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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WHAT DO WE DO WITH MATERIALS

Post 624 –by Gautam Shah

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We use objects for their many different qualities. Some are used for their structural properties, while others are useful due to their surface qualities. We try to find an object with the best combination of such attributes. Where such a combination is not easily or immediately available, we primarily try to change the object appropriately and secondarily we try to combine materials and create geometric compositions.

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Aerogel, extremely low density, low thermal conductive material. It is solid and feels like hard styrofoam to touch > Wikipedia image by Image policy

There are Four categories of essential qualities sought in objects for various purposes:

● Engineering Attributes:

Chemical -composition, phase, resistance, structure.

Physical -thermal, electrical, magnetic, gravity-metric, optical, acoustics.

Mechanical -stress/strength, form-ability, rigidity, toughness, durability.

Dimensional Features

Shape -camber, lay/orientation, out of flat, roughness, waviness.

Size -scale, proportion, orientation, nature of perception.

Surface Properties:

Colour -hue, tone, illumination, refractivity, reflectivity, opacity, transparency, fluorescence.

Texture -level and direction of illumination, perceptive organ, nature of contact, scale.

Pattern -random, rational, orientation of cut, original, altered.

Other Considerations:

Availability -local, seasonal, quality, quantity.

Costs  -access, procuring, conversion.

Conveyance  -distance, time, weight, volume.

Handling -safety, storage, containment

Manufacturing -conversion, processing

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Spider silk Cape from Madagascar golden Orb spider silk > Wikipedia image by Cmglee

For a material to be purposeful two broad considerations are required.

  1.          What one does to a material?
  2.         How the material responds?
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Moulding the earth > Flickr image by Julien Harneis

WHAT ONE DOES TO A MATERIAL ?

We seek an object with a perfect combination of many different qualities. Our quest is however further complicated when we require materials in very large quantities, and of equalized quality. We need materials locally, and often immediately.

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Laterite quarrying for stones at Angadipuram, India > Wikipedia image by Werner Schellmann

HOW THE MATERIAL RESPONDS ?

The material’s response is evident on three counts:

● Other Materials,

● Environment

● User.

● Other Materials: A material responds to other materials within its field. The reaction occurs both, in the presence or absence, of the environment and the user.

A material of a higher phase reacts more readily to a material of the lower phase -, e.g. solid to a liquid. Material with an ion charge reacts to a material with opposite ion charge. A material with lower latent energy becomes recipient.

The response of a material occurs more emphatically, through the surface, than anywhere else. Materials with their own surface systems respond in the same manner as their body would. However, applied surface systems with the same or of foreign materials show different reactions. The surface preparation, application method, and bonding techniques, all play their role in such reactions.

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Doughnut Shop achieving consistent finish > Wikipedia image by Neil T

● Environment: A material-object is affected by many features of the environment. The effects are local if directional (through specific orientation), or occur comprehensively. The constituents of the object also respond differently to specific effects of the environment. For such multilateral environmental demands, single, or mono material systems are inadequate. To serve such demands, separately as well as unitedly, multi-material-objects or composites are conceived. A surface material, covering the entity, forms its own environment for the entity. Here the situation can also be equated to material to environment response.

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Abandoned ship in the former Aral sea, Kazakhstan > Wikipedia image by Staecker

Effects of the environment substantially relate to the movement of earth-sun, and so have a time dimension. The time dimension makes such environmental effects to be temporary, permanent, recurrent, or variable. The effects of environment are structurally causative (capable of causing structural changes in a material), and also sensually attributive (capable of providing the sensorial experiences).

One perhaps cannot terminate the processes of nature, however, the effects of environment can be temporarily delayed or quickened and spatially diffused, or intensified, to programme the functioning of an object.

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Faux rustication > Flickr image by marctasman

● User: A user perceives a material-object in different terms like: Engineering attributes, Dimensional features, Surface properties and for Other considerations. A surface is the most proximate and tangible part of an object. A surface, is often the reason, why an object continues to survive in a particular setting.

