What is vacuum forming? What does it do? What are the methods used in forming vacuums? Vacuum forming is basically the procedure used in shaping any kind of plastic. The shaping of unusual shapes like dishes, boxes and others is called Vacuum forming process. The simplest explanation to its method is by placing the mould into an oven, heated for it to take shape and cooled within a significant amount of time. The advantages of using vacuum forming as a method is limitless and effective. Majority of the vacuum forming products are affordable, since not many produce vacuum forming products. The moulds could be made of low-costing materials and the process of the vacuum forming could be possibly faster than any forming process.
- The most common product made using vacuum forming is a simple plastic toy
- All of the process used includes three important stages. Heating, shaping and cooling.
- There are factors that would be vital in the process selection of the vacuum forming.
- Quantities of the product
- Material of the product
- Shape and details of the product
- Final product's shape and size
1. Clamping process
The clamp or the fastener gives security to the materials being processed. By using this vacuum forming method, you could process even the thickest materials. It is important that the frame of the clamps is strong for the materials not to move during the whole vacuum forming process.
2. Heating process
This vacuum forming method makes use of infra-red heaters and aluminum plates. Although this kind of process is usually handles by larger machines, it could former thicker plastics rapidly. The heaters are located both above the aluminum plates and below it, to produce quality outcomes.
3. Bubble
When the plastic material is inside the machine and it has reached the temperature needed for it to form, this method pre-stretches the plastic to give a smoother outcome product. The bubble method is important because it could assure that unusual shaping materials with extraordinary angles could be reached by the heat.
4. Sheet level
This method involves an electric beam inside the machine that inspects the plastic material and the bottom heater. This method is used when the plastic starts to sag. When the plastic sags, the beam would automatically break down and a quantity of air would enter the machine causing the sagginess to stop.
6. Vacuum
This vacuum forming method pre-stretches the plastic material. The vacuum serves as assistance in the forming of quality sheets. There are two vital parts in a vacuum - the vacuum tank and the vacuum pump. These two parts enable the machine to rapidly mold the hot sheets.
Once the materials have been shaped and formed, a cooling procedure is done before releasing the plastic.
- Cooling is important because when the materials are released, the molds would become deformed and would cause a rejected outcome
- High speed fans are made use to fasten the cooling process. There is also an option in using s spray mist which is directed into the product sheet
- When cooled, it is inserted again into the machine to perform a reverse pressure method that strips excess product from the mould
7. Finishing Up
There are several trimming methods that could be used in vacuum forming. These methods would depend on the size of the part, production number needed, the kind of trimming, and the material's thickness. The finishing of the product or the post-forming processes depends upon the materials processed in the vacuum forming method. Some finishing includes designing, printing of decorations, strengthening of the product and construction. Although there are many kinds of method used in forming plastics, you could always make use of the easiest method - vacuum forming. Anybody could do it. With just the right tools and these friendly procedures, you could make your own toy in a jiffy.
Friday, October 22, 2010
Many Uses of Metal Detectors
Have you ever lost something at the beach or at a park and wondered for weeks what happened to it? Chances are that someone was walking with the ingenious invention, the metal detector, and found it.
How it works and what it does:
It simply does what the name suggests. It finds anything with any metal in it up to a certain length beneath the earth's surface. Many fancy metal detectors will even tell you how deep down the metal object is so you can find it easier.
What Can I Find With a Metal Detector?
You could find rings, bracelets, necklaces, coins or anything metal. Depending on the brand of metal detector you buy and model it is you will get different results. Just ask or research to find out what kind would best suit you.
Other Uses
Schools everywhere are using metal detectors to help filter out violence. The metal detectors can very easily (for this is why they are used) detect a knife or gun. Police stations and Airports use them as well. Even some amusement parks such as "Six Flags Fiesta Texas" use them, you buy your ticket then proceed to the park being stopped momentarily so the patrolmen can search any bags and have you walk through a metal detector.
As you can probably tell metal detectors are very useful not only to find that cherished earring but for our everyday safety and well being. This is a great invention that will be here for years to come.
So next time you loose that ring at the beach or you dime at the park remember there are ways to find you beloved object. Have Fun.
