Why Engineers Still Create 2D Detailed Drawings

Drafting has been a considerable aspect of engineering design for virtually its entire history. Before complex CAD technology, creating 2D drawings for manufacturing and production was essential to creating products. Today, in a world of CAD to CAM and advanced manufacturing techniques, much of how we design has evolved into the current nearly optimized state. One thing remains, however, and that is the presence of 2D detail drawings for parts, components, and assemblies.

CAD has allowed us, engineers, to spend less time refining the 2D detailed drawing, but it has not eliminated the use of these drawings in the industry. The emergence of computer design did bring one influential change around drawings. As CAD got better, we made a 180-degree shift to designing the 3D model first, then detailing the parts in 2D.

This was the first pivot where 2D drawings became less important in the design process but still essential to the overall job of an engineer. 2D drawings have continued to shrink in their importance, but they haven’t gone away. With this in mind, we need to examine why these 2D drawings still exist and see if we can optimize or reduce their use in any way to improve our workflow.

The Progression of 2D Engineering Drawings

Before we can understand how 2D drawings may or may not fit into the life of the modern engineer, we must first look at their history in engineering drafting and design. Most of our drafting techniques as engineers date back thousands of years. The perspective drawing was invented in the 1300s, descriptive geometry was invented in 1765, orthographic projection was invented in 1770, and 2D CAD was invented in the 1980s. All of this progression led us to an age of rapid engineering documentation evolution.

2D

Before there were computers, 2D drawings were used to wholly define a component’s specifications. 2D drawings were used as the sole reference in the creation of a product, like a bolt or fitting. This method of production dates back essentially to the beginning of engineering information. Their history speaks to their importance, 2D drawings were the sole conveyor of design information for millennia – and then came CAD.

2D CAD

At first, 2D CAD programs simply sped up the process of creating these design drawings. These programs also brought ease to making design changes and significantly improved engineering workflows. When 3D CAD programs came along in the 1990s, it too improved workflows and improved designs. Even with 3D capabilities, however, 2D drawings were the main conveyor of a design into a manufacturing setting. For most of the existence of modern design, up until maybe the last decade, 2D drawings were essential.

3D CAD

Increasingly digital and robotic manufacturing is what finally made the shift from 2D to 3D information convey, a reality. It has brought us into a new realm of making things just within the last decade. No longer is there a machinist referring to a 2D plan set. If there is a machinist at all, he is referring to a dynamic CAD model in most applications or he is programming his machine through CAD/CAM software. Information conveyed in engineering design has shifted for the better through the integrated digital revolution, but still, 2D drawings persist in our workflows.

New Manufacturing Processes

As an engineer, you likely realize how advanced modern manufacturing has become, diverging from workflows of even just a decade ago. Additive manufacturing tends to be the trendy new manufacturing technique that everyone talks about changing the design realm. While additive is making big changes and completely eliminates most need for 2D drawings, this new technique isn’t what has brought the biggest change.

Perhaps the most change brought to the engineering design realm has been through slow incremental technological improvement to manufacturing techniques. Methods like CNC machining and other subtractive manufacturing forms. These manufacturing processes used to be completely analog and require a skilled tradesman’s input to achieve a high output. This need for human controls is largely why as engineers, we had to design 2D drawings.

New subtractive machines still require human input, but on a completely digital level. A machinist in the modern manufacturing realm works much more with CAM and HSM programming than he or she ever would with paper spec sheets. CNC machines are programmed now, they aren’t manually controlled. All of this new manufacturing begs the question, if machines can operate fully from 3D CAD models, why are we still producing 2D drawings?

Engineers Have the Data

As we analyze 2D drawings even further and get to the bottom of where they fit in our design process, if they should at all, it’s important that we define just what needs to be communicated in modern engineering design.

Since most products are made within the digital realm in the modern engineering workflow, data about a specific part abounds. In 2D drawings or isometric drawings of old, the data that could be extrapolated from the finished design was limited by what the engineer decided to include on the final spec sheet.

Now, drawings and designs are largely communicated through digital realms. Think about how far cloud-based CAD has brought our ability to share and spread design data. CAD to CAM capabilities have made the communication between departments seamless. For the most part, our engineering data isn’t communicated through static drawings anymore.

Our 3D models that we design have even more data included in them than just 5 years ago as well. We have the ability to include latticed structures, complex material data, infinitesimal dimensions, scaling data, and interfacing data. For all practical purposes, a 3D model in CAD can tell us more about a component numerically than the actual part ever could. So, when we hand off a completed project in the form of a digital design, we are giving the machinist, the manufacturing engineer, the production facility, far more information than we could ever give them on a tediously laid out set of sheets.

Engineers have always had data, what has changed is how we express it. We often resist workflow changes with fervor. While we have adopted the ever-improving world of computer-aided design, it would seem that the one lingering hold-over from engineering past is that of the 2D drawing.

Are we creating drawings for what is needed in the production pipeline or are we just doing things like we always have?

Where 2D Drawings Fit In

Our answer to how 2D drawings fit into the design realm falls somewhere between “get rid of them!” and “keep them right where they are.” Anyone that observes the changes that have taken place in the manufacturing world likely realizes that the usefulness of 2D drawings gets significantly minimized year by year. We can also understand that while there seems to be a downward trend in the usefulness of 2D drawings in the design realm, at some point we will reach an asymptote, likely above zero.

At this point, 2D drawings will still be relevant and useful in some respects, but the time we spend perfecting them or communicating information through them will be as small as possible. So, where is that asymptote and where should 2D drawings land in our design space now?

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These drawings have historically been used to communicate the massive amount of part-level data. With most of this data now being communicated through CAD models, the only data that needs to be communicated on a part level is marked critical. 2D drawings for parts only need to communicate critical information about a part that can be gained through a quick glance. Finding the balance can be done by asking this question: “what would take more time, looking at the CAD model or glancing at a spec sheet?” If critical data can be communicated quickly through a 2D drawing without the need to pull up a CAD model and measure, then it should be. This is right where the balance is found.

As an engineer like yourself, finding this balance properly could result in a significant reduction in time spent on 2D drawings. Optimizing our workflow is anything but superfluous, it’s beneficial to our productivity.

On an assembly level, 2D drawings lend themselves more to basic understanding than any level of numerical analysis. For a manufacturer creating a part, 2D drawings should refine how they understand an assembly. Most modern machinists won’t refer to a spec sheet’s tolerancing and dimensioning for anything but a quick reference, if at all. This important data is now gathered from the original source, the CAD model. On a part and assembly level, 2D drawings only need to include information that improves the ability of the user to understand. While these drawings were the reference to manufacture, they are now simply the reference to understanding. They have become complementary aspects of a design rather than imminent.

Moving Forward

Understanding where 2D drawings fit can help us optimize our workflow. Drawings aren’t going away completely, but don’t just create them because that’s how it’s always been done. Workflows constantly change, and while the 2D drawing might be something that seems fundamental to engineering design, modern CAD and manufacturing capabilities are changing that. Ten years from now, our manufacturing will look more “push-button” than we could ever imagine. We have to anticipate this future and focus on innovation rather than “tradition.”

Engineering hasn’t changed out of 3D, but manufacturing has become digitized.

Reducing the time you spend on 2D drawings and diverting it to spending better time on the 3D model ultimately means a better design. Sequentially, this makes you a better engineer.