Milling Machine Lecture, Milling Machine Types

Milling Machine Data

1. MILLING MACHINE It is A machine which is used to remove metals from the work piece with the help of A revolving cutter called milling cutter. It is used to machined the flat, rough and irregular surfaces and this is done by feeding the work piece against A rotating milling cutter.

2. 1. Column & Base Column including base is the main casting that supports all other parts of milling machine. The column contains an oil reservoir and a pump which lubricates the spindle. The column rests on the base and base contains coolant reservoir and a pump which is used during machining operation that requires coolant . 2. Knee It is a casting that supports the saddle and table. All gearing mechanism is enclosed within the knee. It is fastened to the column by dovetail ways. The knee is supported and adjusted by a vertical positioning screw (elevating screw). The elevating screw is used to adjust the knee up and down by raising or lowering the lever either with the help of hand or power feed. 3 . Saddle and Swivel Table The saddle is present on the knee and supports the table. It slides on a horizontal dovetail on the knee and dovetail is parallel to the axis of the spindle ( in horizontal milling m/c). The swivel table (in universal machines only) is attached to the saddle that can be swiveled (revolved) horizontally in either direction. 4. Power Feed Mechanism It is the knee which contains the power feed mechanism. It is used to control the longitudinal ( left and right), transverse ( in and out) and vertical (up and down) feeds. 5 . Table It is a rectangular casting which is present on the top of the saddle. It is used to hold the work or work holding devices. It contains several T-slots for holding the work and work holding devices (i.e.  jigs and fixtures ). The table can be operated by hand or by power. To move the table by hand, engage and turn the longitudinal hand crank. To move it through power, engage the longitudinal direction feed control lever.

3. 6. Over Arm / Overhanging Arm It is a horizontal beam present at the top face of the column. It may be a single casting which slides on the dovetail ways present on the top face of the column. The overarm is used to fastened arbor support. It may consist of one or two cylindrical bars which slide through the holes in the column. 7. Spindle It is the shaft The spindle is mounted on the bearings and supported by the column. that is used to hold and drives the cutting tools of the milling machine. Spindle is driven by the electric motor through gear trains. The gear trains are present within the column. The face of the spindle which lies near to the table has an internal taper machined on it. The internal taper at the front face of the spindle permits only a tapered cutter holder or arbor. It has two keys at the front face which provides a positive drive for the cutter holder or arbor. The draw bolt and jam nut is used to secure the holder and arbor in the spindle. 8 . Arbor Support It is a casting with bearing that supports the outer end of the arbor. It also helps in aligning the outer end of the arbor with the spindle. It prevents the springing of outer end of the arbor during cutting operations. There are generally two types of arbor supports used in the milling machine. The first one has small diameter bearing hole, 1-inch in maximum diameter. And the other one has large diameter bearing hole, usually upto 23/4 inches. The arbor support has an oil reservoir that lubricates the bearing surfaces. It can be clamped anywhere on the overarm. The arbor support is used only in the horizontal types of milling machine. 9. Ram The overhanging arm in the vertical machine is called ram. One end of the ram is mounted on the top of the column and on the other end milling head is attached. The ram can be a moved transversally ( in and out) on the column by a hand lever.

4. MILLING MACHINE OPERATION 1. Face Milling This operation makes flat surfaces at the face of work piece. This machining operation is done on the surfaces which are perpendicular to the axis of the cutter. The operation is performed by the face milling cutter mounted on stub arbor of the machine.

5. 2. Side Milling It is the machining process which produces flat vertical surface at the sides of a workpiece . This operation is performed by using side milling cutter.

6. 3. Plain Milling It is a Process of milling flat surfaces keeping the axis of the cutter parallel to the  surface being milled. It is also called surface milling or slab milling. A plain milling cutter is used for the plain milling.

7. 4. Straddle Milling It is a process in which two side milling cutter are used to machined two opposite sides of a work piece simultaneously. The straddle milling operation is shown in the figure given below.

8. 5. Angular Milling It is a process of milling flat surfaces which are neither Parallel nor perpendicular to the axis of the milling cutter. It is also called as angle milling. A single angle milling cutter is used to perform this operation.

9. 6. Gang Milling It is the machining process in which two or more milling cutters are used together to perform different milling operation simultaneously. In gang milling the cutters are mounted on the arbor.

10. 7. Form Milling It is the process of machining special contour (outline) composed of curves, straight lines, or entirely of curves, at a single cut. Formed milling cutters shaped to the contour to be cut are used to perform this operation. This operation is accomplish by using convex, concave and corner rounding milling cutters.

