Ask and answer engineering questions

Learn from millions of experts

Feed

What is the difference between class A, B and C surfaces in surface design?

By Karthik Boya on 19 Jan 18:28 4 answers 1289 views 0 comments

Hello, can anyone explain me, how these classes are made in surfaces, what is the major difference class A, B and C surfaces.
Thanks in advance...

4 answers

  • Steendelaar
    Steendelaar 7 months ago

    The distance between each point of the edges of two neighboring patches must comply with the following limits:
    • For class A: no more than 0.01 mm.
    • For class B: no more than 0.02 mm.
    • For class C: no more than 0.05 mm.
    Tangents continuity
    The angle between the tangents to the surface on the edges of two neighboring patches must comply with the following limits:
    • For class A: no more than 6’ (0.1◦).
    • For class B: no more than 12’ (0.2◦).
    • For class C: no more than 30’ (0.5◦).
    Curvature continuity
    The control parameter is the patch curvature along its contour.
    • Class A surfaces must have coincident curvature at least every 100 mm of
    contour of two neighboring patches.
    • Class B and C have no applicable rule.
    Points of maximum curvature or inflection are only allowed along patch contours of Class A surfaces.
    Completion surfaces
    As we have seen, they do not belong to the aesthetic surface (even if part of them is visible and influences the aesthetic evaluation of the body), but are added to represent the part as it can be produced.
    • For class C surfaces: completion surfaces are not required; gaps are represented by double lines drafted onto the aesthetic surface.
    • For class B surfaces: only rounded contours are represented on the surface
    that is always fixed to the body.
    • For class A surfaces: completion surfaces must be designed in all detail.
    Shape tolerance
    The shape tolerances are measured by comparison of a surface patch with the
    counterpart on the aesthetic surface.
    • For class A surfaces: no more than ±0.5 mm on body shell surfaces (or large
    surfaces) and no more than ±0.2 mmfor interior trimming (or small surfaces).
    • For class B surfaces: no more than ±1.0 mm on body shell surfaces (or large
    surfaces) and no more than ±0.5 mm for interior trimming (or small surfaces).
    • For class C surfaces: shape tolerance is not applied.

  • Steendelaar
    Steendelaar 7 months ago

    Btw i copied this answer form the user named : Zoran Andjelic.
    So all credits to him

  • sarath kumar
    sarath kumar 7 months ago

    A surface means visible surface.it will give styler.B surface means thickness of a part it is not visible it is inside part. c surface means A and B combined to give C surface

Add your answer to: "What is the difference between class A, B and C surfaces in surface design?"

Save Cancel