Seminar Topics for mechanical engineers

Replies

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  nilesh shelote

  Re: Seminar Topics for computer engineers
  
  friends i wann some topics for seminar n projetct of final year
  send me computer science or electronics & communication related topics
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  nijas.pk

  Friends plz send me some mechanical engineering topics
• 

  kigsss

  thanks for keeping a good and useful community😁😁
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  drj

  post some imp seminar topics for final year of b-tech (mechanical branch)plzzzz frens post dem as fast as possible......
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  remshad medappil

  Stress variation in pressure vessel,
  micro turbine,
  diaphram micropump,
  rapid prototyping
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  vivekk

  Re: water jet technology
  
  some topics are already suggested by choondu
  i have some information about water jet cutting technology
  
  
  

  WATER JET TECHNOLOGY AS ADVANCED MANUFACTURING PROCESS​

  
  
  
  Introduction
  Low-pressure water jets were first used for mining gold in California in 1852. Steam and hot water jets were used in the early 1900s for cleaning. High-pressure water jets were used for mining in the 1960s, and about 10 years ago industry began using water jets for cutting. Abrasive water jets (abrasive jets) were first used in industry in about 1980. In the past, only one piece of metal could be cut at a time with a saw or other metal cutting mechanical process. It was time intensive and expensive. Computer-controlled water jet and abrasive jet cutting are used today in industry to cut many soft and hard materials. The plain water-abrasive mixture leaves the nozzle at more than 900 mph. The latest machines can cut to within two thousandths of an inch, and have jet speeds around Mach 3.
  The key to cutting metal with water is to keep the spray coherent. Water jets are able to cut because the spray is channeled through a very narrow jeweled nozzle at a very high pressure to keep the spray coherent. Unlike metal cutters, a water jet never gets dull and it cannot overheat.
  Now a days water jets are mainly employed for:-
  Marble, Granite, Stone, Metal, Plastic, Wood, Stainless steel.
  Although Abrasive jet and Water Jet technology has been around for years, abrasive jet equipment has just recently entered the machine tool market. This is extremely exciting stuff, and there are a handful of early innovators making a lot of money replacing and complementing conventional machining with water jet cutting methods.
  According to a recent report from #-Link-Snipped-# , a market research company, abrasive water jets are the fastest growing segment of the machine tool industry with a growth rate forecast at 9.1 percent for the forecast period [1997-2004].
  Both the water jet machining process and the laser machining process cut metals and several other materials. However, the water jet machines are less expensive than laser machines, and are functionally superior to conventional metal cutting machines. Water jet technology has become a viable solution for end users, due to the availability of sophisticated software.
  Water jets (and Abrasive jets) are quickly becoming a new "standard tool" in machine shops around the world. This is because they are fast, flexible, reasonably precise, and in the last few years have become friendly and easy to use. They use the technology of high pressure water being squirted through a small hole to concentrate an extreme amount of energy in a small area to cut stuff.
  You have already heard the terms "Water jet" and "Abrasive jet". It is important to understand that Abrasive jets are not the same thing as water jets, although they are nearly the same. Water Jet technology has been around since the early 1970s or so, and abrasive jets extended the concept about 10 years later.
  
  2. MACHINING USING WATER JET TECHNOLOGY
  2.1 Process: -
  This employs a fine, high pressure , high velocity up to twice the speed of the sound jet of water, which when bombarded on the work piece erodes the material. A high-pressure water jet has two properties, which make it potentially useful in industries. They are its destructive power and its application as a precision cutting tool. A high velocity water jet when directed at a target in such a way that, its velocity in virtually reduced to zero on striking the surface. Practically, most of the kinetic energy of the jet of water is converted in to a very high pressure. In fact, at the initial stage the transient pressure reaches several times greater than the normal stagnation pressure. Because of this water jet will make a hole in the material if the pressure is high enough.
  2.2 Operating principle: -
  Many variables such as nozzle orifice diameter, water pressure, cutting feed rate and the stand distance affect the performance. Generally, high cutting quality would be the result of the conditions(1)pump along with intensifier to generate very high pressure;(2)cutting unit consisting nozzle and work table movement and(3) filtration unit to remove the debris from the water after use.
  