How it works and what it does:
It simply does what the name suggests. It finds anything with any metal in it up to a certain length beneath the earth's surface. Many fancy metal detectors will even tell you how deep down the metal object is so you can find it easier.
What Can I Find With a Metal Detector?
You could find rings, bracelets, necklaces, coins or anything metal. Depending on the brand of metal detector you buy and model it is you will get different results. Just ask or research to find out what kind would best suit you.
Other Uses
Schools everywhere are using metal detectors to help filter out violence. The metal detectors can very easily (for this is why they are used) detect a knife or gun. Police stations and Airports use them as well. Even some amusement parks such as "Six Flags Fiesta Texas" use them, you buy your ticket then proceed to the park being stopped momentarily so the patrolmen can search any bags and have you walk through a metal detector.
As you can probably tell metal detectors are very useful not only to find that cherished earring but for our everyday safety and well being. This is a great invention that will be here for years to come.
So next time you loose that ring at the beach or you dime at the park remember there are ways to find you beloved object. Have Fun.
This Is How Solar Energy Works
Sun is the primary source of energy in our solar system. It provides life to billions of living creatures on planet Earth. It is the source of light and provides life. The bountiful and non-exhaustive resource in the form of solar energy is free, available and omnipotent. Humans have harnessed this resource into a usable energy form and are using it to the benefit of the society. Many claim that this energy is going to replace the other form of polluting energy sources in the near future. The process for this change is an extension of human ingeniousness and a fast change of the technology since the 1970s.
Historically, the sun has been the only source of energy for all living beings on the planet. With the increase in the consumption of energy in the world today and phenomenon like the greenhouse effect becoming a possible threat to the planet's existence, solar energy and other alternative forms of energies are gaining favor. They are relatively cheaper to produce and do not produce harmful emissions like carbon based fuel sources.
So how does solar energy work? The process of converting the rays of the sun into a usable energy form requires conversion, storage and harnessing of the rays in a form which can be used by the energy consuming appliances. The various ways in which this energy is being converted and used depends upon the technology utilized to harness it. For drying out clothes, direct sunlight is enough. For powering satellites, direct sunlight along with a storage mechanism is required. Cars use a combination of hybrid batteries and charge them using sun light.
The primary method of using solar energy is to store them in photovoltaic cells. They were first developed in the 1950s for use on U.S. space satellites program. They are constructed from silicon. When sunlight strikes the solar cell, it makes the electrons to move about. The electrons move toward the treated front surface of the solar panel. This leads to an electron imbalance between the front and the back surface of the panel. On joining the two surfaces, a conductor is formed, just like a wire, and current begins to flow. The individual solar cells are arranged together in a PV module and the modules are grouped together to form an array. This current is used to charge cells and this energy is used to light lamps, tube lights and also to drive cars now. The current can also be used to run appliances.
Another method of using solar energy is to use curved reflectors to direct the solar rays to a convergence point and then make a current flowing system like a photo cell and store energy. Plants like this are operational in the US and in India.
Solar energy is abundantly available in the world and is perhaps the only freely available source of energy, with little or no pollution contribution. Its conversion to usable forms of energy has become possible in recent years and more and more advanced and optimized methods are available to us to harness its full potential.
In the energy crisis ridden world, the SUN might once again come to our rescue.
Historically, the sun has been the only source of energy for all living beings on the planet. With the increase in the consumption of energy in the world today and phenomenon like the greenhouse effect becoming a possible threat to the planet's existence, solar energy and other alternative forms of energies are gaining favor. They are relatively cheaper to produce and do not produce harmful emissions like carbon based fuel sources.
So how does solar energy work? The process of converting the rays of the sun into a usable energy form requires conversion, storage and harnessing of the rays in a form which can be used by the energy consuming appliances. The various ways in which this energy is being converted and used depends upon the technology utilized to harness it. For drying out clothes, direct sunlight is enough. For powering satellites, direct sunlight along with a storage mechanism is required. Cars use a combination of hybrid batteries and charge them using sun light.
