Mechanical Engineering Drawing and Design

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Mechanical Engineering Drawing and Design

Mechanical Engineering Drawings are a critical part of the design process, and any engineering will be expected to understand them. They are used to represent how a part or assembly is designed and how it will be manufactured.

This guide provides a brief overview of the most common types of engineering drawings you may encounter in your studies, as well as some tips on how to read them.

What are mechanical engineering drawings?

What are mechanical engineering drawings?

When working on a custom machanical project that requires many different components, there are multiple engineering drawings that is designed for each part from your engineering team. As a result, it must be ensure you are familar with mechanical engineering drawings to understand all design informations to finish the project well.

Mechanical engineering drawings are created by engineers to show the design of a product. The drawings are usually created using CAD (computer-aided design) software and they are used to communicate with other engineers, suppliers, and customers.

The drawing shows the dimensions of the product and each component that is used in its design. This includes measurements for length, width, height; angles; and other specifications. It also includes various views that show the different sides of a product or its components from different angles to help clarify the design.

What are the basic components of an engineering drawing?

The basic components of an engineering drawing

Every detailed engineering drawing consists of all the essential components of the object or part relevant from the manufacturer’s understanding point for machining or assembly. The basic components of an engineering drawing are:

  • -Title Block
  • Dimensioning and Tolerances
  • -Geometric Constraints and Dimensions
  • -Block Diagrams and Schematics
  • -Detailed Views
  • -Detailed Parts Lists
  • -Component Lists
  • -Assembly Diagrams -Assembly Views

The orthogonal views are the front, back, top and bottom views of an object. These views are also called orthographic projections. They provide a representation of an object as if it is being viewed by a camera from different directions, with each direction forming a right angle to the previous one.

A dimension is a physical property or attribute of an object. Dimensions are usually expressed as length, width, height, diameter, chamfers, circumference and area.

In engineering drawing, dimension refers to the linear measurement of an object. It is a numerical value that is used to represent the size of an object. Dimensions are usually shown as a number followed by one or more letters.

If we were to painstakingly draw the plan, elevation, and side views of an entire oil refinery, we would need more than tens of thousands of pages, which is practically impossible. Therefore, we use a scale used to represent an entire part or object of a paper. 

It is the ratio of an object’s size to the corresponding size of a drawing. Scale is expressed as a fraction or ratio with one part being the object and the other being the drawing.

The scale can be in any unit, but most often it is in millimeters (mm) or inches (in).

A pictorial representation of a design can’t always show the details of complex shapes and structures that contain information helpful for manufacturing the part. A typical projection method represents a 3D object in an easier way to be understood more readily by the manufacturer.

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Projection is a technique used to represent three-dimensional objects in two dimensions. It is typically used in engineering drawings and technical drawings.

The purpose of projection is to create a drawing that can be read without 3D glasses or other special equipment.

This technique can also be used to create an image that has the same perspective as a 3D object, but that can be seen from any angle.

Drawing Standards are the standards that are used to make sure that drawings are consistent and easily understood. Drawing Standards are guidelines for drawing practices. They serve as a reference when it comes to consistency, accuracy, and clarity of drawings.

Drawing Standards can be divided into two categories:

1) The American National Standards Institute (ANSI)

2) The International Organization for Standardization (ISO).

All engineer drawings need document name, title and drawing number. The name or title is based on the part/project and its application. The drawing number is unique and is used for identification purposes and document record internally.

Tolerances are the allowable limits of variation in a product’s dimensions, weight, or other properties. They are typically expressed as an upper and lower limit with an indication of the range of deviations for which the product is still considered to be within specification.

The tolerances for a given component can be specified in engineering drawings and specifications. Tolerances may also be specified by tolerance blocks on engineering drawings.

Material information is must have in an engineering drawing for the manufacturer to know the cost, the manufacturing technique, the quality, and the timing.

Engineering designs also involve the task of different people in the organization. The initials or names indicate respective people with the charge of specific duties. In the title block, you will find all these details.

The signatures indicate responsibility and dictate accountability.

Revisions & Modifications may be necessary because of errors in the original drawing, or because of changes in design specifications, they need to be stated in the engineering drawing.

 

The drawing sheet’s size varies depending on the type of product to be designed. The usually accepted drawing sheet sizes are A0, A1, A2, A3 and A4. For your understanding, An A0 sheet has 1m² of drawing area available. 

