Injection Moulding in detail

Injection Moulding in detail

Injection Moulding

It makes use of heat softening characteristics of thermoplastic materials. These materials soften when heated and reharden when cooled. No chemical change takes place within the material is heated or cooled, the change is entirely physical. For this reason in Injection Moulding, the softening, and rehardening cycle be repeated many number of times.

The granular material is loaded into a hopper from where it is metered out in a heating cylinder by a feeding device. The exact amount of material is delivered to a cylinder which is required to fill the mould completely. The injection ram pushes the material into the heating cylinder and in doing so pushes a small amount of heated material out of the other end of the cylinder through the nozzle and screw bushing and into the cavities of the closed mould.

Injection Moulding diagram

The material is cooled to a rigid state in the mould. The mould is then opened and the piece is ejected out. The temperature to which the material is raised in the heating cylinder is usually between 180-280°C. The higher the temperature the lower the viscosity and more readily it can be pushed into the die. Every type of material has a characteristic moulding temperature, the softer formulations require lower temperature, and the harder formulations require a higher temperature. Intricate pieces, large pieces, several cavities in the die and long runners all tend to increase the temperature requirements.

When the plastic material is pushed from nozzle end of the cylinder, it enter through channels into the closed mould. In the majority of cases, the mould is kept cold, in order to cool the moulded articles ready to the point at which the mould can be opened and pieces ejected without distortion. This is done by circulating water through the mould frame. Sometimes it is necessary to use a warm mould, and mould temperature as high as 150°C is used for very special jobs. However, material sets faster in a cold die and the cycles are shorter. The cooling of plastics under pressure is desirable to avoid “shrink” marks on the surface. Automatic devices are commercially available to maintain mould temperature at the required level. For more related details on Mechanical engineering than click on it.

Electro forming process in detail

Electro forming

Electro forming is a process of producing precision metal parts, that is usually thin in section, by electro-deposition on to a form (variously called mandrel mold, matrices, or die), which is shaped exactly to the interior form of the product and which is subsequently removed. In the process, a slab or plate of the material of the product is immersed into the electrolyte (an aqueous solution of a salt of the same metal) and is connected to the positive terminal of a low voltage, high current d.c. power. So, it becomes an anode.

A correctly prepared master mandrel or pattern of correct shape and size is immersed at some distance from the anode and is connected to the negative terminal (cathode). The mandrels are made from a variety of materials, both metallic or non – metallic. If the material is non-conducting, a conductive coating must first be applied in order to perform electroplating. The mandrel should possess a mirror-like finish.

When the circuit is closed, metal ions are removed from the anode, transported through the electrolyte towards the cathode (master), and deposited there. After the deposition, the master is removed or destroyed. A metal shell is left, which conforms exactly to the contours of the master. It may take hours or days to get a deposit of sufficient thickness. The thickness of electro – forms ranges from 0 25 to 25 mm. The process is very much similar to electroplating, with the difference that whereas in electroplating, the deposit stays in place (on the cathode), in electroforming, it is stripped from the form. The electro-formed products are typically made from Nickel, Iron, Copper, or Silver, and more recently from copper-tin, nickel – cobalt and nickel – manganese alloys.

Advantages:

  1. Low plant cost, cheap tooling, and the absence of heavy equipment.
  2. Low labor operating costs.
  3. The process can be designed to operate continuously throughout day and night.
  4. Electrodeposition can produce good dense deposits, and compared with castings electroforming offers high purity, freedom from porosity with a homogeneous structure. These important qualities are seldom obtained to such a degree in machined parts, stampings, or forgings.
  5. There is no restriction on the internal complexity of electro- forms, and this advantage eliminates in many instances, the costly joining processes.
  6. The process has no equal for the reproduction of fine or complex details.
  7. The use of inserts has widened the application of the process. Metal inserts are attached to or are embedded in wax or fusible alloy master, and, when the master is melted, the inserts remain attached to the electroformed.
  8. A high-quality surface finish is obtained on both the internal and external surfaces of the electro-forms. Accuracies as close as 0.005 min with surface finishes up to 0.125 p.m can be produced.
  9. Complex thin-walled parts can be produced with improved electrical properties.
  10. Shell-like parts can be produced quickly and economically.