The primary method of using solar energy is to store them in photovoltaic cells. They were first developed in the 1950s for use on U.S. space satellites program. They are constructed from silicon. When sunlight strikes the solar cell, it makes the electrons to move about. The electrons move toward the treated front surface of the solar panel. This leads to an electron imbalance between the front and the back surface of the panel. On joining the two surfaces, a conductor is formed, just like a wire, and current begins to flow. The individual solar cells are arranged together in a PV module and the modules are grouped together to form an array. This current is used to charge cells and this energy is used to light lamps, tube lights and also to drive cars now. The current can also be used to run appliances.
Another method of using solar energy is to use curved reflectors to direct the solar rays to a convergence point and then make a current flowing system like a photo cell and store energy. Plants like this are operational in the US and in India.
Solar energy is abundantly available in the world and is perhaps the only freely available source of energy, with little or no pollution contribution. Its conversion to usable forms of energy has become possible in recent years and more and more advanced and optimized methods are available to us to harness its full potential.
In the energy crisis ridden world, the SUN might once again come to our rescue.
Making Biodiesel at Home
It is easy to make your own fuel at home. You need a few simple supplies, all of which are readily available at your hardware stores. Gather up 1 liter of vegetable oil, antifreeze, and lye. The equipment you need to make this clean burning fuel is a blender, scales, a few plastic containers, funnels, and empty water bottles, duct tape, and a thermometer.
Make sure that all of the equipment you plan to use if cleaned and thoroughly dried.
All equipment should be clean and dry and you should make sure that you are careful as you handle the ingredients. Start by measuring out 200 ml of antifreeze and placing it in a half liter plastic container through a funnel. Quickly mix in the lye. Lye absorbs water rapidly, so when you mix it with the antifreeze, work fast. If you work too slowly, it will absorb water from the air and that can interfere with the biodiesel reaction. You can mix the two ingredients by covering the container and shaking the contents rapidly until it starts to react by getting warm. The lye will rapidly dissolve into the antifreeze, foaming up as sodium methoxide. As soon as the sodium methoxide is clear with no particles floating in it, it is ready for the next step.
Using a blender, (one you don't plan to use for food preparation) mix the vegetable oil that has been heated to 130 degrees Fahrenheit with the sodium methoxide. Make sure that the cover is on tightly and blend the mixture on a low speed for twenty minutes.
As soon as you are done processing the mixture, remove it from the blender. Using a funnel, pour it into an empty, 2 liter water or soda bottle and cap tightly. Allow the contents to settle for at least 8 hours.
As the product settles, a dark colored layer will form at the bottom of the bottle with a distinct line of separation from the pale liquid at the top of the bottle. The dark layer is glycerin, and the top layer is biodiesel. Carefully remove the biodiesel to a glass jar or clean water bottle.
Prepare two wash bottles by piercing a small hole in the corner of two cleaned water bottles and covering the holes with duct tape. Pour the biodiesel into one of the wash bottles and add a half liter of fresh water. Screw the cap on tightly. Turn the bottle on its side and roll it about with your hands until oil and water are well mixed and homogenous. Drain the water from the biodiesel by removing the duct tape and letting it drain out. Make sure that when the water has drained out, you block the hole so that the biodiesel remains.
Once the biodiesel is clear, the process is complete and it is ready to use. It can take up tot a week for the biodiesel to clear and ready to use.
Make sure that all of the equipment you plan to use if cleaned and thoroughly dried.
All equipment should be clean and dry and you should make sure that you are careful as you handle the ingredients. Start by measuring out 200 ml of antifreeze and placing it in a half liter plastic container through a funnel. Quickly mix in the lye. Lye absorbs water rapidly, so when you mix it with the antifreeze, work fast. If you work too slowly, it will absorb water from the air and that can interfere with the biodiesel reaction. You can mix the two ingredients by covering the container and shaking the contents rapidly until it starts to react by getting warm. The lye will rapidly dissolve into the antifreeze, foaming up as sodium methoxide. As soon as the sodium methoxide is clear with no particles floating in it, it is ready for the next step.
Using a blender, (one you don't plan to use for food preparation) mix the vegetable oil that has been heated to 130 degrees Fahrenheit with the sodium methoxide. Make sure that the cover is on tightly and blend the mixture on a low speed for twenty minutes.
