Communicating, and explaining ideas with a picture is fast and effective. In industrial design, technical drawing is significant for designers who create real objects. Technical drawings use a set of standard abbreviations to provide all information required to manufacture any given part/product. This guide is intended to improve your knowledge of how to develop engineering drawings for conveying the design intent accurately to the suppliers.
Why Use Engineering Drawings?
An engineering drawing is the graphical presentation of a part structure. It also illustrates dimensions and other required parameters. Single-part drawings are conventionally used for processing within the manufacturing industry. Assembly drawings depict how parts operating simultaneously within a machine/equipment perform functions. They are generally employed to verify if production parts conform to assembly specifications.
Two primary methods are used for creating engineering drawings: manual and computer-based.
Manual Drawings
Manual drawing has tools like boards, rulers, and calipers. These drawings are invaluable for the universities. And colleges. These are used for spatial imagination and form the concepts so crucial for a creative approach.
Computerized Drawings
Computer drawing is often performed using Computer Aided Design (CAD) tools. These are more popular in contemporary manufacturing. CNC systems can directly import virtual/digital files(CAD/CAM) automatically produce machining programs and minimize the amount of work. Computer drawings also allow for easy changes to the designs. These keep different versions of the same design. Eliminating redrawing needs.
Even though 3D models can be provided, engineering drawings are needed to convey important features. For instance; material type, tolerance, and other characteristics. 3D models should be used together with engineering drawings.
How to Make Engineering Drawings?
Before, engineers and technicians used instruments to produce engineering drawings. However, today, these are made on the computer. Engineers incorporate CAD when drawing their plans and perfecting detailed working models. CAD software allows for the creation, as well as modification, and analysis of design at an incredibly fast pace and with high precision.
Here is a breakdown of steps:
1. Plan the Project
When getting into a CAD program, Firstly, you need to think it through. Design teams usually meet engineers or draft technicians who collect all the necessary papers. First and foremost, one needs to know his/her project A to Z; to know its goals and functions inside out. In this planning phase, it’s necessary to determine the product requirements and its primary functions when using commands in the CAD program. For this step, one should imagine it as the preparation for a successful design.
2. Establish Project Files
After planning you should commence by initiating a new project file in the CAD program. The following file can be used as your design base. These include features such as the design size you’re creating, as well as the units of measurement used – whether metric or imperial factors, pertinent to the design.
3. Product Creation
It’s a step where all the design work is done. Designs are coordinated with drafters and other design professionals. Engineers are allowed to begin the construction of the product in the CAD system. When the designing process is in progress, you should monitor the parameters of the design, such as dimensions, materials, accuracy, etc. Because any problems that arise will be solved at the initial stage. So, productivity, and time-consumption could be reduced at greater extent.
4. Input Technical Information
Product appearance is also represented in engineering drawings. However, it’s not limited to aesthetics only. After the general layout is created, the details like dimensions, material, and any other information are incorporated. In addition, this phase may involve some administrative data like the project dates, revisions, and notes among others. This information is generally written in boxes on the drawing side so that it can be easily read by other engineers and any decision-maker.
5. Develop Proofs
Finally, when all technical drawings are complete, it’s time to make proofs. Particularly, it’s true because proofs are preliminary versions of the design. Some important papers can be printed while others can be emailed to the management and other stakeholders for their input.
6. Collect Feedback
After the proofs are created, you will gather feedback from engineers, team members, or even clients, based on the project. In large designs, there may be several individuals who have to give their consent before the process continues. In some cases, the product testing before it goes through large-scale production is also conducted, to ensure design effectiveness.
Fundamental Aspects of Technical/Engineering Drawings
- Title Block:The title block is located in the lower right corner of a drawing. It has the part name, people’s names, company name, and the drawing number. For further clarity, details such as unit, projection angle, material, and scale are also provided.
- Coordinates:These are useful when working with large drawings that may be complicated. Coordinates are used as standards, located along the edges of the drawing for easier presentation of certain aspects.
Types of Lines In Engineering Drawings
Boundary Lines
The continuous line is used to indicate the physical form of an object, outer and inner edges. They get thicker where outlining edges are required and thinner for inside detailing.
Hidden Lines
Hidden lines depict all those parts of the object that are not visible from the point of view of the drawing. For instance, some lines used in the turned part can represent an interior step in one of them.
Centre Lines
Centre lines mark the position of holes and similar center parts. They assist in reducing dimensions in a drawing to reduce confusion and increase the understanding of the picture.
Dimension Lines
Dimension lines are lines that denote measurements. These lines have arrowheads pointing to extension lines, which indicate the size or dimension between two points. For instance, a long part with the same geometry can be drawn having a break to save space.
