View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge. Photoshoped pics are developed. Some pics and GIF from Google. Videos from YouTube ( Engineering Sights ).
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Tolerance & Fits
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Tolerance
It is defined as, "the magnitude of permissible variation of a dimension or other measured value from the specified value".
Purpose ↠ permit dimensional variations of components, performance, specification and design.
As the permissive tolerance goes on decreasing, the manufacturing cost to achieve it goes on increasing exponentially.
Classification of Tolerance:
Unilateral tolerance ↠ If tolerance distribution is only one side of the basic size.
Bilateral tolerance ↠ When tolerance distribution lies on either side of the basic size.
Compound tolerance ↠ When tolerance is determined by established tolerances on more than one dimensions.
Geometric tolerance ↠ Used to indicate the relationship of one part of an object with another.
Classification of Geometric Tolerance:
Form tolerance ↠ group of geometric tolerance applied to individual features (includes straightness, circularity, flatness, cylindricity).
Orientation tolerance ↠ type of geometric tolerance used to limit the direction/orientation of a feature in relation to other (includes perpendicularity, parallelism, angularity).
Positional tolerance ↠ group of geometric tolerances that controls the extent of derivation of the location of a feature from its true position (includes position, symmetry, concentricity).
Fits
It is defined as, "the relationship between the two mating parts that are to be assembled i.e. the hole and the shaft w.r.t the difference in their dimensions before assembly".
Manufactured parts are required to mate with one another during assembly.
Ideally fits is required for proper functioning of mating parts.
Allowance ↠ intentional difference between the maximum material limits (LLH and HLS) of two mating parts.
Types of Fits:
Clearance Fit ↠ The largest permissible diameter of the shaft is smaller than the diameter of smallest hole.
Interference Fit ↠ The minimum permissible diameter of shaft exceeds the maximum allowable diameter of hole.
Transition Fit ↠ Occurs when two tolerance mating parts are sometimes interference fit and sometimes clearance fit when assembled.
References:
Material from Class Lectures + Book named Fundamentals of Modern Manufacturing Materials, Processes and Systems by Groover + My knowledge.
Welded Joints A permanent joint which is obtained by the friction of edges of two parts to be joined, with or without the application of pressure and a filler material. Used in fabrication as an alternative method for casting and forging . Used as a repair medium . If filler material is used ↠ Strength of Joint > Base metal strength . If filler not used ↠ Joint strength < Base metal strength . Grinding Finish ↠ Welding at top and bottom off the plate. Machining Finish ↠ Welding at bottom surface after welding machining operation. Want to learn more about welded joint, click here . Designing of Butt Joint Design of Lap Joint or Fillet Joint Lap or Fillet joint is " formed by the overlapping of plates and then welding the edges of plates " . There are two types of fillet joints: Single and Double Transverse Fillet Joints ↣ are designed for tensile loading. Parallel Fillet Joints ↣ are designe...
Projection: The term Projection is defined as: Presentation of an image or an object on a surface. The principles used to graphically represent 3-D objects and structures on 2-D media and it based on two variables: Line of Sight. Plane of Projection. Line of Sight & Plane of Projection: Line of sight is divided into 2 types: Parallel Projection Converging Projection & A plane of projection is an imaginary flat plane upon which the image created by the lines of sight is projected. Orthographic Projection: When the projectors are parallel to each other and perpendicular to the plane of projection. The lines pf sight of the observer create a view on the screen. The screen is referred to as the Plane of Projection (POP). The lines of sight are called Projection lines or projectors. Rules of Orthographic Projection: Edges that are parallel to a plane of projection appear as lines. Edges that are incl...
Gear Forming by Machining Formation of gear through machining consists of following methods: Form Milling by Disc Cutter Form Milling by End Mill Cutter Shaper, Planner and Slotter Broaching 1. Form Milling by Disc Cutter It is defined as, " Tooth is cut one by one by plunging the rotating cutter into the blank " . Each gear needs a separate cutter. 8 - 10 standard cutters are available for producing 12 - 120 teeth gears. Used for big spur gears of large pitch. 2. Form Milling by End Mill Cutter It includes the cutting of tooth at a time and then indexed for the next tooth space for cutting. For a small volume production of low precision gears. Set of 10 cutters ↠ 12 - 120 teeth gears . Used for teeth of large gears/module. To reduce cost, same cutter is often used for multiple sized gears resulting in profile errors . Characteristics: Use of Hardened stainless steels (HSS) form milling cutters. Use of Ordinary milling machines. Low production rate (need of indexing...
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