Rules for making printed circuit board drawings. Formation of a set of design documentation for ESKD in tandem CAD altium designer - autocad GOST for the preparation of assembly drawings of printed circuit boards
GOST 2.123-93
INTERSTATE STANDARD
UNIFIED SYSTEM OF DESIGN DOCUMENTATION
COMPLETENESS OF DESIGN DOCUMENTS FOR PRINTED BOARDS IN COMPUTED DESIGN
INTERSTATE COUNCIL
ON STANDARDIZATION, METROLOGY AND CERTIFICATION
Preface
1 DEVELOPED by the Russian Federation INTRODUCED by the Technical Secretariat of the Interstate Council for Standardization, Metrology and Certification 2 ACCEPTED by the Interstate Council for Standardization, Metrology and Certification on October 21, 1993, protocol No. 4-93 Voted for adoption of the standard: 3 Resolution of the Committee of the Russian Federation on Standardization, Metrology and Certification dated March 2 1994 No. 44 interstate standard GOST 2.123-93 was put into effect directly as a state standard of the Russian Federation on January 1, 1995.4 REPLACED GOST 2.123-835 RE-ISSUE. June 2002
INTERSTATE STANDARD
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Unified system of design documentation COMPLETENESS OF DESIGN DOCUMENTS FOR PRINTED Unified system for design documentation. |
Date of introduction 1995-01-01
1 AREA OF USE
This standard establishes the completeness of design documents (CD) for single-sided (SPP), double-sided (DPP) and multilayer (MPP) printed circuit boards, as well as requirements for their implementation during computer-aided design and manufacturing.2 REGULATORY REFERENCES
This standard uses references to the following standards: GOST 2.102-68 ESKD. Types and completeness of design documents GOST 2.108-68 ESKD. Specification GOST 2.109-73 ESKD. Basic requirements for drawings GOST 2.113-75 ESKD. Group and basic design documents GOST 2.417-91 ESKD. Printed circuit boards. Rules for the execution of drawings GOST 20406-75 Printed circuit boards. Terms and definitions GOST 28388-89 Information processing system. Documents on magnetic storage media. Order of execution and handling3 BASIC POINTS
3.1 The completeness of design documents for printed circuit boards (PCBs) is established in accordance with the requirements of GOST 2.102 and this standard. The terms used in this standard are in accordance with GOST 20406 and GOST 15971.3.2 When performing automated design on a PCB, the basic method of execution in accordance with with GOST 2.113.3.3 Documents on data carriers (punched tapes, punched cards, magnetic data carriers), included in the set of design documents for the PP, are intended for obtaining design documents in traditional form, mechanical processing, control of the PP and the photomask manufacturer, as well as transferring information about results of designing into a system (subsystem) of automated production of software.3.4. In each specific case, the composition of the design documents transferred for the manufacture of PCBs is determined by the developer together with the manufacturer in accordance with the completeness established by this standard. 3.5 By agreement with the manufacturer, it is allowed to manufacture PCBs using certified documents on data carriers.4 COMPLETENESS OF DESIGN DOCUMENTS FOR PRINTED BOARDS
4.1 The nomenclature of design documents for PCBs made in the basic way is given in Table 1.4.2 The nomenclature of design documents established by this standard can be supplemented depending on the nature, purpose and design and technological manufacturing option, as well as on the technical equipment of automated systems for designing and manufacturing PCBs. 4.3 The set of design documents for the control panel may include program documents obtained as a result of computer-aided design and necessary for the production of the control panel.4.4 By agreement with the manufacturer and the customer (if any), it is allowed to include design documentation for the control panel instead of the tables specified in the nomenclature PP automated control programs.4.5 Programs on data carriers are recorded in the “List of Documents on Data Media” (VN). When three or fewer documents are executed on data media, the VP is allowed not to be released. 4.6 VP is recorded in the PP specification in the “Documentation” section after the documents , provided for by GOST 2.102. In the same order, programs on data carriers are written into the software specification in the case when the VN is released. 4.7 Program documents and programs executed on data carriers are recorded at the end of the “Kits” section of the specification. 4.8 In the composition of permanent data placed in the basic drawing, the following may be included: - image of the PCB; - dimensions and other instructions for machining; - instructions on the material; - markings for installing the electrical connector; - mounting holes for installing the PCB in the assembly unit; - control elements (for control and testing of PP); - technical requirements; - conductive pattern; - marking of positional designations of electrical radio products and (or) design address; - place of designation of PP; - place of designation of the assembly unit; - place of the serial number of the change; - position numbers for MPP, etc. d.4.9 Variable data placed on the design drawing may include: - simplified image of the PP; - conductive drawing of the PP; - marking of position designations of electrical radio products and (or) design address; - designation of the PP; - designation of the assembly unit; - serial change number; - table of vias and mounting holes; - technical requirements; - item numbers for MPP, etc. 4.10 When drawing a design of a PP in an automated way on two or more sheets, the technical requirements are placed on the first sheet, the conductive drawing can be made on subsequent sheets. Above the main inscription of the execution drawing there should be a link to the base document of the type: “The rest - see XXXX. XXXXXXX.XXX.” Above the main inscription of the base drawing there should be a note: “The rest - see the execution drawing.”Table 1
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Document code |
Title of the document |
Instructions for completing the document |
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APP and DPP |
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| Drawing of the part (blank) | PP image, materials, overall dimensions of holes, etc. | Performed for each standard size according to GOST 2.106 | Can be issued according to the rules of GOST 2.109 for parts for which drawings have not been issued | |
| When preparing a part drawing using the basic method, the workpiece drawing is not performed | ||||
| Part drawing (gasket) | Gasket image, material, overall dimensions | Not executed | Can be issued according to the rules of GOST 2.106, GOST 2.109 for parts for which drawings have not been issued | |
| Basic part drawing | Constant data for all standard size versions (PP image, material, overall dimensions, hole sizes, roughness and other requirements) | Performed for each standard size for OPP and DPP | Performed on a printed circuit board as an integral part of the MPP | |
| Part execution drawing | Variable data related to a specific design (image of PP holes and their dimensions, technical requirements, conductive pattern, etc.) | For DPP it is performed for each version of the conductive layer | Performed for each version of the conductive layer of the printed circuit board | |
