Industrial and Production Engineering

Hardened gears are difficult to finish by the shaving and burnishing methods. Since the heat treatment may cause severe distortion and oxide film formation on teeth, therefore there is a necessarily for removing considerable stock from the teeth. With the grinding method it is possible to finish the heat treated gears. The application of this method is limited because it is slower and more expensive. However, it guarantees production of highest quality gears. The grinding may be carried on generating principle or employing formed wheels. The disadvantage of gear grinding is that considerable time is consumed in the process. Also, the surfaces of the teeth have small scratches or ridges that increase both wear and noise. To eliminate the latter defect ground gears are frequently lapped. Credit:- Author-R.K.RAJPUT

                                                           Gear shaving  machine is a solution used in the finishing operation of an external spur and helicalgear. It is also possible to shave an internal gear, although generally the work conditions are less favorable. The shaving process can improve the quality and precision of a hobbed gear of 3 classes. However, the final resultsdepend not only on the accuracy with which the shaving cutter and the gear shaving machine is designed and manufactured, but also on the quality achieved  with the prior machining. Gear shaving is still today the most widely usedmethod for the finishing of gear teeth, especially for the continuous productionof large lots, since it represents the best cost/performance ratio. The main limit of the gear shaving process is the lack of the chance to re...

Rack Planing Process In this process the gear blank, mounted on a horizontal axis, is rotated intermittently in mesh with a reciprocating rack type cutter. This results in generation of involute teeth on a spur gear. This process is mainly employed for generating spur and helical gear teeth with the help of a rack type cutter. The machine used in gear planing work either on the basis of "Sunderland process" or "Maag process". Both these machines are almost identical in principle but the constructions and operations of the machines adopting these processes differ. Rack shaper, the generating tool is segment of a rack which reciprocates parallel to the axis of the gear blank. Because it is not practical to have more than 6 to 12 teeth on a rack cutter, the cutter must be disengaged at suitable intervals and returned to the starting point, the gear blank, meanwhile, remains fixed. Credit:- Author- R.K.RAJPUT

Gear shaping  is a machining process for creating teeth on a gear using a cutter. Gear shaping is a convenient and versatile method of gear cutting. It involves continuous, same-plane rotational cutting of gear. The types of cutters used for gear shaping can be grouped into four categories: disk, hub, shank, and helical cutters. The cutters are essentially gears that are used to form the teeth. This method of gear cutting is based on the principle that any two gears will mesh if they are of the same pitch, proper helix angle, and proper tooth depth and thickness. By using a gear-shaped corresponding cutter that is rotated (in relation to a blank gear) produces the gear teeth. The cutters that are rotated are timed with the workpiece. This process produces internal gears, external gears, and integral gear-pinion arrangements.  The process of gear shaping uses a toothed disk cutter which reciprocates in axial rotations. The workpiece (or blank gear) ...

Hobbing  is a machining process for gear cutting, cutting splines, and cutting sprockets on a  hobbing machine , which is a special type of milling machine. The teeth or splines are progressively cut into the workpiece by a series of cuts made by a cutting tool called a  hob . Compared to other gear forming processes it is relatively inexpensive but still quite accurate, thus it is used for a broad range of parts and quantities. It is the most widely used gear cutting process for creating spur and helical gears and more gears are cut by hobbing than any other process as it is relatively quick and inexpensive. A type of skiving that is analogous to the hobbing of external gears can be applied to the cutting of internal gears, which are skived with a rotary cutter (rather than shaped or broached)  Hobbing uses a hobbing machine with two skew spindles, one mounted with a blank workpiece and the other with t...

Gear cutting on milling machine Gear cutting  is any machining process for creating a gear. The most common gear-cutting processes include hobbing, broaching, milling, and grinding. Such cutting operations may occur either after or instead of forming processes such as forging, extruding, investment casting, or sand casting.  Gears are commonly made from metal, plastic, and wood. Although gear cutting is a substantial industry, many metal and plastic gears are made without cutting, by processes such as die casting  or injection molding. Some metal gears made with powder metallurgy require subsequent machining, whereas others are complete after sintering. Likewise, metal or plastic gears made with additive manufacturing may or may not require finishing by cutting, depending on application. Spur may be cut or ground on a milling machine or jig grinder utilizing a numbered...

