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Choosing Right File Formats for Manufacturing

This article explains the supported file formats for CNC machining, 3D printing, and sheet metal fabrication.

There are various CAD file formats employed in computerized manufacturing processes. Many of these file formats are used interchangeably for CNC machining, 3D printing, and sheet metal fabrication. However, certain characteristics of some CAD file formats make them recommended for only certain processes.

In this article we will go through these categories; their differences, use, and compatibility with manufacturing processes; and the files formats that fall under each category.

CAD Formats Used For CNC Machining

For CNC machining, a 3D model is converted directly from a 3D file into machine code.

There are as many 3D file formats as there are 3D CAD modelling applications. This is because most CAD applications save files in a proprietary file format. The most popular file formats used in CNC machining are:

  • X_T | X_B (Parasolid)
  • IPT (Autodesk Inventor)
  • 3DXML | CATPART (Dassault Systems)
  • PTC (PTC)
  • PRT (Siemens)
  • SAT (ACIS)

There are also standard non-proprietary file formats. They were created for ease of sharing and are compatible with most popular CAD software. The most popular of these are as follows

  • STEP. Also known as STP, this 3D file format was created by ISO (International Standards Organisation). It has the .stp or .step file extension and is widely accepted as a standard file format.
  • IGES. The IGES is an interchange file format created by the US air force. It is widely accepted and is compatible with virtually all CAD software. IGES files have a .igs or .iges file extension.

The popularity of STEP and IGES file formats is such that CAD applications allow you to save files directly in these formats.

CAD Formats Used For Sheet Metal

Sheet metal cutting processes are carried out using CNC devices. Files for this process are therefore prepared similarly. Suitable CAD file formats for sheet metal cutting include:

  • DWG
  • SAT
  • DXF
  • IGES
  • STEP
  • X_T | X_B
  • IPT
  • PTC 
  • PRT 
  • SAT

3D printing file formats

A model needs to be in a 3D printing file format before it can be prepared for 3D printing. 3D printing files can be obtained in either of two ways: by converting an existing 3D model into a 3D file format or by creating a model and saving it directly in a 3D printing file format. The most popular 3D printing file formats are:

  • STL
  • OBJ
  • AMF
  • 3MF

It is important to note that models in 3D printing file formats cannot generate CNC machine code. Hence, such models cannot be used with CNC machining or cutting processes. They are exclusively for 3D printing.

However, you can also upload your 3D models for 3D printing in the following 3D file formats. They’ll just need to be converted later on.

  • X_T | X_B
  • IPT
  • PTC
  • PRT
  • SAT

For more information about the differences between 3D printing file format, check out this article.


3D files can be used for CNC machining, sheet metal fabrication, and 3D printing. For 3D printing, however, these files first have to be converted to a 3D printing file format.

3D printing file formats, on the other hand, are exclusively for 3D printing processes.

Xometry Europe’s instant quoting platform supports the following file formats: STEP, STP, SLDPRT, X_T, X_B, IPT, 3DXML, CATPART, PTC, PRT, SAT, and STL.

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