Technical_Specifications.pdf

SB1341-15-RQ-0672

Technical Specifications

Granite Base Assembly and Steel Frame

National Institute of Standards and Technology

A. Overview/Background

The National Institute of Standards and Technology is developing a laser-based metal powder bed fusion additive manufacturing metrology and process control testbed to incorporate and test various in-process sensing and real-time process control algorithms. To implement such a testbed, NIST needs a granite machine base assembly and associated stainless steel frame to support this base. The granite base assembly will consist of two pieces of granite to provide two mounting surfaces perpendicular to each other as well as a small (3 mm height) step on the horizontal base granite block to provide a reference surface for mounting guideway rails to carry other machine components. This assembly will be supported by a stainless steel frame, which will provide capability to carry the total weight of the machine while providing necessary accessibility for other machine components.

B. Technical Requirements

1. Granite assembly – two pieces permanently attached

1.1. Geometry, dimensions, and the acceptable tolerances are shown in the attached engineering drawings.

1.2. Vertical granite block to be attached to the horizontal granite block permanently meeting all the dimensional and geometric tolerances specified in the attached engineering drawings.

1.3. Material: natural granite

1.4. Vacuum seal coating of all surfaces

2. Support frame

2.1. Material: Stainless steel (304SS)

2.2. Load carrying capacity: The support frame shall have carrying capacity of 600 kg

2.3. Dimensions: The support frame shall have a footprint no larger than 1600 x 730 mm and a height of 785 mm (from floor to the bottom of the granite assembly).

2.4. Overhangs: There shall be minimum of 75 mm and maximum of 175 mm overhang on at least one long end of the frame to allow for cabling.

2.5. Accessibility requirements: The support frame shall have clearance for access to the critical surface of the granite assembly as shown in the attached drawing. There shall be a minimum of

105 mm clearance between the frame and the granite lip to accommodate for a bottom-mounted motorized ball screw assembly as shown in the attached drawing, page 6. There shall be a minimum 250 mm clearance between the bottom of the granite and any structural frame support beam on the side of the granite as shown in the attached drawing, page 6.

2.6. Accommodation for wheel assemblies: The support frame shall have mounting threaded holes to accommodate four wheel assemblies under it (4 holes per wheel).