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This was part of First chapter – Section 1 of my Notes on Surface Finishes Interior Design Notes

 

PLATES, SHEETS and FILM MATERIALS -part I

Post 580 by Gautam Shah

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Sheets are surface materials with stiff to flexible body. Sheets have high proportion of surface area in comparison to volume. A sheet (mainly metal) is thinner than 6mm when compared to the counterpart, the plate. A film is a thinner formation than a sheet. Sheets, Plates and Films, all have different properties and uses. A sheet is used for packing tins, air-conditioning ducts, automobile bodies, furniture, appliances, utensils, pipes, purlins, etc. A plate is used for heavier structural entities like ships, tunnel sections, pressure storage tanks, chemical reaction vessels, reactors etc. A film is an independent entity applied as a cover or foil, formed by material deposition (gas, liquid or solid), or one integrated to a substrate (surface allying, surface ceramic formation or molecule deposition).

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Woolaroc Oklahoma Silver Navajo belt buckle of Sheet metal > Wikipedia image by Wolfgang Sauber

Metal sheets are formed chiefly by hot or cold rolling. Polymer, glass, cement, paper, gypsum sheets are extruded or cast. Foams can be classed as cast sheets. Soft sheets such as fabrics, mats etc. are formed by weaving, netting or pressing the mass of fibres. Palm leaves, leathers, skins, timbers, stones, mica, are naturally formed composite sheets.

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Extruded Sheet metal can for beverage > Wikipedia image by http://www.flickr.com/photos/marcodede/116648094/ by Marcos Andre

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Cement cast sheet (board) > Wikipedia image by Swtpc6800 en:userSwtpc6800 Michael Holley

 In modern age substantial volumes of sheets are manufactured by sheet lamination or layering, particulate forming, impregnating woven or non-woven structures, or by sandwiching various types of sheets. A sheet could have skins formed from other or same materials (that constitutes the core). Sheets formed by rolling or extrusion could be in long lengths or small width strips. Sheets, otherwise, are formed and sized to ‘standard’ sizes. The ISO standard sizes (width and length) are in multiples of 300mm. Sheet forms like fabric are manufactured and sized in multiples of 100mm. Paper is supplied in sizes (ISO standard) of series A & B (such as A0, A1, etc.). Standardization of sheet sizes encourages standardization of manufacturing plants, processes, transport, storage and wastage rationalization.

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Embossed Metal floor deck sheets > Pixabay free images by yourschantz

Plates, Sheets and Films, basically have distinctive processing methods, though some may carry common terms. Plates processing, require greater effort to shape, cut or punch through due to their thickness. Plates have characteristic flexural stiffness. So sheets like plywood and other composites behave like plates. Plates may show different stress behaviour on two faces, such as seen in rolling, bending and welding processes. Plates are assembled by welding, rivetting, forging, mechanical joining and occasionally situational fixing. Sheets are processed by methods such as cutting, punching plain bending and deformation bending. Metal sheets formed by cold-forming. Sheets are assembled by butt welding, adhesion joining, seaming, rivetting, screwing and situational fixing (e.g. dove tail joining of wood materials). Film materials in sheet forms are applied by static charging, adhesion or heat melting.

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Expanded sheet metal Lattice > Wikipedia image by Sven Teschke Budingen

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Sheet metal cabinets > Wikipedia image by sailko

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Thin Film material > Wikipedia image by Fieldsken Ken Fields

Malleable metal sheet products are manufactured mainly by stamping or pressing and drawing. Some drawn parts go through changes in body thickness (such as the kitchen pressure cooker forming). Large plastic deformation is an advantageous property for metals’ sheets. During stamping or micro drawing often there are no changes so some processes like corrugation or furniture are done on pre-coated sheets. Stiffer sheets like wood veneers and plywoods, stone (for cladding), acrylics, etc. must be sawn and in few instances shear cut. Sheets show anisotropy or directional variation of mechanical properties where the material reacts differently in different directions. Metal and composites take advantage of this characteristic while creating geometric compositions.

