Posted tagged ‘temperature’

INFRARED CURVING

August 23, 2011

01-infrared curing process-infrared spectrum wave-conduction, convection, radiation

The coatings and paint industries strive to provide high technology coatings while reducing volatile organic compounds and energy consumption to produce a finished coating. Conventionally Convection ovens are used to cure the coatings. But this process which uses electric heaters is not an optimal process and is associated with various disadvantages.

01-coating surface absorption-infrared energy -infrared curing

Improved technologies are available today, which can either replace or improve the convection curing process. Infrared Curing is such a technology which uses Infrared rays emitted by an Infrared emitter to provide the required cure. Infrared curing applies light energy to the part surface by direct transmission from an emitter. Some of the energy emitted will be reflected off the surface, some is absorbed into the polymer and some is transmitted into the substrate.

01-reduced cycle times on final cure-eliminating manual rack up time

This direct transfer of energy creates an immediate reaction in the polymer and cross linking begins quickly once the surface is exposed to the emitter. Infrared emitters are often custom manufactured to suit the production demand. The various aspects of Infrared curing and convection curing and the possibility of combining these two technologies into a singe system will be discussed in this seminar.

01-infrared wave-infrared heating-infrared emitter-infrared curing

How it Works

Infrared heating is a direct form of heating. The source of the heat (the infrared emitter or lamp) radiates: energy that is absorbed by the product directly from the emitter. That is, the heat energy is not transferred through an intermediate medium. This is one reason for  the  inherent high-energy efficiency of infrared systems. For  example, hot air heating  first needs to heat air; the air then heats the product by convection.

01-infrared emitter-infrared curing systems

Infrared  energy is directed  to  the  product. When  the  product absorbs this energy, it is then converted into heat. Infrared energy is dispersed from the source in much the same  way as visible light. Exposed product surfaces easily absorb  the  infrared  energy and  become  heated. Therefore, heating effectiveness is related to line-of-sight between the source and the product. Depending on the coating and/or product substrate material, this heat is further thermally conducted.


01-table-characteristics of commercially used infrared heat sources

The ability of the product to absorb energy is also known as its “emissivity”. A theoretical body that absorbs all energy is termed a “black body”. A black body has an emissivity of 1. A highly reflective body would have a low emissivity value, approaching 0. (Reflectivity is the inverse of emissivity).

The potential of a product to become heated with infrared is related to the following:
• Watt density (total output power) of the source
• Wavelength (temperature) of the source
• Distance from the source to the product
• Reflective characteristics of the oven cavity
• Air movement and temperature in the oven
• Time product is exposed to the source
• Ratio of exposed surface area to the mass of the product
• Specific heat of the product
• Emissivity of the product
• Thermal conductivity of the product

CURING

Curing is a process of baking surface coatings so as to dry them up quickly. Curing is a broad term which means all the techniques employed for the finishing operations incurred during part production. Curing essentially involves either the melting of the coating or evaporation of volatile fluids present in the coating by the application of heat energy.

Curing is given to a wide range of materials both organic and inorganic. Usually curing is given to materials like ,

” Paints
” Enamel
” Liquor
” Powder coatings
” Varnishes
” Epoxy coatings
” Acrylic coatings
” Primers Etc.

Curing is also given to Rubber and Latex .The principle used for curing can also be used for drying rice and grains.

01-infrared technology-infrared-convection systems-tunnel system

CONVECTION CURING

Convection ovens are usually used for curing purposes. Traditional convection ovens use heated forced air to provide the necessary cure. Convection ovens consist of a chamber lined on the inside with Electric heaters. The shape of the chamber will be in accordance to the shape or geometry of the part being cured. A series of blowers circulate the heated air around providing the required cure. This process depends on convection to transfer heat from hot air to body surface and conduction to transfer heat to the interior of the surface. The air being delivered is held at temperature using closed-loop control, which provides predictable, repeatable results. Typically a temperature of around 250-500 degree Fahrenheit is required for paint or powder. Though convection ovens are widely used today they have certain disadvantages, which chokes the overall productivity of a company
Disadvantages of convection ovens :

” Fairly long heating times:-

Convection is a slow process. It takes a considerable amount of time for the heaters to heat up and raise the temperature of air to the required level. This causes a lag in the process and hence the curing time increases. Longer curing time spells reduced assembly line movement. This in turn reduces productivity.

