Lecture 20
Development of
Surfaces
, DEVELOPMENT OF SURFACES
1. DEFINITION
In sheet metal work or packaging work, full-size patterns of some or all of the faces of
an object are required; for example a pattern to which a sheet may be cut so that
when rolled, folded, or formed it will make the object. The complete surface laid out
in a plane is called the “development” of the surface.
Surfaces about which a thin sheet of flexible material (such as paper or tin) can be
wrapped smoothly are said to be “developable” (These include objects made up planes or single
curved surfaces only).
Double curved surfaces are nondevelopable, and when patterns are required for their
construction, they can be made only be methods that are approximate; but, assisted
by the ductility of the material, they give the required form.
All sizes and shapes of faces on a developed surface must be true.
,
, 2. DEVELOPMENT OF A FULL PRISM
The developed surface will have a shape of a rectangle having the length equal to the
sum of all sides of a base and the height will be equal to the height of the prism. The
folding lines on the developed surface must be shown.
Development of
Surfaces
, DEVELOPMENT OF SURFACES
1. DEFINITION
In sheet metal work or packaging work, full-size patterns of some or all of the faces of
an object are required; for example a pattern to which a sheet may be cut so that
when rolled, folded, or formed it will make the object. The complete surface laid out
in a plane is called the “development” of the surface.
Surfaces about which a thin sheet of flexible material (such as paper or tin) can be
wrapped smoothly are said to be “developable” (These include objects made up planes or single
curved surfaces only).
Double curved surfaces are nondevelopable, and when patterns are required for their
construction, they can be made only be methods that are approximate; but, assisted
by the ductility of the material, they give the required form.
All sizes and shapes of faces on a developed surface must be true.
,
, 2. DEVELOPMENT OF A FULL PRISM
The developed surface will have a shape of a rectangle having the length equal to the
sum of all sides of a base and the height will be equal to the height of the prism. The
folding lines on the developed surface must be shown.
