Selecting the Right 3D Printer

Discover how to choose the right 3D printer for your needs and the key performance attributes to consider.

Essentials of Manufacturing

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STEM Career Outlook

Wages, employment opportunities, and growth projections for STEM jobs.

Mechanical Engineers Outlook

Guide for those interested in becoming a mechanical engineer. Includes qualifications, pay, and job duties.

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Parallelism vs. Flatness
One common area of confusion within GDT is between parallelism and flatness. With, parallelism, a reference is made to a datum plane, while flatness is independent of a datum. Figure PF1.1 shows a block on a surface plate whose three points of contact define the -A- datum plane. As specified, the opposite face of the block must lie within two planes which straddle a plane parallel to and 2.0 from -A- and .125 to either side of it.

Figure PF1.1


Figure PF1.2 shows a flatness specification on the same surface. No datum plane is involved. A "best fit" plane (3 point contact) defines the mid-plane, and all surface points must lie between two planes which are parallel to this plane, and .125 to either side of it.

Figure PF1.2

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Selecting the Right 3D Printer

Discover how to choose the right 3D printer for your needs and the key performance attributes to consider.

Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

STEM Career Outlook

Wages, employment opportunities, and growth projections for STEM jobs.

Mechanical Engineers Outlook

Guide for those interested in becoming a mechanical engineer. Includes qualifications, pay, and job duties.