shaping and planing machine

                       Shaping and planing machines

A mould normally includes a number of steel plates suitably secured

together. Each of these plates must have parallel faces and, ideally, the

four sides should be square. Now, as the primary purpose of a shaping

machine is to produce flat surfaces, this machine tool is used in the initial

preparation of mould blocks.

The principle of the shaping machine 

the workpiece is mounted on a table and a reciprocating single-point tool

removes metal in a series of straight cuts. After each forward stroke, the

table is traversed a preset increment in preparation for the next cut.

The ram is a driven reciprocating member which is guided in slideways

at the top of a vertical column. The length of the stroke of the ram is

adjustable. The tool is attached to the ram via a tool-holder and head,

The depth of cut by the tool is preset by vertical adjustment of the head.

The table, to which the work is securely attached, is mounted on

slideways on the cross-rail. Movement of the table across the face of the

cross-rail is effected by the rotation of a lead screw (not shown), actuated

by the ram via a simple mechanism

The cross-rail can be adjusted vertically on slideways at the front of the

column. Adjustment of this member is carried out only during the

setting-up operation. Once the workpiece is close to the tool the cross-rail

is clamped in the desired position before the cutting operation

commences.

Because of the single-stroke cutting action of this machine, the surface

finish obtained on the work is always in the form of a series of fine

grooves. The depth and width of the groove depend on the depth of cut

and the traverse increment chosen. While this surface finish is suitable for TABLE

 (a) squaring up mould plate
 (b) reducing thickness of mould plate

certain mould parts (for example, the sides of mould plates) it is normal

practice to follow the shaping operation with a surface grinding operation

to produce a finer surface finish.

the sides of a mould block are shown being squared up

(a), and the block is shown in the process of being reduced in thickness

For the squaring up and surface facing of large blocks of steel an

alternative machine tool, called a planing machine is often used. This

machine is similar to the shaping machine in that it employs a

reciprocating action and produces a flat surface by a series of straight cuts

using a single-point tool. However, with the planing machine it is the work

which is reciprocated, the tool being fixed in a head above the workpiece.

 illustrates a simplified version of a planing machine. The

work is rigidly attached to the table which is reciprocated on the slideways

of the bed. The single-point cutting tool is mounted in the cutter head and

this member is adjustable in the vertical direction on the slideways of the

cross-slide. This latter member, in turn, is mounted on the slideways of

the cross-rail, permitting the tool to be traversed across the face of the

workpiece. The cross-rail is supported above the table upon the side

columns.

In operation the depth of cut is preset by suitable adjustment of the

cutterhead. The table is caused to reciprocate and the single-point tool

slices a shaving of steel from the workpiece. At the end of the cutting

stroke the head is automatically traversed by a preset increment in

preparation for the next cutting stroke. This continues until the complete

surface has been planed. If necessary the depth of cut is increased and the

above procedure repeated, until the required thickness of plate is

obtained.