PLASTICS FINISHING

PLASTICS FINISHING

Post 116 ⇒  by Gautam Shah ➔

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The basic purpose of finishing plastics is to remove the nominal imperfections such as scratches, dull spots, dents, protrusions, ridge marks at the junction of moulds, gate marks (entry points of pour). Many of these are avoidable by refined production methods. For finishing, primary techniques like grinding, filing, sanding, buffing, turning, tapping, sawing, etc. are used. Most post-production finishing processes are required for preparing or readying the item for subsequent manufacturing. These are, drilling, splitting, chopping, trimming, cutting, grinding, etc. Plastic products like granules, fibres, powders, liquids, etc. Go through several cycles of finishing and further manufacturing before a utilizable product is achieved. Some plastic entities need a micro size calibration to meet the tolerances’ requirements.

Mechanically ground edges

MACHINING

Rigid plastics, thermoplastics and thermosets can be machined by conventional processes such as drilling, sawing, turning on a lathe, sanding, and other operations. Glass-reinforced thermosets are machined into components like gears, pulleys, sprockets and other shapes, when the small batch size cannot justify fabrication of moulds. Various forms can be stamped out (die-cut) from sheets of plastics. The cups made by vacuum forming, for instance, are cut out of the mother sheet using a sharp die. In the case of a thermoplastic such as polystyrene, the scrap sheet left over, can be re-ground and re moulded. Soft thermoplastics need proper support to prevent distortion during machining. The elastic recovery in plastic materials with low softening point requires precautions so that shrinkage and distortions are prevented, such as with tapped holes that become tapered or smaller than the nominal requirements. Plastics show heat-build up during machining which causes gumming, discolouration, poor tolerance control.

Treated surface Polycarbonate Greenhouse

DRILLING, TAPPING, THREADING, RAMMING

These operations relate to speed, which in case of thermoplastic depends on the type of material, size and depth of the hole. Speeds that are normal for harder materials must be reduced for softer materials and larger size of apertures so as to minimize the heat generation. Thermoplastics require, slightly oversized hole to offset the shrinkage due to elastic recovery of material.

SAWING

Reinforced thermosetting plastics and dense thermoset usually give clean saw-cut. Thermoplastic materials with low melting temperature become soft due heat of friction during cutting. Deep sawing becomes difficult as the saw gets jammed due to elastic recovery of side walls.

Anti-static bag for packing electronic items 

DECORATING PLASTICS

Plastic articles are decorated for technical, functional and sensorial purposes. Colour coats reduce the penetration of UV rays from sun light, whereas clear coats are used for toys and edible storage utilities. Colours are included by multi point injection moulding, or by mixing polymers with slightly a different melting point. Plastics are coloured by paints and organo-sol (liquid plastic formulation) through brushing, spotting, dipping and spraying. For texturizing and branding pad printing, hot-stamping, silk screen printing, are used. Screen printing is done for flat and round surfaces such as dials, bottles etc. Hot stamping and heat transfers involve transferring a pre prepared design from a soft flexible film or foil with heat and pressure. Other than this there are many types printing processes that transfer an image or patterns to specific areas of plastic objects. These include flexography, offset, etc. Valley printing deposits colour only in the depressions. Roller printing deposits colour on the level or ridge like surfaces. Toys and household articles are decorated by a variety of temporary and permanent stickers (labels) that are usually overprinted but in transparent stickers these are under printed. Preprinted designs on foil or film of a compatible material can be inserted in the mould before injection of thermoplastic material.

Embossed Plastic film

Plastic articles are hot and cold stamped by heated plates, rollers, etc. that are engraved or etched with designs, patterns, logos, etc. Rexine, wall papers have such patterns. Plastic surfaces are machine or laser engraved to create patterns or texture. Amorphous plastics such as Acrylics and poly-carbonates are engraved. Acrylic plastics are finished with flame polishing. Extruded plastics are provided with Corona treatment, referred to as air plasma, to modify the surface qualities.

