Surface grinding machine

Surface grinding machine

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  A . Y. DA DA B H A I T E C H . I n s t i t u t e  Name Adavaliya prakash g.  Department Mechanical 5-B  EN. No. 126010319065  Topic Surface grinding machine  Guide By D.G.K.
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  Certificate This isto certify that… Mr. Adavaliya Prakash G. of mechanical department EN. NO. 126010319065 has satisfactorily completed his term work ppt on Surface Grinding machine. In the subject of M.E. – III for the term ending in Date :- _______ _________ _______________ Sign of Teacher Head of the Department
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  Contains of thesurface grinding machine  Principal  Types of Surface grinding machine  Working  Equipment
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   Principle ofthe Surface grinding machine • Surface grinding is used to produce a smooth finish on flat surface. It is a widely used abrasive machining process in which a spinning wheel covered in rough particles cuts chips of metallic or non-metallic substance from a work piece, making a face of it flat or smooth. • Surface grinding is the most common of the grinding operations. It is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or non-metallic materials to give them a more refined look or to attain a desired surface for a functional purpose.
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  Type s of the Sur f ac e gr inding ma chine Basically there are four different types of surface grinding machines characterized by the movement of their tables and the orientation of grinding wheel spindles as follows: 1) Horizontal Spindle Surface grinding machine • Reciprocating Surface grinding machine • Rotary Surface grinding machine 2) Vertical Spindle Surface grinding machine • Reciprocating Surface grinding machine • Rotary Surface grinding machine
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  Horizontal spindle (Reciprocatingtable) surface grinding machine • The periphery (flat edge) of the wheel is in contact with the work piece, producing the flat surface. Peripheral grinding is used in high-precision work on simple flat surfaces; tapers or angled surfaces; slots; flat surfaces next to shoulders; recessed surfaces; and profiles. • Most commonly used • Either hand or hydraulically operated
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  Horizontal spindle (Rotarytable) surface grinding machine • This series features our well proven program of surface grinders with rotary tables. These machines are particularly suitable for high precision surface grinding of thin parts of high accuracy & circular parts where one piece is to be ground at a time flat or with a radial taper. Besides, in applications where batches of small parts are to be ground with a high degree of parallelism & high surface finish this type of machine is a better alternative to a reciprocating machine as a production time will be much less. This is because the grinding wheel is in constant touch with the grinding piece, the operating speed of the work piece is higher and the work piece move constantly in one direction only. It is superior to a rotary table machine with vertical
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  Spindle in respectof accuracy & parallelism & surface finish although production norms will be lower. • Table diameter 500 to 1000mm spindle drive : 3.75 kw to 7.5 kw distance , table to spindle center 300 to 450mm. • Spindle runs in super precision angular contact preloaded bearings with travels in the vertical column in hand scrapped guide ways with power elevation hand manual infeed. Cross feed is through AC Induction motor via precision ball screw. AC Induction motor speed is controlled by inverter to give infinitely variable cross feed . Table drive operates on large , circular ways-well lubricated by means of oil sump. It carries an electromagnetic chuck with circular poles. Drive to the table is through AC induction motor , controlled by inverter for infinitely variable speed. • Optional : All models available with CNC controls for Automatic grinding cycle including wheel dressing and compensation.
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  Vertical spindle (Reciprocatingtable) surface grinding machine • These machines are designed for quick flat grinding of work pieces. • Longitudinal travel 550mm to 800mm • Spindle drive : 1.5 KW to3.75 KW Wheel clearance : up to 200mm • Cross traverse is manual for infeed and powered for positioning Hydraulic drive for table.
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  • This grindingmachine with all working motions is shown in Fig a. The grinding operation is similar to that of face milling on a vertical milling machine. In this machine a cup shaped wheel grinds the work piece over its full width using end face of the wheel as shown in Fig b. This brings more grits in action at the same time and consequently a higher material removal rate may be attained than for grinding with a peripheral wheel.