Gear manufacturing  refers to the making of gears. Gears can be manufactured by a variety of processes, including casting, forging, extrusion, powder metallurgy, and blanking. As a general rule, however, machining is applied to achieve the final dimensions, shape and surface finish in the gear. The initial operations that produce a semi finishing part ready for gear machining as referred to as blanking operations; the starting product in gear machining is called a gear blank. There are multiple ways in which gear blanks can be shaped through the cutting and finishing processes. 1. Gear Forming In gear form cutting, the cutting edge of the cutting tool has a shape identical with the shape of the space between the gear teeth. Two machining operations, milling and broaching can be employed to form cut gear teeth. 2. Form Milling In form milling, the cutter called a form cutter travels axially along the length of the gear to...

A gear is a wheel provided with teeth,  which mesh with the teeth on another wheel, or on to a rack, so as to give a positive transmission of motion from one component to another. Gears constitute the most commonly used device for power transmission or for changing power-speed ratios in a power system. They also afford a convenient way of changing the direction of motion. A number of devices such as differentials, transmission gear boxes, planetary drives etc., used in many construction machines employ gears as basic components. Gears are made from both metals as well as non-metals. "Metals" normally used for making gears include cast iron, cast steel, structural steel, gun metal, brass, etc. The "non-metals" commonly used for gear manufacture include synthetic plastic, fibres and laminated wood. With rapid industrialisation, the gears are called upon to yield noise free operation, ensure high load carrying capacity at a constant velocity ratio. The wear and fatig...

Metal spining, also known as spin forming or spining or metal turning most commonly, is a metal working process by which a disc or tube of metal is rotated at high speed and formed into an axially symmetric part. Spinning can be performed by hand or by a CNC lathe.  Metal spinning does not involve removal of material, as in conventional wood or metal turning, but forming (moulding) of sheet material over an existing shape. Metal spinning ranges from an artisan's specialty to the most advantageous way to form round metal parts for commercial applications. Artisans use the process to produce architectural detail, specialty lighting, decorative household goods and turns, Commercial applications include rocket nose cones, cookware, gas cylinders, brass intrument bells, and public waste receptacles. Virtually any ductile metal may be formed, from Aluminium or stainless steel, to high-strength,...

Blanking is the process of cutting or shearing  blank from sheet or strip material. In the production of many articles from sheet metal under a press or by spinning, the process of blanking is often the first operation in the production cycle. Simply expressed, blanking is the process of shearing from sheet or strip metal a blank of a given shape. The term normally implies two things: (i) The process is carried out under some type of press, and (ii) The entire edge of the resultant blank has been subjected to a shearing operation. Reduced to simplest terms, a set of blanking tools consists of a bed and punch. The latter is attached to the ram of the machine and the former is clamped to the bed to the press. When the tools are set, the punch should first enter the bed without touching the sides in such a manner as to damage the cutting edge. The clearance between the cutting edges is regulated to suit the bed for the minimumm distance necessary to give complete shear. If it is ...

A progressive or follow on die has a series of operations. At each station, an operation is performed on a work piece during a stroke of the press. Between strokes the piece in the metal strip is transferred to the next station. A finished work piece is made at each stroke of the press. While the piercing punch cuts a hole in the stroke, the blanking punch blanks out a portion of the metal in which a hole had been pierced at a previous station. Thus after the first stroke, when only a hole will be punched, each stroke of the press produces a finished washer. The die block is made up of four pieces and fastened to the die shoe. This permits easy replacement of broken or worn die blocks. The stock is fed from the right and registers against a finger stop (not shown). The first stroke of the press produces a square hole and two notches. These notches form the left end of the first piece. During the upstroke of ram, the stock is moved to the next station against a finger stop (not s...

A die in which a cutting operation is combined with a noncutting operation is referred to as a combination die. The cutting operations may include blanking, piercing, trimming, and cutoff and are combined with noncutting operations which may include bending, extruding, embossing, and forming. In a combination die, cutting action is combined with non-cutting actions, i.e. forming. Non-cutting actions may be bending, drawing, extrusion or embossing. More than one operation is possible in one stroke at a single stage, but the die is more useful for two operations onlyThe die ring is mounted on the die shoe. The die ring is counter bored at the bottom to allow the flange of a pad to travel up and down. This pad is held flush with the face of die by a spring. The drawing punch of required shape is attached to the die shoe. The blanking punch is placed in the punch holder. The stripper (spring operated) strips the skeleton from the blanking punch. As the workpiece comes in contact with...