Applications :

There is a wide range of applications of electroforming process:

  1. Molds and dies feature high on the list. Molds for the production of artificial teeth, rubber and glass products, and high -strength thermosetting plastics are now commonplace. The molds can be made with undulating parting lines which have made a considerable impact upon the production of thermoplastic toys and novelties.
  2. Radar and electronic industry Radar waveguides, probes, complicated grids, screens, and meshes can be produced much more easily, to find accuracies and at a lesser cost.
  3. Spline, thread, and other types of form gauges.
  4. Cathodes for ECM arid electrodes for. EDM.
  5. Electro-formed core boxes with inbuilt heating elements. Electro-formed molds for the wax patterns.
  6. Electro-formed precision tubing, parallel and tapered, formed to different shapes to eliminate the need for bending which distorts the bore.
  7. Electrotypes floats, bellows, venturi tubes, fountain pen caps, reflectors, heat exchanger parts, honeycomb sandwich, parts for gas appliances and musical instruments, radio parts, spraying masks and stencils, seamless screen cylinders for textile printing, filters and dies for stamping of high-fidelity records.

Electro-forming is particularly useful for:

  • High-cost metals.
  • Low production quantities
  • Quantity of identical parts, for example, a multi- impression mold.
  • The possibility of using a single master for the production of a number of electro forms.
  • Whereas intricate female impression is required, so that is would be much easier to produce a male form, that is, the master.

For more related topics click on it Mechanical engineering

Acute Myeloid Leukemia (AML)

Acute Myeloid Leukemia

It’s a type of Blood Cancer that starts in the bone marrow the soft inner parts of the bone. Though it can happen in other blood-forming cells as well it primarily happens in blood cells that may turn into white cells. Acute Myeloid Leukemia bone marrow cells don’t grow the desired way but it starts generating immature cells that are called blasts.

If proper treatment not given Acute Myeloid Leukemia can spread to blood and other parts of your body, such as your:

  • Lymph Nodes
  • Liver
  • Spleen
  • Brain and Spinal cord
  • Testicles

Your recovery can be better in case of following conditions-

  • Your age is less than 60.
  • At the time of diagnosis, your white blood cell count is lower.
  • You have not had past history of blood disorder or Cancer.
  • You don’t have a certain gene or chromosome changes.

There is no clear reason why AML happens to a person.There are some risk factors that may lead a person to this disease like-

  • Smoking
  • Exposure to certain chemicals such as benzene which is used in oil refineries, ionizing radiation, pesticides, and detergents.
  • Some blood condition such as Myeloproliferative disorder
  • Some Chemotherapy drugs used to treat cancer such as melphalan, mitoxantrone, and doxorubicin.
  • Exposure to high degree of radiation

As there is no clear reason its prevention is difficult but smoking and exposure to chemicals explained above can be avoided to lower risk.

Symptoms

  • Fever
  • Fatigue
  • Loss of Appetite
  • Headache
  • Usual bleeding
  • Swollen lever or spleen
  • Swollen gums

Acute Myeloid Leukemia Treatment

Since AML spreads faster, it’s important to begin treatment as early as possible. It depends on several things like how much it has spread and your overall health. Treatment can be in two phases- Remission induction therapy-This involves the killing of leukemic cells in your blood and bone marrow so you go into remission with no sign of diseased cells. Further in post-remission therapy remaining infected cells killed if there is any to avoid chances of disease coming back. The main treatment methods are like Chemotherapy, Radiation, and Stem cell transplant. For more related topic click on it Acute Lymphoblastic Leukemia

Acute Lymphoblastic Leukemia

It’s a type of cancer of blood and Bone marrow which affects white blood cells, it occurs when bone marrow develops error in its DNA.The word acute in the name of this disease occurs from the fact that it grows rapidly and creates immature blood cells rather that mature ones.The word lymphoblastic refers to white blood cells called lymphocytes. This disease is also known at Acute Lymhoblastic Leukemia.

This disease is the most common type of cancer which happens in children and after treatment, there is a high chance of recovery but in adults chances of getting cured are relatively weak.

Symptoms:

  • Bleeding from the gums
  • Bone pain
  • Fever
  • Pale skin
  • Shortness of breath
  • Fatigue of general decrease in Energy

Many signs of symptoms mentioned above are of flu but if symptoms doesn’s improve then one should decide about doctor consultation.

Causes: It Occurs when bone marrow cells develop error in its DNA, as a result of which cells continue growing and dividing. While a normal cell would stop dividing and ultimately die, the disease cell will lead to the abnormal production of immature cells that would not function properly and crowd out healthy cells. These immature cells that develop in the leukemic white cells are called lymphoblasts. This is not clear how faulty DNA mutations happen but doctors have found that most cases of Acute Lymphoblastic Leukemia are not inherited.