| Basic assembly drawing | Permanent data common to all versions of the standard size (image of the MPP, dimensions, technical requirements, constant part of the conductive pattern, position numbers) | Not executed | ||
| Assembly drawing of execution | Variable data related to a specific design (simplified MPP image, holes, technical requirements, conductive pattern) | |||
| Basic Specification | ||||
| Execution Specification | According to GOST 2.113, GOST 2.108, GOST 2.417 | Not executed | Performed on every execution | |
| Technical requirements | Same technical requirements for MPP | Performed in accordance with GOST 2.417 | ||
| Installation check table | Data for monitoring electrical connections | Executed for every execution. During automated inspection of printed circuit boards, it is allowed not to perform tables | ||
| Hole coordinate table | Accepted symbols of holes, the corresponding number of holes, coordinates of the location of holes in all layers of PP | |||
| Photomask data (1) | PP Layer Pattern Information | Performed on each layer | ||
| Drilling data (1) | Information about the coordinates of the location of the diameter and number of holes in the PP | Performed for each design, taking into account design and technological options | ||
| Data for contour processing (1) | PCB circuit information | Available for every size | ||
| Control data (1) | Information about the coordinates of contacts or pads, electrically connected to each other, of the PP layer | Performed per execution or layer | ||
| List of documents on data carriers | According to GOST 28388 and 1.3 of this standard | Executed for every execution. Allowed to be carried out in accordance with industry normative and technical documents | ||
| According to the current normative and technical documentation | PCB design results data | Performed on a magnetic data carrier in accordance with GOST 28388. Allowed to be carried out in accordance with industry normative and technical documents | ||
The essence of printed wiring is to apply thin electrically conductive coatings to the insulating base, which perform the functions of installation wires and circuit elements - resistors, capacitors, inductors, contact parts, etc. Below are the main terms that will be used when presenting the material.
A printed conductor is a section of a conductive coating applied to an insulating base that performs the functions of a regular installation wire.
Printed wiring is a system of printed conductors that provide electrical connection of circuit elements.
A printed circuit board is an insulating base with a printed circuit printed on it.
Attachment elements are volumetric electrical and radio elements installed and secured on a printed circuit board by soldering and having electrical contact with printed conductors.
Contact pad is a metallized area around the mounting hole that has electrical contact with the printed circuit conductor and provides electrical connection of the suspended circuit elements with the printed circuit.
Mounting hole - a hole in a printed circuit board designed to secure the leads of attached elements and electrically connect them to printed conductors.
Coordinate grid is a grid applied to the image of the board and used to determine the position of mounting holes, printed conductors and other board elements.
Grid pitch is the distance between adjacent grid lines. The grid step must be a multiple (0.625; 1.25; 1.875; 2.5, etc.)
A grid node is the point of intersection of grid lines.
Free spaces are areas of the printed circuit board where, when placing conductors, the recommended values for the width of conductors and the distance between conductors and pads can be maintained.
Bottlenecks are areas of the printed circuit board where, when placing conductors, the width of the conductors and the distances between them and the contact pads are less than recommended (down to the minimum permissible).
Printed block - a printed circuit board with a printed circuit, attachments and other parts that has gone through all stages of manufacturing.
Design documentation for printed circuit boards and blocks is drawn up in accordance with the requirements of GOST 2.109-73, GOST 2.417-68 and current regulatory and technical standards
documents. A single-sided or double-sided PCB drawing is classified as a part drawing. The drawing of the printed circuit board must contain all the information necessary for its manufacture and control: an image of the printed circuit board from the printed circuit board side; dimensions, maximum deviations and surface roughness of the printed circuit board and all its elements (holes, conductors), as well as the dimensions of the distances between them; necessary technical requirements; information about the material.
The dimensions of each side of the printed circuit board must be a multiple of 2.5 for a length of up to for a length of up to for a length of more than The maximum size of any side of the printed circuit board should not exceed The ratio of the linear dimensions of the sides of the printed circuit board should be no more and is selected from a range The thickness of the boards is determined based on the mechanical requirements for the design of the printing unit, taking into account the manufacturing method. Recommended boards with a thickness of 0.8; 1.0; 1.5; 2.0; 2.5; 3.0 mm. Printed circuit board drawings are made in full size or enlarged
The development of a printed circuit board drawing begins with the application of a coordinate grid.
Rice. 4.18. Hole Picture
For small-sized equipment and in technically justified cases, it is allowed to use additional steps of 1.25 and 0.5 mm.
The centers of all holes on the printed circuit board must be located at the grid nodes. If due to the design features of the hinged element this cannot be done, then the centers of the holes are located according to the instructions in the drawing for this element. This arrangement of hole centers is used for lamp panels, small-sized relays, connectors and other elements. In this case, the following requirements must be met: the center of one of the holes, taken as the main one, must be located in a coordinate grid node; the centers of the remaining holes should, if possible, be located on vertical or horizontal lines of the coordinate grid. In Fig. Figure 4.18 shows the location of the holes on the printed circuit board.
The diameters of mounting and transition holes, metallized and non-metalized, are selected from the range (0.2); 0.4; (0.5); 0.6; (0.7); 0.8; (0.9); 1.0; (1,2); 1.3; 1.5; 1.8; 2.0; 2.2; (2.4); (2.6); (2.8); (3.0). Diameters not in brackets are preferred. It is not recommended to have on one printed circuit board
Table 4.1 (see scan)
Rice. 4.19. Hole table
more than three different hole diameters. The diameters of metallized holes are selected depending on the diameters of the leads of the hinged elements and the thickness of the board, and the diameters of non-metalized holes - depending on the diameters of the leads of the hinged elements installed in these holes (Table 4.1). The need for countersinking of mounting and via holes is dictated by specific design requirements and the method of manufacturing the board.
