1- Incremental shaft encoder
2- Breadboard
3- Biomachining
4- Non contact near object detection
5- Electro jet drilling
6- Operatin hazard analysis
7- Isotrophy & anisotrophy
8- Robot work envelope
9- Clapper Gripper
10- Electro chemical grinding
Showing posts with label 10th week. Show all posts
Showing posts with label 10th week. Show all posts
Tuesday, April 19, 2011
Sunday, April 17, 2011
Kayra Ermutlu-030060081 (10th Week)
Allotropic Transformations (Allotropic Tramsformations)
Materials that can have more than one crystal structure are called allotropic or polymorphic. The term allotropy is normally reserved for this behavior in pure elements, while the term polymorphism is used for compounds. Some materials such as iron and titanium, have more than one crystal structure. At low temperatures, iron has BCC structure, but at higher temperatures, iron transforms to an FCC structure. These transformations result in changes in properties of materials and form the basis for the heat treatment of steels and many other alloys.
(Askeland D.R., Phulé P.P., The Science and Engineering of Materials, pg.62, Kayra Ermutlu)
Die Geometry Angle
The die geometry directly influences material flow. and thereforei it affects the distribution of the effective strain and flow stress in the deformation zone. In forward extrusion, for a given reduction, a larger die angle increases the volume of metal undergoing shear deformation and results in an increase in shear deformation load Pds. On the other hand, the length of the die decreases, which results in a decrease in die friction load, Pdf. Consequently, for a given reduction and given friction conditions, there is an optimum die angle that minimizes the extrusion load.
(Altan T., Ngaile G., Shen G., Cold and Hot Forging:Fundamentals and Applications- Part1, pg.219, Kayra Ermutlu)
Microshrinkage
A casting imperfection, not detectable microscopically, consisting of interdendritic voids. Microshrinkage results from contracting during solidification where the opportunity to supply filler material is inadequate to compansate for shrinkage. Alloys with wide ranges in solidification temperature are particularly susceptible.
(American Society for Metals, ASM Metals Reference Book, pg.59, Kayra Ermutlu)
Acetate (Cellulose)
An amber-colored, transparent material made by the reaction of cellulose with acetic acid or acetic anhydride in the presence of sulfuric acid. In Germany it was made by treating beech-wood pulp with acetic acid in the presence of an excess of zinc chloride. It is employed for lacquers and coatings, molding plastics, rayon, and photographic film. Cellulose acetate may be the triacetate C6H7O2, but may be the tetracetate or the pentacetate, or mixture. It is made in different degrees of acetylation with varying properties.
Unlike nitrocellulose, it is not flammable, and it has better light and heat stability. It has a refractive index of 1.47 to 1.50, and a sheet 0.125 in (0.32 cm) thick will transmit 90% of the light. The specific gravity is 1.27 to 1.37, Brinell hardness 8 to 15, tensile strength 3500 to 8000 lb/in^2 (24 to 55 MPa), compressive strength up to 20000 lb/in^2 (138 MPa), elongation 15 to 80%, dielectric strength 300 to 600 V/mil (12*10^6 to 24*10^6 V/m), and softening point 122 to 205F (50 to 96C). It is thermoplastic and is easily molded. The molded parts or sheets are tough, easily machined, and resistent to oils and many chemicals. In coatings and lacquers, the material is adhesive, tough and resilient, and it does not discolor easily.
(Brady G.S., Clauser H.R., Vaccari J.A., Materials Handbook,15th Ed., pg. 204, Kayra Ermutlu)
Evrim Berk 030060161 10th Week
Luminescence
Luminescence is defi ned broadly as the generation of light in excess of that radiated thermally. Man’s fascination with luminescence stems from when an otherwise invisible power is converted into visible light. The commercial importance of luminescence is ubiquitous, being manifest in lamps, displays, X-ray machines, etc.