As soon as you are done processing the mixture, remove it from the blender. Using a funnel, pour it into an empty, 2 liter water or soda bottle and cap tightly. Allow the contents to settle for at least 8 hours.
As the product settles, a dark colored layer will form at the bottom of the bottle with a distinct line of separation from the pale liquid at the top of the bottle. The dark layer is glycerin, and the top layer is biodiesel. Carefully remove the biodiesel to a glass jar or clean water bottle.
Prepare two wash bottles by piercing a small hole in the corner of two cleaned water bottles and covering the holes with duct tape. Pour the biodiesel into one of the wash bottles and add a half liter of fresh water. Screw the cap on tightly. Turn the bottle on its side and roll it about with your hands until oil and water are well mixed and homogenous. Drain the water from the biodiesel by removing the duct tape and letting it drain out. Make sure that when the water has drained out, you block the hole so that the biodiesel remains.
Once the biodiesel is clear, the process is complete and it is ready to use. It can take up tot a week for the biodiesel to clear and ready to use.
How Do I Start A Hot Engine In Summer?
It is usually a cold engine, which is exposed to extreme weather that most often is difficult to start. However, hot engines sometimes have problems too. Hot engines can be tough to start, and many people do not know how to deal with this situation when it occurs. With the intention of overcoming this dilemma, it is important to know exactly why it happens.
The most common reason why a hot engine will not start is because the problem is related to fuel. When your car engine is too hot, fuel cannot circulate well, due to the way vapour obstructs it workings and therefore the engine just will not start, as it should. You can find out more information on this subject online at autopages.com.au who suggest to keep your engine running at the correct temperature and to protect its alloys and metals, you need to use a properly designed coolant.
A car engine will keep gaining temperature until it has been turned off. During this time is when the highest concentration of vapour is circulating around and chances are, that it shall obstruct the engine to a greater extent. Obviously, when and if you are driving in hot weather and have just turned off the car engine you may experience start problems. The solution is simple; you must wait for a few minutes until trying to start it again. The most sensible solution of course, is to use a high quality engine coolant.
Fuel injected engines do not experience this problem as much as other engines, because the fuel remains inside the injectors under high pressure. Owing to this, fuel injected engines do not become so easily subjected to vapours as other engines. Therefore, the vehicle does not have the same issues when it comes to starting a hot engine. It may be time to change over your old vehicle to a newer model with fuel injection, and when this becomes an important issue, you can go online to OzFreeOnline.com and begin a quick search by entering and submitting all the data you have researched for your new car. Let OzFreeOnline.com do all the work for you.
Another reason why you may have an engine, which is hard to start while hot, is that it may be due to seasonal weather as refiners change from one fuel blend to another. Petrol refiners often change a higher volatility fuel to a lower one when summer approaches. This is simply because hot weather causes fuel to evaporate more quickly. If refiners change back to a higher volatility fuel, while vehicles are still exposed to days of extreme temperatures, this may cause swift evaporation of the fuel which, in turn would create too much vapour within the engine.
The most common reason why a hot engine will not start is because the problem is related to fuel. When your car engine is too hot, fuel cannot circulate well, due to the way vapour obstructs it workings and therefore the engine just will not start, as it should. You can find out more information on this subject online at autopages.com.au who suggest to keep your engine running at the correct temperature and to protect its alloys and metals, you need to use a properly designed coolant.
A car engine will keep gaining temperature until it has been turned off. During this time is when the highest concentration of vapour is circulating around and chances are, that it shall obstruct the engine to a greater extent. Obviously, when and if you are driving in hot weather and have just turned off the car engine you may experience start problems. The solution is simple; you must wait for a few minutes until trying to start it again. The most sensible solution of course, is to use a high quality engine coolant.
Fuel injected engines do not experience this problem as much as other engines, because the fuel remains inside the injectors under high pressure. Owing to this, fuel injected engines do not become so easily subjected to vapours as other engines. Therefore, the vehicle does not have the same issues when it comes to starting a hot engine. It may be time to change over your old vehicle to a newer model with fuel injection, and when this becomes an important issue, you can go online to OzFreeOnline.com and begin a quick search by entering and submitting all the data you have researched for your new car. Let OzFreeOnline.com do all the work for you.