When using other diameters of metallized holes in accordance with GOST 10317-79, the difference between the diameter of the metallized hole and the diameter of the lead should be no more for leads with a diameter of 0.4 to for leads with a diameter over
The surface roughness of non-metalized mounting holes and ends of printed circuit boards must be in accordance with GOST 2789-73. Surface roughness of mounting and transition metallized holes -
To simplify the graphics of the board, the holes are shown as circles of the same diameter with the designation according to the table. 4.2 (according to OST 27-72-694-834).
When making holes in this way, a table of holes is placed on the drawing field (Fig. 4.19). The dimensions of the columns and the shape of the table are not established by GOST.
All mounting holes must have contact pads. The shape of the contact pad can be arbitrary, round, rectangular or close to them. The center of a symmetrically shaped contact pad must coincide with the center of the mounting hole; for rectangular and oval shaped pads, the center of the mounting hole can be shifted (Fig. 4.20). Round pads and holes with countersinks are depicted as one circle, the diameter of which must correspond to the minimum size of the pad. The size of the diameter of the contact pads should be indicated in the technical requirements of the drawing. If there are contact pads on the board that are not specified in size, or in shape other than round,
Table 4.2 (see scan)
Rice. 4.20. Image of contact pads
It is allowed to represent all contact pads with a circle equal to the diameter of the hole. The shape and dimensions should be specified by writing in the technical requirements “The shape of the contact pads is arbitrary,
To set the dimensions of group contact pads, it is recommended to display the image of the contact group on an enlarged scale with the required dimensions placed on the drawing field
Rice. 4.22. Image of a pad with a conductor
It is recommended to make a smooth transition from the contact pad to the conductor. In this case, the axis of symmetry of the printed conductor must be perpendicular to the tangent to the contour of the contact pad or the contour of the contact pad itself (Fig. 4.22). The distance between the edge of the conductor, pad, non-plated hole and
Rice. 4.21. (see scan) Image of the contact group
the edge of the board must be no less than the thickness of the board. Printed conductors should be depicted in the form of line segments coinciding with the lines of the coordinate grid, or at an angle that is a multiple of 15°. It is allowed to make conductors of any configuration and rounding the bends of the conductors (Fig. 4.23).
Printed conductors should be made of the same width throughout. In narrow places, conductors are narrowed to the minimum permissible values at the shortest possible length. The relative position of the conductors is not regulated. If it is necessary to lay conductors with a width along the entire length, it is recommended to provide for an extension of the conductor such as a contact pad after 25-30 mm.
Rice. 4.24. Image of conductors wider than
Conductors less than a width are depicted with one line, which is the axis of symmetry of the conductor, with more than two lines and hatched at an angle of 45° or blackened. Wider conductors should be designed as a screen (Fig. 4.24). The shape of the cutouts in wide conductors and screens must be shown in the drawing and determined by dimensions (see Fig. 4.21). In order to simplify the drawing, it is allowed to make conductors of any width in one line, while the technical requirements of the drawing indicate the width of the conductor.
When laying printed conductors, conductor branches should be avoided if possible (Fig. 4.25); The ends of printed conductors intended for connecting a printed circuit are recommended to be positioned taking into account the ease of use of transition elements (Fig.
4.26). The boundaries of areas of the printed circuit board that are not allowed to be occupied by conductors are limited by a thick dash-dotted line.
Rice. 4.25. Image of printed conductors: a - correct; b - incorrect
Rice. 4.26. Image of contacts for connecting a printed circuit board: a - correct; b - incorrect
The overall dimensions of the printed circuit board, the diameters and coordinates of holes, pads and their relative location are shown in the drawing in one of the following ways:
a) in accordance with the requirements of GOST 2.307-68 using dimension and extension lines;
b) applying a coordinate grid;
c) in a combined way using dimension and extension lines and a coordinate grid;
d) using a coordinate table.
In Fig. Figure 4.27 shows an example of a drawing of a double-sided printed circuit board. The dimensions of all elements are plotted using dimension and extension lines. With this method of drawing, a coordinate grid is not applied. In this example, the center of the lower left hole of the board is taken as the reference point. Holes of various diameters are designated in accordance with the data in table. 4.2. Contact pads and
Rice. 4.27. (see scan) Drawing of a double-sided printed circuit board
Rice. 4.28. Option for applying a coordinate grid
Countersinked holes are simplistically depicted as a single circle.
When specifying dimensions by applying a coordinate grid, the grid lines must be numbered. The numbering step is determined constructively, taking into account the saturation and scale of the image. The coordinate grid, depending on the method of completing the documentation, is applied to the entire field of the board (see Fig. 4.18, 4.21) or with marks along the perimeter of the board (Fig. 4.28). It is allowed to draw not all lines of the coordinate grid; in this case, a note of the type “The lines of the coordinate grid are drawn alternately” is placed on the drawing field (Fig. 4.29). The center of the extreme left lower hole, the lower left corner, is taken as zero in the rectangular coordinate system on the main view of the board board, the lower left point formed by constructions, for example, a continuation of the board contour line, the corners of which are cut off.
In Fig. Figure 4.29 shows an example of making a printed circuit board drawing using a combined method of dimensioning - using dimension and extension lines and a coordinate grid. The coordinate grid lines are drawn one at a time, and therefore a corresponding entry is given in the technical requirements of the drawing. A table of holes is made on the drawing field. All missing data regarding printed wiring are indicated in the technical requirements of the drawing.
An example of a printed circuit board drawing indicating dimensions with a coordinate table is shown in Fig. 4.23. The dimensions of the hole diameters are indicated in the drawing, the relative location of the holes is in the coordinate table; all holes are marked with Arabic numerals in accordance with GOST 2.307-68.