” High energy consumption:-

A convection column dryer uses around 2000 BTU(British Thermal Unit) of energy to remove 1 pound of moisture. They use around 7.7 KW of electrical energy to dry a ton of rice. These are significantly larger figures for any company trying to bring energy consumption under control. The additional use of blowers and compressors further increases energy consumption.

” Large floor area required:-

Convection ovens are bulky in nature. Due to the presence of compressors and blowers, additional space is needed, which in turn increases the floor area requirement.

” Air circulation is required:-

Convection heating requires a medium for transmission of heat. Hence blowers are employed for good circulation of heated air. This increases the overall cost of the equipment.

CASTING

August 23, 2011

Methods are:

    1. Pressing
    2. Centrifugal Casting
    3. Slip Casting
    4. Extruding
    5. Gravity Casting
    6. Rolling
    7. Iso-static Moulding
    8. Explosive Compacting
    9. Fibre Metal processes

Pressing:

The function principles of the mechanic press machines differ in how to ensure the upper punch main movement by cams, spindles and friction drives, eccentric, knuckle-joints or by the round table principle, independent if the die or lower punch movement is realized by cams  or eccentric systems or other mechanically or hydraulically combined systems. The executions of auxiliary movements are also not decisive for a term-classification. These auxiliary movements can also base on pneumatic and hydraulic principles. In comparison to hydraulic press machines the maximum compaction forces of mechanical powder presses are limited and are placed in the range </= 5000 kN. For the requirements of wet and dry pressing techniques in the field of Technical Ceramics cams, eccentric, knuckle joint as well as round table presses have proved and tested, whereas cam presses especially used for wet-press-techniques of pourable materials. The range of compaction force of mechanical presses for products of the Technical Ceramics is < 2500 kN, what is caused from the less density of the ceramic materials. Normally the upper punch, lower punch and die systems of mechanical presses don’t work on base of multi subdivided punches.

01-powder pressing-metallurgy

Centrifugal Casting:

It employed for compacting heavy metal powders such as Tungsten Carbide. The powder is twirled in a mould and packed uniformly with pressures up to 3 MPa. The uniform density is obtained as a result of centrifugal force, acting on each particle of powder.

06-centrifugal-casting-process

05-centrifugal-casting-mold-metal-parts

Slip Casting:


Green compact of metal powder may be obtained by slip casting. The slurry, consisting of metal powder is poured in to porous mould. the free liquid in a slurry is absorbed by the mould tearing the solid layer of material on the surface of mould. The mould may be vibrated to increase the density of component. The Components are dried and sintered to provide sufficient strength.

07-slip casting-process-powder metallurgy

Extruding:

It employed to produce the components with high density and excellent mechanical properties.

Both hot and cold extrusion processes are used for compacting special materials. In cold extrusion the powder is mixed with binder and the mixture is often compressed into billet before being extruded. The binder must be removed before or during sintering. In hot extrusion the powder is compacted in to billet and is then heated to extruding temperature in non oxidizing atmosphere.

04-extrusion-direct-indirect-rod-pipe-process

Gravity Casting:

It used for making sheets having controlled porosity, the powder is poured on a ceramic tray to form a uniform layer and then sintered up to 48 hrs in Ammonia Gas at high temperature. The sheets are then rolled to desired thickness and to obtain a better surface finish. Porous sheets of stainless steel, made by this process are used for filters.

09-gravity-casting-metal-mould

10-indirect-gravity-casting-metal-mould

Rolling:

It employed for making continuous strips and rods having controlled porosity with uniform mechanical properties. In this method the metal powder is feed in to two rolls, which compress and interlock the powder particles to form a sheet of sufficient strength. It is then sintered, re-rolled and heat treated if necessary. Metal powders which can be compacted in to strips include Copper, Brass, Bronze, Nickel, Monel and Stainless Steel.

