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INTRODUCTION
Shapers can be defined as a process for removing metal surfaces in horizontal, vertical and angular planes by the use of a single point cutting tool held on the ram that reciprocates the tool.
The Shaper is a machine tool used primarily for:
Producing a flat or plane surface which may be in a horizontal, a vertical or an angular plane.
Making slots, grooves and keyways.
Producing contour of concave/convex or a combination of these.
CLASSIFICATION
There are mainly two types of shapers:-
Horizontal Shapers.
I) Plain Shapers II) Universal Shapers.
Vertical Shapers.
Crank Shapers.
Gear shapers.
Hydraulic Shapers.
Both shapers depending upon whether the ram and the cutting tool reciprocates in the horizontal plane or in the vertical plane.
Crank shapers are most commonly used. A rocker arm, operated by a crank pin from the main driving gear, gives the ram of the crank shaper a back-and-forth (reciprocating) motion.
Gear shapers are driven by a gear and rack assembly. Gear shapers have a reversible electric motor or mechanical mechanism which quickly returns the ram, in readiness for another cut.
Hydraulic shapers are driven by movement of a piston in an oil-filled cylinder. Mechanical features on these shapers are the same as those on crank shapers.
Base- The base is the necessary bed or support required for all machines tools. All other parts are mounted on and above the base. The bed takes up the total dead weight of the machine as well as the dynamic load during machining operations.
Cross rail-The cross rail is mounted on the front of the body frame and can be moved up and down. The vertical movement of the cross rail permits jobs of different heights to be accommodated below the tool. Sliding along the cross rail is a saddle which carries the work table.
Column-The column of the shaper is a hollow casting and is mounted on the base. It houses the drive mechanism for the ram and the table.
Table- The worktable of a shaper is fastened to the front of the column. The table moves across the column on crossrails to give the feed motion to the job.
Ram- The ram carries the tool head at its front end and travels in “guide ways” to give straight line reciprocating motion to the tool. The ram is either mechanically driven or hydraulically operated. A single point tool is fastened in the tool post.
Tool Head- It holds the cutting tool and is fastened to the front of the ram. The tool is held in a tool holder/tool post similar to the lathe tool post. The tool post and the tool block fit snugly in the clapper box and is hinged at the upper edge.
PRINCIPLE OF WORKING
The job is rigidly fixed on the machine table. The single point cutting tool held properly in the tool post is mounted on a reciprocating ram. The reciprocating motion of the ram is obtained by a quick return motion mechanism. As the ram reciprocates, the tool cuts the material during its forward stroke. During return, there is no cutting action and this stroke is called the idle stroke. The forward and return strokes constitute one operating cycle of the shaper.
Cutting Tool Materails, Shapes and Sizes
Shapers are used to make many different cuts on flat surfaces. Most shaper cutting tools are made from high speed steel (HSS). For cutting very hard materials, tungsten carbide tools are used. Shaper cutting tools are ground for cutting horizontally right or left, vertically right or left, and for grooving. Cutting tool shape varies with the material to be machined and the type of cut required.
ADVANTAGES OF SHAPERS
The single point cutting tools used in shapers are inexpensive, these tools can be easily grounded to any desirable shape.
The simplicity and ease of holding work, its easy adjustment, and the simple tool give the shaper its great flexibility.
Shaper set up is very quick and easy and can be readily changed from one job to another.
Thin or fragile jobs can be conviniently machined on shapers because of lower cutting forces.