SHAPING MACHINE

A type of machine tool that follows a linear toolpath with linear relative motion between the workpiece and a single-point cutting tool is a shaping machine or shaper. The cut produced by the machine is similar to that produced by a lathe machine.  A shaping machine is a mechanical device used to shape and form metal workpieces. It operates by removing material through a reciprocating cutting motion, resulting in the desired shape or contour. Shaping machines are commonly used in metalworking industries for various applications, including creating flat surfaces, slots, and grooves. 

Working Principle of Shaping Machine

The working principle of a shaping machine is based on a quick return mechanism like Whitworth.

A rigid table on the machine supports the workpiece. Over the workpiece, the ram moves back and forth as shown in the animation above. A vertical tool slide is adjusted to either side of the vertical plane along the stroke axis, which is located at the front of the ram. 

The geometry of the linkage causes the ram to travel more quickly on the return stroke than the forward stroke (cutting stroke). As the shaper works on the quick return mechanism, the sliding action of the slider is aided by the rotating link.

One of the four mechanisms i.e. crank and slotted, whitworth quick return, hydraulic, and automatic table feed mechanism, is responsible for the quick return mechanism and reciprocating movement of the ram. The automatic table feed is commonly used today which employs a pawl and ratchet mechanism in a shaping machine.

Parts of Shaping Machine

We came across various terms related to a shaping machine while studying the working principle. Let us study all the parts that are common in all types of shapers below.

Base

The base of the shaper holds all of the weight of the machine tool, and it is bolted to the shop floor. It is generally made of cast iron. It absorbs vibrations and other forces imparted during shaping operation.

Column

The column is also made of cast iron in a box shape. It is set on the base of the shaper. It has precisely machined guideways on top that allow the ram to move back and forth. For the cross rail to move, there are guideways on the front vertical face. The ram-driving mechanism is inside the column. The base holds the column in place.

Table

The table is one of the crucial components of the device which is mounted on the saddle. The elevating screw and crossfeed rod can be turned to move the table both horizontally and vertically. It is a casting that resembles a box with precisely machined top and side surfaces. The table has T-Slots to clamp the work and is secured with support to increase rigidity.

Vice

Clamp or vice is mounted on the table to hold the workpiece firmly while the shaping process is in progress.

Crossrail

This part is fixed to the vertical guideways of the column. By turning an elevating screw, which enables the cross rail to glide on the vertical face of the column, the table can be elevated or lowered to meet the varying sizes of the task.

Saddle

It is fixed to the Crossrail securely on the top of the table. The rotation of the crossfeed screw causes the crosswise movement of the saddle which moves the table in the same direction.

Ram

It is a component in the shaping machine that reciprocates using a quick return motion mechanism on the guideways at the top of the column while holding the tool in place. It contains a screwed shaft to adjust the working position.

Tool Head

With the down-feed screw handle, the tool head secures the cutting tool and allows for both vertical and rotational movement. A tool head of shaping machine assembly has a vertical slide is made up of a swivel base with graduated degrees. 

A micrometre dial is located on top of the feed screw which can be used to change the feed rate or depth of cut. The components of a tool head are an Apron, a Clapper box, and a clapper block.

• The screw secures an apron made up of a tool post and clapper box to the vertical slide. The apron swivel pin allows the apron to be turned to the left or right.

• Using a hinge pin, the clapper block is housed inside the clapper box.

• The clapper block is where the tool post is mounted.

Operations on Shaping Machine

With the knowledge of the parts of the shaping machine, we can now learn the operations that are generally performed on it. Refer to the diagram of operations as we discuss them.

Machining Vertical Surface

When finishing a workpiece, a block, or cutting a shoulder, the vertical surface machining process is employed. The surface that needs to be machined is properly aligned with the ram axis and positioned in a tight vice or clamp or directly on the table.

Machining Horizontal Surface

A shaper is mostly employed in horizontal operation to create a flat surface on a workpiece, held in a vice. The table is raised until there is a 25 mm to 30 mm gap between the tool and the workpiece.

The position of the stroke is adjusted such that the tool moves 12 mm to 15 mm before the shaping operation. The stroke should be 20 mm longer than the work. For roughing work, the depth of cut often ranges between 1.5 and 3 mm, whereas for finishing work, it typically ranges between 0.075 and 0.2 mm.

Cutting Slots, Grooves, and Keyways

A shaper can easily machine slots, grooves, and exterior and interior keyways on shafts and pulleys or gears with the right equipment (Eg. Gear shaping machine). A square nose tool is used to machine slots or keyways.

The hole diameter has to be kept 0.5 mm to 0.8 mm larger than the keyway width. The depth should be greater than 1.5 mm. In this process, lubrication minimises tool wear.

Machining Splines or Cutting Gears

With the help of an index centre, a gear or spline with identical spacing can be cut on a shaping machine. The workpiece is positioned between two centres, and a spline is cut in the shape of the keyway. With the index pin and plate, the workpiece is turned after the first spline is cut using a gear shaping machine and method as discussed.

Machining Angular Surface

An angular cut is produced at any angle other than 90 to the horizontal or vertical plane in the shaper. The workpiece is placed on the table, and the tool head vertical slide is rotated to the required angle, either to the left or right, from its vertical position.

The apron is then turned further away from the work to clear the surface on the return stroke. Without rotating the tool head, the angular surface can likewise be machined using a universal shaper. 

Machining Irregular Surface

A shaper can also create a contoured surface, such as a concave or convex surface or a combination of these on an uneven surface. A round nose shaping tool is used to create a small shaped surface or cut these uneven surfaces.

Types of Shaping Machines

We now have a broader understanding of the principle and operations of the machines. These machines are sometimes referred as metal shaping machines and are classified based on their functions as discussed below.

Hydraulic Shaping Machine

Horizontal Type Shaping Machine

Vertical Type Shaping Machine

Crank Type Shaping Machine

Geared Type Shaping Machine

Standard Type Shaping Machine

Universal Type Shaping Machine

Travelling Head Shaping Machines

Push Type Shaping Machines

Draw Type Shaping Machines

Universal Type Shaping Machine

In these shaper machines, in addition to the vertical and horizontal movements, the table can move along an inclined axis with the ability to swivel on its axis. The workpiece that is mounted on the vice can be adjusted in multiple planes. Hence the term "Universal."

Advantages of Shaping Machines

We now studied the operations and types of shapers. This leads us to learn their advantages.

• Single-point cutting tools are affordable.

• These machines have holding mechanisms for any workpiece.

• It can make sharp or smooth edges.

• The machine has a simple setup process and quick tool changes.

• In many cases, the machine user interface is easily understood.

• There is a negligible delay between the parts.

Disadvantages of Shaping Machine

Any machine has a disadvantage. The shaping machines are replaced by honing, milling, or grinding machines due to these disadvantages.

• The cutting speed is slow and action happens only in the forward stroke.

• There is only one cutting tool and no other tools are utilised in this machine.

• Machines with more than one cutting tool, only one can be serviced. 

• There is a restriction of using one shaping tool at a time.

Applications of Shaping Machines

Despite the disadvantages, shaping machines once revolutionized the surfacing and finishing industries. Let us discuss their applications.

• Internal splines are made with a shaper machine.

• It makes straight and flat planes in horizontal, vertical, or angle.

• It can also make teeth for gears. 

• Pulleys or gears can be made with keyways in these machines.

• It also makes shapes that are convex, concave or a mix of the two.