08-cold-rolling-process-plate-sheet-foil

Iso Static Moulding:

It used to obtain the products having uniform density and uniform strength in all directions. metal powder is placed in elastic mould (Deformable Mould) which is subjected to Gas pressure (65 to 650 MPa). After pressing the compact is removed.

02-cold-iso-static-pressing-compacting

Explosive Compacting:

It employed for pressing hard particles. The metal powder are placed in water proof bags which are immersed in water. It contained in a cylinder having wall thickness. Due to sudden deformation of change at the end of cylinder the pressure in the cylinder increases. The pressure used to press the metal powders to form green compact.

11-explosive-moulding-compacting

Fibre Metal Processes:

In this process, the metal fibers (Fine wires of Convenient length) are mixed with a liquid slurry and poured over a porous bottom. The liquid is drawed off leaving the green mat of fibre. The mat in which the fibers are randomly distributed is pressed and sintered. The products are mainly used for Filters, Battery Plates and Damping’s.

 12-fibre-metal-processes

HYDRATION SYSTEM

August 23, 2011

04-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

Is it possible to drink too much water during ride without stop the vehicle?

Adequate hydration is as important as calorie replacement to an athlete’s performance, yet dehydration continues to be a condition many experience. This is especially true in cycling where evaporative losses are significant and can go unnoticed. Sweat production and losses through breathing can exceed 2 quarts per hour. To maximize your performance pre-hydration is important, and it is essential that fluid replacement begin early and continue throughout a ride.

Approximately 75% of the energy your body produces is converted to heat rather than being delivered to your muscles to power your pedal stroke. Keeping your body cool and re-hydrated during exertion will result in greater efficiency, higher power output, extended endurance, and a quicker, more thorough recovery. Say good-bye to the Wet Spot!


Individual fluid and electrolyte needs are widely variable during physical exercise due to differences in metabolic rate, body mass and size, environmental conditions (e.g. temperature, humidity, wind, solar load, clothing worn), heat acclimatization status, physical fitness, activity duration, and genetic variability. Sweat rates can vary from 0.5L/hr to more than 3 L/hr. Similarly, sodium concentration may vary from less than 460 mg/L to more than 1840 mg/L

03-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

Technology:

Why use a perfectly good water bottle on your bike when you could use a complex, expensive and awkward to use “hydration system” instead? That’s the promise of the VelEau Bicycle Mounted Hydration System.

01-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

The VelEau comes in several parts. First, there’s a saddlebag which holds 42 ounces (1.4 liters) of water. Then there’s a tube through which you drink, much like those found on CamelBak water bags. This runs from under the seat, along the top-tube to the handlebars, where it is secured to a retracting cord on the stem. This cord pulls the mouthpiece back into place when you’re done drinking, where it is secured by magnets.

02-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

If that seems like it’s complex, unnecessarily heavy and annoying to use, that’s because it probably is. However, there is at least a compartment to carry a multi tool in the same bag, which adds some utility.

HYDRATION SYSTEM

August 23, 2011

04-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

Is it possible to drink too much water during ride without stop the vehicle?

Adequate hydration is as important as calorie replacement to an athlete’s performance, yet dehydration continues to be a condition many experience. This is especially true in cycling where evaporative losses are significant and can go unnoticed. Sweat production and losses through breathing can exceed 2 quarts per hour. To maximize your performance pre-hydration is important, and it is essential that fluid replacement begin early and continue throughout a ride.

Approximately 75% of the energy your body produces is converted to heat rather than being delivered to your muscles to power your pedal stroke. Keeping your body cool and re-hydrated during exertion will result in greater efficiency, higher power output, extended endurance, and a quicker, more thorough recovery. Say good-bye to the Wet Spot!