Materials that generate luminescence are called phosphors. Commercial phosphors are mostly inorganic compounds prepared as powders (with grain sizes usually in the order of 2-20 µm) or thin films. The phosphor materials contain one or more impurity ions or activators (A), typically present in 0.01-100 mol % concentrations. The actual emission is generated on these activator ions.
Luminescence Science and Display Material, Ronda C., Srivastava A., The Electrochemical Society Interface, Spring 2006, Page: 55)
Direct Driven Press
In a direct driven press configuration. All rollers are driven independently by a
direct-drive rotary motor, without the need for gears or gearboxes. When the load is directly coupled, the settling time is no longer limited by the transmission, so the servo loop gain can be increased. This provides the necessary servo stiffness to achieve excellent speed regulation and phase control between the anilox, plate, and central impression cylinders. Press speeds using direct-drive technology can be increased in many applications because the accuracy of the mechanical transmission system is often the limiting factor.
Switching to direct-drive further improves press throughput by reducing setup and maintenance time. A typical flexo press servo system equipped with gearboxes requires periodic tuning
adjustments of the antibacklash control system to compensate for gear wear. DDR systems, on the other hand, since they are directly coupled to the load, require no periodic tuning. There is complete elimination of backlash and the need for antibacklash controls. Years later, the tuning settings are typically the same as the day the machine was installed. With a direct-drive press, the parts count on a typical Bill of Material (BOM) is reduced by up to 10 parts per color print deck.
(Direct Drive Technology - Improving Flexo Printing Quality and Throughput, England T., Flexo August 2009, page: 50 - 54)
Active Fillers
Filler materials are classified into two categories. Active and non - active fillers. Active fillers are composed of chemically active materials or compounds that convert readily and permanently from one composition to another when subjected to sufficient energy initiate reaction. For the purposes of this discussion, the active filters to be considered are often composed of active elements, such as titanium, aluminium, hafnium, zirconium, vanadium, and niobium, and the energy applied to initiate the conversion is heat. Brazing with active filler materials is a relatively simple method and is generally preferred over brazing with inactive fillers.
(Implantable Neural Prostheses 2: Techniques and Engineering Approaches, Zhou D., Greenbaum E., Page: 37)
Inactive Fillers
Inactive filler materials often require prior metallization of the ceramic substrate to provide for enough wetting, so an interface (usually reactive) is formed. Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), or mechanical metallization can be used to deposit metallic films such as molybdenum, manganese, tungsten, or their combination onto ceramic surfaces prior to brazing. This additional metallization step can complicate the brazing process and makes quality control of the joint more difficult.
(Implantable Neural Prostheses 2: Techniques and Engineering Approaches, Zhou D., Greenbaum E., Page: 37)
Burcu Atay, 140060029,10th week
Pipe Defect
Pipe defect is also known as tail pipe or fishtailing. In many cases, during extrusion the surface oxides and impurities are driven twards the cenre of the bilet , much like a funnel (called pipe). The length of the extruded part with this defect has to be discarded and cut off as scrap. The piping defect can be minimized by proper designing of the die so that a more uniform metal flow pattern may be obtained.
(Kaushish,J.P., Manufacturing Processes, Eastern Economy Edition, pg. 407)
Arrowhead Crack
Internal cracking, also called center-cracking, center-burst, arrow head, fracture or chevron cracking in which the extruded product develops cracks in its centre. To reduce this defect, the die angle and impurities in the billet should be reduced.
(Kaushish,J.P., Manufacturing Processes, Eastern Economy Edition, pg. 407)
Hot Spinning
The hot spinning process is schematically shown in fig. the process is carried out on thick steel sheets to form a dish or other circ
ular cross-sectional shapes which are symmetrical about the axis of rotation. In hot spinning,
metal blank is heated to forging temperature and then it is held on lathe with the help of metallic form or chuck attached to the lathe spindle. The adapter at the tail stock end helps in the holding the hot blank against the chuck. Blunt hand spinning tools when fed forward(or pushed with pressure), bend and give shape to the revolving hot blank. Thin sheets are formed to various shapes by ‘cold spinning’ process discussed later.