Cutting Plane Lines:
Cutting plane lines depict the cutting plane through a component. The intended plane displays the part’s internal features. For instance, a cutting line may be referred to as A-A and may show internal details such as holes.
Types of Engineering Drawing
In the field of engineering, we group drawings into four primary types: Civil and Structural, Mechanical, Electrical & Electronics, and Geometric. These categories help us organize the design process. All of them have their particular usage to transmit particular technical data. Knowledge of these categories assists us in being accurate in our communication during project implementation. Now let’s take a look at each type in more detail.
Geometric Drawing
In geometric drawing, we illustrate such shapes as rectangles, cones, and spheres. These we categorize based on dimensions as plane geometric drawings and solid geometric drawings. Plane drawings represent objects having only length and width, for example, squares, triangles, etc. When we add depth we get three-dimensional geometrical figures such as a cube or cylinder.
Mechanical Engineering Drawings
When we have mechanical drawings, we depict machinery and its parts. They help us convey the complicated ideas involved in mechanical projects, typically very useful for engineers. We can dissect every part and assembly through part and assembly diagrams. This clarity serves to let everyone know how to build or fix the machinery.
Civil Engineering Drawing
Civil drawings are important when we are designing such items as buildings or bridges. These drawings assist us in presenting concepts that construction teams can understand well. Starting from roads to dams, we use these visuals as a reference for developing such structures. The civil engineering drawings employed in our projects guarantee that the construction of every project is done safely and effectively.
Electrical and Electronics Drawings
In electrical and electronics drawings, emphasis is on the power, the circuit, and the devices. These drawings help to plan and execute electrical projects in the best way possible. They enable the representation of all from motors to sophisticated electronic systems. These drawings are used effectively in the installation of electrical components into panels. Graphics assist in making work simple and systematic.
Sectioning Techniques in Engineering Drawings
Sectioning is used to show how an object is arranged inside or divided inside. This method makes an object seem like it has been cut right down the middle. Separation is used in many industrial designs. The division creates two blocks, labeled A and B. An object in a drawing can be separated in several ways just like separating an apple into slices. There are so many sectioning techniques when it comes to drawings as will be explained below.
Full Sectioning
In full section, the cutting plane completely cuts across an object. This section is where the object is shown in two parts. This way sectioning can be used anytime to perform a close examination of the object.
Semi-Sectional View
It is possible to project on the perpendicular projection plane when we have a symmetrical plane. One half is depicted in the sectioned form and the other half in the broken line form. The semi-sectional view shows balanced members and exposes interior and exterior layouts. The dividing line is represented by one dotted line only. This way there are no hidden lines which makes the representation of the internal structure clear.
Broken-Out Sections
Broken-out section views cut away material up to a given depth. This technique will help to reveal the internal structure of the model in the best way. The broken-out part is normally defined by a closed profile, usually a spline. The user can enter an exact depth or use another view to set a location precisely.
Cross-Sectional Views
Areas of its cross-sectional layers are equal to the object’s total area. For instance, the height of a cylinder and the radius of a cylinder are labeled in orthographic projections. When this cylinder is viewed orthogonally, the geometric properties of the cylinder are visible.
Partial Enlargement View
Technical drawings may use partial views to provide more information. These views make it easier to provide more details about a part. The use of partial views improves the comprehension of the concept during part analysis.
4 Common Mistakes in Engineering Drawing
1. Incomplete, Messy, or Repeated Dimensions
- Important dimensions of the parts should be marked directly on the drawing.
- Do not use closed dimensions because they may confuse the users.
- In any case, make sure that dimensions are symbolically marked in a way that will be convenient for further analysis and calculations.
2. View Errors
- Mismatches and improperly oriented views or views that overall do not align can hinder the understanding of the design.
- Make sure all the views are as communicative as what the design is supposed to signify.
3. Lack of Dimensional Tolerance
- Specifically, when the dimensional accuracy requirements are high, it is necessary to indicate the dimensional tolerances.
- If this is not done, there will be extensive machining inaccuracies and waste of workpieces.
4. Non-standard Technical Requirements
- The technical requirements for the parts such as dimensions tolerances, form tolerances, and surface roughness should always be standardized and marked.
Conclusion
To the designers, engineers, and machinists, engineering drawings are essential means of communication. They educate and share ideas and concepts in addition to describing features of a part. Much information is incorporated in these drawings and serves to explain design intent. It is possible to find important details and define proper strategies for machining for suppliers.
Tops Precision’s skills at work
We focus on offering precision solutions at Tops Precision. Our engineers and machinists work hand in hand with CAD analysts. Together they go through all aspects of engineering drawings as stated above. Instant Design for Manufacturability (DFM) is available to guarantee the best results. It also ensures that all the machined parts that come out of the process are of premium quality.
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