Tab_02_-_Statement_of_Work.pdf

STATEMENT OF WORK FOR EBF3 LOW‐PROFILE ROTARY POSITIONER

1.0 PURPOSE

1.1 This specification covers the design, manufacture and performance requirements for a vacuum‐compatible, single‐axis, low‐profile rotary positioner suitable for use with the large Electron Beam Freeform Fabrication (EBF3) system at NASA Langley Research

Center.

1.2 The device described in this specification shall be designed for use with a Sciaky electron beam welder, model VX.4‐108x78x100, s/n 11629.

1.3 The rotary positioner shall be essentially self‐contained in that the only mechanical interface required is attachment to the existing Y‐axis slide‐out table; the only electrical interface shall be connection to the existing (high‐profile) rotary/tilt positioner cable(s).

2.0 APPLICABLE INDUSTRIAL SPECIFICATIONS AND CODES

2.1 Applicable industrial specifications and codes such as, but not limited to, the following shall be observed during the design, construction and testing of the positioner:

2.1.1 Federal, Virginia, and NASA‐specific safety codes

2.1.2 Occupational Safety and Health Administration (OSHA) standards

2.1.3 National Electrical Code (NEC) standards

2.1.4 American Welding Society (AWS) standards

3.0 DESIGN AND CONSTRUCTION

3.1 Mechanical

3.1.1 The intended use for the positioner is described in Section 1.0 of this document.

The positioner shall be capable of being programmed for precise and repeatable rotational speed using the existing Sciaky W20x0 v4.0.241 computer control system. The positioner shall mount to the existing Y‐axis slide‐out table T‐slots, and incorporate provisions for lifting, moving and leveling in the chamber.

3.1.2 The complete positioner shall be designed and manufactured to the highest commercial practice using new, high quality, commercial‐off‐the‐shelf (COTS) components to the maximum practical degree.

3.1.3 Components and mounting shall be manufactured to tolerances that permit field replacement of a like component or subassembly without machining or other modifications required.

3.1.4 All mechanical components that determine or maintain accuracy of motion or position shall use dowel pins (or similar means) to permit assembly and disassembly without losing alignment.

3.1.5 The positioner shall be constructed of non‐magnetic materials to the maximum extent practical. Any magnetic components shall be degaussed or magnetically shielded to prevent deflection of the electron beam in operation.

3.1.6 For vacuum compatibility, the positioner shall be unpainted and will contain provisions for venting all trapped air during vacuum pumpdown. Bearings and gearboxes should be lubricated with suitable high‐vacuum rated grease or oil rated for at least 10‐6 torr.

3.1.7 The rotating work table shall be 33 inches in diameter, constructed of 316 stainless steel and equipped with 6 industry‐standard, Bridgeport compatible T‐ slots. A sketch of the desired T‐slot arrangement will be provided.

3.1.8 The top surface of the work table shall be located 17 inches above the base of the positioner. No portion of the positioner shall overhang the front or rear edges of the Y‐axis slide‐out table when properly installed.

3.1.9 The maximum load capacity of the positioner shall be at least 1000 pounds located anywhere within the perimeter of the work table.

3.1.10 The rotational speed of the work table shall be variable within a range of 0.01 to

10.00 rpm, bidirectional, infinite rotation, while loaded to its maximum rated capacity.

3.1.11 The work table shall be equipped with a precision center hole and centering ring. Detailed specifications for the hole and ring will be provided.

3.2 Electrical

3.2.1 The rotary axis shall be provided with vacuum‐rated motor(s) compatible with the existing Indramat TDM 1.2‐50‐300‐W1 Mod 02/1X0297‐050 controller and cable.

3.2.2 Rotational speed shall be variable, bidirectional, and programmable from 0.01 to 10.00 rpm in increments of 0.01 rpm using the existing servo drive controller.

Homing capability shall be provided to return the table to an operator‐ designated starting position.

3.2.3 Encoder(s) shall be provided for the rotary axis that are suitable to permit the existing servo drive controller to maintain rotational speed accuracy of +/‐ 1% or

+/‐ 0.01 rpm, whichever is greater, across the range of rotational speeds at maximum rated table load.

3.3 Tolerances

3.3.1 Rotary axis position accuracy: +/‐ 0.1 degree of rotation.

3.3.2 Rotary axis position repeatability: +/‐ 0.05 degrees of rotation

3.3.3 Work table flatness: maximum 0.001 inches per foot, any direction; maximum

0.003 inches peak‐to‐peak deviation between any two points on the surface.

3.3.4 Work table wobble: maximum 0.003 inches over 33 inches of diameter

3.3.5 Work table radial runout: maximum 0.003 inches at perimeter

3.3.6 Rotary axis perpendicularity (tilt): maximum 0.003 inches at work table surface relative to positioner base

4.0 DOCUMENTATION

4.1 Model and serial numbers shall be assigned to the completed positioner and all documentation provided with the unit.

4.2 A Service Manual containing engineering drawings and a service parts listing sufficient to permit future maintenance and repair shall be provided upon delivery. The service manual should also include electrical schematic diagrams to enable troubleshooting.

4.3 A set of Operating Instructions shall be provided to instruct the customer in the proper use and care of the positioner.

4.4 The services of a manufacturer’s field engineer shall be provided for the initial installation, customer instruction, checkout and final acceptance testing of the positioner after delivery to NASA.

5.0 WARRANTY

5.1 A warranty covering parts and labor against manufacturer’s defects in all supplied components of the positioner (including COTS parts) for a minimum period of one year shall be included in the contract purchase price. Normal wear and maintenance parts and labor will not be subject to this warranty.