Assembly Modeling

Assembly is the combination of parts, components, and subassemblies. These parts fit together in assembly modeling by the designer.

There are two techniques for Assembly Modeling

• Top-Down Approach (Assembly to Parts)
• Bottom-Up Approach (Parts to Assembly)

Top-Down Approach: The designer creates assembly files first and parts are modeled in this assembly file.

Bottom-Up Approach: The designer creates parts file for the assembly separately and then fits these parts in the assembly file. (Your design basics, shape, dimensions should be exactly specified for Bottom-Up Approach)

The usage of the methods depends on the machine structure, the complexity of the machine… It is your decision on which method will be used. Also, you can combine or change your design approaches during your design period.

Important Notes for Assembly modeling:

• Try to use different colors for different parts. (I define the color to a solid body of the part, so parts color not changes in different assemblies, sub-assemblies)
• Check hole positions for mating parts in the assembly. (It’s a most common mistake made by designers)
• Siemens NX file extensions are the same for Part design, Assembly modeling, Drafting, Sheet model design, etc… I use prefixes for different file types.
  Ex: assy for assembly file, asm for sub-assembly, draft for drafting files (assy_electronic-box, asm_boards, draft_box)

• Do not use names like the final design, end design, end end end design, the latest design… for the file names. You can use dates, versions, and revisions for the file names. (I used versions during the design period and revisions after first prototype.)
  Ex: Assy_electronic-box_Rev-A_2019-05-23
         Asm_board_Ver-1_2019-06-21 (Date should be written year-month-day)