Polished Poly(methyl meth-acrylate)

Many plastics are sensitive to solvents so latex dispersion paints, NC clear and pigmented Lacquers, epoxies, etc. are applied. Plastics need to have electrically conductive surface which is imparted through plating and vacuum metallizing. It can be made to certain categories of plastics such as ABS, Polypropylene, Polyesters and some Nylons. Electroplating is done to achieve matt or glossy surfaces. Automobile accessories, tape, radio and TV trims have electroplating finish for providing metal like a look. Metals in very fine particulate size are deposited on plastics not only to provide metal like a look but also provide electrically a conductive surface. Vacuum metallizing involves spraying vaporised metal on a plastic article in a vacuum chamber (to prevent oxidation). Electrical parts, auto-spares, toys, artificial Jari threads, sun control films, etc. are, metallized in a variety of silvery, golden, copper or bronze effects using aluminium compounds. Gold, Silver Palladium, Platinum Coppers etc. are applied through a cathode (electrodes) sputtering. Metals are also spray deposited through suspensions.

Indian Space Satellite wrapped for Protection in Polyester Gold metallized foil 

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CORE COMPETENCE and ORGANIZATIONS

Post 115 -by Gautam Shah

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 A person individually can have expertise or keen interest in a specific field. The person, however joins an existing organization to contribute the specific know-how, or such individuals come together to explore it. All organizations intend to work intensively in areas that are analogous to their aims. Organization, however, cannot operate just by intent or facilities. Organization needs opportunities to build up the core competence.

 

Core competence leads an organization into specific jobs, by way of excelling in results, efficiency of work procedure or job handling, efficiencies of input-benefit ratio, and client satisfaction. The repetition of opportunities leads to learning, experimentation and satisfaction. Core competence is perceived as an innovative pursuit that can cause enough synergies, to make the organization behave like self correcting or continuously adjusting biological entities. 

Core competence is also seen as Generalization versus Specialization. Some organizers believe that generalization, as a capacity to handle all types of projects and under whatever circumstances, is very essential for continuance. And if the need arises experts can be hired to meet the exigency. The generalization allows them to handle projects of routine nature, in an efficient, economic and time bound manner. Projects that are very large in scale, requiring little innovation, and of repetitive nature are handled by such organizations. Their service or fee’s charges are very competitive. 

Specialization cannot be achieved by intent alone. One must grab projects that reinforce their skills, even by discounting the fees or profits. And, if opportunities in the desired field are few, one must strive for excellence in the smaller sections of the routine (or ‘bread-butter’ jobs). Specialization is equated with a single person in charge of organization, rather than group based practices. An Autocratic leader stimulates an organization towards an acute specialization, whereas a Bohemian leader dissipates the energy and de-focuses and strives for generalization. A Democratic leader will continuously review and revise, the aims of the organization, and plan the resources, to make the organization creative.

Creativity is not in specialization (capacity to excel in limited fields) nor in generalization (capacity to handle many different situations) in any field. Design creativity is seen in radical solution, proficiency in sustaining the technical superiority and learning. Design efficiency is perceived for being productive, cost efficacy and organizational ranking or super-ordination.

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HUMAN BEHAVIOUR in SPACE Course 2015

HUMAN BEHAVIOUR in SPACE 

Course for Faculty of Design CEPT University Ahmedabad India > Jan 2015 offered by Gautam Shah

Human behaviour is evident in responses related to: Body, Environment, Space and the Occupants.

BODY: The human behaviour is seen through body-limb movements or postures, gestures, and as overt expressions in modes like speaking, writings, painting, etc as in expression and communication. . Physiological components of behaviour show up in survival, health, well being and comfort, spatial occupation with dimensional accommodation and fitments of the human-body, task functionality. Human behaviour sensed through Cognition, Psychological factors, Sensorial perception, Response mechanisms.

ENVIRONMENT: Environmental responses are of becoming aware of a space. These permeate into a space depending on the spatial characteristics, such as the size, shape, sequencing, quality of barriers, etc.