Another reason why you may have an engine, which is hard to start while hot, is that it may be due to seasonal weather as refiners change from one fuel blend to another. Petrol refiners often change a higher volatility fuel to a lower one when summer approaches. This is simply because hot weather causes fuel to evaporate more quickly. If refiners change back to a higher volatility fuel, while vehicles are still exposed to days of extreme temperatures, this may cause swift evaporation of the fuel which, in turn would create too much vapour within the engine.
Wire EDM
In wire electrical discharge machining (WEDM), also known as wire-cut EDM and wire cutting, a thin single-strand metal wire, usually brass, is fed through the workpiece, submerged in a tank of dielectric fluid, typically deionized water.Wire-cut EDM is typically used to cut plates as thick as 300mm and to make punches, tools, and dies from hard metals that are difficult to machine with other methods.
The wire, which is constantly fed from a spool, is held between upper and lower diamond guides. The guides, usually CNC-controlled, move in the x–y plane. On most machines, the upper guide can also move independently in the z–u–v axis, giving rise to the ability to cut tapered and transitioning shapes (circle on the bottom square at the top for example). The upper guide can control axis movements in x–y–u–v–i–j–k–l–. This allows the wire-cut EDM to be programmed to cut very intricate and delicate shapes.
The upper and lower diamond guides are usually accurate to 0.004 mm, and can have a cutting path or kerf as small as 0.12 mm using Ø 0.1 mm wire, though the average cutting kerf that achieves the best economic cost and machining time is 0.335 mm using Ø 0.25 brass wire. The reason that the cutting width is greater than the width of the wire is because sparking occurs from the sides of the wire to the work piece, causing erosion. This "overcut" is necessary, for many applications it is adequately predictable and therefore can be compensated for (for instance in micro-EDM this is not often the case). Spools of wire are long—an 8 kg spool of 0.25 mm wire is just over 19 kilometers in length. Wire diameter can be as small as 20 micrometres and the geometry precision is not far from +/- 1 micrometre.
The wire-cut process uses water as its dielectric fluid, controlling its resistivity and other electrical properties with filters and de-ionizer units. The water flushes the cut debris away from the cutting zone. Flushing is an important factor in determining the maximum feed rate for a given material thickness.
Along with tighter tolerances, multiaxis EDM wire-cutting machining center have added features such as multiheads for cutting two parts at the same time, controls for preventing wire breakage, automatic self-threading features in case of wire breakage, and programmable machining strategies to optimize the operation.
Wire-cutting EDM is commonly used when low residual stresses are desired, because it does not require high cutting forces for removal of material. If the energy/power per pulse is relatively low (as in finishing operations), little change in the mechanical properties of a material is expected due to these low residual stresses, although material that hasn't been stress-relieved can distort in the machining process.
The workpiece may undergo a significant thermal cycle, its severity depending on the technological parameters used. Such thermal cycles may cause formation of a recast layer on the part and residual tensile stresses on the workpiece.
The wire, which is constantly fed from a spool, is held between upper and lower diamond guides. The guides, usually CNC-controlled, move in the x–y plane. On most machines, the upper guide can also move independently in the z–u–v axis, giving rise to the ability to cut tapered and transitioning shapes (circle on the bottom square at the top for example). The upper guide can control axis movements in x–y–u–v–i–j–k–l–. This allows the wire-cut EDM to be programmed to cut very intricate and delicate shapes.
The upper and lower diamond guides are usually accurate to 0.004 mm, and can have a cutting path or kerf as small as 0.12 mm using Ø 0.1 mm wire, though the average cutting kerf that achieves the best economic cost and machining time is 0.335 mm using Ø 0.25 brass wire. The reason that the cutting width is greater than the width of the wire is because sparking occurs from the sides of the wire to the work piece, causing erosion. This "overcut" is necessary, for many applications it is adequately predictable and therefore can be compensated for (for instance in micro-EDM this is not often the case). Spools of wire are long—an 8 kg spool of 0.25 mm wire is just over 19 kilometers in length. Wire diameter can be as small as 20 micrometres and the geometry precision is not far from +/- 1 micrometre.
