Page 575 - Dormer
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GENERAL HINTS




       MILLING

       GENERAL HINTS ON MILLING


       Milling is a process of generating machined surfaces by progressively removing a predetermined amount of
         material or stock from the workpiece at a relatively slow rate of movement or feed by a milling cutter rotating at a
         comparatively high speed.
       The characteristic feature of the milling process is that each milling cutter tooth removes its share of the stock in the
       form of small individual chips
       TYPE OF MILLING CUTTERS
       The three basic milling operations are shown below: (A) peripheral milling, (B) face milling and (C) end milling.
















                         A                                                           C
                                                                B


       In peripheral milling (also called slab milling), the axis of cutter rotation is parallel to the workpiece surface to be
       machined. The cutter has a number of teeth along its circumference, each tooth acting like a single-point cutting tool
       called a plain mill. Cutters used in peripheral milling may have straight or helical teeth generating an orthogonal or
       oblique cutting action.


       In face milling, the cutter is mounted on a spindle with an axis of rotation perpendicular to the workpiece surface. The
       milled surface results from the action of cutting edges located on the periphery and face of the cutter.

       In end milling, the cutter generally rotates on an axis vertical to the workpiece. It can be tilted to machine tapered
       surfaces. Cutting teeth are located on both the end face of the cutter and the periphery of the cutter body.


       DIFFERENT APPLICATIONS FOR END MILLS
       The MRR and the applications are strongly related. For each different application we have a different MRR that
       increases with the engagement section of the cutter on the workpiece. The recent Dormer Catalogue was produced
       with simple icons that show the different applications.

            Side Milling         Face Milling          Slot Milling        Plunge Milling        Ramping













       The radial depth of cut   The radial depth of   Machining of a slot for  It is possible to drill   Both axial and radial
       should be less than 0.25  cut should be no   keyways. The radial   the workpiece with an  entering into the
       of the diameter of the   more than 0.9 of the   depth of cut is equal   end mill only with the   workpiece.
       end mill.             diameter, axial depth   to the diameter on the  cutting centre. In this
                             of cut less than 0.1 of  end mill.        operation the feed
                             the diameter.                             has to be halved.


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