CAD DRAWING CREATION MODULE OVERVIEW

Audio: CAD drawing creation module overview

Creating engineering drawings is part of every mechanical design engineer’s job. So far, we have discussed the theory behind CAD modeling and looked into how parts and assemblies are made in CAD software. Now, we will go a step further and look into CAD drawings and how they are created in CAD software.

For this article, I am using Autodesk Fusion 360 to show you general concepts of CAD software. I will keep it as generic as possible so that you learn the general idea behind CAD modeling and that you can use this knowledge on any other CAD software out there.

Introduction to CAD drawing creation

I am very excited about this article because I have been writing a lot about engineering drawings and the theory behind it. Recently I published a new article category, starting to teach you about the theory behind CAD software.

We covered the general CAD introduction, CAD parts, and assemblies, and now we are finally coming to the CAD drawings. This article will connect so many important topics that we have discussed so far and open a world of possibilities for new exciting articles that will connect the theory with the practice.

We still have upcoming articles on CAD theory to round everything up, and then we will dive directly into the articles on how to apply all this engineering drawing and CAD theory to real-life engineering problems. Hopefully, you are excited about this as I am, and stay tuned because many things are coming your way. Now, let us go back to the article.

We could create many types of engineering drawings as mechanical design engineers. The most common ones are part (detailed) drawing and assembly drawing. We already covered a lot of topics regarding engineering drawings in our previous articles, and I will share with you the links as we progress through the article.

In introduction to engineering drawings, we learned that “We can observe engineering drawing as a unified language that engineers use to communicate independently of each other’s spoken or written language. According to ISO 29845:2011, drawing is “technical information, given on an information carrier, graphically presented in accordance with agreed rules and usually to scale.””

Before the invention of CAD, engineers used to create drawings with their hands with pen and paper. As CAD developed, the drawing creation process became easier, faster, and more efficient. However, the rules mainly stayed the same, so it is still essential to learn rules for creating engineering drawings.

As a mechanical design engineer, you will use engineering drawings to communicate your design intent with your own production, procurement, suppliers, etc., and it is crucial and precious for your career to understand the process of creating CAD drawings. Knowing the basics of engineering drawing creation and how to do that efficiently in CAD software will definitely help you in the long run.

I know I said this in my previous articles, but I will repeat myself again and emphasize that CAD software is a tool that mechanical design engineer use to, based on mechanical engineering fundamentals, build real-life solutions. CAD is an extension arm of our knowledge of mechanical engineering principles, not the other way around. Keep in mind that software is only smart as the person using it.

Basic terminology

Let us know to look into some of the basic terms that you will encounter when creating a drawing in CAD software.

Part

According to ISO 29845:2011, part model is a model in which the product described is one single item. We already covered this topic in depth.

Assembly

According to ISO 29845:2011 assembly model is a model in which the product described is an assembly of two or more items. We already covered this topic in depth.

Document types

Mechanical design engineer needs to create a range of different documents to ensure that the product is fulfilling customer requirements, that it is manufacturable, and that its quality is satisfactory. Often we will use CAD software to either to create these documents or create images for these documents. If you did not already familiar with this topic, you can read it here.

Building elements of engineering drawings

In order to create an engineering drawing, we need to know what we need to know what are the building elements of an engineering drawing. So, to get familiarized with it, read Introduction to engineering drawings.

Basic elements of engineering drawings

To create usable and standardized drawing templates in CAD software, we have to get familiarized with the basic elements of engineering drawings. You can read about it here.

Projection methods on engineering drawings

We have to represent our 3D model in 2D in the most efficient way to be able to communicate our design intent. If you did not get yourself familiarized with it, make sure to check projection methods on engineering drawings.

Section and detailed views on engineering drawings

In addition to the previous points, sometimes, we will not be able to clearly and unambiguously show our design intent using standard projections. For that reason, we will have to use sections and detailed views.

Exploded view

An exploded view is used on the assembly drawings. We are using them to show the relationships between different parts in the most realistic manner. Read more about it here.

Parts list and BOM

Assembly is created from two or more components, and the Parts list and BOM tell us which those parts are (BOM includes raw materials too). Read more about it here.

Additional tables

Additional tables are used to display additional information about the part or assembly. For example, configuration table on tabular drawing.

Dimensions

Dimensions on engineering drawings are necessary to define the size and shape of components or to define the relative position/or shape of assembled parts. If you are not yet familiarized with the dimensions of engineering drawing, I would suggest you read this article.

Tolerances

It is hard to manufacture the part to be the exact size we defined on the drawings. For that reason, we define tolerances on the engineering drawing to give our manufacturer a range that he can deviate from the defined value. Tolerances are important topics, so make sure that you are familiarized with them. Read more about engineering tolerances here.