(Kaushish,J.P., Manufacturing Processes, Eastern Economy Edition, pg. 411)
SCARA
SCARA is an acronym for Selective Compliance Assembly Robot Arm. This configuration is similar to the jointed arm robot except that the shoulder and elbow rotational axes are vertical, which means that the arm is very rigid in the vertical direction, but compliant in the horizontal direction. This permits the robot to perform insertion tasks (for assembly) in a vertical direction, where some side-to-side alignment may be needed to mate the two parts properly.
(Groover,M.P., Automation, Production Systems and Computer-Integrated Manufacturing, 3rd Edition, pg.217)
Buğra Cengiz 030060178 10th week
Compression Test
The compressive stress-strain curve is similar to the tensile stress-strain curve up to the yield strength. Thereafter, the progressively increasing specimen cross section causes the compressive stress-strain curve to diverge from the tensile curve. Some ductile metals will not fail in the compression test. Complex behavior occurs when the direction of stressing is changed, because of the Bauschinger effect, which can be described as follows: If a specimen is irst plastically strained in tension, its yield stress in compression is reduced and vice versa.
Mark's Standard Hanbook For Mechanical Engineers, P. 5-5
Cold Rolling
Cold Rolling is practical in production of thin coil stock with the more ductile metals. The number of passes or amount of reduction between anneals is determined by the rate of work hardening of the metal. Successive stands of cold-rolling help to retain heat generated in working. Tension provided by mill reels and between stands helps to increase the practical reduction per step. Bright annealing in a controlled atmosphere avoids surface pockmarks, which are difficult to get out. For highfinish stock, the rolls must be maintained with equal finish.
Mark's Standard Hanbook For Mechanical Engineers, P.13-16
Polycarbonate
Polycarbonates show excellent dimensional stability, with good impact resistance and ductility. They are employed as a base for photographic film and also for lenses. Their toughness makes them appropriate for the manufacture of safety helmets. ( John Martin, Materials For Engineering, Third Edition, P.160 )
Polycarbonates, one of the strongest, toughest, and most rigid thermoplastics, are not generally considered good barrier materials. It is possible to use polycarbonate as the structural layer in a composite (co-extruded) film for use in barrier application. In such cases, polycarbonate contributes
toughness and heat resistance to the final product while other components in the composite film may provide the barrier properties
Processing Methods: Injection molding, extrusion, blow molding, and rotational molding
Applications:
• Packaging. Milk bottles, baby bottles, food containers.
• Medical. Dialysers, artery cannulas.
• Electrical. Distribution box lids, fuses, sockets, lamp holders, and covers.
Liesl K. Massey, Permability properties of Plastics And Elastomers. Chapter 26
Process Flow Chart
Process Flow Charts are to manufacturing as road maps are to drivers. They provide detailed view of the process, and increase understanding of how the process flow. With a process flow chart teams repetitive steps, bottlwnecks, and inefficiencies in the process wich in turn helps the team identify potential failures, effects and solutions.
The best way to create a flowchart is to walk through the process as if you were the thing being processed or created. the process steps should be followed sequentally and notes should be taken during walk through.
once the walk through is complate each steps should be listed on a self stick-stick note. It helps to have several people do this as each will contribute ideas that others missed. The steps should then be grouped and organized according to their order in the process
For complicated process with a several steps and substeps it helps to create a top-down flowchart, where each of major steps in the process listed in order of flow across the top of the chart and sub-steps are listed underneath each major steps
Robin E. McDermott,Raymond J. Mikulak,Michael R. Beauregardi The Basics of FMEA, P. 59
The compressive stress-strain curve is similar to the tensile stress-strain curve up to the yield strength. Thereafter, the progressively increasing specimen cross section causes the compressive stress-strain curve to diverge from the tensile curve. Some ductile metals will not fail in the compression test. Complex behavior occurs when the direction of stressing is changed, because of the Bauschinger effect, which can be described as follows: If a specimen is irst plastically strained in tension, its yield stress in compression is reduced and vice versa.