Compound Die:                                                          In these dies, two or more operations may be performed at one station. Such dies are considered as cutting tools since, only cutting operations are carried out. The washer is produced by simulation blanking and piercing operations. Compound dies are more accurate and economical in production as compared to single operation dies.                              Simultaneous blanking and piercing is achieved by providing blanking and piercing element in both the member of die, i.e. the upper and the lower member of the die. These elements are set exactly opposite to each other so that piercing punch acts in the opposite direction with respect to the blanking punch.          ...

Punching  is a forming process that uses a punch press to force a tool, called a  punch , through the workpiece to create a hole via shearing. Punching is applicable to a wide variety of materials that come in sheet form, including sheet metal, paper, vulcanized fibre and some forms of plastic sheet. The punch often passes through the work into a die. A scrap slug from the hole is deposited into the die in the process. Depending on the material being punched this slug may be recycled and reused or discarded. Punching is often the cheapest method for creating holes in sheet materials in medium to high production volumes. When a specially shaped punch is used to create multiple usable parts from a sheet of material the process is known as blanking. In metal forging applications the work is often punched while hot, and this is called hot punching. Slugging is the operation of punching in which punch is stopped as soon as the metal ...

The different types of dies used in sheet metal operations are as follows: Simple Die Compound Die  Progressive Die  Transfer Die  Combination Die  Multiple Die The Detailed Explanation of all the above mentioned dies are described below. 1. Simple Die: If only  one  operation is performed in One Stroke  and at  One Stage  is called as Simple Die. 2. Compound Die: If  more than one  cutting operation is performed in  one stroke  and at  one stage  called as Compound Die. 3. Progressive Die In this,more than  one cutting operation  will be performed in  one stroke  but at  different stages  and punched out sheet is progressing from one stage to another stage for completing the punching operations so that  Blanking will be the last operation.  In this also,one component is produced for stroke. Therefore production rate is same as tha...

Deep drawing  is a sheet metal forming  process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch.   It is thus a shape transformation process with material retention. The process is considered "deep" drawing when the depth of the drawn part exceeds its diameter. This is achieved by redrawing the part through a series of dies. The flange region (sheet metal in the die shoulder area) experiences a radial drawing stress and a tangential compressive stress due to the material retention property. These compressive stresses (hoop stresses ) result in flange wrinkles (wrinkles of the first order). Wrinkles can be prevented by using a blank holder, the function of which is to facilitate controlled material flow into the die radius. Credit:-  https://en.m.wikipedia.org/wiki/Deep_drawing

Coining  is a form of precision stamping in which a workpiece is subjected to a sufficiently high stress to induce plastic flow on the surface of the material. A beneficial feature is that in some metals, the plastic flow reduces surface grain size, and work hardens the surface, while the material deeper in the part retains its toughness and ductility. The term comes from the initial use of the process: manufacturing of coins. Coining is used to manufacture parts for all industries and is commonly used when high relief or very fine features are required. For example, it is used to produce coins, badges, buttons, precision-energy springs and precision parts with small or polished surface features. Coining is a cold working process similar in other respects to forging, which takes place at elevated temperature; it uses a great deal of force to plastically deform a workpiece, so that it conforms to a die. Coining c...

Sheet metal embossing  is a stamping  process for producing raised or sunken designs or relief in sheet metal.  This process can be made by means of matched male and female roller dies,  or by passing sheet or a strip of metal between rolls of the desired pattern. It is often combined with foil stamping  to create a shiny, 3D effect. The metal sheet embossing operation is commonly accomplished with a combination of heat and pressure on the sheet metal, depending on what type of embossing is required. Theoretically, with any of these procedures, the metal thickness is changed in its composition. Metal sheet is drawn through the male and female roller dies, producing a pattern or design on the metal sheet. Depending on the roller dies used, different patterns can be produced on the metal sheet. The pressure and a combination of heat actually "irons" while raising the level of the image higher than the substrate to make it smooth. The term "impressin...