MATERIALS HANDLING PROCESSES

Post 664  –by Gautam Shah

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Hand GrindingMany of the Materials handling processes in use today are essentially the same as those employed in ancient times. These processes evolved from day to day activities like farming, irrigation, cooking, hunting, storage, shelter-making and rituals. For a very long time, the process were not purpose-specific, but tools or means oriented. And as a result refinement has come from tools and rationalization of procedures. Many such processes are now highly mechanized saving time and energy, and some even are fully automatized, using programmed automats and robotics that allows faster, accurate and safer production.

American boys' handybook of camp lore and woodcraft (1920)Sommer,_Giorgio_(1834-1914)_-_n._11141_-_Museo_di_Napoli_-_Strumenti_di_chirurgiaSome of the traditional Materials Handling Processes

  • Removal of Materials for surface texturizing, levelling, form-making, polishing, finishing etc.
  • Addition of Material for levelling, filling-in, daubing, coating, plastering, rendering etc.
  • Joining of Materials by mechanical (screwing, tying), adhesion, proximate placement, knitting, knotting etc.
  • Downsizing of Material by breaking, cutting, splitting, chopping etc.
  • Extraction of Material by mining, excavation, selection, separation, sieving, winnowing, floating, fishing, cultivation, hunting etc.
  • Plastic Moulding of flours, clays, minerals etc.

640px-Right_Ground Roller Compactor Wikipedia Image byTechniques of Materials handling include: Shaping of the form is the prime technique for treatment of materials, by plastic moulding, casting, extruding, pressing, shaping, embossing, reforming, deforming, removal of material, stretching, compressing and forging. Materials like Clay with important quality of plasticity allowed the shaping at ambient temperature. Materials like Wood and Stone were shaped by removal of the mass. Metals were workable by heating, beating (forging) and addition or removal of the mass.Wattle_and_daub_constructionMaterials’ Depositions are used to add upon mass or surface, and create mixes with use of the same or foreign materials for alloying, embellishing, cladding, layering, fixing, daubing, coating etc. Materials’ Compositions are used in assembling, entwining, joining, tying, bracing, weaving, knitting, embroidery, stitching, etc. Forming Composites of materials is used through Matrix and Filler mixes, such as layering, particle composites, etc.Weaving_espartoCutting and crushing are the oldest of all material processes. Farming, irrigation, land levelling, minerals mining, cleaning the hunt and the hides, collecting and preparing fuel woods, skinning and shaving of hides, debarking timers, all require some form of cutting. Bare hands or sharp stones and sticks used as the cutting tools were aided by percussive tools like pounding sticks or stones and leveraged by long arms. Hammering was used for grinding foods, breaking and crushing nuts and compressing leather. Tools and arms served different purposes and required materials, creating processes of tying, wrapping, holding, fixing etc.

Peasant_in_the_vegetable_gardenShaving is done to remove material’s components such as outward hair or fibres, layers, etc. Leather surfaces are shaved to remove the surface hair and also for thinning. Leathers are also surface split to separate leather suitable for uppers and soles. The palm leaves are shaved to remove the stems and make them smoother for writing. Tree-barks are removed by axes and choppers to retard insect attack and increase moisture removal. Timbers are re-cut or planned with finer tools to achieve a smoother surface. Timbers are split very finely to create veneers. Wood planning is also a shaving technique. Carpets and rugs require close shearing by scissors to shave of protruding fibres.

Wet kneading shapingKneading soft or plastic materials to shape them, extract juices, forming homogeneous mixes were important material phase change processes. These were multi variant processes and gave magical capacity of material transformation. These were easiest and territorial universal processes. Using water for kneading, grinding, rubbing, levelling, polishing, coating, drilling, cutting, liquidizing, separation by flotation, emulsion-making, are processes used in food preparation, ceramics and metallurgical works.

Fireplace Cook Fire Wood Flame Heat Boil WaterFire processing of materials created a whole new set of chemistry. It began by cooking, but most important innovations included clay baking into ceramics and reshaping metal nodules by hot forging. Later it included refining metals, and processes of oxidation, carbonation, etc. Controlled burning allowed development of many processes and products, by selection of fuel material, distancing, exposure timing, environmental conditions, shielding, etc.

Controlled Burning Gasbbq

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MACHINE TOOLS and MACHINES

Post 297 – by Gautam Shah

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Machine tools are power driven utilities, and are of two basic types: Hand held or mobile tools and Stationary tools. Hand-held tools are apparently small, and lightweight. Whereas stationary tools often called, Machine tools, are large, fixed to a position. The large size requires stationary positioning. Both types of machine tools are classifiable into home or hobby machine tools and Industrial or Engineering machine tools.

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Machines and machine tools both are automated entities, and so have slightly overlapping categorization. A machine is a specific product entity which can be conducting several sequential or concurrent processes. A machine tool is a multi-purpose entity, and used for several processes. It can have attachments of (non-machine) tools, or it may be part of a machine. All machine-tools are a type of machine, but conversely all machines may not be called machine tools. To use a tool or machine tools some form adaptation, recognized as craftsmanship is required. Machines do not need personal creativity or craftsmanship except basic technical knowledge.

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Machines and machine tools are powered by human, animal, kinetic, hydraulic and pneumatic power, wind mills, steam and electric power. Machine tools need to be manipulated or the feed-stock requires positioning, adjustment, etc. When this input processes are guided or automated, a machine tool becomes a machine. The guidance or automation may be to free the hands, other limbs and sensory nodes. So, in this sense a machine can have several machine tools, each of which has time-space feeds mechanisms. Advance machines have feed-forward and feed back systems to reduce or correct errors.

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A machine-tool can take up various types of tools. Such as a drill can take different types of bits or a potter uses different shapes of spatulas to shape and finish the turned-clay item. A CNC machine, has predefined set of feed-guide processes controlled by the computer input. A machine tool that is handy will have to be very quite and vibration free. Very fine work tools like a dentist or orthopaedic surgical drills are operated through pneumatic or compressed air, rather then electric motors. The pneumatic technology offers vibration free and noiseless movement at very high speeds. Similarly Air-jet looms working on suction reduce the nominal noise associated with yarn bobbin shuttles.

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Machines were stationary entities due to the robust size, stability and power needs. This created batch production system, creating lots of cross traffic within the plant. Batch production with fixed machines required power locally. This was difficult proposition when steam or a large electric motor generated power was transferred through shafts and belts to the machine. Batch based products tended to be holistic in nature. The need for faster production forced rethinking of product design into component-based entities. Components were produced by machine tools or machines and brought to the assembly line. The assembly line was operated through handy machine tools.

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Assembly lines had many grey areas. A slowdown or stoppage affected the entire production systems. Processes, tasks, etc., were carefully apportioned in terms duration, speed and space. All these studies provided opportunities for automation of assembly processes. The automation allowed multiple operation at a station which drastically reduced the length of assembly lines. The automation is now seen in use of robots handling several processes at a station. A human assembler cannot go into narrow spaces, take difficult body postures and require rest or diversion, but a robot is beyond these difficulties. A robot is a machine with several machine tools.

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