SPACE: Space is the setting where environment and cognition actualize concurrently. Nature of cognition is one major factor that governs the Space experience. Environment is continually variable and so a space experience is ever expounding. Some environmental conditions and spatial features often occur in concert. And so we expect the presence of one to trigger the other.

OCCUPANTS: Occupants for cultural reasons or social norms show varied behaviour. It is also affected by factors like age, sex, level of adaptation, familiarity, limb capacity, body-limb coordination, sensorial abilities and reach extension tools, etc. Behaviour (even of lone beings) is substantially in the context of ‘awareness’ of other human beings (and not necessarily the physical presence). Forms of interpersonal relationships of various races and cultures are different. The space, environment and the occupants together foster a social-contact mechanism.

List of Topics forming the Semester Course

1 HUMAN BEHAVIOUR :           Space is the setting where environment and cognition actualize concurrently. Environment is continually variable and so a space experience is ever expounding. Space experience is one major factor that governs the nature of cognition. Our responses with other beings and social interactions regulate what we share and empathise. Responses with other occupants depend on the awareness about sex, age, stature, need, social position, degree of familiarity, distance and recognition (through cognition).

2 INHABITATION                       Possession and Occupation of a spatial entity are acts of inhabitation. These acts allow a person or a group of persons to establish a Role Locus (a stage or setting). A role locus is established by delineating a territory and then recognising it as a zone of effectuality. The territorial marking is a deliberate creation, whereas recognising the zone of effectuality could be both, conscious as well as subconscious action.

3 PLACE IDENTITY                   How an individual establishes a role locus is one of the most important aspect of sociological responses. Possession and occupation of a space immediately translates as to the degree of social reactivity. It regulates the nature of interaction with others, privacy, degree of accessibility or isolation, as reflected in aloofness, loneliness, alienation, participation, leadership, devotion, cohabitation, etc.

4 DOMAINS                                A domain is an ambit over which there is some form of control. The domain could be a physical territory or an abstract effectuality. The control could be through possession, occupation, ownership, or authority. In case of territory the controlled or dominated place is used as a space to proliferate and survive. The abstract effectuality is an idea of a space, exploited to sustain and proliferates the myth of a place.

5 DOMAINS AND SPACES        Domains have Three basic constituents Formatted Space, Environment and Individual/s. A domain, as a space, is a segmented entity. Its primary segments are Core and Peripheral zones. A core is usually single, but peripheral zones are many. The core and peripheral zones often converge. Different peripheral zones impinge over each other.

6 EXT AND INT SPACES           Very vast exterior spaces are recognised for the endless sensorial ‘effects’. Other exterior spaces are finite, shaped and sized by bounding elements. The bounding elements are natural, and exploited or improvised. Spaces for inhabitation require greater degree of intervention then improvisation, and so are designed. For each of this intervention the spatial definitions are different. Very vast exterior spaces are recognized through markings. Neighbourhood spaces are known through their bounding elements. Whereas spaces for inhabitation need an enclosure, often much more elaboration then anything nature can offer or can be improvised upon it, so are designed.

The enclosures of the interior spaces have varied levels of transparencies. The openings in the shell allow escapes at many places. The transgressions across the enclosure occur as outward push and inward pull of the interior space. The outward push or encroachments are often ‘costless’, though may ‘load’ the enclosure (shell) body. It increases the interior volume and permits a restrained exterior. The inward intrusions, however, consume interior space or estate and reduce the nett enclosed space.

7 SPACES SIZES - SHAPES     Size and Shape of a space are perceived in terms of their utility (functional adequacy), ergonomics requirements, past experiences and sensorial reach capacities. The size and shape together also define the nature of Core and Peripheral zones of a Space. For any space, shape and size are two major formative factors. The shape is an absolute function and can have many different configurations. The size is a large variant but is a relative function (to the human body). Within a space various forms have interrelationships of proportions, analogy, sequencing, proximity, etc.; all these are absolute functions.

