Parts that have special requirements need 3D models and a 2D drawing to fully define them. The 3D model often defines the geometry of the part, while the 2D drawing defines any tolerances, threads, surface finishes, or other information that can’t be captured in the 3D model.
Since they are two separate documents, it is possible for there to be conflicting information between a 2D drawing and 3D model about what is needed for the part. This article explains China Manufacturing parts’s policy on how we use 3D models and 2D drawings, and what actions we take if a discrepancy is discovered.
How we use 3D models and 2D drawings
In general, China Manufacturing parts, Inc. and our Manufacturing Partners will use the provided 3D model as the basis for fabricating the part and then inspect against the 2D drawing to make sure all requirements were met. This is because the software used to program machines for manufacturing require a 3D model to generate the toolpaths needed to fabricate the part. Extra requirements are then added to the program by the machinist, and then inspected after the part is fabricated.
What happens if a discrepancy is found
If a discrepancy between the 2D drawing and 3D model is found during quoting, the quote will be failed, with details on what needs to be fixed.
If a discrepancy is found during the production of the part, the Manufacturing Partner will place the order on hold. China Manufacturing parts, Inc. will contact you for clarification, and request an updated 2D drawing or 3D model in some cases. The parts will remain on hold until clarification is received, which could push out the ship date of the order. Additionally, the customer will be responsible for any additional cost needed to manufacture or rework the parts to the correct document.
Examples of possible discrepancies
The length of the part that is dimensioned in the drawing does not match the length shown in the model.
The diameter of a hole in the model is too large or too small to create a thread called out on the drawing.
The placement of a hole in the model does not match the location that is dimensioned in the drawing.
There is a feature in the drawing that is not present in the model or vice versa.