The drawing of the printed circuit board indicates the overall dimensions of the board, the width of the conductors having a strictly defined or variable width (in this case, the calculated width should be indicated on each section between two adjacent pads, vias or mounting holes); diameters and coordinates of fastening, technological and other holes not related to printed wiring.
The field of the drawing indicates the method of manufacturing the board, technical conditions (if not all data is contained in the drawing), grid pitch, width of conductors and distances between them, distances between contact pads, between the contact pad and conductor, tolerances for the execution of conductors, contact pads, holes and distances between them, design features, technologies and other parameters of printed circuit boards.
Technical requirements are placed above the main inscription, formulated and presented in the following sequence:
1. Make the board using......method.
2. The board must comply with (GOST, OST).
3. Grid pitch
4. Maintain the configuration of the conductors according to the coordinate grid with deviation from the drawing
5. Rounding of the corners of contact pads and conductors is allowed.
6. Places outlined with a dot-dotted line should not be occupied by conductors.
(click to view scan)
7. Requirements for the parameters of the board elements - in accordance with the design data.
8. Width of conductors in free places in narrow
9. The distance between two conductors, between two contact pads or a conductor and a contact pad in free spaces in narrow -
The shape of the contact pads is arbitrary,
11. It is allowed to lower the contact pads of metallized holes: on the outer layers to the countersink, on the inner layers
12. Maximum deviations of the distances between the centers of holes, except as otherwise specified, in narrow places in free places
13. Maximum deviations of the distances between the centers of the contact pads in the group
14. Mark enamel font according to GOST...
An example of recording technical requirements depending on the content of a printed circuit board drawing is shown in Fig. 4.23, 4.27, 4.29.
It is allowed to indicate markings on the board image (Fig. 4.29) in accordance with the requirements of GOST 2.314-68. Marking can be primary or additional. The main marking includes the symbol of the board, the serial number of the drawing change; manufacturing date, serial or serial number of the board and batch of boards. The symbol of the board should be done by etching foil. The last three digits of the designation of the board drawing or the alphanumeric designation of the functional group are taken as a symbol, for example. The rest of the marking is done with paint.
Additional markings include positional alphanumeric designations of the hinged elements according to the electrical circuit diagram, an image of the outline of the hinged elements, digital designation of the terminals of the hinged elements, control points, designation of the positive terminal of the polar hinged elements.
Additional marking symbols should be made by etching foil if there is free space on the printed circuit side of the board or by using paint using grid-graphic printing on the printed circuit side of the board, and, if necessary, on the solder side.
The features of printed wiring include the flat arrangement of printed conductors, which does not allow the transition from one board to another without jumpers, adapter blocks or connectors; installation of hanging elements and fastening of leads only by passing them into the holes; simultaneous soldering of all elements installed on the printed circuit board.
Rice. 4.30. Placement of mounted elements on the printed circuit board: a - recommended; b - not recommended
(click to view scan)
The hanging elements should be placed in correct rows, parallel to one another, on the side of the board where there are no printed conductors (Fig. 4.30). This arrangement allows you to install and secure attachments on automatic lines and perform immersion soldering, eliminating the impact of solder on the attachments.
All attachments are attached to the board using leads, which are inserted into the mounting holes and bent. It is not recommended to place two or more leads in the mounting hole. Some elements, such as low-power transistors, are secured with glue.
An assembly drawing of a printed circuit board, with a minimum number of images, should give a complete picture of the location and execution of all printed and mounted elements and parts. The assembly drawing is carried out in accordance with the requirements of GOST 2.109-73, taking into account the requirements of GOST 2.413-72. The designs of the hinged elements are drawn in the form of simplified images, they are assigned an alphanumeric positional designation in accordance with the electrical circuit diagram, according to which the electrical installation of the board is carried out (Fig. 4.31). The assembly drawing of the printed circuit board must indicate the position numbers of all components, overall and connecting dimensions, and must contain information about the methods of connecting attachments to the printed circuit board.
The technical requirements of the assembly drawing must contain references to documents (GOST, OST) that establish the rules for the preparation and fastening of hinged elements, information about solder, etc.
The main design document of a printed circuit board assembly drawing is a specification, drawn up in the form of a table according to the rules of GOST 2.108-68. When recording components that are elements of an electrical circuit diagram in the specification, the alphanumeric positional designations of these elements are indicated in the “Note” column (Fig. 4.32, 4.33).
The development of design documentation for printed circuit boards can be carried out by manual, semi-automatic or automated methods.
The manual method involves dividing hanging elements into functional groups, placing groups of elements on the board area, routing printed conductors and ensures optimal distribution of the conductive pattern.
With the manual design method, a board drawing is developed containing an image of a board with a conductive pattern and holes, as well as, if necessary, an additional separate image of a part of the board that requires graphical explanation or drawing dimensions, a coordinate grid made in accordance with the requirements of GOST 2.417-78, dimensions all elements of the conductive pattern and their maximum deviations; technical requirements. The board drawing must be made to a scale of at least the maximum format
The semi-automated method involves the placement of attachments using a computer during manual routing of printed conductors or the manual distribution of attachments during automated routing of conductors; it ensures acceleration of the design process with optimal placement of the conductive pattern. The board drawing must contain all the information necessary for its manufacture and control. An image of the layers of the board is obtained from a drawing device in the form of a schematic drawing, photo diagram, photo print to scale or In the schematic drawing and photo diagram, contact
Rice. 4.32. (see scan) Specification of printed circuit board assembly drawing
sites can be depicted conventionally as one circle. A schematic drawing, photographic diagram or photo print is pasted onto the original board drawing.
Permanent drawing data, such as technical requirements, hole table, should be typed from the original drawing of the permanent part. The design document format should be no larger than A2.
Rice. 4.33. (see scan) Continuation of the specification of the printed circuit board assembly drawing
The automated method involves coding the source data, placing hanging elements and routing printed conductors using a computer. This method ensures high labor productivity in the production of drawings. With the automated method, the designer develops a coding drawing containing the nominal values of the dimensions of the board's structural elements.
