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1-) Planer ( New ) ( Better ) ( Manufacturing tools )

A planer is a large machine tool used for machining flat surfaces by means of single point cutting tools. The work to be machined is fastened securely to the planer table with suitable holding device. This table has a reciprocating movement and the length of the stroke is 3-5 cm longer than the length of the surfaces to be planed. A cutting operation on a planar is carried out by the stationary cutting tool against the reciprocating job.

Classification of Planing Machines

Planers can be classified in a number of ways:

1. Accourding to drive

i.Gear drive
ii.Hydraulic drive
iii.Belt drive
iv.Crank drive
v.Variable-speed motor drive

2.Accourding to general construction

i.Double-column planer
ii.Open-side planer
iii.Pit-type planer
iv.Edge or plate planer

PRINCIPAL PARTS OF A PLANER

The principal parts of a planer are:

i.Bed
ii.Table
iii.Housing
iv.Cross-rail
v.Saddle
vi.Tool head

Bed The bed is a large rigid box-like casting that acts as the foundation of a machine. It supports the column and all the moving parts of the planer. The length of the bed is slightly more than twice the length of the table, so that the full length of the table can move in it.

Table The table of a planer is a large rectangular thick cast plate that moves over the bed on sliding V-ways. The upper surface of the table has T-slots to facilitate the clamping of the workpieces, special fixture and vices with T-bolts. Its main function is to hold the workpieces and reciprocate on guideways to impart motion to the job for a planing operation.

Housing The housing is a vertical casting that straddles the table and the bed of a planer. It acts as a support for the mechanism of tool head operations. Its accurately machined parts provide precision. to the surface for an accurate movement of cross-rails. The side tool heads also slide upon it.

Cross-rail The mechanism that acts as a guide for the transverse travel of the saddle is known as a cross-rail. It supports the tool heads by means of feed screws. The cross-rail can be moved up and down by means of feed screws. For accurate working, the table and cross-rail must be parallel. Cross-rails are rigidly connected to castings for accurate operation.

Saddle The unit fitted to the ways of the cross-rail is known as a saddle. The front of the saddle is provided with ways to hold the tool head and feed screws. The saddle can be moved in the crosswise direction over the table.

Tool head The tool head of a planer is the part attached to the saddle that contains the tool post. In turn, the tool post holds the cutting tool. The tool post is so hinged to the head that the cutting tool is raised during the idle stroke. This saves the cutting edge of the tool. The tool head of a planer is similar in design and operation to the tool head of a shaper. A planer may be fitted with two or more tool heads to perform more than one operation.

( Bawa, H. S. Manufacturing Processes - I, pg. 78-81 )

(old answer)Planer and shaper are popular single point precision machining methods. A shaper operates by moving a cutting tool backwards and forwards across the workpiece. The workpiece mounts on a rigid square table that can traverse sideways underneath the reciprocating tool, which is mounted on a ram. The table motion is controlled by a precise feed mechanism. The ram slides back and forth about the workpiece and the tool can be positioned to cut the flat surface on the top of the workpiece. A Planer is a type of machining tool analogous to a shaper, but larger and with the entire workpiece moving beneath the cutter instead of the cutter moving above a stationary workpiece. Planers and shapers are generally used for two types of work: generating large accurate flat surfaces and cutting straight microgrooves. Modern planers are used for producing precision stamping dies and plastic injection molds for light-guiding plates of liquid crystal displays, large scale linear fresnel lenses.

( J. Paulo Davim, Mark J. Jackson, Nano and micromachining, page 178)

2-) Boronizing ( New ) ( Better ) ( Finishing Processes/Manufacturing )

Boriding or boronizing is a thermochemical process that produces wear-resistant boride coatings on tool steels, carbon and alloy steels, and other materials. The boron may be supplied by gaseous, liquid, and solid media, and plasma, PVD, and CVD techniques of applying boron and boron compounds have been evaluated. The use of solid boronizing agents, containing largely boron carbide, as applied by packing tools in powders or applying pastes, has proved the most technologically viable method of boronizing. Steels are boronized at temperatures between 850 and 950 centigrates ( 1560 and 1740 F ), and a layer of iron boride, Fe2B forms on the surface. The iron boride FeB may also form but is considered undesirable because of its tendency to flake from coatings. When present, the FeB can be removed by diffusion annealing. Some elements, such as chromium, molybdenum, nickel, manganese, vanadium, and cobalt, are incorporated into the boride layer, and others, such as carbon, silicon, aluminum, and copper, are insoluble in the boride layer and diffuse into the steel substrate as the boride layer forms. Thus, most of the alloying elements in steeel retard the growth of the boride layer to some degree and tend to reduce the attainable thickness of the boride layers.