Risk Factors: Factors that may increase risk of this disease may include:

Previous cancer treatment:if there have been Chemotherapy or radiation therapy for other types of cancer then there is high risk of developing this disease.

Exposure to Radiation: People who are exposed to high degree radiation such as survivors of nuclear accidents may have a high risk of developing Acute Lymphoblastic Leukemia.

Genetic Disorder: Certain genetic disorders such as down syndrome is associated with an increased risk of this disease.

Polymerization

Polymerization:

The process of linking together of monomers, that is, of obtaining macromolecules is called “‘polymerization”. It can be achieved by one of the two processing techniques. (a) Addition Polymerization: In addition or chain polymerization under suitable conditions of temperature and pressure and in the presence of a catalyst called an initiator, the polymer is produced by adding a second monomer to the first, then a third monomer to this dimer, and a fourth to the trimer, and so on until the long polymer chain is terminated. Polyethylene is produced by the addition polymerization of ethylene monomers. This linear polymer can also be converted to a branched polymer by removing a side group and replacing it with a chain. If many such branches are formed, a network structure results.

“Co-polymerization” is the addition polymerization of two or more different monomers Many monomers will not polymerize with themselves. but will copolymerize with other compounds

(b) Condensation Polymerizations:

In this process, two or more reacting compounds may be involved and there is a repetitive elimination of smaller molecules, to form a by-product. For example, in the case of phenol-formaldehyde (bakelite), the compounds are formaldehyde and phenol. Meta cresol acts as a catalyst and the by-product is water. The structure of the ‘Mer’ is more complex. Also, there is a growth perpendicular to the direction of the chain. This is called cross-linking’.

Size of a Polymer:

The polymer chemist can control the average length of the molecules by terminating the reaction. Thus, the molecular weight (the weight of the average molecule, in grams, of 6.02x molecules) or degree of polymerization, D.P., (the number of members in the average molecule) can be controlled. For example, the length of molecules may range from some 700 repeat units In low-density polyethylene to 1,70,000 repeat units in ultrahigh-molecular-weight polyethylene.

Thermosetting plastics:

These plastics undergo a number of chemical changes on heating and cure to infusible and practically insoluble articles. The chemical change is not reversible Thermosetting plastics do not soften on reheating and can not be reworked. They rather become harder due to the completion of any left-over polymerization reaction. Eventually, at high temperatures, the useful properties of the plastics get destroyed. This is called degradation. The commonest thermosetting plastics are alkyds, epoxies, melamines, polyesters, phenolics, and ureas. for a more related topic click on it Mechanical engineering.

Types of Composite Materials

Composite Materials:

These have superior mechanical properties and yet are lightweight. The reinforcing fibers are usually glass, graphite, boron, etc. Epoxies and polyester commonly serve as a matrix material. Reinforced plastics are being developed rapidly. New developments concern metal-matrix and ceramic-matrix composites and honeycomb structure (Honeycomb structure consists of a core of honeycomb or other corrugated shapes bonded to two thin outer skins. Ceramic-matrix cutting tools are being developed, made of silicon carbide reinforced alumina, with greatly improved tool life. A composite material, as stated above, contains more than one component. The compound materials are incorporated into the composite to take advantage of their attributes, thus obtaining improved material. They become cohesive structures made by physically combining two or more compatible materials. Fiber-reinforced composites are heterogeneous materials prepared by associating and bonding in a single structure of materials possessing different properties. Due to complementary nature, the composite material possesses additional and superior properties. These thus become ideal materials for structural applications requiring high strength-to-weight and stiffness-to-weight ratios. Fiber-reinforced materials exhibit anisotropic properties. Glass fibers are strong but if notched they fracture readily. By encapsulating them in a polyester resin matrix, they can be from damage. Fibers of graphite and boron are also used in composites. Commonly used fibers for composite materials are-glass, silica, and boron for amorphous structure, ceramic and metallic for single crystals as well as polycrystals, carbon, and boron (amorphous) materials for multiphase structure, and organic material for macromolecular structure. For two-dimensional structural applications such as in plates, walls, shells, cylinders, pipes, etc. a planar reinforcement is much more advantageous as compared to the linear reinforcement.