The wire-cut process uses water as its dielectric fluid, controlling its resistivity and other electrical properties with filters and de-ionizer units. The water flushes the cut debris away from the cutting zone. Flushing is an important factor in determining the maximum feed rate for a given material thickness.
Along with tighter tolerances, multiaxis EDM wire-cutting machining center have added features such as multiheads for cutting two parts at the same time, controls for preventing wire breakage, automatic self-threading features in case of wire breakage, and programmable machining strategies to optimize the operation.
Wire-cutting EDM is commonly used when low residual stresses are desired, because it does not require high cutting forces for removal of material. If the energy/power per pulse is relatively low (as in finishing operations), little change in the mechanical properties of a material is expected due to these low residual stresses, although material that hasn't been stress-relieved can distort in the machining process.
The workpiece may undergo a significant thermal cycle, its severity depending on the technological parameters used. Such thermal cycles may cause formation of a recast layer on the part and residual tensile stresses on the workpiece.
Refresh Engine with Radiators
Automotive radiators are the important components of a vehicle's cooling system. A vehicle's cooling system is intended to protect the engine from the destructive forces of too much heat. Radiators take charge of removing excess heat from the engine even under the most extreme conditions. Cooling the motor helps it last longer, taking the vehicle to the distance. If the system isn't in good repair, simple tasks such as sitting idle in rush-hour traffic can cause a vehicle to overheat even when temperatures drop below the freezing mark.
Radiators extend engine life, and keep the vehicle's engine at a safe and efficient operating temperature. Without passing the hot coolant through the cool metal grates or cooling cores of the radiator, the incredible heat under the hood of the car or truck would cause the vehicle to very rapidly overheat, potentially leaving the driver stranded. Intense heat could also destroy other parts of the engine that can be very costly to replace. The radiator is a heat exchanger designed to transfer thermal energy from one medium to another for the purpose of cooling and heating. After which, it transfers the heat from the fluid inside to the air outside, thus cooling the engine. This heat-dissipating device is connected to channels running through the engine and cylinder head, through which pumps a liquid.
On some cars, the radiator fan is electrically driven and comes on automatically even after the engine has been turned off. Disconnect the ground wire from the battery before starting to work to keep away from injury. Since the engine works harder than most of auto parts, it has a tendency to overheat; therefore, it needs a cooling system that would keep it operating at the right temperature. Radiators protect the engine from the destructive forces of too much heat.
When you find a leak because of a rock, a hose, or sometimes because of an accident, replace the radiator to allow motor to continue working and be cooled as it should. Overtime, dirt, dust and rust can build up and clog the essential components of the car's radiator. Therefore, routine maintenance can slow this process and makes the life of the radiator temporarily longer. Timely radiator replacement is also important when the current car radiator wears out.
Be aware of the serious responsibility that comes with driving and car maintenance. Reduce much of the risks with cars by simply being safety conscious and always check radiators to guarantee protection and long time performance of automobiles.
Radiators extend engine life, and keep the vehicle's engine at a safe and efficient operating temperature. Without passing the hot coolant through the cool metal grates or cooling cores of the radiator, the incredible heat under the hood of the car or truck would cause the vehicle to very rapidly overheat, potentially leaving the driver stranded. Intense heat could also destroy other parts of the engine that can be very costly to replace. The radiator is a heat exchanger designed to transfer thermal energy from one medium to another for the purpose of cooling and heating. After which, it transfers the heat from the fluid inside to the air outside, thus cooling the engine. This heat-dissipating device is connected to channels running through the engine and cylinder head, through which pumps a liquid.
On some cars, the radiator fan is electrically driven and comes on automatically even after the engine has been turned off. Disconnect the ground wire from the battery before starting to work to keep away from injury. Since the engine works harder than most of auto parts, it has a tendency to overheat; therefore, it needs a cooling system that would keep it operating at the right temperature. Radiators protect the engine from the destructive forces of too much heat.
