Manufacturing data used to be simple. Drawings were prepared on tracing film using drafting pens, and notes and dimensions added either by hand or using stencils. They took days to produce. The advent of 2D CAD simplified the process dramatically, with all the notes and dimensions typed in, and the ability to change or adjust the geometry on the drawing in an instant.
With the introduction of 3D CAD, the situation changed. Production data was now embedded in the CAD files themselves, and digital production tools could take the information and use it to form parts or tooling. The CAD software could also now create highly complex surfaces that defied definition with conventional geometry.
These new techniques mean that creating the appropriate design and manufacturing data for a product is now more complex than it used to be. We need to consider the whole process and think about which parts should be defined by digital data and where conventional dimensioned drawings still have a role.
In many cases, the main role for the drawing is now to define specific features, tolerances and critical issues that need to be included in the process - and to check the finished parts. Sometimes, this still requires fully dimensioned drawings, and geometric tolerances that can overcome language difficulties and regional variations, but not always.
Often, the only dimensions that can be checked from a drawing are overall sizes, holes centres and other points that interface with a mating part. Housing geometry is now so complex, it is impossible to measure without complex scanning tools – which again make the humble drawing largely redundant.
The primary point here is that we need to know why we need a drawing when making a particular part – not simply default to the position that manufacture requires engineering drawings.
If you would like to read a far more extreme view on this topic, please click here!