Next is the drawing sheet reference; many detailed designs require multiple sheets to define their content adequately. Numerous views, auxiliary views, sections, extensive title blocks and notes may require more space than is available on a single sheet. Therefore, multiple sheets are needed, and all should have specific reference to each other.

A multiple sheet drawing can be represented as SHEET 1 of 4, SHEET 2 of 4, SHEET 3 of 3, SHEET 4 of 4.

The organization’s name is crucial from a legal and identification point of view. The name of the company or organization is a must in the title block.

Why are Mechanical Engineering Drawings useful?

Drawings are a crucial part of the design process. They provide a visual representation of all the components and their dimensions. They present important information to the people who will be assembling, designing and manufacturing the product, also communicate with their clients, investors, and other stakeholders.

Drawings can be used as a legal document if they have been signed off by a professional engineer. The drawings will be used for guidance in the future construction, manufacturing or maintenance of the project.

In conclusion, drawings are an essential part of any project and should always be considered when designing something new.

Tips for Using Mechanical Engineering Drawings

Tips for Using Mechanical Engineering Drawings

The best way to use a mechanical engineering drawing is to know the different types of drawings, what they are used for, and how to read them.

Mechanical engineering drawings can be divided into four main categories: general arrangement drawings, detail drawings, assembly drawings, and auxiliary views. General arrangement drawings show the overall design of a machine or device and are used when there are many parts that need to be shown. Detail drawings show more specific parts of a machine or device and are used when there is only one part that needs to be shown in detail. Assembly drawings show how different components fit together and are used when there is more than one part that needs to be shown in detail. Auxiliary views show the same machine or device from different angles and help with understanding how it operates or what it does.

The most important step in reading a mechanical engineering drawing is understanding which type of drawing it is before reading it in detail. There will also be symbols on the drawing that provide.

1. materials

There might be multiple materials used in the overal project, hence the engineering drawings must  is a vital component of the overall project. The drawings must clearly mark what material is used in each component/part of the project, that you can have a BOM for a big project which required different components. 

2.Geometry

Geometry in Mechanical Engineering Drawings is a major topic for anyone who is studying Mechanical Engineering. It is important to have a good understanding of Geometry and its applications in the field of Mechanical Engineering.

The following are some tips that will help you understand Geometry better and improve your performance on this topic:

  • – Learn about the various types of Geometric shapes such as circles, rectangles, triangles, etc.
  • – Practice with these shapes by drawing them on paper or using a computer software to draw them.
  • – Learn about geometry proofs and how they are used to prove the validity of geometric statements.

3.Dimensions

A good dimension should be easy to read and understand. A dimension should also be accurate and clear.

There are different types of dimensions for different purposes.

  • 1.Dimensioning should be done in a logical sequence.
  • 2.Use the same units of measure, and decimal points, throughout the drawing.
  • 3.Placing dimension lines close to the object they represent makes them easier to find and read.
  • 4.Use multiple dimension lines to represent the same parameter if it changes in different directions or by different amounts at a point on an object (i.e., length, width, height).
  • 5.Place dimensions on their own line that starts with a letter or number so they are easy to identify and locate later in the document (i.e., A1).
  • 6.Give complete dimensions when you can; give approximate dimensions when you can’t provide all of them; don’t leave out any dimension if you can help it; and use numbers instead of words for dimensions whenever possible (i.e., “5 cm” instead of “about 5 cm”).

Mechanical Parts with Manufacturing Solutions

If you’re a mechanical engineer want to start a project that have questions for your design drawing, then make sure you get in touch with us today. We specialise in helping customers to evaluate engineering drawings from manufacturing aspect to have instant feedback and advices. We have helped many customers just like you to complete design drawing modificaiton and deliver high quality parts for custom mechanical part projects.

For a chat with one of our friendly team, contact us today or simply upload your drawing and one of our experts will get back to you.

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Table of Contents

Author: Mose Li

Author: Mose Li

Director of Project Engineering at 3Q Machining

Materials

The guideline for raw materials, understand more to choose best material for your custom part projects.

Machining Techniques

The guideline for different machining technique, understand more to choose best technique for your custom part projects.

Equipments

The guideline for different machining equipments, understand more to choose best equipments for your custom part projects.

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