GOST 2.417-91
Group T52
INTERSTATE STANDARD
Unified system of design documentation
PRINTED BOARDS
Rules for the execution of drawings
Unified system for design documentation. Printed circuit boards. Rules for making drawings
ISS 01.100.25
31.180
OKSTU 0002
Date of introduction 1992-07-01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Committee for Standardization and Metrology of the USSR and the Ministry of Radio Industry of the USSR
DEVELOPERS
G.M. Khrobinsky, Ph.D. tech. sciences; L.E. Grakhova
2. APPROVED AND ENTERED INTO EFFECT by Resolution of the Committee for Standardization and Metrology of the USSR dated December 12, 1991 N 1941
3. INSTEAD GOST 2.417-78
4. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS
Item number |
|
GOST 2.113-75 | |
GOST 2.123-93 | |
GOST 2.307-68 | |
GOST 10317-79 | |
GOST 20406-75 |
5. REPUBLICATION. December 2010
1. This standard establishes the rules for the execution of drawings of printed circuit boards and flexible printed cables (FPC) (hereinafter referred to as printed circuit boards) for any method of documentation execution.
The terms used in this standard and their definitions are in accordance with GOST 20406 *.
________________
* The document is not valid on the territory of the Russian Federation. GOST R 53386-2009 is in force. - Database manufacturer's note.
2. Drawings of printed circuit boards must be made in accordance with the requirements of the standards of the Unified System of Design Documentation (ESKD) and this standard.
3. Drawings of single-sided (SPP), double-sided (DPP) and multilayer (MPP) printed circuit boards must have the name “Printed Board”.
4. The GPC must have the name “Printed flexible cable”.
5. An assembly drawing is issued at the MPP.
The image of each MPP layer is placed on separate sheets of the assembly drawing, indicating the serial number of the layer. The material of printed layers should be recorded in the specifications in the “Materials” section, indicating their dimensions and number of layers, or in the “Parts” section, as parts without a drawing.
6. It is preferable to make drawings of the same type of printed circuit boards in accordance with GOST 2.113, taking into account the requirements of this standard.
7. On the printed circuit board drawing, dimensions must be indicated in one of the following ways:
in accordance with the requirements of GOST 2.307*;
________________
* GOST 2.307-2011 is in force on the territory of the Russian Federation, hereinafter in the text. - Database manufacturer's note.
drawing a coordinate grid in a rectangular coordinate system (Fig. 1);
drawing a coordinate grid in the polar coordinate system (Fig. 2);
in a combined way using dimension and extension lines and a coordinate grid in a rectangular or polar coordinate system;
in the form of a table of coordinates of the elements of the conductive pattern (conductors, contact pads, etc.).
8. When applying dimensions using a coordinate grid, grid lines must be numbered. The numbering step is determined constructively taking into account the saturation and scale of the image (Fig. 3, 4) and can be expressed in millimeters or in the number of grid lines.
9. It is allowed to highlight individual coordinate grid lines in the drawing, alternating at certain intervals (see Figure 2), while in the technical requirements of the drawing instructions should be placed such as: “The coordinate grid lines are drawn one at a time.”
10. The coordinate grid, depending on the method of performing documentation, should be applied to the entire field of the drawing (see drawings 3, 4) or to part of the surface of the printed circuit board, or with marks along the perimeter of the contour of the printed circuit board (see drawing 1). It is allowed to apply marks along the perimeter of the circuit board outline (see Figure 1) or at some distance from it.
11. Coordinate grid step in a rectangular coordinate system - according to GOST 10317.
12. The following should be taken as the origin in the rectangular coordinate system in the main view of the printed circuit board drawing:
the center of the leftmost or lower right hole (see Figure 1);
left or right lower corner of the printed circuit board (see Fig. 3);
the left or right lower point formed by the construction lines (see drawing 4).
13. In drawings of round printed circuit boards, it is allowed to take the center of the printed circuit board or the point formed by the intersection lines of two tangents to the circle as the origin in a rectangular coordinate system.
14. A coordinate grid in the polar coordinate system is used for drawings of printed circuit boards with a certain sequence of arrangement of repeating printed conductors with radial orientation.
15. The pitch of the coordinate grid in the polar coordinate system is set by angle and diameter and is assigned depending on the location of the printed circuit board elements (see Figure 2).
16. If the dimensions and configuration of the printed circuit board drawing are specified in the technical requirements of the drawing, then it is allowed to depict elements of printed circuit boards conditionally.
17. Areas of the printed circuit board that are not allowed to be occupied by printed conductors and contact pads must be outlined in the drawing with a thick dash-dotted line.
The dimensions of the sections are determined by a coordinate grid or plotted on the drawing.
18. For applying dimensions, surface roughness designations, etc. It is allowed to include an additional view in the drawing, in which the printed circuit board design should be shown partially. It is permissible not to depict a drawing of a printed circuit board. In this case, an appropriate inscription should be placed above this view, for example, “Conductors are not shown.”
19. Round contact pads with holes, including those with a countersink, and contact pads of any shape, the dimensions of which are not indicated, are depicted in the drawing as one circle.
Contact pads are allowed, incl. round, depending on their size, conventionally depicted in the drawing as a square, rectangle, polygon, etc.
The dimensions and shape of the contact pads are indicated in the technical requirements of the drawing.
20. Holes that are similar in diameter are depicted as a circle of the same diameter with the obligatory indication of a symbol in accordance with GOST 2.307.
21. The diameter of the hole, its symbol, the diameter of the contact pad, the presence of metallization, the number of holes should be combined into a table.
22. Conductors in the drawing should be indicated by one line, which is the axis of symmetry of the conductor. The drawing should indicate the numerical value of the conductor width.
Conductors can be depicted as two lines, and if they coincide with the grid lines, the numerical value of the width is not indicated in the drawing.
