Issue link: https://cp.revolio.com/i/989729
ista views • May 2018 • www.ista.org Evaluation of Stability of Unit Loads for Tilt and Shock Events During Distribution > CONTINUED FROM PAGE 16 16 The specific objectives of this study were: • Design apparatus for and establish tilt test and incline impact test procedures. • Observe and record the amount of offset of the unit load to evaluate the stability of the unit load per the tilt test and incline impact test procedures • Test two different pallet patterns as a mean for comparison of unit load stability MATERIALS AND METHODS Load specifications Following are the details for the packaging components and unit load used in this study. The best practice stack and pallet pattern specifications are based on the input from Niagara Bottling, LLC. • Primary packaging: Twenty-four 0.5L PET water bottles (Niagara Bottling, LLC, Ontario, California, USA) • Secondary packaging: Polyethylene shrink film • Pallet: CHEP timber block pallet, 121.92 cm x 101.60 cm x 14.22 cm • Stretch wrap: 50.80 cm, 0.7 mil, multi-layer cast film - Model MP2 (Berry Plastics Corp., Evansville, Indiana, USA) • Unit load: 125.73 cm x 105.41 cm x 132.08 cm, 1082 kg • Wrap pattern: 11 total revolutions, 2 additional top wraps, 76-102 mm layer-by-layer film overlap, 13-51 mm top overwrap and 76-102 mm bottom overwrap. Applied (measured) stretch level: 180-210%. Containment force per ASTM D 4649 Testing: 5.89 ± 0.91 kgf [24]. For stretch wrapping unit loads, the Synergy 4 Automatic Stretch Wrapper (Highlight Industries Inc., Grand Rapids, MI, USA) was used. Towards obtaining the targeted containment force, the portable film force system used for this project consisted of a primary load cell and two secondary load cells each attached to 152.40 mm diameter force plates (Portable Film Force System, Highlight Industries Inc., Grand Rapids, MI, USA) [7]. Figure 3 shows this system as placed on the unitized load. After being stretch-wrapped, all unit loads were allowed to relax for one hour. • Stacking pattern: Layer patterns "A" and "B" were used to construct six- tier stacking patterns of "AABBAA" and "AAAABB" for the two types of unit loads used in this study (Figure 4). The product cases were maintained upright, evenly centered on the pallet to within 5.08 cm and within 2.54 cm alignment between repeat layers. Figure 3: Load Cell Assembly to Measure Containment Force Figure 4: Layer (top) and Stacking (bottom) Patterns Used for Unit Loads