Mark's Standard Hanbook For Mechanical Engineers, P. 5-5
Cold Rolling
Cold Rolling is practical in production of thin coil stock with the more ductile metals. The number of passes or amount of reduction between anneals is determined by the rate of work hardening of the metal. Successive stands of cold-rolling help to retain heat generated in working. Tension provided by mill reels and between stands helps to increase the practical reduction per step. Bright annealing in a controlled atmosphere avoids surface pockmarks, which are difficult to get out. For highfinish stock, the rolls must be maintained with equal finish.
Mark's Standard Hanbook For Mechanical Engineers, P.13-16
Polycarbonate
Polycarbonates show excellent dimensional stability, with good impact resistance and ductility. They are employed as a base for photographic film and also for lenses. Their toughness makes them appropriate for the manufacture of safety helmets. ( John Martin, Materials For Engineering, Third Edition, P.160 )
Polycarbonates, one of the strongest, toughest, and most rigid thermoplastics, are not generally considered good barrier materials. It is possible to use polycarbonate as the structural layer in a composite (co-extruded) film for use in barrier application. In such cases, polycarbonate contributes
toughness and heat resistance to the final product while other components in the composite film may provide the barrier properties
Processing Methods: Injection molding, extrusion, blow molding, and rotational molding
Applications:
• Packaging. Milk bottles, baby bottles, food containers.
• Medical. Dialysers, artery cannulas.
• Electrical. Distribution box lids, fuses, sockets, lamp holders, and covers.
Liesl K. Massey, Permability properties of Plastics And Elastomers. Chapter 26
Process Flow Chart
Process Flow Charts are to manufacturing as road maps are to drivers. They provide detailed view of the process, and increase understanding of how the process flow. With a process flow chart teams repetitive steps, bottlwnecks, and inefficiencies in the process wich in turn helps the team identify potential failures, effects and solutions.
The best way to create a flowchart is to walk through the process as if you were the thing being processed or created. the process steps should be followed sequentally and notes should be taken during walk through.
once the walk through is complate each steps should be listed on a self stick-stick note. It helps to have several people do this as each will contribute ideas that others missed. The steps should then be grouped and organized according to their order in the process
For complicated process with a several steps and substeps it helps to create a top-down flowchart, where each of major steps in the process listed in order of flow across the top of the chart and sub-steps are listed underneath each major steps
Robin E. McDermott,Raymond J. Mikulak,Michael R. Beauregardi The Basics of FMEA, P. 59
Saturday, April 16, 2011
Gani Can Öz (10th Week) - 503101305
Each term is a polymer additive.
1-Antioxidants
2-Light Stabilizers
3-Heat Stabilizers
4-Flame Retardants
5-Colorants
6-Active Fillers
7-Inactive Fillers
8-Compatibilizers
9-Biocides
10-Processing Additives
1-Antioxidants
2-Light Stabilizers
3-Heat Stabilizers
4-Flame Retardants
5-Colorants
6-Active Fillers
7-Inactive Fillers
8-Compatibilizers
9-Biocides
10-Processing Additives
Friday, April 15, 2011
A. Selim PARLAKYİĞİT - 10th Week
1. Block Tool System(BTS)
2. Diffusion Bonding
3. Multiple-Cutting-Edge Tools
4. Electrohydraulic Forming
5. Tube Spinning
6. Stretch Forming
7. Embossing
8. Twisting
9. İroning
10.Flanging(Bending Operation)
2. Diffusion Bonding
3. Multiple-Cutting-Edge Tools
4. Electrohydraulic Forming
5. Tube Spinning
6. Stretch Forming
7. Embossing
8. Twisting
9. İroning
10.Flanging(Bending Operation)
ÖMER TAYLAN BOYA 030070099 10th WEEK
Canadize (titanium) (in Magnaplate) (11:31 am 15.04.2011)
--A system for hardfacing each material has been developed which is basically an electrochemical process. The synergistic coating system is still far the best for a wear application, however, and special fluoropolymers or dry are infuesed into the hardfacing.