Duplex Composite Components:

Components subjected to severe wear and high contact stresses can be made of duplex composite, the composite layer is located on the outer or inner. Surface depending on the requirement. Aluminum composite alloys reinforced by ceramic have been developed and these have a relatively high strength to weight ratio, high modulus of elasticity, and good wear characteristics.

Silicon carbide particles are incorporated into the surface of aluminum alloy heated to its mushy state and pressure is applied to get a good wetting between the aluminum alloy and the silicon carbide particles. Experiments can be carried out to determine the semi-solid forming conditions. Specimens surrounded by SiC particles are heated up to this temperature for about 45 minutes in order to homogenize the temperature through the specimen. A hydraulic press is used to apply the necessary low pressure for the semi-solid forming process. There is an optimum combination of temperature and pressure values to obtain optimum mechanical properties. In this way, a composite layer of about 2.5 mm width can be formed with uniformly distributed particles having a good bond with the aluminum matrix, with no separation or porosity at the composite layer/matrix interface.
The surface composite layer has the hardness and wears resistance about 1.75 and 10 times those of as-received aluminum matrix alloy.
for more related topic to Mechanical engineering click on it.

Types of Surface Coatings for Tooling

Surface Coatings for Tooling

In almost every type of production tooling, the most desirable feature to have is a very hard surface layer on a low strength but the tough body. Toughness is needed to survive mechanical shocks, that is, impact loading in interrupted cuts. Shocks occur in even continuous chip formation processes when the tool encounters a localized hard spot. The examples of such tooling include metal cutting tools, rock drill, cutting blades, forging
screws for extrusion of plastic and food products and sawmills and so on. Other applications, including parts for earth moving machinery, valves and valve seats for diesel engines, and many such parts involving high heat applications and in general, applications requiring wear resistance. Surface Coatings for Tooling

The various techniques employed for this purpose are discussed below:

1. Hard Facing This is a welding technique and has already been discussed in Chapter on “Welding Process”, under Art.
2. Nitriding Case Hardening : Discussed in Chapter.
3. Hard Chrome Plating : Hard chrome plating is done by the Electrolytic electroplating technique (See Art.). It is the most common process for wear resistance.
4. Flame Plating Flame plating is a process developed to prolong the life of certain types of cutting tools and for severe wear applications. By this process, a carefully controlled coating of tungsten carbide, chromium carbide (Cr, C2) or aluminum oxide is applied to a wide range of base metals. The more common materials which have been successfully flame – plated include aluminum, brass, bronze. Cast iron, ceramics, copper. glass, H.S.S., magnesium, molybdenum, nickle, steel and titanium and their alloys.
The process uses a specially designed gun into which is admitted metered amounts of oxygen and acetylene. A change, of fine particles of the selected plating mixtures, is injected into the mixture of oxygen and acetylene. Immediately after this, a valve opens to admit a stream of nitrogen to protect the valves during the subsequent detonation. The mixture is now ignited and an explosion takes place which plasticizes the particles and hurls them from the gun barrel at 750 m/s. The particles get embedded in the surface of the component and a microscopic welding action takes place, which produces a highly tenacious bond.

Each particle in the coating is elongated and flattened into a thin disc. The coating has a dense, fine – grain laminar structure with negligible porosity and an absence of voids or visible oxide layers. The layer of the plated material is about 0.006 mm, and this layer can be built up, by repeating the explosions, to thicknesses ranging from 0.05 to 0.75 mm, according to the requirements of any subsequent operations. The resultant coating is dense, hard and well bonded. Because of the hard dense structure of the coatings, flame – plating has provided the industry with a valuable tool for the solving of many abrasion, erosion and wear problems. For example, bushes for many applications, core pins for powder metallurgy, dies, gauges, journals, mandrels, and seals for high – duty pumps, have all been given much longer lives.

The process has influenced considerably certain types of cutting processes, especially in the glass, leather, paper, rubber, soap and textile industries and has proved to be of great advantage for components involving high heat applications such as “hot-end” of gas turbines. The coatings show an excellent resistance to galling and corrosion. Flame-plated coatings can be ground and lapped, if necessary. Resultant surface finish can be within the region of 0.025 Another advantage is that the components can be masked to enable the coatings to be placed precisely where required. The mixture of tungsten carbide coating material consists of cobalt ranging from 7 to l7% and the balance of tungsten carbide. Aluminum oxide plating mixture is almost of A103 (Above 99%). Chromium carbide plating mixture consists of about 75 to 85% of Cr3C, and balance of (Ni-Cr). for more related topics on mechanical engineering topics.

