Make your weldment drawing simple

Approximately 25 years ago, drafting was a fundamental skill required for mechanical engineering, and a drafting board, pencils, and rulers were standard tools used to create drawings. The introduction of AutoCAD near the end of this period marked a significant difference in creating drawings, as it expedited the process and improved accuracy. However, both drafting board and AutoCAD were limited to 2D tools that enabled designing and drawing simultaneously. Drawings were then passed on to the shop floor or supplier to manufacture the part.

Today, most mechanical designers utilize 3D software such as Solidworks, Catia, and Pro-E, which create 3D models that subsequently populate drawings. This revolutionary change has freed designers and engineers from the arduous task of drafting, enabling them to focus more on designing. Consequently, there is no longer a need for "drafters."

However, the process of conveying engineering information to the shop floor has not significantly changed, as most shops still rely on 2D prints. Although some advanced shops allow technicians to access a computer to check the model while building the machine, the majority of smaller mechanical shops lack this technology. Therefore, people still depend on 2D prints to build machines.

Looking back at "old" drawings created by AutoCAD or even hand drafting, one can observe the lack of detail in them, particularly in "one-time" projects. Designers had insufficient time to include all the necessary details in the drawing to meet the schedule, leading to the omission of important information. Nonetheless, the information remaining on the drawing was adequate for the shop technician but nothing more. In contrast, current drawings, particularly weldment or assembly drawings, are far more detailed, with an excess of information.

However, an abundance of information can often lead to confusion for shop technicians, resulting in mistakes that are expensive to fix. Therefore, it is essential to simplify the drawings. One technique that can help is to remove hidden lines and tangent lines, making the drawing cleaner and more straightforward. Hidden lines should only be shown when necessary. Another useful technique is to use sub-weldments, similar to assembling IKEA furniture. Sub-weldments contain fewer components than the primary weldment, and several sub-weldments can be welded together.

If it is impossible to break down the weldment into several sub-weldments, it can be divided into different manufacturing stages to reflect the actual manufacturing process. Each stage contains only a few parts, built based on the previous stage. Configurations or display states can be used in Solidworks to reflect different manufacturing stages. Talking to the welder about a rough plan of how they will put everything together is critical. Although the plan may change during the manufacturing process, the drawing is still easier to read than those with all the parts together.

In conclusion, a clear drawing is essential for successful products, and a good drawing can save time and money for the company. Simplifying drawings by removing unnecessary details and dividing them into sub-weldments or manufacturing stages can make the drawings easier to read, reducing the risk of costly mistakes.