23. Individual elements of the printed circuit board design (conductors, screens, insulating sections, etc.) can be highlighted in the drawing by shading, blackening, rasterizing, etc.
24. The image of a printed circuit board with repeating elements may not be completed in full to the extent that ensures unambiguous reading of the drawing. In this case, the pattern of arrangement of such elements must be indicated.
25. It is allowed to put inscriptions, signs, etc. on the image of the printed circuit board, which may not be on the products themselves, which should be noted in the technical requirements of the drawing.
In places where inscriptions are applied on the drawing, it is allowed not to apply a coordinate grid.
26. The image of the printed circuit board may partially lack information about individual elements of the printed circuit board; however, the technical requirements of the drawing must contain a link to a document containing the missing information.
27. For printed circuit boards and GPCs that have the same technical requirements, it is allowed to draw up technical requirements in a general design document of subclass “0”, which must be referenced in the technical requirements of the printed circuit board design drawing.
28. In the technical requirements of the drawing, it is allowed to provide explanations about the interaction of elements. Example: "The conductors form four short-circuited twenty-five-turn windings with a half-turn pitch of twelve divisions and equal to 43° 12" ".
29. The printed circuit board markings are placed on a free space on the board.
When marking using a conductive pattern, it is allowed to use any font, although the technical requirements of the drawing do not indicate the marking method.
30. With an automated and semi-automated design method, it is allowed to produce drawings of printed circuit boards without an image of the conductive pattern, including in the set of design documentation documents on data carriers that define the design and method of manufacturing printed circuit boards and their components.
As the second and subsequent sheets of the drawing, it is allowed to use images of the layers of the printed circuit board on photographic film, photographic paper or other materials.
Documents on data carriers are recorded in the specification of the assembly unit.
31. The set of design documentation for a printed circuit board using the automated design method must comply with GOST 2.123.
Electronic document text
prepared by Kodeks JSC and verified against:
official publication
ESKD. Rules for the execution of drawings
various products: Sat. GOST. -
M.: Standartinform, 2011
According to GOST 2.217-78.
A drawing of a single-sided or double-sided board is called “Board”. The drawing shows the main projections of the board.
It is also possible to make an additional type of board without a conductive pattern and mesh, on which the dimensions for machining, reduction of the marking to the mark, and coating are determined. The caption “View without guides” is written above this view.
The board drawing is made on an enlarged scale 2:1, 4:1, 5:1, 10:1.
The drawing of the board is carried out with a coordinate grid in the case when indicating the dimensions of the drawing and position is difficult due to the complexity or high density of graphic images, as well as in the case of constructing a board in a coordinate grid. It is recommended to choose grid steps: the main step is 2.5 mm, and the remaining steps are 1.25 mm or 0.5. And combine the beginning of the mesh with the structural bases.
Grid lines are drawn in continuous thin lines. If the step is small, select a line every five. It is allowed to draw lines through one (in those requirements it is written “Lines are drawn through one”).
Lines are indicated in one or more steps, but not more than 5.
Conductors whose width in the drawing is at least 2 mm are depicted as a solid thick line.
Round-shaped contact pads, as well as pads whose shape is not specified, are depicted as concentric circles. The dimensions of the outer circle must correspond to the minimum dimensions of the contact pad.
The shape and dimensions of printed contacts, cutouts and wide conductors are indicated directly on the board view; allowed in the form of callouts indicating their number.
Areas of the boards that are not allowed to be occupied by conductors in the drawing are outlined with a dashed line indicating the dimensions of this area.
The holes on the board are depicted as one circle.
The position of the holes is specified: - using a coordinate grid, - drawing dimension lines, - numbering the holes indicating their coordinates along the X and Y axes in the table.
The designation of the board base material is indicated in the title block of the drawing.
Technical requirements are grouped as follows:
a) method of manufacturing the board;
b) requirements for the base material of the board;
c) grid step;
d) permissible deviations of the board design;
e) requirements for parameters of board elements (in table form)
f) instructions on the configuration of basic elements;
g) requirements for machining accuracy;
h) instructions on coatings, etc.
Requirements for the execution of assembly drawings of printed circuit boards.
Assembly drawing is a type of design documentation, a document containing an image of an assembly unit and other data necessary for its assembly and control.
Requirements for the execution of assembly drawings are established in GOST 2.109 (ESKD. Basic requirements for drawings).
The assembly drawing must contain:
· An image of an assembly unit, which gives an idea of the location and mutual connection of the components connected according to a given drawing, and provides the ability to assemble and control the assembly unit.
· Dimensions to be made or controlled according to this assembly drawing.
· Instructions for making permanent connections.
· Position numbers of components included in the product.
· Overall dimensions of the product.
· Installation, connecting and other necessary reference dimensions.
· If necessary, the technical characteristics of the product.
· If necessary, coordinates of the center of mass.
The assembly drawing is included in the main set of design documentation.
The assembly drawing must show the housings of all components of the printed circuit board. There should be a number 1 near the first legs of the microcircuits. The assembly drawing should show the places where cables are laid and soldered, as well as the places where screens are installed and where radiators or other structural elements present on the board are attached. It is also advisable to indicate the location of all structural holes on the board, such as the points where the board is attached to the block. It is recommended to indicate the dimensions of the board, as well as the distances from the edges of the board to all kinds of structural elements. For example, high-frequency connectors that extend beyond the boundaries of the board.
The essence of printed wiring is the formation of thin electrically conductive coatings on an insulating base, which perform the functions of installation wires and circuit elements - resistors, capacitors, inductors, contact parts, etc.
Below are the main terms used to describe the Documentation.
Printed conductor- a section of a conductive coating applied to an insulating base that performs the functions of a regular installation wire.
Printed Editing - a system of printed conductors that provide electrical connection of circuit elements.
Printed circuit board - insulating base with printed wiring applied on it.
