![]() ![]() All NC/CNC machine tools are provided with drive motors and other accessories to do auxiliary functions of the machine along with the work table, spindle and other hardware of the traditional machine tools. Avoidance of human intervention, omission of conventional tooling and fixturing and quick change capability of NC system are the primary factors considered to decide the level of acceptance of machine tools for a particular job. This programme is translated into electrical signals to drive various motors to operate the machine to carry out the required operations. In computer-aided part programming, much of the tedious computational work needed in manual programming is performed by the computer microprocessor. The complete set of coded instructions responsible for executing an operation is called part programme. Numerical control or computerised numerical control is a technique of automatically operating a productive facility based on code of letters, numbers and special characters. CNC Milling Machine: Principles of working classifications of CNC milling machines operations-milling cutters. This prevents scratching of the work piece and wear of the tool due to tool dragging. The clapper box-blocks assembly provides a rigid support to the tool in the forward or cutting stroke but on the return stroke the clapper block is lifted out of the clapper box to clear the tool from the work piece. The clapper block which carries the tool post is connected to the clapper box by means of a hinge pin. It can be swivelled about the apron swivelp in by releasing the clamping screw. The apron consisting of the clapper box, the clapper block and the tool post is clamped on the vertical slide by a screw. The tool slide swivel base is held on the circular seat on the ram and is graduated to indicate the angle of swivel. The motion of the table along the cross rail for feeding is powered by a paul and ratchet arrangement and timed by actuating the paul by the shaper ram drive the feed is provided at the end of return stroke. The motion of the tool slide on the tool head in conjunction with the swivel base provides feed motion for vertical and angular cuts. Motion of the table along the cross rail provides the feed motion for horizontal shaping. ![]() The vertical movement of the cross rail permits jobs of different heights to be accommodated below the tool and is a machine setting. The reciprocating motion of the ram provides the straight line motion to the tool which is the speed for cutting. On the front end of the ram is fitted a tool head which holds the tool and is provided with means for feeding the tool into the work. ![]() Sliding along the cross rail, perpendicular to the line of motion of the ram is a saddle which carries the work table. The top of the frame provides guide ways for the ram.The front of the frame provides guide ways for a cross rail which can be moved up and down. The frame houses the drive mechanism of the shaper. This type of shaper consists of a frame or column supported on abase, a reciprocating ram and a work table. The most common type of horizontal shapers is the production push cut shaper. ![]()
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