12-09-2013, 03:30 PM
SHAPER AND PLANeR
SHAPER .pptx (Size: 266.73 KB / Downloads: 26)
INTRODUCTION TO SHAPER
The metal working shaper was developed in the year 1836 by ‘James Nasmyth’.
The shaper is a reciprocating type of machine tool intended primarily to produce flat surfaces. These surfaces may be horizontal, vertical, or inclined .
In general the shaper can produce any surface composed of straight line elements.
Modern shapers can generate contoured surface.
TYPES OF SHAPER
Shapers are classified in number of ways depending upon the general features of design or the purpose for which they are intended.
Shapers are classified under the following headings.
1. According to the type of mechanism used for giving reciprocating motion to the ram: -
(a) Crank type
(b) Geared type
© Hydraulic type.
CONSTRUCTION:-
The main parts of the Shaper machine are:-
Base: The base is a heavy cast iron casting which is fixed to the shop floor. It supports the body frame and the entire load of the machine. The base absorbs and withstands vibrations and other forces which are likely to be induced during the shaping operations.
Body (Pillar, Frame, Column): It is mounted on the base and houses the drive mechanism compressing the main drives, the gear box and the quick return mechanism for the ram movement. The top of the body provides guide ways for the ram and its front provides the guide ways for the cross rail.
OPERATION
A shaper operates by moving a hardened cutting tool backwards and forwards across the workpiece. On the return stroke of the ram the tool is lifted clear of the workpiece, reducing the cutting action to one direction only.
The ram is adjustable for stroke and, due to the geometry of the linkage, it moves faster on the return (non-cutting) stroke than on the forward, cutting stroke. This action is via a slotted link or Whitworth link.
Helical planing
Although the archetypal tool path of a planer is linear, helical tool paths can be accomplished via features that correlate the tool's linear advancement to simultaneous workpiece rotation (for example, an indexing head with linkage to the main motion of the planer).
To use today's terminology, one can give the machine other axes in addition to the main axis. The helical planing idea shares close analogy with both helical milling and single-point screw cutting.
Although this capability existed from almost the very beginning of planers (circa 1820),[1] the machining of helical features (other than screw threads themselves) remained a hand-filing affair in most machine shops until the 1860s, and such hand-filing did not become rare until another several decades had passed.