--For titanium synergistic coating is called Canadize. For titanium application thickness is difficult to build up, so the normal application thickness is between 0.0002 and 0.0005 in.
--A classic application for Canadizing is titanium hardware for aircraft. Such components are anodized with an infusion to a thickness of 0.0002 - 0.0004 in. to prevent the titanium from seizing.
--A system for hardfacing each material has been developed which is basically an electrochemical process. The synergistic coating system is still far the best for a wear application, however, and special fluoropolymers or dry are infuesed into the hardfacing.
--For titanium synergistic coating is called Canadize. For titanium application thickness is difficult to build up, so the normal application thickness is between 0.0002 and 0.0005 in.
--A classic application for Canadizing is titanium hardware for aircraft. Such components are anodized with an infusion to a thickness of 0.0002 - 0.0004 in. to prevent the titanium from seizing.
(Donates Satas, Coating Technology Handbook 2nd edition revised and expanded, page 308)
Babbiting (about coating) (13:57 pm 15.04.2011)
--Babbitting consists of attaching a layer of softer metal (usually a tin-lead composition) to a part of much sturdier composition which acts as a supporting element. The soft layer, or the babbitt, has excellent antifrictional properties. In shafts, the babbitt averts galling and scoring of the surface, while the inner, stiff core acts as its support in torsion, when rotating.
--Babbitting is used with bearing shells, hardware elements, automotive connecting rods, jewelry, and numerous other applications. The babbitt is attached to the supporting metal by either of two methods:
• Mechanical bonding of babbitting is performed by using fasteners, dovetails, and other grooves.
• Heating of the babbitting material along with its supporting part and allowing the assembly to first cool at the area of contact between the babbitt and its support. This method is useful with shells, where the babbitt is introduced in the form of a mandrel.
(Ivana Suchy, Handbook of die design , page 678)
In-Die Welding (14:08 pm 15.04.2011)
--In-die resistance welding has lately achieved a large popularity. Years ago, nobody even dared to think about attaching a spot welder to the progressive die and produce welded assemblies right there, automatically. But then, we must realize that years ago, sensors were not as common as they are nowadays, and without sensors in-die welding may not be possible.
--Sensors in the in-die welding process are necessary to ensure a total protection to the die. A thorough monitoring of parts’ feed length, die components’ position, scrap removal, and the overall die function as combined with the control of the moving strip, is essential. The welded-on objects must be monitored for their proper positioning within the die to make sure the welding electrode will engage the material right where it was planned and exactly the way it was planned.
--The amount of pressure the upper electrode exerts toward the assembly-to-be-welded must be carefully monitored as well, and this information must be reported back to the PLC controller. This pressure is necessary not only to hold the parts in place, but to provide for a firm contact of the two, so that welding can occur. Without a positive contact of the components, a resistance weld is very difficult to produce. As can be easily imagined, oil, grease, or dirt on the surfaces may impair the weld quality.
(Ivana Suchy, Handbook of die design , page 507)
In-Die Tapping ( 14:13 pm 15.04.2011)
--In-die tapping, not long ago considered impossible to achieve, is quickly becoming an industry standard. So far, the on-going research came up with three different types of tapping systems:
• Tapping with an external lead screw
• Tapping with an internal lead screw
• Tapping with a rack and pinion system
--External lead screw systems use a series of gears, which are driven by a helix lead screw on descent of the press ram. The lead screw does not rotate; it only drives the gear assembly to generate and transfer the motion necessary for a tap cartridge to produce the thread. The length of the travel of the tap cartridge with respect to the ram travel is adjusted by changing the gear ratio. The gears are further adjustable to accommodate for a different thread pitch; they can tap downward or upward, vertically, horizontally, or under any angle.