( George Adam Roberts, George Krauss, Richard L. Kennedy, Tool Steels, pg. 320 )

Boronizing ( Old )

Boronizing is one of the recent methods of surface hardening, which may applied to any ferrous material but is generally adopted for carbon steels and tool steels. Both pack and gaseous techniques can be applied for surface hardening. In the case of pack process, the components are packed in heat-resistant boxes with mixtures of granules or paste of boron carbide or other boron compounds with additions of activators and diluents at 900-1000 centigrade degree. Boron diffuses inwards and iron borides (FeB and Fe2B) layers are formed. On the surface, FeB phase forms, while in the interior, Fe2B phase is formed. FeB phase is more brittle and is not desirable. Higher temperatures, longer treatment times and higly alloy steels favour teh formation of FeB phase. The boride layers are very hard. They have hardness which is even greater than 1500VPN.

The heat threatment time required for a case depth of 0.15mm is 6 hours at about 900 centigrade degree. This layer has high wear resistance, and such components are used in tractor parts, drop forging dies and jig bushes.

In this process, threatment temperature is very high, and hence hardening of components before boronizing is not required. Only in the case of tool steels after boronizing, hardening and tempering are required to have the desired mechanical properties.

(T. V. Rajan, C. P. Sharma, A. Sharma, Heat Treatment: Principles and Techniques, pp.163-164)

3-) Hot Dipping ( New ) ( Better ) ( Manufacturing methods )

Hot dipping is a process in which a protective coating is applied to a metal by immersing it in a molten bath of the coating metal. Hot-dip coatings can be used to protect a number of metals; those used to protect steel are most common.
Hot-dip coatings have a number of advantages, including the ability to coat recessed or difficult areas ( such as corners and edges ) with a standart minimum coating thickness, resistance to mechanical damage ( because the coating is metallurgically bonded to the steel ), and good resistance to corrosion in a number of environments. However, the process has two limiting factors. First, the coating must melt at a resonably low temperature. Second, the base metal must not undergo undesirable property changes during the coating process.
Hot-dip coatings can be applied by continuous or batch processes. Materials such as steel sheet and wire can be hot dipped by continuously passing the steel through the molten metal bath. Continuous processing is highly automated and mechanized and is often associated with steel mill operations. Zinc, aluminum, and zinc-aluminum alloy hot-dip coatings are applied on steel. Materials that are batch processed are generally fabricated before hot dipping. Articles that can be hot dipped by the batch process range in size from large steel structural members to small items such as fasteners.
( Davis, Joseph R. Corrosion: Understanding the basics, pg. 387 )

Hot Dipping ( Old ) 

Zinc is the metal most widely applied by this method, and for heavy steel sections is the only one. Tin and lead are commonly applied by hot-dipping but not for structural steelwork. Aluminum is also applied by this method, particularly to sheet steel, which is marketed as a pre-coated product, often as Zn-Al-coated steel. Although aluminium can be applied to havier sections of steel by hot-dipping, it is a more difficult and expensive process then for zinc and is rarely, if ever, used. However, if an economic form of this process could be developed it might well prove to be a suitable method of coating with alıminium, which, in many situations, provides a higher degree of corrosion resistance than does zinc.

Zinc is particılarly suited to hot-dipping because of its low melting point (420 ⁰C) and the nature of the alloy layer formed during the process. For many years hot-dipped galvanising has been specified by BS 729:1971 (1986). A new International and European Standard BS EN ISO 1461:1999 has now been published. Aluminium is by no means as easy to apply by dipping techniques. It has a higher melting point than zinc (660⁰C) and this means that the bath usually has to be operated at a temperature over 700⁰C. At this temperature the reaction between aluminium and steel is rapid, resulting in high dross formation. Futhermore, at this temperature, because of the reaction with steel, it is necessary to use ceramic-lined tanks, which are more expensive than the standart steel type used for Zinc. Aliminium oxides readily to produce an oxide (Al₂O₃) and this makes fluxing more difficult than with zinc. Oxide particles may also become entrapped in the coating.