Hanging elements- volumetric electrical and radio elements installed and fixed on a printed circuit board and having electrical contact with printed conductors.
Contact pad- a metallized area around the mounting hole, which has electrical contact with the printed conductor and provides electrical connection of the suspended circuit elements with the printed circuit.
Mounting hole- a hole in the printed circuit board intended for securing the leads of the hinged elements and their electrical connection with the printed conductors.
Grid- a grid applied to the image of the board and used to determine the position of mounting holes, printed conductors and other elements of the board.
Grid pitch- the distance between adjacent grid lines. The grid pitch must be a multiple of 0.625 mm (0.625; 1.25; 1.875; 2.5, etc.).
Grid node- point of intersection of grid lines.
Free places - areas of the printed circuit board where, when placing conductors, the recommended values for the width of conductors and the distance between conductors and contact pads can be maintained.
Narrow places - areas of the printed circuit board where, when placing conductors, their width and the distances between them and the contact pads are less than recommended (down to the minimum permissible).
Printing block - a printed circuit board with a printed circuit, attachments and other parts that has gone through all stages of manufacturing.
Design documentation for printed circuit boards and blocks is drawn up in accordance with the requirements of GOST 2.109-73, GOST 2.417-91 and current regulatory and technical documents. A single-sided or double-sided PCB drawing is classified as a part drawing. The drawing of the printed circuit board must contain all the information necessary for its manufacture and control: an image of the printed circuit board from the printed circuit board side; dimensions, maximum deviations and surface roughness of the printed circuit board and all its elements (holes, conductors), as well as the dimensions of the distances between them; necessary technical requirements; information about the material.
The dimensions of each side of the printed circuit board must be a multiple of 2.5 for a length of up to 100 mm, 5 for a length of up to 350 mm, 20 for a length of more than 350 mm. The maximum size of any side of the printed circuit board should not exceed 470 mm. The ratio of the linear dimensions of the sides of the printed circuit board should be no more than 3:1 and is selected from the range 1:1; 1:2; 2:3; 2:5. The thickness of the boards is determined based on the mechanical requirements for the design of the printed circuit block, taking into account the manufacturing method. Recommended boards with a thickness of 0.8; 1.0; 1.5; 2.0; 2.5; 3.0 mm. Printed circuit board drawings are made in full size or with a magnification of 2:1, 4:1. 5:1. 10:1.
The development of a printed circuit board drawing begins with drawing grid coordinates. The main pitch of a rectangular coordinate grid according to GOST 10317-7 is taken to be 2.5 mm. For small-sized equipment and in technically justified cases, it is allowed to use additional steps of 1.25 and 0.5 mm.
The centers of all holes on the printed board must be located at a grid node. If this cannot be done due to the design features of the hinged element, then the center of the holes is located according to the instructions in the drawing for this element. This arrangement of hole centers is used for lamp panels, small-sized relays, connectors and other elements. In this case, the following requirements must be met: the center of one of the holes, taken as the main one, must be located in a coordinate grid node; the centers of the remaining holes should, if possible, be located on vertical or horizontal lines of the coordinate grid. In Fig. Figure 4.18 shows the location of the holes on the printed circuit board.
The diameters of mounting and adapter holes for metallized and non-metalized holes are selected from the range (0.2); 0.4; (0.5); 0.6; (0.7); 0.8; (0.9); 1, (1,2); 1.3; 1.5; 1.8; 2.0; 2.2; (2.4); (2.6)
(2.8); (3.0). Diameters not in brackets are preferred. It is not recommended to have more than three different hole diameters on one PCB. The diameters of metallized holes are selected depending on the diameters of the leads of the hinged elements and the thickness of the board, and the diameters of non-metalized holes - depending on the diameters of the leads of the hinged elements installed in these holes (Table 4.1).
The need for countersinking of mounting and via holes is dictated by specific design requirements and the method of manufacturing the board.
When using other diameters of metallized holes in accordance with GOST 10317-79*, the difference between the diameter of the metallized hole and the diameter of the lead should be no more than 0.4 mm for leads with a diameter of 0.4 to 0.8 mm and 0.6 mm for leads with a diameter over 0 .8 mm.
The surface roughness of non-metallized mounting holes and ends of printed circuit boards must be Rz< 80 according to GOST 2789-73*. Surface roughness of mounting and transition metallized holes - Rz< 40.
To simplify the image of the board, the holes are shown in circles of the same diameter with the designation according to the table. 4.2.
When making holes in this way, a table of holes is placed on the drawing field (Fig. 4.19). Dimensions
the graph and form of the table are not established by GOST.
All mounting holes must have contact pads. The shape of the contact pad can be arbitrary, round, rectangular or close to them. The center of a symmetrically shaped pad must coincide with the center of the mounting hole; for rectangular and oval shaped pads, the center of the mounting hole can be shifted
(Fig. 4.20). Round pads and holes with countersinks are depicted as one circle, the diameter of which must correspond to the minimum size of the pad. The diameter of the contact pads should be indicated in the technical requirements of the drawing. If there are contact pads on the board of unspecified sizes or shapes other than round, it is allowed to depict all contact pads with a circle equal to the diameter of the hole. The shape and dimensions should be specified by writing in the technical requirements “The shape of the contact pads is arbitrary, i> mjn = = ...mm.”
To set the dimensions of group contact pads, it is recommended to display the image of the contact group on an enlarged scale with the required dimensions placed on the drawing field (Fig. 4.21). It is recommended to make a smooth transition from the contact pad to the conductor. In this case, the axis of symmetry of the printed conductor must be perpendicular to the tangent to the contour of the contact pad or the contour of the contact pad itself (Fig. 4.22). The distance from the edge of the conductor and the contact pad of the non-metalized hole to the edge of the board must be at least the thickness of the board T. Printed conductors should be depicted in the form of line segments coinciding with the lines of the coordinate grid or at an angle that is a multiple of 15°. Conductors of arbitrary configuration and rounding of conductor bends are allowed (Fig. 4.23).
