How would you indicate a datum target on curved surfaces?

How would you indicate a datum target on curved surfaces?

• A. Attach a sticker
• B. Use a flat plate
• C. Ignore the curved surface
• D. Place a datum target on curved surface with coordinates to define the datum location

Answer: (C)

On curved surfaces, you establish a datum by placing a datum target directly on the surface and giving its coordinates to define the exact location of the datum reference. The target creates a defined reference area or point on the curved geometry that can be measured and reproduced, and the coordinates fix where that reference sits on the part. This is necessary because a curved surface cannot provide a single flat plane as a datum without clearly locating where on the surface the datum originates. A sticker or any non-controlled feature isn’t a formal datum reference, using a flat plate would not accurately represent the curved surface, and ignoring the curved surface leaves you without a defined datum. Therefore, indicating a datum target on the curved surface with coordinates to define the datum location is the appropriate approach.

On curved surfaces, you establish a datum by placing a datum target directly on the surface and giving its coordinates to define the exact location of the datum reference. The target creates a defined reference area or point on the curved geometry that can be measured and reproduced, and the coordinates fix where that reference sits on the part. This is necessary because a curved surface cannot provide a single flat plane as a datum without clearly locating where on the surface the datum originates. A sticker or any non-controlled feature isn’t a formal datum reference, using a flat plate would not accurately represent the curved surface, and ignoring the curved surface leaves you without a defined datum. Therefore, indicating a datum target on the curved surface with coordinates to define the datum location is the appropriate approach.