Design Guidelines	Issue No :	05	DG 06
	Date :	August ‘13

Design Guidelines For pcb Drawings

1. Drawing Definition

A PCB design document is a controlled document that contains all necessary information about schematic, electronics components, physical properties and any other vital details which are required to produce a PCB.

2. Purpose & Application

The purpose of this document is to establish a guide in order to aid Designers to fully complete drawings. All Drawings shall be fully detailed in order to allow potential users of the information to produce or supply components for the PCB without error or confusion.

3. Drawing Details

Methode PCB Assembly drawings will consist of multiple sheets organised as follows:-

– Manufacturing notes and full revision history

– Schematic and last revision

– PCB assembly view, component BOMs, Manufacturing notes and last revision.

Assembly drawing numbers will begin 16xxx, where xxx will be defined by the part number issuing authority.

Bare Board drawings will be prepared separately from the assembly drawings. Their numbers will begin 44xxx, where xxx will be defined by the part number issuing authority

Amendment Block

1. Zone

Zone shall be filled in to identify the area where an amendment has taken place. The Y axis is lettered and the X axis is numbered. The X-axis shall be typed in front of the Y axis, e.g. 4G (First the number followed by a letter.) All drawings shall be prepared on the standard template.

2. Index

All drawings shall be issued with a “00A” index and marked “DRAWING ISSUED”. Index level shall start from top to bottom of the amendment block. When the amendment description is longer than one line, the index number shall be typed on the first line of the amendment and the date and name shall be typed in line with the end of the amendment description.

3. Amendments

Amendments shall be recorded as concisely as possible, but shall contain a clear record of what has been changed. All modifications shall be cross referenced to Change Notice (CN) and Change Reference (CR) as applicable. This number shall be recorded in the next column – Supporting Document field (SPRT DOC). Any modifications in the drawing shall be marked with an encircled amendment index letter placed on the location where the amendment has taken place, as shown below. The supported document should refer to the Index No.

In those sheets where no changes have been effected, the entry in the Amendments field shall read “REFER TO SHEET x”, where x denotes the sheet number where changes are present. In case of multiple sheets containing changes, these should be all listed in the same entry reading “REFER TO SHEETS x, y, z”.

4. CR & CN Usage

A CR is to be used to amend typing errors and to bring drawings in line with the mechanical PCB (due to mechanical tolerances and so on).

A CN is to be used for anything else like change in resistor value, change in component and so on.

5. Date/Name

Date/Name shall be entered when Drawing is issued or amended. Name shall be written in the following manner: first name initials only and surname in full, both in block form.

6. DWG NO. (Drawing Number)

All drawings shall be initially issued with “00A” index. The drawing shall get the next higher number and letter index for amendments effected by an Engineering Change Notice e.g. from 00A to 01B.

The Drawing shall get the next revision letter only for every amendment effected by a Change Reference e.g. from 00A to 00B.

Title Block

7. DWN BY (Drawn By)

‘Drawn by’ shall be typed in by the PCB Designer.

8. CHK BY (Checked By)

‘Checked by’ shall be typed in by someone within the Product Development Department. This shall commonly be the product designer nominated as Lead Engineer for the project.

9. APVD BY (Approved By)

‘Approved By’ shall be typed in by the PCB Designer’s Principal, or in his absence the Product Development Manager.

10. CAD Filename

The full Drawing file name and extension shall be identified in the field.

11. Title

The title of the drawing shall identify the PCB name and Product Function. e.g. “PCB Assy. – Main Board - SAS” etc. It is not acceptable to simply write “PCB Assembly”.

IV. Drawing Types

The above guidelines shall apply to all PCB drawings.

1. The PCB Assembly Drawing – 16xxx

All sheets of all PCB Assembly drawings will carry the standard border, including the Title Block and Amendment Block (see Figure 1). Special notes related to standards, finishes and any other notable features which affect the PCB assembly shall be included in the first sheet. All notes should be collected in a single numbered list, except where individual notes may relate specifically to a particular view. In that case it is acceptable to place the unnumbered note close to the corresponding view.

The number of sheets in the drawing shall be kept to the minimum amount possible, by using larger page sizes where necessary. However, it is important that the drawing maintains clarity and avoids clutter; hence when necessary it is acceptable to increase the number of pages if this enhances readability. All sheets should have the same page size, where possible.

Where multiple variants of a PCB exist, each variant shall have as unique assembly number. All assemblies will refer to the same bare board number. The assemblies will traceable through their use of a common bare board.

Figure 1: The Standard PCB Assembly Border. Note that that Amendments block should be extended to the maximum amount of lines possible on the sheet, to allow room for detailed descriptions of modifications.