Individual fluid and electrolyte needs are widely variable during physical exercise due to differences in metabolic rate, body mass and size, environmental conditions (e.g. temperature, humidity, wind, solar load, clothing worn), heat acclimatization status, physical fitness, activity duration, and genetic variability. Sweat rates can vary from 0.5L/hr to more than 3 L/hr. Similarly, sodium concentration may vary from less than 460 mg/L to more than 1840 mg/L

03-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

Technology:

Why use a perfectly good water bottle on your bike when you could use a complex, expensive and awkward to use “hydration system” instead? That’s the promise of the VelEau Bicycle Mounted Hydration System.

01-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

The VelEau comes in several parts. First, there’s a saddlebag which holds 42 ounces (1.4 liters) of water. Then there’s a tube through which you drink, much like those found on CamelBak water bags. This runs from under the seat, along the top-tube to the handlebars, where it is secured to a retracting cord on the stem. This cord pulls the mouthpiece back into place when you’re done drinking, where it is secured by magnets.

02-The Future Of Bicycling Hydration, Bicycle Mounted Hydration System, Hydration System Mounts On The Bicycle Rear

If that seems like it’s complex, unnecessarily heavy and annoying to use, that’s because it probably is. However, there is at least a compartment to carry a multi tool in the same bag, which adds some utility.

MECHANICAL TESTING

August 23, 2011

Various tests:

  • Tensile Test

A tensile test, also known as a tension test, tests a material’s strength. It’s a mechanical test where a pulling force is applied to a material from both sides until the sample changes its shape or breaks. It’s is a common and important test that provides a variety of information about the material being tested, including the elongation, yield point, tensile strength, and ultimate strength of the material. Tensile tests are commonly performed on substances such as metals, plastics, wood, and ceramics.

01-Electronic_Tensile_Testing_Machine-calculate tensile strength-yield strength-ultimate strength-break value-elongation-testing steels, iron, plastics and composite materials

Tensile testing systems use a number of different units of measurement. The International System of Units, or SI, recommends the use of either Pascals (Pa) or Newtons per square meter (N/m²) for describing tensile strength. In the United States, many engineers measure tensile strength in kilo-pound per square inch (KSI).

01-TensileStrength-tensile test-Calculate Ultimate tensile strength-tensile property testing of plastics, steel, iron-material strength calculate - pascals - newton per square meter

  • Tensile test with electronic extensometer

01-electronic_extensometer-calculate proof stress - youngs modulus values-material stress-acccepts load-extension value

This instrument is to be used on Tensile or Universal testing machines to find out Proof stress & Young’s modulus values. In case of many brittle materials such as high carbon steels, alloy steels, light aluminium & magnesium alloys, it is difficult to get yield values. For such materials stress corresponding to a certain allowable amount of plastic deformation is termed as proof stress say 0.1% or 0.2% proof stress. The measuring range is up to 5mm & resolution is 0.001mm.

01-mechanical_extensometer-tensile test calculation-universal testing machine-utm

  • Tensile testing at elevated temperature.

01-tensile test at elevated temperature-high temperature tensile test-specialist tensile test

High temperature tensile testing is a procedure to test the properties of a material at above room temperature. It will determine the following parameters:

  • Tensile strength (breaking strength)
  • Yield strength
  • Elongation
  • Reduction of area

Specialist testing, measurement and control equipment is required to perform this test.
The results of such a test will provide a good indication of the static load bearing capacity of the material and therefore establishes the suitability of a material for its intended purpose.

  • Tensile test on Tor steel Bars

01-tor-steel-bar-rods-TMT steel Bars-concrete technology-durable-corrosion resistant-engineering and construction

TOR steel is one of the best grade of steel used in concrete reinforced. It’s a kind of high adherence steel. Other types of steel are used for less resistance concrete. Thermo mechanically Treated (TMT) bars are a type of corrosion resistant steel reinforcing bar used in concrete construction.

  • Bend test on plates

01-bend test on steels- cold bars -cold bend testing for steels

A bend test is used to determine whether a specific piece of metal in question will break or fracture under pressure. This is important in the construction of any project using metal, otherwise the building or the item being made could collapse from the immense pressure exerted on it. Every piece of metal made cannot be tested, therefore certain pieces are tested and if they pass, the other pieces are made using the same process. The results of a bend test are reported differently depending on the type of material tested. There is no standard method for reporting the durability that applies to all materials, rather each group has its own set by which it is judged and compared to other metals in that group.