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  Vertical spindle (Rotarytable) surface grinding machine • This series is designed for flat grinding of one side of the job at a time for each table load.
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  • Rotary worktable operates on large , circular ways-well lubricated by means of an oil sump. It carries an electro magnetic chuck with circular poles. • Access to work table is unique in that a greater proportion of work table is opened for easier and safer work handling. Being a fixed Centre table , the initial accuracies are maintained for entire life if the machine. • Wheel spindle head is of extremely rigid construction with precision bearings duly preloaded. Segmented wheel is directly mounted at lower end.
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  • Column hasoversize vertical vee and flat ways-fully protected from grinding steel guards. Wheel feed can be applied by hand or power. Precision screw gives positive down feed on the head for accurately controlling small increments of feed.
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   Controls asoptional • Automatic electronic gauging is provided. It gives continuous measurement of work during grinding cycle and visual indications that the work is approaching size. When work reaches a preset dimension grinding stops , the ,machine sparks out and the head retracts –since the job is directly probed , wheel wear is directly compensated. • CNC Controls for vertical axis with servo drives via precision ball screw.
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  Wo rking of the sur f ac e gr inding ma chine • The surface grinder is composed of an abrasive wheel, a work holding device known as a chuck, and a reciprocating or rotary table. The chuck holds the material in place while it is being worked on. It can do this one of two ways: ferromagnetic pieces are held in place by a magnetic chuck, while non-ferromagnetic and non-metallic pieces are held in place by vacuum or mechanical means. A machine vise (made from ferromagnetic steel or cast iron) placed on the magnetic chuck can be used to hold non-ferromagnetic work pieces if only a magnetic chuck is available. • Factors to consider in surface grinding are the material of the grinding wheel and the material of the piece being worked on. • Typical work piece materials include cast iron and mild steel. These two materials don't tend to clog the grinding wheel while being processed. Other materials are aluminium, stainless steel, brass and some plastics. When grinding at high temperatures , the material tends to become weakened and is more inclined to corrode. This can
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  also result ina loss of magnetism in materials where this is applicable. • The grinding wheel is not limited to a cylindrical shape and can have a myriad of options that are useful in transferring different geometries to the object being worked on. Straight wheels can be dressed by the operator to produce custom geometries. When surface grinding an object, one must keep in mind that the shape of the wheel will be transferred to the material of the object like a mirror image. • Spark out is a term used when precision values are sought and literally means "until the sparks are out (no more)". It involves passing the work piece under the wheel, without resetting the depth of cut, more than once and generally multiple times. This ensures that any inconsistencies in the machine or work piece are eliminated.
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   Equipment forSurface grinding machine • Surface Grinder with electromagnetic chuck, inset shows a Manual magnetic chuck • A surface grinder is a machine tool used to provide precision ground surfaces, either to a critical size or for the surface finish. • The typical precision of a surface grinder depends on the type and usage, however +/- 0.002 mm (+/- 0.0001") should be achievable on most surface grinders. • The machine consists of a table that traverses both longitudinally and across the face of the wheel. The longitudinal feed is usually powered by hydraulics, as may the cross feed, however any mixture of hand, electrical or hydraulic may be used depending on the ultimate usage of the machine (i.e.: production, workshop, cost). The grinding wheel rotates in the spindle head and is also adjustable for height, by any of the methods described previously. Modern surface grinders are semi-automated, depth of cut and spark-out may be preset as to the number of passes and, once set up, the machining process requires very little operator intervention.
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  • Depending onthe work piece material, the work is generally held by the use of a magnetic chuck. This may be either an electromagnetic chuck, or a manually operated, permanent magnet type chuck; both types are shown in the first image. • The machine has provision for the application of coolant as well as the extraction of metal dust (metal and grinding particles).
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   References •Books : Manufacturing engineering – III • Websites : http://en.wikipedia.org/wiki/Surface_grinding, www.surfacegrinding.co.in, http://www.alexmachinetools.com/rhseries.htm