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Strapping Training. Ersoy Tuncay – 2012. GENERAL COMPARISON. RANGE OF USEs OF STRAPPING. Chains, wire rope, Woven polyester, etc. LASH ING. Weight of Application. STEEL Strap. COMPOSITE STRAPPING. PET Strap. PP Strap / Stretch film. Market Volume. Strapping typ e s in General.
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Strapping Training Ersoy Tuncay – 2012
RANGE OF USEs OF STRAPPING Chains, wire rope, Woven polyester, etc. LASHING Weight of Application STEELStrap COMPOSITE STRAPPING PETStrap PPStrap/ Stretch film Market Volume
Strapping types in General • Steel strapping: • Magnus-strap 1000 - 1070 Newton/mm2 • Heavy packs • Apex-strap 780 - 900Newton/mm2 • Simple / medium typ applications / cost reductions • Plastic strapping: • PET strap • PET high strength 16 – 32 mm (6.000 – 18.800 Newton) • Normal PET 9 – 16 mm (2.000 – 5.000 Newton) • PP strapping • Machine strapping 5 – 16 mm (500 – 4.500 Newton) • Manual strapping 11 - 15 mm (2.000 – 3.000 Newton) • Polyester Corded Strapping • Manuel Application • As strong as Steel Strap and excellent retain tension performance ( 2000 kgf Break Strength)
STRAP PROPERTIES • Strength • Tensile Strength • Break Strength • Joint Efficiency • Working Range • Retained Tension • Elongation and Recovery • Impact Resistance
Tensile Strength Tensile strength is characteristic of a type of material and the way it has been processed PP320 N/mm2 PET400 N/mm2 PET450 N/mm2 Apex STEEL 850 N/mm2 Magnus STEEL 1050 N/mm2 CompositeStrapping n/a ( No homogenousCrossection)
Break Strength Break strength is characteristic of a specific strap. It is the product of cross-sectional area and tensile strength PET 19mm x 1.27mm x 450N/mm2 = ~ 11,000N Magnus Steel Strap19mmx0.63mm = 19mm x 0.63mm x 1.050N/mm2= ~ 12,500N
JointStrengts The joint strength determines the loopstrength! Examples for PET Strapping: • Pneumatic hand tools45 to 60% (Stick to min for variations in airpressure and flow or PET sheet material.) • Battery Charged Tool 60 to 75% (Depending on strap type sheet single extruded) • Machines 80 to 90 % single extruded
JointStrength of CompositeStrapping JOINT EFFICIENCY of POLYESTER CORDED COMPOSITE STRAPS : 80 – 90 %
RetainedTension Retained tension is the strap tension that remains over time Applied tension is the tension that is initially applied to a strap Tension decay is the tension that is lost over time • Retained tension : • Steel 90 to 95% • PET 65 to 75% • PP 25 to 35% • CompositeStrap 80 to 90% • The size of the strap does not affect the RT.
Working Range • Working range of PET and steel strap are about 50% of their break strengths. • Working range of PP is about 35% of its break strength. • Working range elongation is the main reason why PET is tougher than steel. Steel 0.2 -0.3 % PET 2 - 4% PP- Special 6% CompositeStrapping 4 – 6%
Impact resistance • Impact resistance is measured by work (energy necessary) to break/deform the strap. Calculation: Working range (%) x Joint strength (N) x Working range elongation (%) • Comparison between Steel Strap 32 x 0,8 applied with a double notch seal, and a PET 19 x1,27mm PET Strapwithbatterytool : • Apex 31,75 x 0,8 mm BS is 20.000Nx70% JS = 14.000 N • 50% x 14.000 x 0,3 = 2.100Nmm • PET 19,05 x 1,27 BS is 10.000 N x 75% JS = 7.500 N • 50% x 7.500 x 4 = 15.000Nmm So the PET Strap and also COMPOSITE STRAPsin thiscase is half the strength but 7 ( Seven) timestougher!!!!