Printed conductors should be made of the same width throughout. In narrow places, conductors are narrowed to the minimum permissible values at the shortest possible length. The relative position of the conductors is not regulated. If it is necessary to lay conductors with a width of 0.3-0.4 mm along the entire length, it is recommended to provide for an expansion of the conductor such as a contact pad after 25-30 mm.
Conductors with a width of less than 2.5 mm are depicted with one line, which is the axis of symmetry of the conductor, more than 2.5 mm - with two lines and are hatched at an angle of 45° or blackened. Conductors with a width of more than 5 mm should be made as a screen (Fig. 4.24). The shape of the cutouts in wide conductors and screens must be shown in the drawing and determined by dimensions (see Fig. 4.21). In order to simplify the drawing, it is allowed to make conductors of any width in one line, while indicating the width of the conductor in the technical requirements of the drawing.
When laying printed conductors, conductor branches should be avoided if possible (Fig. 4.25); the ends of printed conductors intended for connecting a printed circuit are recommended to be placed with
Rice. 4.25. Examples of tracing printed conductors:
a - correct; b - incorrect
In Fig. Figure 4.29 shows an example of making a printed circuit board drawing using a combined method of dimensioning - using dimension and extension lines and a coordinate grid. The coordinate grid lines are drawn one at a time, and therefore a corresponding entry is given in the technical requirements of the drawing. A table of holes is made on the drawing field. All missing data regarding printed wiring are indicated in the technical requirements of the drawing.
An example of a printed circuit board drawing with dimensions indicated in the coordinate table is shown in Fig. 4.23. The diameters of the holes are indicated in the drawing, the relative location of the holes is in the coordinate table; all holes are marked with Arabic numerals in accordance with GOST 2.307-68*.
The printed circuit board drawing indicatesoverall dimensions of the board, conductors having a strictly defined or variable width (in this case, the calculated width should be indicated in each section between two adjacent pads, vias or mounting holes), diameters and coordinates of fastening, technological and other holes not related to printed wiring.
The drawing field is indicatedboard manufacturing method, technical specifications (if not all data is contained in the drawing), grid pitch, width of conductors and distances between du them, the distances between the contact pads, between the contact pad and the conductor, tolerances for the execution of conductors, contact pads, holes and distances between du them, design features, technologies and other parameters of printed circuit boards.
Technical requirements are placed above the main inscription, formulated and presented in the following sequence:
1. Make a board using... method.
2. The board must comply with (GOST, OST).
3. Grid pitch... mm.
4. Maintain the configuration of the conductors according to the coordinate grid with a deviation from the drawing... mm.
5. Rounding of the corners of contact pads and conductors is allowed.
6. Places outlined with a dot-dotted line should not be occupied by conductors.
7. Requirements for the parameters of the board elements - in accordance with the design data.
8. Width of conductors in free places... mm, in narrow places... mm.
9. The distance between two conductors, between two contact pads or a conductor and a contact pad in free places... mm, in narrow places -... mm.
10. The shape of the contact pads is arbitrary.
11. It is allowed to lower the contact pads of metallized holes: on the outer layers to the countersink, on the inner layers...
12. Maximum deviations of the distances between the centers of holes, except as otherwise specified, in narrow places ± ... mm, in free places ± ... mm.
13. Maximum deviations of the distances between the centers of the contact pads in the group ± ... mm.
14. Mark with enamel... GOST..., font... according to GOST...
An example of recording technical requirements depending on the content of a printed circuit board drawing is shown in Fig. 4.23, 4.27, 4.29.
The features of printed wiring include: flat arrangement of printed conductors, which does not allow the transition from one board to another without jumpers, adapter blocks or connectors; installation of hanging elements and fastening of leads only by passing them into the holes; simultaneous soldering of all elements installed on the printed circuit board.
The hanging elements should be placed in correct rows, parallel to one another, on the side of the board where there are no printed conductors (Fig. 4.30). This arrangement allows you to install and secure attachments on automatic lines and perform immersion or wave soldering, eliminating the impact of solder on the attachments.
All attachments are attached to the board using leads, which are inserted into the mounting holes and bent. It is not recommended to place two or more leads in the mounting hole. Some elements, for example, low-power transistors, are attached with glue.
An assembly drawing of a printed circuit board, with a minimum number of images, should give a complete picture of the location and execution of all printed and mounted elements and parts. The assembly drawing is carried out in accordance with the requirements of GOST 2.109-73* taking into account the requirements of GOST 2.413-72*. The designs of the hinged elements are drawn in the form of simplified images, they are assigned an alphanumeric positional designation in accordance with the electrical circuit diagram, according to which the electrical installation of the board is carried out (Fig. 4.31). The assembly drawing of the printed circuit board must indicate the position numbers of all components, overall and connecting dimensions, and must contain information on methods for connecting attachments to the printed circuit board.
The technical requirements of the assembly drawing must contain references to documents (GOST, OST) that establish the rules for the preparation and fastening of hinged elements, information about solder, etc.
The main design document of the assembly drawing of a printed circuit board is a specification, drawn up in the form of a table according to the rules of GOST 2.106-96. When recording components that are elements of an electrical circuit diagram in the specification, in the “Note” column indicate the alphanumeric positional
designations of these elements (Fig. 4.32, 4.33).
The development of design documentation for printed circuit boards can be carried out manually, semi-automatically or automatically.
The manual method involves dividing hanging elements into functional groups, placing groups of elements on the board area, routing printed conductors and ensures optimal distribution of the conductive pattern.
With the manual design method, a board drawing is developed containing an image of the board with a conductive pattern and holes, as well as, if necessary, an additional separate image of the part of the board that requires graphical explanation or sizing, a coordinate grid made in accordance with the requirements of GOST 2.417-91, the dimensions of all conductive pattern elements and their maximum deviations; technical requirements. The board drawing must be made on a scale of at least 2:1, maximum format A1.