When you find a leak because of a rock, a hose, or sometimes because of an accident, replace the radiator to allow motor to continue working and be cooled as it should. Overtime, dirt, dust and rust can build up and clog the essential components of the car's radiator. Therefore, routine maintenance can slow this process and makes the life of the radiator temporarily longer. Timely radiator replacement is also important when the current car radiator wears out.
Be aware of the serious responsibility that comes with driving and car maintenance. Reduce much of the risks with cars by simply being safety conscious and always check radiators to guarantee protection and long time performance of automobiles.
The Theory of a Variable Area Flow Meter
There are many different types of flow meters that are available and that are out there today, and so it is incredibly important to recognize the particular flow meter that you want and need, and then to learn about it so that you are fully aware of all the functions and capabilities of that particular flow meter.
The variable area flow meter is one of the many flow meters that are available, and the variable flow meter is a device which can be used efficiently in many different types of situations, and so if you are interested and/or needing to learn more about the variable area flow meter, then read on to find out what it is all about and the given theories behind it.
What is the Variable Area Flow Meter?
A variable area flow meter which is also often referred to as a rotameter, measures flow rate of a liquid or gas by relating that of linear displacement of an internal float or otherwise sharp-edged orifice plate to that of a corresponding flow rate. Variable area monitors either allow flow through that of a peripheral orifice which is formed between a tapered wall and a float as is done in the traditional rotameter.
Furthermore, the non-linear increase in orifice area compensates for that of a non-linear increase in the pressure differential characteristic in the fixed orifice monitors; flow rate is actually read on variable-area meters and works by aligning the position of the piston involved to a calibrated scale that is adjacent to the particular piston.
Annular and Peripheral Orifices
This is a matter which is extremely important to take into consideration in regards to this situation, as the most significant difference between that of the traditional rotameter and the lake's flow meter for instance is in the design of the actual fluid path in which the measured fluid is forced to take.
Additional Information
In order to be able to satisfy that of both system and media requirements, these variable area flow meters are available in numerous materials of construction, and this includes that of: plastic, aluminum, brass, stainless steel, glass, and cast iron, for instance - there are many more options as well.
In case you did not know, lake monitors have the ability to sense and then electronically output the position of the piston inside this monitor, and the basic purpose of doing this is so that flow rate can be provided properly and as accurately as possible.
The variable area flow meter is one of the many flow meters that are available, and the variable flow meter is a device which can be used efficiently in many different types of situations, and so if you are interested and/or needing to learn more about the variable area flow meter, then read on to find out what it is all about and the given theories behind it.
What is the Variable Area Flow Meter?
A variable area flow meter which is also often referred to as a rotameter, measures flow rate of a liquid or gas by relating that of linear displacement of an internal float or otherwise sharp-edged orifice plate to that of a corresponding flow rate. Variable area monitors either allow flow through that of a peripheral orifice which is formed between a tapered wall and a float as is done in the traditional rotameter.
Furthermore, the non-linear increase in orifice area compensates for that of a non-linear increase in the pressure differential characteristic in the fixed orifice monitors; flow rate is actually read on variable-area meters and works by aligning the position of the piston involved to a calibrated scale that is adjacent to the particular piston.
Annular and Peripheral Orifices
This is a matter which is extremely important to take into consideration in regards to this situation, as the most significant difference between that of the traditional rotameter and the lake's flow meter for instance is in the design of the actual fluid path in which the measured fluid is forced to take.
Additional Information
In order to be able to satisfy that of both system and media requirements, these variable area flow meters are available in numerous materials of construction, and this includes that of: plastic, aluminum, brass, stainless steel, glass, and cast iron, for instance - there are many more options as well.
In case you did not know, lake monitors have the ability to sense and then electronically output the position of the piston inside this monitor, and the basic purpose of doing this is so that flow rate can be provided properly and as accurately as possible.
Material removal mechanism
The first serious attempt of providing a physical explanation of the material removal during electric discharge machining is perhaps that of Van Dijk. Van Dijk presented a thermal model together with a computational simulation to explain the phenomena between the electrodes during electric discharge machining. However, as Van Dijk himself admitted in his study, the number of assumptions made to overcome the lack of experimental data at that time was quite significant.