3,000 / 13345 3,000 2,500 / 11,120 2,500 POUNDS / NEWTONS 2,000 / 8,896 2,000 1.500 / 6,672 Pounds 1,500 1,000 / 4,448 1,000 500 / 2,224 500 0 1 2 3 4 5 6 7 8 ELONGATION Steel StrapBreak Strength (BS) = 11,120 Newtons: PET StrapBS = 5,560 Newtons LOAD - ELONGATION CURVE Steel Strap Composite / PET Strap • Work to break Steel • 400 units • WORK = 1/2x0.3x2000 • 300 units Work to break Composite / PET Strap WORK = 1/2x1000x4 2000 units
Factors affecting strap choice Function or purpose of the strap Package characteristics Shipping or handling considerations • Strapping may perform the following functions: package reinforcement, carton closure, securement, unitization, baling, bundling, bracing, paletization, compression retention and pilferage reduction. • Package characteristics that influence strap selection are: weight, stability, rigidity, integrity and sharpness of the edges (sharp edges may demand heavier strapping or corner protection). • Shipping considerations that affect the choice of strapping include: how far the package is shipped; how it’s handled by both the shipper and receiver; and where and how it’s stored.
EQUIPMENT BY PACKAGE TYPES • Shape: • Rectangular Normal hand-tools / Machines • Round Push type tools / (Machines) • Weight: • How much mass has to be held together? • Weight Straps • Package stability: • Is the product stabile by itself, is the stacking stabile? • Strapping to hold pack on pallet, or to hold pack together? • What happens when a strap breaks? • Costs • Safety • Product edges: • Does strap damage product?Corner-protection • Does product damage strap? • Need to distribute more tension?
Transport (Intern/Extern) You may ask yourself the following questions: • How is the pack lifted / handled? • Forklift, magnetic overhead crane, roller-conveyor, etc. • How long is the pack in storage? • Shrinking, corrosion. • Conditions of storage? • Moisture, dust, sunlight, heat, ice, etc. • Way of storage? • Stacked, in racks • Way of transport? • Truck, train (shunting), ship, airfreight. • Distance of transport? • Domestic or Export, the more transport actions, the higher the risk .
At the end customer • How does the end customer handle the package? • Forklift truck, roller conveyor, magnetic crane, etc. • How / when does he take the packaging apart? • Any hazards, complications? • Is there intermediate storage? • Many more handlings, very long storage times. • Does the pack get resold? • Needs to be broken down to smaller units. • Try to think further …..
Types of Steel Strapping Apex is a cold-rolled, low carbon steel strapping. It is used for light and medium duty loads that needhighstrength and high retained tension but are notsubject to impacts or shock. Magnus steel strapping is made from higher-carbon, cold-rolled,heat treated steel. It is used on heavy/very heavy loads thatrequire high strength and are subject to impacts andshockduring transit and handling. USLM steel strapping is made from higher-carbon, cold-rolled,heat treated steel. It is used on very heavy/extreme loads.
Why waffled strap • Advantages: • A thicker strap with a lower Gram / Meter (Cheaper) • Stiffer, good feeding through chutes • Disadvantages at heavy waffling: • Longer weldtime, or weaker weld. • Less meterage per Kg. • Tension-wheel grips in “air” • A smaller smooth strap can replace a wider waffled strap.
NUMBER of STRAPS REQUIRED CALCULATION Minimum Number of Straps =(LoadWeight x G Force x 1,5 )/SystemStrength 1,5 : Safety Factor Safety Factor can be varied according the transportation mode and also type of the product. System Strength of Composite Strapping = 1,6 x Nominal Break Strength
Çember Miktarı Hesaplama Örneği : Palet Weight : 3000 kg StrapUsed : CS32ESTR CompositeStrap Break Strength of theStrap : 1600 kg SystemStrength of theStrap : 2560 kg Safetyfactor : 1,5 Minimum # of Strapsshould be on thePallet = 3000 x 1,5 / 2560 = 1,76 Two ( 2 ) Straps
Steel Strapping vs PET / Composite Strapping Steel Strapping has :
Thank You Ersoy Tuncay / 2012