Problems in the design phase
Problems in the engineering or production phase
The geometry problems from the design phase also can appear in downstream processes i.e. CAM, FEA, CFD, mould tools and production runs causing slow analysis, introduces inaccuracies in the manufactured part.
Models which are changed by the suppliers due to having to fix bad geometry cause a mismatch between the design team’s CAD model and manufactured part. This change is never recorded by the design team, this change is typically only noticed if there is a fault with the product. In this case who is to blame? Who is liable? Ultimately, trust between the client and supplier is lost and valuable investment time and money is wasted.
Fixing problems in the engineering or production phase costs nine to ten times more than in the design phase. If the 3D model needs to be changed due to geometry imperfections or because the design needs to be modified at this stage (due to insufficient design time from having to struggle with a slow performing CAD model) then the mould tools often need to be scrapped and made again. This is typically a large investment cost which needs to be written off. There could also have been a small production run of product which would also need to be scrapped.
Future problems which would make it worse
With the increasing 'drawingless' environment, high-quality 3D geometry will become more relevant and important as dimensions and annotations are applied to faces and if these faces are unstable then the dimensions may not update properly when the model is changed.
Detailed views of 3D geometry also highlight any poor geometry and may even cause the symbols to show a different face or may disappear altogether. For example, dimensions may be placed on fillets which can be split into many faces when applied to bad underlying geometry. These fillet faces often change a lot when the radius changes and the dimensions or PMI dimensions may not change or disappear.