(Bayliss D. A., Deacon D. H., Steelwork Corrosion Control, 2002 p.169)

4-) Pyrolysis ( New ) ( Better ) ( Manufacturing methods )

Pyrolysis is a chemical degradation reaction that is induced by thermal energy ( alone ) and generally refers to an inert atmosphere. The sample is subjected to a short burst of intense heat that initiates thermal fragmentation and the production of a range of smaller molecular species that are related to the original sample composition. Pyrolysis of polymeric materials is performed either for analytical purposes or for producing useful materials. Applied polymer pyrolysis is used as a process for transformation of polymers or polymer-containing materials into gases, liquids or solids. Analytical pyrolysis is one of several commercially available thermal degradative techniques used routinely for characterisation of synthetic polymers. Progress in pyrolysis as an analytical tool is well documented. The techniques of analytical pyrolysis were largely developed in the 1970s, and books by Irwin. Liebman and Levy, Wampler and Moldoveanu have dealt with the basic subjects of polymer analysis by pyrolytic methods. Analytical pyrolysis involves an integrated analysis system, which is carefully controlled to produce reproducible results, and which uses small amounts of sample ( often in the nü*g range, up to 100 mg ). The small, characteristic volatiles ( desorption ) and molecular fragments ( degradation ), which are generated, are used to qualitatively identify the structure of the original polymeric matrix and to determine quantitative information on composition.

( Bart, Jan C. J. Plastics Additives: Advanced Industrial Analysis, pg. 214,215 )

Pyrolysis: (21:15) ( Old )Pyrolysis is the chemical decomposition of organic materials by heating in the absence or controlled amount of oxygen. Pyrolysis and gasification are thermo-chemical conversion routes which recovers energy from biomass and waste fuels. Pyrolysis is heavily used in the chemical industry, for example, to produce charcoal, activated carbon, methanol and other chemicals from wood. It is an important chemical process in several cooking procedures such as baking, frying and grilling. Pyrolytic processes are involved in basic research as well as in applied fields such as the industry. This book will survey the use of the pyrolysis in these fields and will also examine current research done in the nanoscience field.

(Walker S. Dnahue, Jack C. Brandt, Types, Processes, and Industrial Sources and Products, pg:259)

5-) Wire Drawing ( New ) ( Better ) ( Manufacturing methods )

The process of wire drawing is to obtain wires from rods of bigger diameter through a die. The dies are normally made of hardened alloy steel, cemented tungsten carbide, diamonds and chilled cast iron. Die material selection would depend upon the size of wire and composition of its material. The wire drawing die is of conical shape as shown in Fig. 3.4 and 3.5.

The end of the rod or wire which is to be further reduced is converted into a pointed shape and is inserted through the die as shown in the Fig above. The gripper would then pull the wire through the die in which the pointed end of wire or rod has been gripped.

Thus, wire drawing is an operation to produce wire of various sizes within certain specific tolerances. In normal practice the process involves reducing the diameter of wire by passing it through a series of dies ( wire drawing die ) with each successive die having smaller bore diameter than the one proceeding. Such system with one die and endless chain for pulling drawn wire is shown in Fig. 3.6.

The wire can be pulled through the die so that wire can be attached to a power operated reel. The reel is then rotated to draw the wire through the die at desired speed. In view of erroneous pressure between the die and wire being drawn, it is essential to lubricate the area of contact as shown in Fig. 3.6.

( Sharma, S. K. Sharma, Savita, Manufacturing Processes, pg. 54-56 )

Wire Drawing: (01.04.2011 ; 02:30) ( Old )

Drawing wire is a method similar to extrusion. Copper wire often starts as coils of thick wires produced by hot rolling, with successive coils welded together to maintain continuous production. Copper wire is then fed through an insulate line. Each insulate line performs several different functions, such as additional wire drawing, annealing (softening), and applying insulation.

The first step in the pulling process is to reduce the size of the copper wire by drawing it again, which uses diamond dies and reduces the wire to another size based on American Wire Gauge (AWG) codes (discussed in section 5.3, “Labeling and Certifying Cable”).

After being drawn, wire is very brittle and can be easily fractured if flexed. Finished copper wire has to be flexible to be useable, so the wire is annealed by passing a large electrical current through the wire for a fraction of a second. This raises the wire’s temperature briefly to 1000F. Wire is annealed in water to prevent oxidation, and also to cool and clean the wire before applying insulation. Wire that is not properly annealed tends to be brittle and break easily.

The wire is then passed through an extruder, where a thin coating of plastic containing high-density pellets of the insulating material is applied. As the wires are pushed through the extruder, the insulation pellets heat until they melt onto the wire.

(R. Shimonski, R.T. Steiner, S.M. Sheedy, Network Cabling Illuminated, page 124-125)