Covid Crisis Delhi

Despite all efforts Capital city of the country stands at 2nd position just after Maharashtra in terms of total number of active cases and the way Chief Minister Mr Kejriwal was boasting of perfect arrangements to fight with it proved hollow and now the state machinery is struggling to bring the situation in control. So much so that arch political rival and Union home minister Mr Amit Shah had to intervene . Mr Amit Shah did a series of Meetings with Chief Minister and Bureaucrats to ensure availability of beds and increase in testing capacity. Around 500 Isolation coach has been provided to increase bed availability as 80000 beds will be required by end of Covid Crisis Delhi July.

The government had also considered recommendations by Dr V K Paul committee to cap testing and bed charges plus prices for PPE and ICU as there were complains of exorbitant charging by few private players.Now testing charges fixed at Rs2400 which private hospitals are not finding comfortable with.Some private hospital owners said that after this capping there will be less testing because it doesn’t cover the cost.Until now the cost was Rs 4500 if Private hospitals take sample and uses their kit,Rs3500 if Government collected the sample and Private labs used their kits to test and Rs 2200 if the government collected the sample and used their kits.Government has also started rapid antigen testing which will surely help people get tested.

Amit Shah also said that there will be house to house survey of covid cases in present 241 containment zones across the city and aggressive contact tracing in equal no of buffer zones across the hotspots.Six senior IAS officers also deputed from center to look after management of resources.Also a panel has been set up to allocate 60% private hospital beds at low rate.To bring all political parties on  one page against covid fight he had also convened an all party meeting. more related covid 19 click on it. Covid Crisis Delhi

Techno-economic analysis

Techno-economic analysis is mainly concerned with the identification of project demand potential and the selection of the optimal technology suitable for achieving the project objectives. This analysis provides necessary information on which the project design can be based. It also indicates whether the economy is in a position to absorb the output of the project.


The size of the project and the technology used depend very much on the demand potential. Technology in a broader sense includes methodology or process. where the technical operations are not included. An optimal size and technology
enable to achieve the economies of scale. The techno-economic analysis makes an analysis of the market and technology.
Therefore an techho-economic feasibility of project has to be conducted before preparing a feasibility report of the project.
(a) Determination of project demand potential: Estimation of demand potential is the starting point of techno-economic analysis. Demand forecasting helps to firm up the qualitative parameters of the project and also provides a basis for selecting the optimal strategy for the project. It involves the determination of market characteristics, quantitative market analysis and appraisal of project demand
potential. The quantitative market analysis is made to estimate the industry demand of goods and service which a project may be expected to produce and to produce necessary information for developing project demand forecasts.

The analysis is taken up in three stages:

(i) Situation analysis
(i) Data collection and Compilation
(ii) Interpretation and Presentation
Then the data is used for projection of future demand.
Technical feasibility is carried out to find out the following information:
(a) Demand forecasting firstly helps to identify the qualitative parameters e.g. whether they are consumer goods or capital goods? What is the market competition?
(b) Market analysis, give the quantitative estimations. It involves the analysis of situation& alternatives; then the data collection & finally the interpretation of facts collected.
(c) Availability of needed materials & supplier; it analysis whether the materials & suppliers are available & where?

  • If delivery is at competitive /reasonable rates?
  • Do we need to import material?
  • What will be the lead time delay time delay? (Required for inventory to be maintained so that to keep production running fill the next delivery comes)- Are there any legal controls? (e.g. fire hazards for crackers, etc.)

(d) Personal required, to know whether skilled or unskilled labor is available at the site itself or we have to import/ hire from outside. The training requirement should also be considered (the cost of training, material wastage in training, etc).
(e) Infrastructure & facilities, like transportation (both for material & labor); storage go downs for inventory; power/fuel/water, sewage or even waste disposal and communication facilities should be adequate enough.
(b) Selection of optimal project strategy: Optimal project strategy refers to that combination of controlled variables which will ensure the achievement of the project objectives with the minimum expenditure of resources. As an infinite number of project strategies is available, selection of optimal strategy may appear to be difficult. This economical or optimal strategy is used to calculate how the minimum resources can be spent so as to achieve the objectives of projects in best ways. The optimal strategy may be selected by comparing the representative strategies and identifying the optimal a representative strategy which meets the project ends in the hand.

