Strapping Training

Strapping Training

Ersoy Tuncay – 2012

GENERAL COMPARISON

TENSILE STRENGTH N/MM2

ELONGATION WORKING RANGE

ELONGATION AT BREAK

PP DYLASTIC 300 6% 26%PP-Machine Grade DYLASTIC T 350 3,5% 18%PET TENAX 400 2% 15 - 20%PET - High Strength TENAX HS 450 2% 13%STEEL STRAP APEX 850 0,2% 13%STEEL STRAP MAGNUS 1050 0,2% 13%COMPOSITE STRAPPING CO-STRAP n/a 4% 12 - 15%

STRAP TYPES

RANGE OF USEs OF STRAPPING

Market Volume

Weight of Application

PPStrap / Stretch film

PET Strap

STEEL Strap

COMPOSITE STRAPPING

Chains, wire rope, Woven polyester, etc. LASHING

Steel strapping: Magnus-strap 1000 - 1070 Newton/mm2

Heavy packs Apex-strap 780 - 900 Newton/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)

Strapping types in General

Sıra No Norm Kodu Açıklama1 EN 13246 Specification of Tensional Steel Strapping2 EN 13247 Specification for tensional steel strapping for lifting, lashing and securing of loads

3 EN 13394 Specification for Non-Metallic tensional strapping4 EN 13891 Tensional strapping — Guide to selection and use of tensional strapping5 ASTM D 3950 Standard Specification for Strapping, Nonmetallic (and Joining Methods)6 ASTM D 3953 Standard Specification for Strapping, Flat Steel and Seals

Ambalaj Çemberi ile İlgili Normlar

STRAPPING NORMS AND STANDARTS

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 processedPP 320 N/mm2PET 400 N/mm2PET 450 N/mm2Apex STEEL 850 N/mm2Magnus STEEL 1050 N/mm2Composite Strapping n/a ( No homogenous Crossection)

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 = ~ 11,000NMagnus Steel Strap 19mmx0.63mm

= 19mm x 0.63mm x 1.050N/mm2 = ~ 12,500N

The joint strength determines the loop strength!Examples for PET Strapping:

Pneumatic hand tools 45 to 60% (Stick to min for variations in air pressure and flow or PET sheet material.)

Battery Charged Tool 60 to 75% (Depending on strap type sheet single extruded)

Machines80 to 90 % single extruded

Joint Strengts

JOINT EFFICIENCY of POLYESTER CORDED COMPOSITE STRAPS

: 80 – 90 %

Joint Strength of Composite Strapping

Joint Strength of Steel Strapping at Different Joint Types

Retained Tension

Retained tension :• Steel 90 to 95%• PET 65 to 75%• PP 25 to 35%• Composite Strap 80 to 90%

The size of the strap does not affect the RT.

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

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%

Composite Strapping 4 – 6%

Working Range

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 Strap with battery tool : Apex 31,75 x 0,8 mm BS is 20.000Nx 70% JS = 14.000 N 50% x 14.000 x 0,3 = 2.100 Nmm PET 19,05 x 1,27 BS is 10.000 N x 75% JS = 7.500 N 50% x 7.500 x 4 = 15.000 Nmm

So the PET Strap and also COMPOSITE STRAPs in this case is half the strength but 7 ( Seven) times tougher!!!!

Impact resistance

3,000

2,500

1,000

500

1,500

2,000

021 6543 7 8

ELONGATION

Poun

ds

LOAD - ELONGATION CURVE

Steel Strap

Composite / PET Strap

Work to break Steel400 units WORK = 1/2x0.3x2000 300 units

Work to break Composite / PET Strap WORK = 1/2x1000x42000 units

3,000 / 13345

2,500 / 11,120

2,000 / 8,896

1.500 / 6,672

1,000 / 4,448

500 / 2,224

POU

ND

S / N

EWTO

NS

Steel Strap Break Strength (BS) = 11,120 Newtons: PET Strap BS = 5,560 Newtons

Choosing Your Strap

Function or purpose of the strapPackage characteristicsShipping 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.

Factors affecting strap choice

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?

EQUIPMENT BY PACKAGE TYPES

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 .

Transport (Intern/Extern)

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 …..

At the end customer

Types of Steel Strapping

Apexis a cold-rolled, low carbon steel strapping. It isused for light and medium duty loads that needhigh strength and high retained tension but are not subject to impacts or shock.Magnussteel strapping is made from higher-carbon, cold-rolled, heat treated steel. It is used on heavy/very heavy loads that require high strength and are subject to impacts andshock during transit and handling.USLMsteel strapping is made from higher-carbon, cold-rolled, heat treated steel. It is used on very heavy/extreme loads.

Chemical Analysis of Steel Strap Types

APEX MAGNUS USLMC [%] 0,13 - 0,17 0,29 - 0,33 0,44 - 0,46

Mn [%] 0,45 - 0,70 1,25 - 1,45 0,70 - 0,90

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.

TRUCK TRANSPORTATION

RAILWAY TRANSPORTATION

SEA TRANSPORTATION

Minimum Number of Straps =(Load Weight x G Force x 1,5 )/System Strength

1,5 : Safety FactorSafety 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

NUMBER of STRAPS REQUIRED CALCULATION

Palet Weight : 3000 kg Strap Used : CS32ESTR Composite Strap Break Strength of the Strap : 1600 kg System Strength of the Strap : 2560 kg

Safety factor : 1,5

Minimum # of Straps should be on the Pallet = 3000 x 1,5 / 2560

= 1,76 Two ( 2 ) Straps

Çember Miktarı Hesaplama Örneği :

Advantages DisadvantagesHigh Corner Strentgth Low ElasticityHigh Breaking Strength Low Elongation RecoveryTensionable with hand, pneumatic or fully automatic machines

Low Shock Absorbency ( Impact )

High Static System Strength if closed properly

Low3 Dynamic System Strength

Can be tensioned manually or sealed with battery tensioner

Dangerous to users , Damage to products

Also fully automatic possible Expensive than PET / Composite strapping

Steel Strapping vs

PET / Composite StrappingSteel Strapping has :

Thank You

Ersoy Tuncay / 2012