With the evolution of computers and modern CAD systems allowing companies to create 3D designs and 3D renderings, one might think 2D drawings are no longer necessary. But surprisingly, 2D drafting and drawing are the main gateway to manufacturing and have been the primary form of communication on the shop floor. Hence, most 3D design software support automatic 2D drafting workflows that allow for automatic conversion of 3D design data into various 2D views. Depending on the requirement, the same 2D drawing can be annotated for documentation, dimensioning and tolerancing, assembly instructions, manufacturing plans and additional processing instructions. We will see them in more detail.
While 3D design files are still necessary to store the core geometric and assembly features, it is often easy to keep 2D drawings of the design for documentation purposes. Information such as when the design is created, when it is revised, and what feedback is received from customers etc. can be written in the drawing file itself in the title block of the drawing. Such documentation is not possible within the 3D CAD environment.
Portability and Sharing
Unlike the 3D data files, the 2D drawing files have smaller file sizes and can be exported in PDF formats. So it is easy to exchange via email for other teams. Also, the 2D format of the drawing allows for taking prints on sheets of suitable size, like A4 or A3, and can further be used for analysis, evaluation and documentation.
Machining and other Technical Information
GD&T applies to each dimension of the part. It is not possible to annotate this information in a 3D design file. Hence, 2D drawings of the design or part have to be used to indicate dimensions, datum features, tolerances and surface finish requirements.
Quicker Quotation Times
As mentioned earlier, machinists and manufacturing experts can arrive at a quick quote if the detailed 2D drawing is provided as it gives them all the required information like size, material, tolerance and surface finish required. Also, some old machine shops still use manual machines that cannot read computerized 3D CAD data and the way possible is by providing a 2D drawing file.
If the production manager has to brief the machinists about any precautions or specific tools to be used for that particular part, it becomes easy to make a few notes on the 2D drawing itself. Also during the machining process, if any potential issue is identified, it can be immediately marked on the drawing sheet and conveyed to the concerned person.
Lack of Universal CAD Adoption
All CAD packages allow for the creation of 3D designs that can be exchanged between teams. However, only native file formats allow for opening and extracting the design information from them. And not everyone involved in manufacturing will have access to design software or systems. So it is likely that if a design file is sent to a production partner, they might not be able to open and extract key information from the native 3D file. Although there are neutral formats like STEP/IGES to solve this problem, they are not yet capable of storing dimensional details, thus requiring you to open the STEP files and extracting each feature using measure/inspect tools to get the dimensions. This process is a really time-consuming and daunting task. All these hassles can be dealt with by the creation of 2D drawings.