[Business Communication]

Design of A Compression SpringSUPERIOR COLLEGE OF TECHNOLOGY, LAHORE

2Group MembersGhulam AliHafiz Mirza Sharaz AkbarHafiz IrfanIrfanRana ZunairContents:Helical spring

Types of Spring

Introduction to Spring

Types of helical spring

Helical compression spring

Helical compression spring design

Process flow

Application of helical compression springWhat Is a Spring?Spring is a mechanical device which store and release energy.Types of SpringsHelical SpringLeaf Spring

Helical Spring

Leaf Spring

Helical SpringThe helical springs are made up of a wire coiled in the form of a helix and are primarily intended for compressive or tensile loads.

Types of Helical Spring Compression SpringExtension SpringTorsion Spring

Compression SpringExtension SpringTorsion SpringHelical Compression SpringThe helical springs are made up of a wire coiled in the form of a helix and are primarily intended for compressive

Application Of Helical Compression Spring Helical compression springs are our most common spring type. They have a wide range of applications and can be found in almost all mechanical products, for example as important components in door locks, in compressors, in automobiles, in electric switches and more.

Engine valveCar Suspension

Spring DesignFeb-2014Customer requirement (Load & Fitment)Selection of materialMaterial select with factor of safety. Minimum 10% extra load design at spring designing time And 50% maximum extra load design at spring designing time.

Calculation formulaeTable 1 below shows the symbols used for the design of springs. The values of the modulus of rigidity G to be used for the design of springs shall be as shown in Table2.Table 1 Symbols used for the calculationsSymbolDescriptionUnitdwire diametermmD1Inside diameter of coilmmD2Outside diameter of coilmmDmean diameter of coilmmNtTotal number of coilsNanumber of active coilsHsSolid heightmmHffree heightmmc=D/dspring indexGshear modulusN/mm2PloadNdeflectionmmkspring constantN/mm0Torsional stressN/mm2Corrected torsional stressN/mm2stress correctionTable 2 Modulus of rigidity:GUnit N/mm2)MaterialValue of GSpring steel materialsHard steel wirePiano wireOil tempered steel wire7.85104Stainless steel spring wireSUS304SUS3166.85104SUS631J17.35104Brass wireNickel-silver wire3.9104Phosphor bronze wire4.2104Beryllium copper wire4.4104Fundamental calculation formulae(1)Relationship among load, spring rate and deflection

(2)Obtaining spring rate from spring dimensionsSince, with a compression coil spring, the deflection occurs from the torsion of the wire diameter, the spring rate k is shown as:

Fundamental calculation formulae(3)Wire diameterWire diameter find from stress. We know force and area.

(4)Torsional stress

Fundamental calculation formulae(5)Corrected torsional stress

(6)Spring index

Fundamental calculation formulae(7)Solid height (in case of ground coil end)

(8)Pitch

where, (t1 + t2): sum of thicknesses of both coil ends

Process Flow1st Process coiling: A series of connected spirals or concentric rings formed by gathering or winding of wire with machine to wind into a shape resembling a coil with require dimensions.

CoilingProcess Flow2nd Process creep tempering:Spring clamp in fixture with the help of hydraulic press and pressing block press springs with hydraulic press till Spring Coil Should be Solid. After clamping springs creep temper with require temperature and Socking timeCreep tempering

Fixture After Clamping

Fixture Pressing Block Fixture Before ClampingTempering furnace Tempering fixture

Process Flow3rd Process tempering:Temper the spring for stress relieving after tempering spring cool in the air. Tempering is a low temperature heat treatment process normally performed after neutral hardening, double hardening, atmospheric carburizing, carbonitriding or induction hardening in order to reach a desired hardness/toughness ratio.

Tempering furnaceProcess Flow4th Process grinding:Grind The spring With Require Length Or end Thickness. Spring squareness is the angular difference between the outermost limit of a spring diameter when compared to a straightedge at a right angle to a horizontal flat plate on which the spring is standing. This affects how the axial force produced by the spring can be transferred to adjacent parts in a mechanism. Grinding

Process Flow5th Process straightening:Squareness of a compression spring refers to the perpendicularity of the spring to its own axis. A spring that is "square" will exert more uniform loads, which may be needed in critical applications. Springs with ground ends generally offer better squareness than those with closed only ends. Straightening

Process Flow6th Process shoot peening:Shot peening is a cold working process in which the surface of a spring is bombarded with small spherical media called shot. Each piece of shot striking the surface creates a small indentation or dimple. Overlapping dimples develop an even layer of metal in residual compressive stress. Fatigue cracks will not start or propagate in a compressively stressed zone. When a residual compressive stress is produced in the surface, the tensile stress created by the applied load must first overcome the residual compressive stress before the resultant surface stress becomes tensile. Shoot peening

Process Flow7th Process load testing:Compression tests are used to determine how a product or material reacts when it is compressed, squashed, crushed or flattened by measuring fundamental parameters that determine the specimen behavior under a compressive load.Load testing

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