8 BEHAVIOUR IN SPACES       The human behaviour results from many individual factors, such as the cognition system, metabolism, past experiences, etc. Perception of things and happenings results from cognitive capacities, and physiological needs which are further moulded by the inherited (intuitive) and learnt (intellectual) faculties. The inhabitants behave in response to the presence of other beings as well as the nature of communication (expression and its perception) being used.

9 MANIFESTATION OF BEHAVIOUR

For a space designer the study of behaviour in response to space is very useful because as it indicates how a person will respond to a given setting. Alternatively one can predict how an individual or group will behave in certain setting. The two-way exchange between the space and the person is so rapid that is not possible to separate cause and effects. Forms of Behaviour are > Shift in space, Change of orientation, Orientation of the body, Change of place, Anchoring to a place, Sequencing in space, Movements, Aids for posturing, Postures, Open body postures, Closed body postures, Eye level and focus, Inclination of body, Synchronous or empathetic behaviour, Designing for postures and relevant behaviour, Flexibility, Gestures.

10 EXPRESSION AND COMMUNICATION

Expressions used for communication are intentional, and which may not occur for any particular audience. Expressions for aesthetic satiation are always intentional. Expression for aesthetic satiation occur through representative forms like singing, writing, art, craft, etc. The intent here is communication of an abstract content, either for personal satisfaction or an audience.

11 PRIVACY AND INTIMACY    Behaviour in space is conditioned by two personal notions: Privacy and Intimacy. Privacy is a personal notion and is basically achieved by obscuring own self, or by isolating from people. One can obscure own self by merging with background or by becoming less perceptible. Isolation is achieved by barricading and distancing. A person or group achieves insulation through body posturing. By posturing one can adjust the exposure, control the communication, command the expression and re-calibrate the reach of the body as well as the sensorial perception. Privacy can help overcome many inhibitions through mental isolation. Psychological motivation helps one to ignore some of the side effects of lack of privacy.

12 TASK SETTINGS                  Tasks are identifiable units of work at home or at places like office, industry, etc. Tasks require specific setting. Task settings are the parameters required to perform a task. The parameters include space forms, environment, time management, amenities, facilities, structures, enrichments and social interactions. Tasks are attached to various entities like: space forms, environmental conditions, structures, amenities (these are attached to architectonic elements and are relocatable ), facilities (these are integrated architectural configurations and are mostly fixed, but sometimes demountable), and other enrichments (these do not have apparent functionality but add specific character or interest to the space). Some tasks happen where there are chances of intra-personal interactions. Tasks occur at places from where some degree of command can be enforced over a larger domain.

13 AMENITIES AND FACILITIES

The habitable space with Amenities and Facilities allows various tasks, but to endow a personal value, a sense of belonging a space requires enrichments.

14 SPACE PLANNING               Spaces need validation from time to time and on occasions. The validation by a user is continuous one, but as handled by a professional it is a contractual and periodical assignment. The change in space by a user, a lay person, relates to the rearrangements of the demountable and movable entities. However, a contractual assignment to a professional is far more encompassing, and may even reconfigure the space shell. Domestic space planning is self authored where as commercial spaces are rejuvenated by professionals.

15 REAL AND VIRTUALLY REAL

Habitable spaces are substantially real and physical, but could also have features that transcend the reality. Such conditions occur because the human cognition sometimes functions ambiguously. The subconscious human behaviour expresses itself free from the rationality, restrictive customs and structural limitations.

The ambiguities in cognitive processes arise as the Time and Space gets mixed up to produce incoherent and surprising effects. The elements nominally distanced in time or space are ‘virtually’ juxtaposed in a make-believe world.

Time is seen as a measure of change, and Space is perceived for its consistency (or even lack of it) over a time. The percepts in time and space like the primitive man, watching a star and noting its almost intangible movement in sky, or watching own-self becoming old, must be comprehended only in mind. To note the difference, two such distinct frames must be juxtaposed. This was done through expression (of behaviour) for wider confirmation. When the dream and reality transcend there is sense of ‘Avidya’ (lack of knowledge), a Maya as the cause of illusion.