Technical Drawings

Introduction Technical drawings Is a visual communication of how something functions or how it is constructed. Are tools that communicate ideas between people in industry and engineering. Need to be precise, objective and accurate unlike expressive drawings which are subjective.

A Technical drawing must include: Geometrical and isometric 3D view Shape of the object Multiple angle projections. Dimensions Tolerances Material Finish

The Right-angled parallel projection An object can have six views It’s location and orientation to one another are derived from orthographic projection.

Example A Red octagon symbolizes "stop" even without a word

Staircase in two-point perspective

Circuit Diagrams Circuit diagrams show how electronic components are connected together. Each component is represented by a symbol and a few circuit diagrams are shown below.

Circuit Diagrams

What is PCB Artwork: A computer generated drawing using a CAD software such as PCB Wizard 3.5 and Orcad. It displays the physical arrangement of the components and the interconnection between them . A circuit schematic is first converted into an artwork & a PCB is fabricated using this. Artwork arranges the required electrical connections as patterns. The patterns are narrow copper tracks (strips) which wind their way across a layout to connect two or more intended components, as per the schematic

What is PCB Artwork

General Assembly drawing / Mechanical parts drawing The general assembly drawing (GA) of a product includes a list of all components and sub assemblies that make up the product assembly. GA includes details of assembly sequence & overall dimensions of the components. A Bill of Materials (BOM) of the GA drawing list out each part number, part name, and quantity. Each of these entities have what is known as a part number.

Plastics parts drawing Similar to General Assembly drawing / Mechanical parts The material is plastic instead of metal. To that extent plastic moulds will have to be designed

Fabricated parts drawings The Fabrication drawings are a group of assembly drawings. Contains a material parts list which specifies the type of material used to build up the fabrication. All welding details are included using BS standards. Includes details on the heat treatment needed before fabrication. The dimensions of parts used are also part of the drawing

Fabricated parts drawings

Jigs and Fixtures drawings A Jig is a holding device that can keep a job in place by holding it securely with appropriate support and guiding a cutter or a drill bit precisely. The fixture merely supports and locates the workpiece in place. It does not guide the cutting tool or the drilling tool. A jig differs from a fixture in that it can guide the tool to its correct position in addition to locating and supporting the workpiece. Examples: Vises, chucks

Jigs Vs Fixtures A jig differs from a fixture in that it can guide the tool to its correct position in addition to locating and supporting the workpiece. Examples: Vises, chucks