  3. MECHANISM OF JET CUTTING
  3.1. Pumps
  3.1.1. INTENSIFIER pumps
  Early ultra-high pressure cutting systems used hydraulic intensifier pumps exclusively. At the time, the intensifier pump was the only pump capable of reliably creating pressures high enough for water jet machining. Figure shows a schematic drawing of a hydraulic intensifier pump. An engine or electric motor drives a hydraulic pump which pumps hydraulic fluid at pressures from 1,000 to 4,000 psi (6,900 to 27,600 kPa) into the intensifier cylinder. The hydraulic fluid then pushes on a large piston to generate a high force on a small-diameter plunger. This plunger pressurizes water to a level that is proportional to the relative cross-sectional areas of the large piston and the small plunger.
  The intensifier cylinder is a double-acting cylinder: hydraulic fluid is introduced alternately into one side and then the other. The hydraulic piston alternately pressurizes the water using small-diameter plungers at each end of the intensifier assembly. A series of check valves allows low pressure water into the plunger cylinder as the plunger retracts and then directs the pressurized water into the outlet manifold as the plunger moves into its compression stroke. The back and forth action of the intensifier piston produces a pulsating flow of water at very high pressure. To help make the water flow more uniform (thus resulting in a smoother cut), the intensifier pump is equipped with an "attenuator" cylinder, which acts as a high-pressure surge vessel. The use of this attenuator reduces pressure fluctuations to a few thousand psi per stroke.
  
  
  
  
  
  
  Figure shows Schematic Drawing and Picture of Hydraulic Intensifier Pump
  
  
  
  3.1.2. Crankshaft pumps
  The centuries-old technology behind crankshaft pumps is based on the use of a mechanical crankshaft to move any number of individual pistons or plungers back and forth in a cylinder. Check valves in each cylinder allow water to enter the cylinder as the plunger retracts and then exit the cylinder into the outlet manifold as the plunger advances into the cylinder.
  Crankshaft pumps are inherently more efficient than intensifier pumps because they do not require a power-robbing hydraulic system. In addition, crankshaft pumps with three or more cylinders can be designed to provide a very uniform pressure output without needing to use an attenuator system. Crankshaft pumps were not generally used in ultra-high pressure applications until fairly recently. This was because the typical crankshaft pump operated at more strokes per minute than an intensifier pump and caused unacceptably short life of seals and check valves. Improvements in seal designs and materials, combined with the wide availability and reduced cost of ceramic valve components, made it possible to operate a crankshaft pump in the 40,000 to 50,000 psi (280,000 to 345,000 kPa) range with excellent reliability. This represented a major breakthrough in the use of such pumps for abrasive jet cutting.Today, crankshaft pumps can operate reliably up to 55,000 psi. Experience has shown that an abrasive jet does not really need the full 60,000 psi (414,000 kPa) capability of an intensifier pump. In an abrasive jet, the abrasive material does the actual cutting while the water merely acts as a medium to carry it past the material being cut. This greatly diminishes the benefits of using ultra-high pressure. Indeed many abrasive jet operators with 60,000 psi (414,000 kPa) intensifier pumps have learned that they get smoother cuts and more reliability if they operate their abrasive jets in the 40,000 to 50,000 psi (276,000 to 345,000 kPa) range.
  
  
  
  
  
  
  
  
  
  NOZZLES
  Both the technologies that is water jet and abrasive jet system uses the principle of pressurizing water to extremely high pressures, and allowing the water to escape through a very small opening (typically called the "orifice" or "jewel").Water jets use the beam of water exiting the orifice (or jewel) to cut soft stuff like diapers and candy bars, but are not effective for cutting harder materials. The inlet water is typically pressurized between 20,000 and 55,000 Pounds Per Square Inch (PSI). This is forced through a tiny hole in the jewel, which is typically 0.007" to 0.015" in diameter. This creates a very high velocity beam of water! Abrasive jets use that same beam of water to accelerate abrasive particles to speeds fast enough to cut through much harder materials: A diagram of an abrasive jet. Notice that it is just like a water jet with more stuff underneath the jewel. The high velocity water exiting the jewel creates a vacuum which sucks abrasive from the abrasive line, which mixes with the water in the mixing tube to form a high velocity beam of abrasives.
  