Various factors contributing to economic factors for deciding an optimal strategy are as follows:
(i) The market demand,
(i) Costing,
(iii) Raw Materials,
(iv) If the market is stable for,
(v) Capital requirement, to be checked for,
Whether entrepreneur can remain invested for long?

For related topics to mis (management information system click on it)

Evaluation of MIS Management Information Systems

Evaluation of MIS is an integral part of the management control process, in which the organization determines or appraises the quality or worth of their information system. Evaluation of MIS is a process of measuring the performance of organizational information system. The feedback so obtained help in determining the necessary adjustment to be made in their information system.

Evaluation approaches in Evaluation of MIS:

These are different approaches to evaluate MIS in an organization. The MIS evaluation approaches provide the different means to measure a accomplishment of system objectives. The scope of each evaluation is as follows:
(i) Quality assurance review: Quality assurance reviews or technical reviews focus on assessing the information system technical quality e.g., comparison of standards and operations acceptance procedures. The technical evaluation includes variables like data transmission rate, CPU capacity etc.
(ii) Compliance audit: Compliance audit or application control reviews assess the adequency and completeness of control of system inputs, outputs, processing seanity and access. Compliance audit are typically performed by an autonomous internal audit function.

2. Preparation of tender specifications in Evaluation of MIS:

After studying the feasibility and deciding upon the configuration, tender documents are prepared for the benefit of vendors to clarify the details of various specifications as listed below:

(i) Purchase procedure and schedule: it includes:
(a) Date of tender submission
(b) Evaluation criteria
(c) Scope for negotiations, if any and
(d) Expected usage environment and load pattern

(ii) Equipment specification:

Detailed technical specifications of each item required for both mandatory and optional items.

(iii) Quotation format:

(a) Format for stating technical details and quoting prices.
(b) Whether deviations from specifications should be specifically listed.
(c) Prices and levies (duties, taxes etc.) could be quoted as the lump sum or required separately.
(d) Required validity of the quotation.
(e) Earnest money deposit required, if any.

(iv) Proposed terms of the contract:

(a) Expected delivery schedule
(b) Uptime warranties required
(c) Penalty clause, if any
(d) Payment terms (Whether advance payment acceptable)
(e) Arbitrary clauses
(f) Training needs
(g) Post warranty maintenance terms expected

(v) Any additional information required.

3. Inviting tenders:

After the preparation of tender specifications, tenders are invited. Invitation of tenders may depend upon the magnitude of purchase (estimate equipment cost). It may be through
(i) Open tender (through newspaper advertisement)
(ii) Limited tender (queries sent to a few selected vendors)
(ii) Propriety purchase (applies mostly to upgrade requirements)
(iv) Direct purchase from market (applies mostly to consumables)

4. Technical scrutiny and short listing:

This step involves the following activities.
(i) All tendered bids are opened on a per-defined date and time.
(ii) Deviations from the specifications, if any, in each bid are noted. (iii) A comparative summary is prepared against the list of tendered technical features. Additional factors to considered are:

(i) Financial health of the vendor (from balance sheets)
(ii) Nature and extent of support (from information provided on number of support staff per installed site an cross-check with selected customers)
(iii) Engineering quality of products (factory inspection of product facilities, QA procedures and R and D)

5. Detailed evaluation of shortlisted vendors:

This step primarily involves getting any finer technical clarifications. Visits to customer sites and factory inspections may be planned. If any specific performance requirement is stipulated, the offered product is to be examined at this stage through suitable benchmark tests. For benchmark tests, standard benchmarks may be used as adequate performance indicators.

6. Negotiation and procurement decision:

Because of the extensive competition, computer system vendors may offer significant concessions. Negotiations are held to maximize these concessions. However, price negotiations are often not permitted by some organizations. When price negotiations are permitted, the committee members should have a good knowledge of the prevailing market prices, current trends, and also the duty/ tax structure.

(i) Computer magazines
(ii) Vendor directories
(iii) Contact with other users
(iv) Past personal experience

7. Delivery and installation:

In this step, the vendor delivers the hardware/software to the buyers organization, where it is matched with the specifications mentioned in the purchase order. If conforms to these specifications, the vendor installs the system in the premises of the organization.

8. Post-installation review:

After the system is installed, a system evaluation is made to determine how closely the new system conforms to the plan. A post installation review, in which system specifications and user requirements are audited, is made. The feedback obtained in this step helps in taking corrective decision.

More related topic on click on it MIS development.