Material extrusion detection method

A non-transitory computer readable data storage medium having recorded thereon a computer program having instructions for performing a method for material extrusion detection in a portion of a mechanical part having a distribution of material, the method comprising:

• obtaining a computer-aided design 3D model of the mechanical part, the computer-aided design 3D model being obtained from physical measurements on the mechanical part, the computer-aided design 3D model including a skin portion representing an outer surface of the portion of the mechanical part;
• obtaining an extrusion axis;
• computing a ratio of an area of an orthogonal projection of the skin portion on a plane orthogonal to the extrusion axis, over an area of the skin portion;
• and
• determining whether or not that the distribution of material is arranged as an extrusion, by determining that the outer surface is an extrusion surface when the ratio is lower than a ratio threshold and that the outer surface is not the extrusion surface when the ratio is not lower than the ratio threshold,
• wherein the ratio is of a type:
• R
• N
• =
• µ
• ⁡
• (
• Ω
• )
• ⁢
• P
• N
• 𝒜
• S
• ,
• with S the area of the skin portion, S the skin portion, and S=∫SdvolS where volS is a canonical measure on S, with Ω a bounded 3D domain encompassing at least the skin portion and μ(Ω) an area of the bounded 3D domain Ω, and with PN an estimation of an expected value of a number of respective lines intersecting the skin portion.

A system comprising:

• a processor coupled to a memory, the memory having recorded thereon a computer program for material extrusion detection in a portion of a mechanical part having a distribution of material that when executed by the processor causes the processor to be configured to:
• obtain a computer-aided design 3D model of the mechanical part, the computer-aided design 3D model being obtained from physical measurements on the mechanical part, the computer-aided design 3D model including a skin portion representing an outer surface of the portion of the mechanical part,
• obtain an extrusion axis,
• compute a ratio of an area of an orthogonal projection of the skin portion on a plane orthogonal to the extrusion axis, over an area of the skin portion, and
• determine whether or not the distribution of material is arranged as an extrusion, by determining that the outer surface is an extrusion surface when the ratio is lower than a ratio threshold and that the outer surface is not the extrusion surface when the ratio is not lower than the ratio threshold,
• wherein the ratio is of a type:
• R
• N
• =
• µ
• ⁡
• (
• Ω
• )
• ⁢
• P
• N
• 𝒜
• S
• ,
• with S the area of the skin portion, S the skin portion, and S=∫SdvolS where volS is a canonical measure on S, with Ω a bounded 3D domain encompassing at least the skin portion and μ(Ω) an area of the bounded 3D domain Ω, and with PN an estimation of an expected value of a number of respective lines intersecting the skin portion.