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Corrugated Paper boards Image attribution: Chris 73 / Wikipedia Commons

Sheets are further processed like folding, corrugation, embossing, and perforation to impart geometric qualities. Sheets are engraved or etched by mechanical, laser and plasma-based processes. Simple processes like grinding, rubbing, ironing, burnishing, flame treatments are applied on wood, paper, leather, fabrics and plastics to remove or suppress surface irregularities. Chemical treatments include Linear Plasma-based processes, nitridation, oxidation electroplating, zinc coating, chromate and phosphate treatments, coating, painting, material deposition, surface hardening, surface alloying and cementation. These alter the surfaces for polarity, wettable, electrical conductive, weldable or solderable, corrosion resistant, tarnish proof, chemical resistant, high wear, hardness and remove surface irregularities.

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Storage tanks of Plates > Wikipedia image by Alex Marshall (Clarke Energy)

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METAL-MATRIX COMPOSITES

METAL-MATRIX COMPOSITES

Post 346 ⇒   by Gautam Shah 

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Composite materials have at least two materials, with distinct roles. One acts as MATRIX and the other functions as a FILLER. The structure and properties of the filler-matrix interface play a major role in the mechanical properties of composite materials. The stresses acting on the matrix are transmitted to the fillers across the interface. A series of strips held together offers strength equal to one strip but when clamped together all layers take the load.

Metal matrix composite components

Some engineering parts have to operate at temperatures high enough to melt or degrade a polymer, so a polymer matrix is not useful. In such a situation Metal matrices offer high-temperature resistance, and strength and ductility, or bend-ability. The main problem with metal-matrix composites (MMC) is that even the lightest metals are heavier than polymers, and they are very complex to process.

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MMC can be used in such areas as the skin of a hyper-sonic aircraft, and Space shuttle, commercial airliners, electronic substrates, bicycles, automobiles, golf clubs, and a variety of other applications. Metal matrix composites have good thermal conductivity, high shear strength, very high abrasion resistance, high-temperature bearing capacity, non-flameability, not affected by solvents. These composites can be machined or processed further through conventional engineering tools and equipments.

Air craft shell -metal matrix composites

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Majority of commercially used metal matrix composites have Aluminum as the matrix, but in specialty metal sections, large number of applications employ matrix properties of super-alloys, titanium, copper, magnesium, or iron. Aluminum-matrix composites are not a single material, but a group of materials whose stiffness, strength, density, and thermal and electrical properties can be defined. The matrix alloy, the reinforcement material, the volume and shape of the reinforcement, the location of the reinforcement, and the fabrication method can all be varied to achieve required properties. Regardless of the variations, however, aluminum composites offer the advantage of low cost over most other MMCs.

Tungsten_carbide

Aluminum MMCs are produced through several routes such as casting, powder metallurgy, in situ development of reinforcements, and foil-and-fiber pressing techniques. For Metal matrix composites fillers as reinforcements are like, continuous fibers, discontinuous fibers, whiskers, particulates, and wires. With the exception of wires, which are metals, reinforcements generally are ceramics. Metal wires include tungsten, beryllium, titanium, and molybdenum. Metal matrix composites are typically made by infiltrating liquid metal into a fabric or a prearranged fibrous configuration called a preform.

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PROCESSING of MATERIALS

Post 257 – by Gautam Shah 

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Main Objectives of Materials Processing:

  1. Shape and size formation
  2. Alteration and induction of properties
  3. Endowing finishes

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1   SHAPE AND SIZE FORMATION

Body forming processes change the dimensional format of the material through phase-change of the material (solid to liquid to gas, or vice versa), within the same material phase (heat treatments, hot and cold working, and through mechanical work like mixing, stirring), and through material compositions (structuring, assembly).

Steel_Kithen_utensils_at_Nizampet

Grains or dust mixed with a binder material can be cast into solids, or melted-fused as alloy, or sintered to a ceramic. Solids can be rolled into sheets or melt-spun into fibres, ground to powders, or drawn into wires. Fibres and wires are woven into fabric sheets.

