What is a technical drawing? Technical drawing standards you should know
07-10-2025 400
Technical drawing is a form of expressing information about products, parts or mechanical systems through symbols, images, scales and specifications.
What is a technical drawing?
Technical drawings are not just simple images but also contain important information that helps ensure that the product is manufactured exactly as required. Designers can copyright their technical drawings, protect their intellectual property rights and legally exchange and sell these drawings.
>>> What is the difference between technical drawings and detailed drawings? See now at: What is a detailed drawing?
Types of technical drawings
- 2D drawings: Previously, 2D drawings were the most popular type, showing product images on a flat surface with length and width. This drawing helps determine the basic parameters of the product.
- 3D drawings: With the development of technology, 3D drawings were born, helping to simulate products in a more detailed and intuitive way, making it easier to understand and check the elements of the product. Thanks to this feature, 3D drawings are increasingly replacing 2D drawings in many industries.
What are technical drawings used for?
Technical drawings are an important tool in design and production, helping to form works, products and equipment that meet technical standards. It plays an essential role in many fields, from building houses and buildings to manufacturing and manufacturing mechanical products and equipment.
- Manufacturing and production: Technical drawings provide detailed information about the structure, shape, size and materials of the product, helping the production process to be accurate and efficient.
- Information exchange: Technical drawings are a means for engineers and designers to exchange ideas and technical specifications, ensuring that the product meets the requirements and quality standards.
- Assembly and completion: Based on technical drawings, technicians can assemble and complete the product accurately, ensuring that the parts fit together according to the design.
- Quality inspection and supervision: Technical drawings are the basis for checking and evaluating product quality, helping to detect errors and promptly repair substandard parts.
- Technical drawings not only help create quality products, but are also a tool to control the production process and ensure accuracy in each stage.
Classification of technical drawings
Technical drawings can be classified based on the object of description and the field of application. Below are the common types of technical drawings:
1 - Mechanical Drawing
This drawing is used to describe the details or the overall mechanical product. It helps to clearly show the technical parameters of the mechanical parts to be manufactured.
2 - Construction Drawings (Construction Drawings)
Construction drawings are often used in construction projects. This type of drawing describes construction plans and construction details, helping to shape projects from the beginning.
3 - Explosive Drawing
A disassembly drawing shows the details of a product's components, showing the shape, location, and function of each part in the overall product.
4 - Structural Drawing
This is a drawing used in construction, showing the structures, sequential steps, and construction processes. It helps to clearly identify the elements needed to create a solid structure.
5 - Part Drawing
A detailed drawing provides complete information about a technical detail, including dimensions, materials, and processing requirements. It is often used in the production of product parts.
6 - Schematic Drawing
A schematic drawing is often used to describe an overview of a structure or system, such as an electronic circuit board. It uses symbols to simplify the details, helping to understand the overall structure.
Each type of technical drawing plays an important role in ensuring that products and structures are manufactured, assembled and tested according to technical standards.
Technical drawing standards you should know
Technical drawing standards include rules and principles that determine how to create, present and interpret drawings. They help ensure accuracy, consistency, clarity, and optimize work efficiency. Here are the main elements of technical drawing standards:
1 - Paper size
Usage regulations: TCVN 7285:2000.
Size: From A0 to A4. Standard paper sizes ensure drawings are suitable for printing devices and are easy to store and exchange.
2 - Drawing lines
Applicable regulations: TCVN 8-24:2002.
Types of lines in technical drawings include:
- Solid bold lines: Represent boundaries, edges, drawing frames and names.
- Solid thin lines: Used for dimension lines, extension lines and cross-section lines.
- Wavy lines: Represent the limits of the section.
- Thin dashed lines: Used for contours or hidden edges.
- Long dashed – dotted – thin lines: Represent center lines and axes of symmetry.
- Long dashed – dotted – bold lines: Used to indicate cross-section positions.
3 - Zoom ratio
Applicable regulations: TCVN 7286:2003.
Standard ratios include:
- Enlarge: 2:1; 5:1; 10:1; 20:1; 50:1...
- Original: 1:1.
- Reduce: 1:2; 1:5; 1:10; 1:20; 1:50.
Applying the correct ratio helps to show the actual size of the product accurately and easily for manufacturing.
4 - Letters in drawings
Applicable regulations: TCVN 7284-0:2003.
- Uppercase letter size (h): 1.8; 2.5; 3.5; 5; 7; 10; 14; 20 mm.
- Lowercase letter stroke width: h/10.
For example: With A4 paper, the size of lowercase letters is 2.5 mm and the size of uppercase letters is 3.5 mm.
Using the correct size and font makes the drawing clear and easy to read.
5 - Dimensioning
Applicable regulations: TCVN 7583-1:2006.
- Dimensions are recorded only once on the drawing, clearly displayed on the main projection.
- Unit of measurement: Millimeter (mm). This helps to minimize errors and ensure consistency between elements.
6 - Projection and projection layout
There are 3 main types of projections:
Front projection: View from the front.
Top projection: View from above.
Side projection: View from the left.
In addition, cross-sections and sections are used to show internal structural details. This regulation helps to describe the product clearly and completely.
7 - Title box and symbols
Applicable regulations: TCVN 17-63, TCVN 221-66.
- The title box records basic information about the drawing, paper size, and type of design drawing. Standard symbols help readers understand the content without causing confusion.
The Importance of Drawing Standards
Applying drawing standards correctly helps:
- Optimize information exchange between parties in the design and production process.
- Ensure quality through inspection and acceptance processes.
- Limit errors, save time and costs.
Understanding and complying with technical drawing standards is a decisive factor in creating products and works that meet quality standards and efficiency.
Applications of technical drawings
Technical drawings play an important role in many fields that require high precision, especially in mass production. Some common applications of technical drawings include:
- Construction industry: Technical drawings support the design and construction of works, ensuring that construction steps take place accurately and according to plan.
- Mechanical processing: In processing, technical drawings help describe in detail the size and shape of the product, ensuring consistent production quality.
- Machine manufacturing: Drawings provide detailed images of components and assembly methods, helping the machine manufacturing process become efficient and limit errors.
Technical drawings are not only a production support tool but also a standard communication language between departments in the industry. Understanding and applying technical drawings correctly helps optimize work efficiency and quality.