  
  
  
  
  
  
  4. COMPARISION WITH OTHER NON CONVENTIONAL MACHINING PROCESS:-
  When comparing with Lasers:
  · Abrasive water jets can machine many materials that lasers cannot.
  · Uniformity of material is not very important to an Abrasive jet.
  · Abrasive jets do not heat your part. Thus there is no thermal distortion or hardening of the material.
  · Precision abrasive jet machines can obtain about the same or higher tolerances than lasers (especially as thickness increases).
  · When comparing with EDM:
  · Abrasive jets are much faster than EDM.
  · Abrasive Jets machine a wider variety of materials (virtually any material).
  · Abrasive jets make their own pierce holes.
  · Abrasive jets do not heat the surface of what they machine.
  · Abrasive jets require less setup.
  · Make bigger parts.
  · When comparing with flame cutting
  · Abrasive jets provide a much nicer edge finish
  · Abrasive jets don't heat the part
  · Abrasive jets can cut virtually any material
  · Flame cutting is typically faster
  · When comparing with milling
  · There is only one tool to qualify on an abrasive jet
  · Cleanup is much faster with an abrasive jet
  · Programming is easier and faster
  · Machine virtually any material.
  · When comparing with punch presses
  · Place holes closer to the materials edge
  · Thick materials are fine
  · Brittle &Hard materials are no problem.
  · 5. ADVANTAGES TO ABRASIVE JET MACHINING:-
  · Extremely fast setup and programming.
  · Very little fixturing for most parts
  · Machine virtually any 2D shape (and some 3D stuff)
  · Almost no heat generated zones on the part i.e. cold cutting
  · No start hole required.
  · Environment friendly.
  · Clippings are valuable
  · Machine thick stuff.
  · There is only one tool.
  · Very low side cutting forces during cutting
  
  
  6. HOW IMPORTANT IS PRESSURE IS MAXIMUM PRESSURE ALWAYS BETTER?
  Generally speaking, the higher the pressure of the water, the faster the speed of cutting. However, pressure is only one of many factors to consider. Among them are:
  · Operating cost
  · Maintenance
  · Fatigue limits of all high pressure components
  · Cutting speed
  
  CONCLUSION
  · From above discussion we have concluded that “Water jet Machining” has various advantages as
  · Cheaper than other process.
  · Cut virtually any shape &material
  · Make all sorts of shapes with only one tool.
  · Cut wide range of thickness’ to reasonable tolerance up to 2” thick
  · No mechanical stresses
  · Fast turn around on the machine.
  · Leaves a satin smooth finish, thus reducing secondary operations
  · Clean cutting process without gasses or oils
  · Your "scrap" metal is easier to recycle or re-use (no oily chips!)
  · Modern systems are now very easy to learn.
  · Can easily switch between high production, and single piece production, on the same machine, with no extra effort.
  · Are very safe.
  · No "scaly" edges, which makes it easier to make a high quality weld
  · Machine composite materials.
  · Machine stacks of thin parts all at once.
  
  REferences:
  Mr. Samir Dorle (UMR)
  Omax Corporation
  ISWJT
  “Water jetting Technology”, - By Dr. David A. Summers.
  American Machinist.
  
  Toro Company Promotional Literature.
  Modern Machining Process By P.C.Pandey & H.S. Shan
  New Technologies by Dr Amitabh.
• 

  remshad medappil

  Add this topics also
  1.High altitude aerodynamics
  2.Magnetic Bearing
  3.Valvless micro pump
  4.Pizo electric micro pump
• 

  er.vyas

  hey some new topics from edufive.com
  
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• 

  er.vyas

  nice work vivek
• 

  Kaustubh Katdare

  er.vyas

  nice work vivek

  I doubt it's his work. Seems copy-paste job from : How can water cut through steel? | HowStuffWorks
  
  Offtopic: Recommended Read: #-Link-Snipped-#