The bend test is essentially measuring a metal’s ductility. Ductility defines how easily a metal can bend without breaking. The higher the ductility of a metal, the more it can bend without breaking or becoming deformed from its original shape. This is important because certain metals must handle pressure without snapping yet still be ductile enough to bend slightly and not lose their support or shape. Copper and steel are two metals that have a high ductility and do well under pressure.

  • Bend test on pipes

01-bend test on pipes

Bending tests are carried out to ensure that a metal has sufficient ductility to stand bending without fracturing. A standard specimen is bent through a specified arc and in the case of strip, the direction of grain flow is noted and whether the bend is with or across the grain.

  • Bend Test on Tor steel

01-wire-rods-rebend test on steels

The purpose is to make certain the weld and the base metal are properly fused, and that the weld metal and the heat affected zone (HAZ) have appropriate mechanical properties

  • Re-Bend test on Tor steel

01-wire-rods-rebend test on steels

The purpose of re-bend test is to measure the effect of strain ageing on steel. Strain ageing has embrittlement effect which takes place after cold deformation by diffusion of nitrogen in steel. Hence, there is limitation stated in some design codes to restrict the nitrogen content of steel to 0.012%.

  • Nick Break Test

01-nick break test-welding-fabrication-on sheets

The NICK-BREAK TEST is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions,  gas  pockets,  lack of  fusion,  and  oxidized  or burned metal. To accomplish the nick-break test for checking a butt weld, you must first flame-cut the test specimens from a sample weld.

MECHANICAL TESTING

August 23, 2011

Various tests:

  • Tensile Test

A tensile test, also known as a tension test, tests a material’s strength. It’s a mechanical test where a pulling force is applied to a material from both sides until the sample changes its shape or breaks. It’s is a common and important test that provides a variety of information about the material being tested, including the elongation, yield point, tensile strength, and ultimate strength of the material. Tensile tests are commonly performed on substances such as metals, plastics, wood, and ceramics.

01-Electronic_Tensile_Testing_Machine-calculate tensile strength-yield strength-ultimate strength-break value-elongation-testing steels, iron, plastics and composite materials

Tensile testing systems use a number of different units of measurement. The International System of Units, or SI, recommends the use of either Pascals (Pa) or Newtons per square meter (N/m²) for describing tensile strength. In the United States, many engineers measure tensile strength in kilo-pound per square inch (KSI).

01-TensileStrength-tensile test-Calculate Ultimate tensile strength-tensile property testing of plastics, steel, iron-material strength calculate - pascals - newton per square meter

  • Tensile test with electronic extensometer

01-electronic_extensometer-calculate proof stress - youngs modulus values-material stress-acccepts load-extension value

This instrument is to be used on Tensile or Universal testing machines to find out Proof stress & Young’s modulus values. In case of many brittle materials such as high carbon steels, alloy steels, light aluminium & magnesium alloys, it is difficult to get yield values. For such materials stress corresponding to a certain allowable amount of plastic deformation is termed as proof stress say 0.1% or 0.2% proof stress. The measuring range is up to 5mm & resolution is 0.001mm.

01-mechanical_extensometer-tensile test calculation-universal testing machine-utm

  • Tensile testing at elevated temperature.

01-tensile test at elevated temperature-high temperature tensile test-specialist tensile test

High temperature tensile testing is a procedure to test the properties of a material at above room temperature. It will determine the following parameters:

  • Tensile strength (breaking strength)
  • Yield strength
  • Elongation
  • Reduction of area

Specialist testing, measurement and control equipment is required to perform this test.
The results of such a test will provide a good indication of the static load bearing capacity of the material and therefore establishes the suitability of a material for its intended purpose.

