Tài liệu Package Evaluation Training_ 4_ longtitudnal sealing

22/09/2012 Package Evaluation T i i Training Longitudinal Sealing PE-04/2012-04-01 Agenda 1. Principle of LS and SA sealing 2. Evaluation – Visual inspection + Practical 3. Evaluation – Mechanical tear down + Practical 4. Evaluation – Red ink injection + Practical 5. Sample of the defect PE-04/2012-04-01 / 2 1 22/09/2012 1. Principle of LS and SA sealing li Longitudinal Sealing PE-04/2012-04-01 1. Principle of LS and SA sealing LS Strip Function The e Longitudinal o g ud a Strip S p in Tetra e a Brik Aseptic sep c system sys e has 3 main functions: 1) 2) 3) To prevent product absorption into the packaging material edge To improve the gas barrier properties of the longitudinal seal area To strengthen the longitudinal seal PE-04/2012-04-01 / 4 2 22/09/2012 1. Principle of LS and SA sealing LS Strip application - terminology The strip p applicator pp side ((SA)) of the seal is where the strip (2) is attached to the packaging material by the strip applicator. The SA is the side of the strip where the packaging material (3) is double. The Longitudinal sealing side (LS) is the side if the strip (2) where the packaging material (1) is single. An air gap (4) is present in the middle of the seal. PE-04/2012-04-01 / 5 1. Principle of LS and SA sealing SA Sealing The Operations are: 1)The edge of internal surface of packaging material is heated to melt the plastic layer either by hot air, or by induction heating. 2))The strip p is laid on the surface and pressed onto the packaging material using pressure rollers. 3) The SA is then made. PE-04/2012-04-01 / 6 3 22/09/2012 1. Principle of LS and SA sealing LS Sealing  The LS makes a tight tube of packaging material just prior to coming in contact with the filling product.  The flat PM (strip on one edge), is guided into a tube form.  The edge without strip is heating (hot air or induction heating) by the longitudinal element.  The heated edge meets the underlying y g unheated one and the two are pressed together between two rollers.  This sealing is achieved between the inner and the outer surfaces of PM and between the strip and the inside of the tube. PE-04/2012-04-01 / 7 1. Principle of LS and SA sealing Type of sealing system Tetra Pak A3/CF hot air hot air PE-04/2012-04-01 /8 4 22/09/2012 1. Principle of LS/SA sealing LS sealing component – Lower forming ring and LS spring PE-04/2012-04-01 /9 1. Principle of LS/SA sealing LS sealing component – Spring Force PE-04/2012-04-01 / 10 5 22/09/2012 1. Principle of LS/SA sealing LS sealing component – Hot air and Induction Heating Longitudinal sealing Hot air Longitudinal sealing inductor PE-04/2012-04-01 / 11 1. Principle of LS and SA sealing LS strip Application ► The LS Strip application evaluation consists of three steps: 1) 2) 3)) Visual inspection of LS position and check of heat and pressure distribution Sealing quality check, by performing the mechanical tear down of the LS Strip. LS Strip p tightness, g by yp performing g the red ink injection j test. PE-04/2012-04-01 / 12 6 22/09/2012 2. Evaluation – Visual I Inspection ti Longitudinal Sealing PE-04/2012-04-01 2. Evaluation – Visual inspection Preparation Sample 1.Unfold the Flaps of package sample 2. Cut two opposite corners 3. Empty the package content 4. Cut the sample corner to corner PE-04/2012-04-01 / 14 7 22/09/2012 2. Evaluation – Visual inspection Preparation Sample 5. Open up the sample, rinse it with water and dry it. PE-04/2012-04-01 / 15 2. Evaluation – Visual Inspection Why Visual inspection ► By y visuallyy examining g the LS, will g get quick indication if there are any malfunctioning sealing components in the machine. ► Check for scratched, stretch marks, overheated area and strip position. ► Use Zonoscope to examine heat distribution g the longitudinal g seal. along Note! Good light is important when evaluating the seal quality PE-04/2012-04-01 / 16 8 22/09/2012 2. Evaluation – Visual inspection Strip Position The LS strip is not always centred with respect to the seal. For MPM and MSE LS strip types, 60-70% of the strip covers the SA side or ~ 4.2 – 4.9 mm. Guideline G id li : The Th air i gap (4) should be simply visible and not exceeding 1.0 mm. PE-04/2012-04-01 / 17 2. Evaluation – Visual Inspection Heat distribution by Zonoscope X  X TBA/lk TBA/jl PE-04/2012-04-01 / 18 9 22/09/2012 2. Evaluation – Visual inspection Scratches mark Defective Defective Deep scratches – Compromise package