NAS9300-115 describes the requirements, and particularly theinformation required, for the long term archiving and retrieval ofa mechanical CAD explicit assembly structure. This will allow theretrieval of the assembly structure including the placementinformation.
The CAD assembly structure defines the collection of CAD partsinto assemblies, and assemblies into higher level assemblies. Anassembly can contain several occurrences of the same part orsubassembly.
The assembly structure is a tree, in which the leaf nodes areindividual parts, and the non-leaf nodes are assemblies. Theparent/child relationship between two nodes records not only thatthe child is part of a higher assembly, but also the relativeposition of that child in that assembly.
This standard covers the archiving of the tree structure and theassociated positioning information. The geometry of the individualcomponent parts is out of scope.
The assembly structure can be recorded in the same file as thegeometry, or can cite the geometry as an external reference.
The assembly structure can be supplied as a single file, or as aset of files, with cross references between files.
Note: An assembly node may contain geometry that is defineddirectly in the coordinate system of the assembly rather thanthrough a child node with a corresponding transformation matrix tomove the part into the assembly co-ordinate system. Some modelingsystems call this a hybrid assembly. This kind of assembly iswithin the general scope of this part; however no specificverification and validation rules for this geometry aredefined.
Out of scope:• The archiving of the geometric model of the components;• The management of different occurrences of the same part thathave different geometry.• The management of different occurrences of the same part thathave different attributes.• The archiving of assembly-by-constraint (where, for example, theposition of a part is given as “perpendicular to part X”, ratherthan given as a positioning matrix);• The archiving of the Geometrical Dimensioning and Tolerance(GD&T);• The archiving of assembly Form Features.
Note: Product assembly structure may be defined based on thedata base management system approach. This case uses otherfundamental concepts not covered in this part. Ref. family NAS 93002xx.
- Edition:
- NEW
- Published:
- 04/27/2012
- Number of Pages:
- 15
- File Size:
- 1 file , 620 KB
Reviews
There are no reviews yet.