Shop Copper Tableware Old Antiques

SHAPING PROCESSES

  • Solid forming: Forging, beating, pressing, rolling, drawing, casting, extrusion, moulding.
  • Sheet forming: Bending, punching, stamping, cutting, seaming, forming, moulding.
  • Linear forming: Drawing, spinning, entwining, weaving.
  • Grain forming: Blowing or granulation, chopping, grinding.

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Expanded Metal lattice

Shaping processes can also be classed as:

1a  Flow processes: casting, moulding, extruding, drawing, rolling, forging, hammering, beating, powder-technology, material deposition, stamping, punching, pressing, bending, folding, seaming.

Deep_Draw_Line_example_by_Pressteck_Italy

1b  Additive processes: lamination, crystal growth, foaming (lower phase material dispersion in a higher phase material), plating, cladding, mounting, joining, material deposition, fabrication, joining, supporting, holding, keying, positioning, plugging, arranging.

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1c  Reducing processes: cutting, chopping, sizing, splicing, scooping, drilling, boring, machining, planning, chiselling, chipping, grinding, rubbing, sand blasting, cleaning, washing, melting, dissolving.

1d  Other forming processes: spinning, weaving, knitting.

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2  ALTERATION AND INDUCTION OF PROPERTIES

Alteration and Induction of properties cause a change in the engineering or structural quality of the material, frequently accompanied by the modification of the surface characteristics. The alteration processes are also designed to regain the lost or the reduced properties during other processing.

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2a  Heat treatments: boiling, liquidizing, melting, softening, sintering, baking, drying, fusing, welding, soldering, forging, annealing, heating, hardening, crystal forming, blowing.

2b Non heat treatments: magnetizing, static discharging, infection proofing, cleaning, washing, earthing, wetting, drying, stretching, strenting, stressing, compressing, stretching (tensile), twisting, filling.

2c  Material applications: coatings, depositions, claddings, Panellings, enamelling, inlaying, gilding, printing, moisture proofing, fuming.

2d  Non material processes: embossing, engraving, polishing, burring, charring, burnishing, chasing, buffing.

2e  Chemical treatments: dyeing, bleaching, etching.

Artist Pottery Decoration Ceramic Blue Pot

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3  ENDOWING FINISHES

Finishes are created: By altering the surface properties of the materials at a raw material stage and also after the formation of the object, By reforming the objects, and By applying other materials at a raw material stage or at an object formation stage.

The need for a peculiar finish could be varied, but essentially for: Imparting specific sensorial characteristics, for survival of the object in an environment, for changing the structural properties, as an aid in material processing and forming operations, for storage and handling of the raw materials or components, and for receiving the next treatment.

3a  Processes for Natural Surface Finishes: Natural Finishes result due to many different factors, such as: Elemental conditions of formation, subsequent responses like weathering, cognitive affectations, and later, natural or man-made interventions (angle of cut, tools and techniques used, etc.).

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Natural surface finishes have three main cognitive affectations: Colour, Pattern and Texture. The colours are of original formation, subsequent weathering, readjustment of stresses, or induced by physical and chemical changes. The patterns result from the stresses, mixing of constituents, weathering, and the varied reactivity of different parts and constituents. Patterns also result from granular or fibrous orientation, method of cut, cyclic nature of growth, formation of residual products, deposition of contaminants, and tools-techniques of handling and processing. Textures primarily result from the degree of homogeneity, angle of cut, differential weathering, and various formative processes.

Astroturf

3b  Processes for Manufactured Surface Finishes: Manufactured Surface Finishes result at three levels: Raw material stage, Product formation stage, and later, through Application of surface finish on completion of the system. In an integrated production setup all three could be a single stage or plant process, but in most other fabrication shops only the last two processes are combined. For a site fabricated systems like buildings, the last process, i.e. surface finish application, is a distinct process as it is carried out at a site. Manufactured surface finishes as a result are of two categories: Plant based and Site-based systems. Though lot of preparatory work may occur in the industrial plant for the site-based surface finish application. Products fully surface finished in industrial plants require very careful handling (transportation, loading, storage, delivery and positioning), and so may carry protective but removable coatings or shields.

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