11. DRILL MACHINES It is the simplest and accurate machine, which is used in production shop . The work piece is hell stationary means clamped in position and  drill bits  rotate to make a hole.

12. PARTS OF DRILLING MACHINE AND THEIR FUNCTIONS There are following parts of drilling machine and their functions are used in drilling machine Drill Chuck Head Table Column Spindle Drill Base Sleeve Socket Drill Drift Electric Motor Hand Wheel

13. Drill Chuck Drill chuck plays very most important role in a drilling machine because it's used as a  work holding device .  Basically, drill chuck, hold the straight shank cutting tools. Drill chucks, may be three jaws or four jaws which is also move simultaneously when drilling machine outer sleeve turned . Head The top part of the drilling machine is called the head, which has a spindle that moves in the upward and downward directions . Table The table is used to hold the work piece or a job and can be adjusted by moving it upward or downward direction. Column It supports the table and head as well as all other mechanism which is attached to the head . Cast iron or steel is used to make columns. Because its mechanical properties are of high strength and also hardened . Spindle It is used to hold and rotate the drill bits tool. It is fitted with the head of drilling machine . High carbon chromium steel or steel alloys are used to make the spindle . Drill Base It is the most important part of the drilling machine because it carries a whole weight of the drilling machine . Cast iron or steel material is used to make the base of the drilling machine . The drill base is very rigid due to made of cast iron material.

14. Drill Base It is the most important part of the drilling machine because it carries a whole weight of the drilling machine. Cast iron or steel material is used to make the base of the drilling machine. The drill base is very rigid due to made of cast iron material . Sleeve Sleeve is used in a drilling machine for the purpose of fed cutting tools into a work piece or a job. Socket When the diameter of taper shank of a drill is more than the hole of the spindle of the machine, a special sleeve is used on the drill, which is called socket. Drill Drift Drill drift is a wide steel strip that is tapped towards the width of the edge which taper angle is 8 ° - 19 °. It is used for removing the taper shank drills. Hand Wheel Hand wheel is a very important part of drilling machine because with the help of this, how much feed is to be given in a job or work piece is controlled . The spindle moves in the up and down direction when the hand wheel is rotated.

15. Operation of Drilling Machine Drilling In this process, a hole is made in a solid working by rotating drill . Reaming In reaming process previous size of hole is enlarging in perfect accuracy manner . It is a multi-tooth cutting tool. In the reaming, the accuracy of +/- 0.005 mm can be achieved . Boring Boring operation is a drilling machine operation in which enlarging the hole of a workpiece or a job . Boring operation is done after drilling and use single point cutting tool . Through boring operation we produce accurate and finishing job. Counter Boring Counter boring is a drilling machine operation in which enlarging the bore. And this operation always performs after drilling . In this process use multipoint cutting tool . This operation is used to made cylindrical hole as per requirement.

16. Operation of Drilling Machine Counter Sinking Counter sinking operation is performed when requirement of making conical edge at any angle . This operation also performed after drilling . The cone angles are of 60°, 82°, 90°, 100°, 110 and 120 °. Spot Facing The holes made in the process of making flat surface on bore face or upper face of a hole in the casted job are called spot facing . Tapping It is the process by which internal threads are formed. It is performed either by hand or machine. Minor diameter of the thread drilled and then tapping is done . Lapping In this process firstly two work pieces rubbed together that is called lapping and then after fix both the job in accurate manner after that drilling is performed . Trepanning The process of making big diameter hole or cutting of round job by drill machine is called trepanning. In this system, two bits are fitted in a holder center at same distance and in the middle, a hole size pilot is fitted.

17. Grinding Machine Definition : A grinding machine is a production machine tool used in the manufacturing industry in which the grinding wheel is attached in the tool post and the work piece is fixed to the work table and when the operation starts it removes the unwanted material to get the desired surface finish, correct size, and accurate shape of the work piece.

18. Grinding Machine Parts and Function: The Grinding Machine Consists of Following Main Parts: Base or Bed Column Headstock Tailstock Worktable Wheel Head Grinding or Abrasive Wheel Cross feed or Traversing Wheel and Coolant Supply Nozzle

19. Grinding Machine Operations: The following different types of Operation that can be performed on Grinding Machine: Surface Grinding Operation Cylindrical Grinding Operation Thread grinding Operation Internal and External Grinding Centerless Grinding Form Grinding Operation Wet and Dry Grinding Operation