagram. The position numbers are generally marked near the left or upper side of the component and device appearance drawing and graphic symbol (Figure 13).
3,3,2 The position number of the components and devices in the printed circuit board assembly drawing refers to the position code of the components and devices in the assembly drawing. Generally, the position number can be marked from left to right and from top to bottom (Figure 15): the position number can also be marked according to the vertical and horizontal coordinate partition code. For components and exposed parts with large appearance, the position number can be marked according to the vertical and horizontal coordinate code corresponding to the lower left corner of the figure, such as the position code B1 of the large-scale integrated circuit in the lower left corner of Figure 16.
GB548985
3.4 Conductive graphics and jumper wires in printed circuit board assembly drawings 3.4.1 The printed circuit board assembly drawing is generally small! Conductive graphics are not shown. If the reverse conductive graphics need to be shown, they can be shown with dotted lines or negative lines (Figure 17). Figure 17
GB5489--85
3.4.2 The visible cross-over lines in the printed board assembly drawing are drawn with thick solid lines, and the invisible ones are drawn with dotted lines and marked with position numbers W,, W,, and can also be shown in the figure.
3.5 Simplified drawing method
In the printed board assembly drawing, for the repeated (partial) unit graphics, only one of the units can be drawn, and the remaining units can be simplified. In this case, the limit of the valley must be drawn with thin solid lines, and the unit sequence number must be marked (Figure 18). +
Additional instructions:
This standard was proposed and drafted by the Standardization Research Institute of the Ministry of Electronics Industry of the People's Republic of China, Factory 712 and Beijing Television Equipment Factory. The main drafters of this standard are Li Guanghao, Wu Hanmin and Dong Hongchang.
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