AIA NAS930

Purpose:

This specification is intended to serve as a guide for
procurement specification preparation for any of a series of sheet
and extrusion stretch-forming machines, including transverse and
longitudinal, horizontal wrap, rotary, and s tretch-draw
configurations. This standard lists minimum requirements and is not
intended to limit design advances.

Classification:

The following types of sheet and extrusion (formed and extruded
shapes) stretch-forming machines are presently in use within the
aerospace industry.

Type:

I – Transverse:

Stretch-forming machine with sheet-jaw carriages transversely
positionable during machine set-up and may or may not be
positionable during period of stretch load application (forming).
The die table may be tiltable in the vertical plane parallel to the
sheet jaws.

II – Longitudinal:

Stretch-forming machine with jaw carriages longitudinally
positionable during machine set-up. The tension cylinder provides
necessary motion during the period of stretch load application
(forming). The die table is generally tiltable in the vertical
plane perpendicular to jaws. Multiple die tables may or may not be
provided. The die tables may or may not act independently of one
another.

III – Horizon tal Wrap:

This configuration is generally characterized as a stretch
forming machine in which the part is formed around a stationary or
moveable die in the horizontal plane. This type is notmally used to
form extrusions (formed or extruded shapes), but may be used for
sheet materials within limits.

IV – Rotary:

This configuration is generally characterized as a stretch
forming machine on which continuous rotational forming is
accomplished. A horizontal wiper ram is normally provided. This
type of stretch forming machine may be used to form both extrusions
(formed or extruded shapes) and sheet materials.

V – Stretc h-Draw:

This configuration is characterized as a longitudinal type
stretch forming machine that combines function of stretch forming
with press forming. The machine is generally used on parts that
have flats, reverse contours, or indentations that require matched
upper and lower dies.

Size:

Stretch forming machine size shall be a direct relationship of
the maximum tension tonnage per side.