As a kind of engineering language, engineering drawing can clearly express technical information. but what kind of information is in the drawing and how does another engineer clearly understand the drawing? In this blog, we will talk about everything about engineering drawing.
What is an engineering Drawing?
An engineering drawing is a kind of technical drawing that is used to show all information about a product including size, shape, surface finishing, materials, dimensions, tolerances, and more that is needed to manufacture the product.
Benefits of Engineering Drawing
Clear Communication
Engineering drawings can standardize the technical information of specifications and requirements. They convey information about the size, shape, and tolerances which can put all the team members on the same page for all the technical information.
Visualization Of Design
Engineering drawings can help engineers understand the design concept clearly, they can see where are the function areas of each component and how each component fits with another component. So when in the manufacturing process, engineers will take care of this area.
Precise Dimensions
Engineering drawings can define the dimensions of the drawing precisely. with section view and detail view, the dimensions that are critical to the functions of components can be shown clearly to the manufacturing engineers. for example, Geometric Dimensioning and Tolerancing can be shown in the engineering drawings.
Quality Control
Engineering drawing is a standard document needed in the quality control process. manufacturing engineers will use these drawings as a reference standard to check the produced parts, only the parts that meet the specifications listed on the drawings can be qualified. in this case, engineers’ drawings help to control the quality of parts and avoid errors in production.
Types of engineering drawings
Assembly Drawing
Assembly drawings show how multiple components connect in their designed positions to form a complete product. these components are manufactured separately, and assembly drawings help engineers to understand fit and match relations between these components.
Schematic Diagrams Drawing
Schematic diagrams present a simplified representation of a system or process using symbols, lines, and labels. They focus on conveying the functional relationships and connections between components without detailing their physical appearance. Schematic diagrams are commonly used in electrical, electronic, and hydraulic systems.
Part Drawing
Part drawings provide an in-depth representation of individual components. They feature exact measurements, material details, tolerances, surface finish requirements, and production notes. These drawings are essential for production, directing manufacturers and machinists to make a good quality product.
Main components of an engineering drawing
Title Blocks
In an engineering drawing, the title blocks are located in the lower right-hand corner. the title blocks show information like the part’s name, the company’s name, the drawing number, and the name of the designer and reviewer. Furthermore, this block provides technical information such as unit measurements, projection angle, surface finish standards, drawing scale, and the material used.
Drawing Views
Basic View
Place the part in the projection system composed of six basic projectors, and project to the six basic projectors respectively to obtain six basic views. In most cases, 3 basic views such as front view, side view, and top view are used in an engineering drawing.
Regionally, the views are a little different. Compare the US and ISO layouts by taking a look at this image. Drawing layouts in ISO and the United States are in direct opposition to one another. The one on the left is known as a first-angle projection, on the right is known as a third-angle projection.
Directional view
A direction view indicates a view according to the projection direction on the main view or another view, it is a view that is not configured according to the projection of basic views. If a view cannot be configured according to the projection, it can be drawn according to the direction view.
Sectional View
The section view is mainly used to express the internal structure of the parts, it is supposed to use a section plane or surface to cut the parts, the part between the observer and the section plane is removed, and the rest of the part is projected on the plane.
Detail View
The detailed view focuses on a specific area or feature of the object, providing an enlarged and magnified view for accurate representation and dimensioning.
Auxiliary View
The auxiliary view is used to display inclined or non-orthogonal surfaces that cannot be accurately represented in other views.
Dimensions And Tolerances on Engineering Drawing
Due to machining stability, the actual dimensions can’t be the same as the dimensions in the 3D data of a product. this is where tolerance comes from, The actual size after manufacturing should be within the specified range of the maximum and minimum limit dimensions. below are the related definitions of dimension and tolerance.
- Basic size: The dimension given by the designer.
- Actual size: The dimension obtained through measurement.
- Limit dimensions: The two extreme permissible values of a dimension variation, which are the maximum and minimum limit dimensions, are determined based on the basic size.
- Zero line: A baseline in the tolerance band diagram (limit and fit explanatory diagram) that determines deviation, i.e., the zero deviation line. The basic size is usually represented by the zero line.
- Dimensional Tolerance: Abbreviated as tolerance, it is the difference between the maximum and minimum limit dimensions, and it represents the allowable amount of variation in size. Dimensional tolerance is always a positive value.
- Standard Tolerance: In the system of limits and fits, any prescribed tolerance. The national standard stipulates that for a certain basic size, there are 20 tolerance grades of standard tolerances.
- Tolerance Zone: In the tolerance band diagram, the area is defined by two straight lines representing the upper and lower deviations.
Geometric Dimensioning And Tolerancing
Every part is composed of points, lines, and surfaces, which are referred to as elements. After machining, the actual elements of a part always have deviations when compared to the ideal elements, including shape deviation and positional deviation. These types of deviations affect the function of mechanical products, and corresponding tolerances should be specified during design and indicated on the drawings with standardized GD&T symbols.
How to Create an engineering drawing
In the past, drawings are created manually, tools such as drawing boards, rulers, and round gauges are used at that time. this method will take days to weeks to finish one component’s drawing which is slow and easy to make mistakes on the drawings.
Today, Engineering drawing is created by CAD software which allows the drawing on a computer. Various types of CAD software are available and some types of software are specific to particular industries. With CAD software, engineers can either create a drawing from nothing or create a 3D model and then translate it into a drawing.
Conclusion
Engineering drawings are one of the best ways to communicate all the technical information. At KUSLA prototype, our team of skilled engineers and machinists is proficient in analyzing every facet of engineering drawings, providing prompt Design for Manufacturability (DFM) feedback to guarantee the finest machined components. Take the next step by uploading your CAD files and receiving a quote today!
FAQ
How do you read engineering drawings easily?
Engineering drawings are composed of some key parts. read them in the following step, you can quickly understand the drawing:
1. Get critical product information from Information Blocks which contains the object depicted in the drawing and the people who were involved in creating it.
2. Understand the symbols and abbreviations including specifications and dimensions.
3. Read the lines and views to understand how they are reflected in the 3D data.
Why not just use a 3D model?
Some information can not be shown in the 3D model. but engineering drawings can provide this information such as Geometry, Tolerances, Materials, surface finish, and more.
What are the common mistakes in engineering drawings?
The common mistakes in engineering drawings include Inconsistency in dimension data, over-dimensioning, Critical specification, incorrect tolerances, and more. all these mistakes will make manufacturer can not produce parts well.