  • Tensile test on Tor steel Bars

01-tor-steel-bar-rods-TMT steel Bars-concrete technology-durable-corrosion resistant-engineering and construction

TOR steel is one of the best grade of steel used in concrete reinforced. It’s a kind of high adherence steel. Other types of steel are used for less resistance concrete. Thermo mechanically Treated (TMT) bars are a type of corrosion resistant steel reinforcing bar used in concrete construction.

  • Bend test on plates

01-bend test on steels- cold bars -cold bend testing for steels

A bend test is used to determine whether a specific piece of metal in question will break or fracture under pressure. This is important in the construction of any project using metal, otherwise the building or the item being made could collapse from the immense pressure exerted on it. Every piece of metal made cannot be tested, therefore certain pieces are tested and if they pass, the other pieces are made using the same process. The results of a bend test are reported differently depending on the type of material tested. There is no standard method for reporting the durability that applies to all materials, rather each group has its own set by which it is judged and compared to other metals in that group.

The bend test is essentially measuring a metal’s ductility. Ductility defines how easily a metal can bend without breaking. The higher the ductility of a metal, the more it can bend without breaking or becoming deformed from its original shape. This is important because certain metals must handle pressure without snapping yet still be ductile enough to bend slightly and not lose their support or shape. Copper and steel are two metals that have a high ductility and do well under pressure.

  • Bend test on pipes

01-bend test on pipes

Bending tests are carried out to ensure that a metal has sufficient ductility to stand bending without fracturing. A standard specimen is bent through a specified arc and in the case of strip, the direction of grain flow is noted and whether the bend is with or across the grain.

  • Bend Test on Tor steel

01-wire-rods-rebend test on steels

The purpose is to make certain the weld and the base metal are properly fused, and that the weld metal and the heat affected zone (HAZ) have appropriate mechanical properties

  • Re-Bend test on Tor steel

01-wire-rods-rebend test on steels

The purpose of re-bend test is to measure the effect of strain ageing on steel. Strain ageing has embrittlement effect which takes place after cold deformation by diffusion of nitrogen in steel. Hence, there is limitation stated in some design codes to restrict the nitrogen content of steel to 0.012%.

  • Nick Break Test

01-nick break test-welding-fabrication-on sheets

The NICK-BREAK TEST is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions,  gas  pockets,  lack of  fusion,  and  oxidized  or burned metal. To accomplish the nick-break test for checking a butt weld, you must first flame-cut the test specimens from a sample weld.

FINISHING OPERATIONS

August 23, 2011

Sizing:

Repressing the sintered component in a die to meet required tolerances.

06-measurement-sizing-tolerance-measurement

02-Sizing-Sintering-Height gauge

Coining:

Repressing the sintered component in a die to increase the density and to give additional strength.

03-coldforge-coining

Infiltration:

Filling the pores of sintered product with molten metal to improve the physical properties.

Impregnation:

Filling of Oil, Grease or other Lubricants in a Sintered components such as Porous Heating

Machining:


Removing excess material by using cutting tool to imparts specific features such as Threads, Grooves, Undercuts etc, which are not practicable in powder metallurgy process.

04-thread cutting-powder metallurgy

Heat Treatment:

Process of Heating & Cooling at a desired rate to improve Grain Structure, Strength & Hardness.

05-heattreatment-metals-hardening

Plating:

Used for obtaining Resistance to Corrosion or better appearance.

05-electro plating-methods-examples

05-electro plating-application-examples

Powder metallurgy is used in the following industries:

  • Automotive (Brake pads, Gear parts, Connecting rods, Planetary carriers, Sintered Engine Bearings);

07-composite gears-automobile-parts

  • Aerospace (Light weight Aluminum base structural materials, High temperature Composite materials);

07-Aeroplane-boeing-powder-metallurgy-applications

07-composite-parts-Aerospace

  • Cutting tools (Hard metals, Diamond containing materials);

07-milling-cutters-tooling

  • Medicine (Dental implants, Surgical instruments);

07-medical-applications-powder metallurgy

  • Abrasives (Grinding and Polishing wheels and Discs);
  • Electrical, Electronic and Computer parts (Permanent magnets, Electrical contacts).

 

07-electronics-computer parts