Fits

The relationship between different joining components in assembly is defined by fits. Fits can sometimes be confusing to young engineers, so if you are not sure about this topic, make sure to read our article about fits.

Geometrical Product Specification

Geometrical Product Specification (ASME standard name: Geometric dimensioning and tolerancing – GD&T) is a complicated topic in engineering drawings. At this moment, this is not covered because I decided to focus more on the basic and intermediate complexity topics. However, this topic will be covered on our website in the future.

Part file formats

Usually, each CAD software has its own file formats to store relevant design and manufacturing data. Let us now look into some of the most known CAD software on the market and their file extensions used to store drawing data:

CAD software	Part file extension
NX CAD	.prt
Catia V5	.catdrawing
SOLIDWORKS	.slddrw
Autodesk Inventor	.idw
Autodesk Fusion 360	.f3d
AutoCAD	.dxf, .drw
PTC Creo	.drw

CAD Drawing templates

Every engineering drawing you create will contain the building elements we mentioned before. One of the things that will always be a constant and is necessary to have on every drawing are font type, line types, drawing border, and title block.

Considering that these are constant occurrences on our drawings, we do not want to waste our time setting them up each time we want to create a new drawing. For this purpose, CAD software has this beautiful option called drawing templates.

Drawing templates can be created for any paper size with any rules that we want to follow. We can create templates for ISO standard, ASME standard, and nonstandardized internal use. Furthermore, we can create drawing templates for different manufacturing techniques. For example, we have drawing templates used for machined parts and ones used for injection molding or 3D printing. The possibilities are endless.

The best part is that once we create drawing templates, we are just a click away from assigning them to our drawing. Furthermore, to make this even more powerful, we can create the part and assembly templates with different attributes that will automatically populate fields in our drawing temple.

Not only that this is efficient and time-saving, but it is also helping you standardize the drawing creation process in the company. From your personal standpoint, when your drawings are unified as much as possible, this communicates your expertise to anyone using your drawings. Creating a good personal brand in the company is always beneficial for your career.

Let us now look into the example I created with the Fusion 360. keep in mind that other CAD software has similar possibilities to create drawing templates like this.

Part CAD drawings

Once you understand what the engineering drawing should look like and the underlying theory behind it, it is easy to create a drawing using CAD software. CAD drawings are literally created by using the set of predefined commands that are doing 90% of the work for us. We, as mechanical design engineers, “only “need to know the rules on how to create engineering drawings.

Before when CAD was not available, we had to draw orthographic views, add sections and hatch everything, and add dimensions, tolerances, and everything else by hand. Now all this is done almost automatically with CAD software. The knowledge required to create a good engineering drawing was not significantly changed, but the tool we use to create them made it much easier and more efficient than before.

So, according to experts at ISO, they defined in ISO 29845:2011, a part drawing depicts a single part that cannot be further disassembled and includes all the necessary information required to define the part.

Basically, it means that every piece of information that we need to manufacture the part should be defined on the drawing.

Assembly CAD drawings

The same thing I mentioned regarding creating part CAD drawings applies here. We still have the rules we must follow to create a good assembly drawing, but the tool we use is changing the game significantly.

According to experts at ISO, they defined in ISO 29845:2011, an assembly drawing represents the relative position and/or shape of a group of assembled parts. Basically, we will not define the manufacturing details of individual components on the assembly drawing, but all the relevant relationships between the individual components on how they should be assembled.

Closing words

Learning to create drawings in CAD software is quite easy. If you are persistent enough, you will learn the commands and easily create CAD drawings. The hard part is to learn all the rules that need to be applied to the drawing and when to apply them. To become a good mechanical design engineer, it is necessary to have knowledge of both. Implementing the CAD software in the day-to-day practice in an efficient and time-saving manner, with high-quality drawings incorporated with the best engineering practices and internal company processes, may be a challenge.

Creating robust CAD drawing templates linked with the part and assembly attributes is the first step in achieving quality internal processes. Furthermore, as always, I would suggest you spend additional time to better learn your CAD software (if you already did not) and polish your knowledge of creating engineering drawings.

In this article, we covered the creation of drawings in CAD software, and now finally, all the articles are coming together. There are still a few articles that we need to cover to finish with the CAD fundamentals, and then we are jumping into connecting these topics into one, as we will connect theory with the praxis.

Now you have an excellent overview of what engineering drawing is all about. However, I suggest you go through the text once more and identify areas you think need more understanding and clarity. Then, once you have identified those areas, start building up your knowledge in those areas.

To make it easier for you to find related posts, check the “Further reading” chapter below. Do you have any questions or need something to be clarified better? Leave a comment below, and I will give my best to adjust the post accordingly.

Do you like what you read? Then, share it with your friends, colleagues, and on your social media channels. And if you want to become a part of the Newtonians, make sure to subscribe to our newsletter!