integrity Check inside surfaces for scratches. Inside deep scratches might cause package integrity problem. If there are any defects, corrective actions should be taken. PE-04/2012-04-01 / 19 2. Evaluation – Visual Inspection Overheated, Blistering and Bubbles Defective – Compromise package tightness Overheated Blisters Bubbles PE-04/2012-04-01 / 20 10 22/09/2012 2. Evaluation – Visual Inspection LS strip wrinkle / Fish bone Defective – Compromise package tightness Wrinkle in strip, most likely due to strip position too much on LS side. Too high spring pressure or temperature. Pressure Rool??? (con lan chia mep giay) PE-04/2012-04-01 / 21 2. Evaluation – Visual Inspection Overheated Defective Overheated Excessive settings or uneven pressure (LS roller may not in control) result in risk of affecting the performance. PE-04/2012-04-01 / 22 11 22/09/2012 2. Evaluation – Visual Inspection Blistering/Overheated Defective Blistering/Overheated Check for any blister or bubble along the heated zone of strip. The presence of blisters in the LS or SA side of the strip p indicates too high sealing setting, either energy or pressure PE-04/2012-04-01 / 23 2. Evaluation – Visual Inspection PE residue Defective – Blocked seal PE residue LDPE residue are trapped below the strip g the sealing g affecting PE-04/2012-04-01 / 24 12 22/09/2012 2. Evaluation – Visual Inspection Blocked seal Defective Blocked seal Strip and inside PE not seal PE-04/2012-04-01 / 25 3. Evaluation – M h i l Tear Mechanical T down d Longitudinal Sealing PE-04/2012-04-01 13 22/09/2012 3. Evaluation – Tear down Preparation Sample 1.Unfold the flaps of package sample 2. Cut two opposite corners 3. Empty the package content 4. Cut the sample corner to corner PE-04/2012-04-01 / 27 2. Evaluation – Tear down Preparation Sample 5. Open up the sample, rinse it with water and dry it. 6. Cut the package sample along the middle of LS (1) and LS air channel (2) Cutting line is (3) PE-04/2012-04-01 / 28 14 22/09/2012 2. Evaluation – Tear down Tear down evaluation – Check Overlap Pull off the outer layer where it is double, overlap. Check that the overlap is properly sealed since is giving strength to the final package. Good overlap when the seal is even and rupture at least on outside PE layer Double layer not complete separate Double layer must be complete separate PE-04/2012-04-01 / 29 2. Evaluation – Tear down Tear down evaluation – Bad/uneven seal Overlap PE-04/2012-04-01 / 30 15 22/09/2012 2. Evaluation – Tear down Tear down evaluation – Good Overlap Outer PE layer removed Outer PE and some fibred removed PE-04/2012-04-01 / 31 3. Evaluation – Tear down GOOD SEAL Separation between the two inner coatings When the strip is pulled off and one of the inner coating comes off with the strip (1) leaving a rupture edge (2) along the seal. PE-04/2012-04-01 / 32 16 22/09/2012 3. Evaluation – Tear down GOOD SEAL Separation between the Alfoil and the inside coatings When the strip (1) is pulled off and the two p inner coatings come off leaving the Al- foil uncovered PE-04/2012-04-01 / 33 3. Evaluation – Tear down GOOD SEAL Rupture in the paperboard When the strip is pulled outwards and all inner layers including the Al-foil come off with the strip (1), leaving paperboard fibres (3) PE-04/2012-04-01 / 34 17 22/09/2012 3. Evaluation – Tear down GOO SEAL GOOD S Separation in the LS strip When the strip(1) is pulled off and one of the strip is left on the packaging material. This can happen also in the cross, where LS and TS meet. PE-04/2012-04-01 / 35 3. Evaluation – Tear down Laminate PE GOOD SEAL Separation of laminate PE When all inner layers including the Al-foil come off with the strip ((1)) leaving gp part of the lamination layer (4) on the paper board. PE-04/2012-04-01 / 36 18 22/09/2012 3. Evaluation – Tear down Defective seal Cold or blocked seal When the strip (1) is pulled off and it comes off leaving the inner coatings unaffected or with a grayish surface. PE-04/2012-04-01 / 37 4. Evaluation – Red I k Injection Ink I j ti Longitudinal Sealing PE-04/2012-04-01 19 22/09/2012 4. Evaluation – Red Ink Injection Preparation of the sample 1. Unfold the flaps of package sample 2. Cut two opposite corners. Empty the package content and cut the sample corner to corner. 3. Open the sample ,rinse it with water and dry it PE-04/2012-04-01 / 39 4. Evaluation – Red Ink Injection Preparation of the sample Be careful not to over stress samples during their preparation PE-04/2012-04-01 / 40 20