Further models of what occurs during electric discharge machining in terms of heat transfer were developed in the late eighties and early nineties, including an investigation at Texas A&M University with the support of AGIE, now Agiecharmilles. It resulted in three scholarly papers: the first presenting a thermal model of material removal on the cathode, the second presenting a thermal model for the erosion occurring on the anode and the third introducing a model describing the plasma channel formed during the passage of the discharge current through the dielectric liquid. Validation of these models is supported by experimental data provided by AGIE.
These models give the most authoritative support for the claim that EDM is a thermal process, removing material from the two electrodes because of melting and/or vaporization, along with pressure dynamics established in the spark-gap by the collapsing of the plasma channel. However, for small discharge energies the models are inadequate to explain the experimental data. All these models hinge on a number of assumptions from such disparate research areas as submarine explosions, discharges in gases, and failure of transformers, so it is not surprising that alternative models have been proposed more recently in the literature trying to explain the EDM process.
Among these, the model from Singh and Ghosh reconnects the removal of material from the electrode to the presence of an electrical force on the surface of the electrode that could mechanically remove material and create the craters. This would be possible because the material on the surface has altered mechanical properties due to an increased temperature caused by the passage of electric current. The authors' simulations showed how they might explain EDM better than a thermal model (melting and/or evaporation), especially for small discharge energies, which are typically used in μ-EDM and in finishing operations.
Given the many available models, it appears that the material removal mechanism in EDM is not yet well understood and that further investigation is necessary to clarify it, especially considering the lack of experimental scientific evidence to build and validate the current EDM models. This explains an increased current research effort in related experimental techniques
Further models of what occurs during electric discharge machining in terms of heat transfer were developed in the late eighties and early nineties, including an investigation at Texas A&M University with the support of AGIE, now Agiecharmilles. It resulted in three scholarly papers: the first presenting a thermal model of material removal on the cathode, the second presenting a thermal model for the erosion occurring on the anode and the third introducing a model describing the plasma channel formed during the passage of the discharge current through the dielectric liquid. Validation of these models is supported by experimental data provided by AGIE.
These models give the most authoritative support for the claim that EDM is a thermal process, removing material from the two electrodes because of melting and/or vaporization, along with pressure dynamics established in the spark-gap by the collapsing of the plasma channel. However, for small discharge energies the models are inadequate to explain the experimental data. All these models hinge on a number of assumptions from such disparate research areas as submarine explosions, discharges in gases, and failure of transformers, so it is not surprising that alternative models have been proposed more recently in the literature trying to explain the EDM process.
Among these, the model from Singh and Ghosh reconnects the removal of material from the electrode to the presence of an electrical force on the surface of the electrode that could mechanically remove material and create the craters. This would be possible because the material on the surface has altered mechanical properties due to an increased temperature caused by the passage of electric current. The authors' simulations showed how they might explain EDM better than a thermal model (melting and/or evaporation), especially for small discharge energies, which are typically used in μ-EDM and in finishing operations.
Given the many available models, it appears that the material removal mechanism in EDM is not yet well understood and that further investigation is necessary to clarify it, especially considering the lack of experimental scientific evidence to build and validate the current EDM models. This explains an increased current research effort in related experimental techniques
Electrical discharge machining
Electric discharge machining (EDM), sometimes colloquially also referred to as spark machining, spark eroding, burning, die sinking or wire erosion, is a manufacturing process whereby a desired shape is obtained using electrical discharges (sparks). Material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the ‘tool’ or ‘electrode’, while the other is called the workpiece-electrode, or ‘workpiece’.
When the distance between the two electrodes is reduced, the intensity of the electric field in the volume between the electrodes becomes greater than the strength of the dielectric (at least in some point(s)), which breaks, allowing current to flow between the two electrodes. This phenomenon is the same as the breakdown of a capacitor (condenser) (see also breakdown voltage). As a result, material is removed from both the electrodes. Once the current flow stops (or it is stopped - depending on the type of generator), new liquid dielectric is usually conveyed into the inter-electrode volume enabling the solid particles (debris) to be carried away and the insulating proprieties of the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is commonly referred to as flushing. Also, after a current flow, a difference of potential between the two electrodes is restored to what it was before the breakdown, so that a new liquid dielectric breakdown can occur.
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