--Internal lead screw systems depend on a cam for transfer of the ram travel into tapping of openings to specified depths. Here the lead screw rotates when driven by the roller nut on its way down. The system can be designed as vertical or horizontal, with dependence on the preferences of the user.
--Rack and pinion system of in-die tapping is similar to the external lead screw system, the difference being in a rack and pinion replacing the helical lead screw. Multiple tapping units can be attached with chain drives to the main drive system.
(Ivana Suchy, Handbook of die design , page 504)
--Babbitting consists of attaching a layer of softer metal (usually a tin-lead composition) to a part of much sturdier composition which acts as a supporting element. The soft layer, or the babbitt, has excellent antifrictional properties. In shafts, the babbitt averts galling and scoring of the surface, while the inner, stiff core acts as its support in torsion, when rotating.
--Babbitting is used with bearing shells, hardware elements, automotive connecting rods, jewelry, and numerous other applications. The babbitt is attached to the supporting metal by either of two methods:
• Mechanical bonding of babbitting is performed by using fasteners, dovetails, and other grooves.
• Heating of the babbitting material along with its supporting part and allowing the assembly to first cool at the area of contact between the babbitt and its support. This method is useful with shells, where the babbitt is introduced in the form of a mandrel.
(Ivana Suchy, Handbook of die design , page 678)
In-Die Welding (14:08 pm 15.04.2011)
--In-die resistance welding has lately achieved a large popularity. Years ago, nobody even dared to think about attaching a spot welder to the progressive die and produce welded assemblies right there, automatically. But then, we must realize that years ago, sensors were not as common as they are nowadays, and without sensors in-die welding may not be possible.
--Sensors in the in-die welding process are necessary to ensure a total protection to the die. A thorough monitoring of parts’ feed length, die components’ position, scrap removal, and the overall die function as combined with the control of the moving strip, is essential. The welded-on objects must be monitored for their proper positioning within the die to make sure the welding electrode will engage the material right where it was planned and exactly the way it was planned.
--The amount of pressure the upper electrode exerts toward the assembly-to-be-welded must be carefully monitored as well, and this information must be reported back to the PLC controller. This pressure is necessary not only to hold the parts in place, but to provide for a firm contact of the two, so that welding can occur. Without a positive contact of the components, a resistance weld is very difficult to produce. As can be easily imagined, oil, grease, or dirt on the surfaces may impair the weld quality.
(Ivana Suchy, Handbook of die design , page 507)
In-Die Tapping ( 14:13 pm 15.04.2011)
--In-die tapping, not long ago considered impossible to achieve, is quickly becoming an industry standard. So far, the on-going research came up with three different types of tapping systems:
• Tapping with an external lead screw
• Tapping with an internal lead screw
• Tapping with a rack and pinion system
--External lead screw systems use a series of gears, which are driven by a helix lead screw on descent of the press ram. The lead screw does not rotate; it only drives the gear assembly to generate and transfer the motion necessary for a tap cartridge to produce the thread. The length of the travel of the tap cartridge with respect to the ram travel is adjusted by changing the gear ratio. The gears are further adjustable to accommodate for a different thread pitch; they can tap downward or upward, vertically, horizontally, or under any angle.
--Internal lead screw systems depend on a cam for transfer of the ram travel into tapping of openings to specified depths. Here the lead screw rotates when driven by the roller nut on its way down. The system can be designed as vertical or horizontal, with dependence on the preferences of the user.
--Rack and pinion system of in-die tapping is similar to the external lead screw system, the difference being in a rack and pinion replacing the helical lead screw. Multiple tapping units can be attached with chain drives to the main drive system.
(Ivana Suchy, Handbook of die design , page 504)
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