New paradigms for the design, manufacturing and operation of food processing and packaging equipment 3rd Presentation of Final Workshop PARADIGM 1 DEMONSTRATOR ELEMENTS Aimed at the rationalization of components and cost, increase of yield and of hygienic design Bonding and Friction Stir Welding for the assembly of AISI 316 carpentry as alternatives to TIG welding Project web site: http://www.npfp.it/en

1. Reduced laminar flow tunnel of filling machines:
bonding and Friction Stir Welding for the assembly
of AISI 304 carpentry as alternatives to TIG welding
Ing. Filippo Dazzi
Sidel

2. NPFP 2
TIG WELDING vs. ADHESIVE BONDING IN FILLER REDUCED ENCLOSURE TUNNEL FINAL ASSEMBLY
 Required operations for filler housings assembly in final phase
 Welding blocks any other operation on the machine (piping, cabling)
 For adhesives needed manual or pneumatic applicators and locking devices
 For welding needed welder machine, inhert gas and chemicals for pickling
 In terms of LT (including curew time of adhesive) adhesive bonding is 40% time saving respect
to welding.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
- CASO 1 CASO 2 CASO 1 CASO 2
- CONFIGURAZIONE 1 CONFIGURAZIONE 2
LEADTIME**[%]
SALDATURA
DISPOSITIVO PNEUMATICO
DISPOSITIVO MECCANICO
Adhesives vs. welding: benefits
2
𝐿. 𝑇. [𝑔𝑔] =
𝑡 𝐿𝐴𝑉𝑂𝑅𝑂 [ℎ]
𝑛 𝑂𝑃 ∙ ℎ 𝐿𝐴𝑉𝑂𝑅𝐴𝑇𝐼𝑉𝐸[ℎ/𝑔𝑖𝑜𝑟𝑛𝑜]
+
𝑡 𝐹𝐼𝑆𝑆𝐴𝐺𝐺𝐼𝑂 [ℎ]
24
Adhesive joining requires
about 1/6 working time
compared to welding**
TIG WELDING ADHESIVE BONDING
Edges cleaning Surfaces cleaning
Tack welding after positioning Adhesive deposition
Welding execution Adherends
Chemical pickling of welded zone Cure time
**LT estimation from a previous project on CSD filler reduced enclosure tunnel

3. NPFP 3
CSD Filler
WATER Filler
Reduced enclosure housings tunnel
TECHNICAL SPECIFICATIONS
 Aggressive environment
 Butt or corner joints
 1.5-2 mm thick AISI 304 sheet
 Loads: only gravity and dynamic actions during transport
 Maneuverability within 24 hours of assembly
 Duration: 20 years
 Cleaning with chemically aggressive agents
 TMAX 40°c (occasional near 70°C)

4. NPFP 4
Adhesives selection for the application
1) MARKET ANALYSIS
 Known reference of Henkel adhesives (2K epoxy, MS) tested in the past for similar application;
 Suppliers involved: 3M, Sika, Dow, Elantas;
 Requirements:
• Good adhesive strenght on stainless steel;
• Resistant to water, alkali and acids (v. 1.1);
• Cure at TROOM (mandatory) and joint transportable after 24 h
2) SUPPLIERS CONTACT
o Selection through the support of Supplier’s technical consultants;
o Selection of a short draft of applicable adhesives;
3) ADHESIVES DRAFT
o 3M: 7240 (2K epoxy);
o Sika: Sikaflex 221 and Sikaflex 252 (1K flexible PU) to be applied using a tape as support;
o Elantas: Elan-tech® AS 50/AW 50 (2K epoxy);
o Dow: no answer

5. NPFP 5
o Complete immersion condition:
‒ Less representative of real foaming done during COP cleaning
+ More severe on adhesive bonding between adhesive and metal surface
Experimental COP test
 Target: adhesive bonded joints behavior in contact with COP chemicals;
 Chemicals: Acid solution (Diversey VE9 Enduro ECO) - Alkaline solution (Diversey Diverfoam
VF34)
 Total contact time: 1200 h (corresponding to total contact time for estimated machine life)
 Intermediate step of 600 h to monitor strenght evolution with contact time;
 Temperature: max T reached during COP cleaning (40°C)
 Benchmark: residual lap shear strenght (according to UNI 1465 / ASTM D 1002) after
immersion steps, compared to lap shear strenght of as cured samples
1
2

6. NPFP 6
COP tests: synthesis
1
2
As cured
(White)
Adhesive 2Adhesive 1

7. NPFP 7
Output of COP tests:
 Adhesive 2 shows high rate of failed (de-bonded) samples both in acid and alkaline
solution  DROP-OFF
 Adhesive 1 showed failure of samples near the end of conditioning time, maintaining
good average residual strength -> test re-run using primer prior to bonding
2 - acid1 - acid
1 - basic 2 - basic

8. NPFP 8
 Only epoxy adhesive 1 tested (output of COP test 1)
 Samples realized applying primer on aderhend surfaces prior to samples joining;
 Benchmarks:
 Residual lap shear strenght after conditioning steps, compared to lap shear strenght of as cured
samples
 Increased intermediate steps to map with higher precision the variation of residual strength
 Absence of samples de-bonded inside chemical solution;
COP test with primer
 COP test to be completed by beginning of June 2018 – NO failure after 1000 h
1

9. NPFP 9
 Friction stir welding (FSW) welding process has been inquired for reduced enclosure housings
application
 Benefits vs. arc welding:
 Low T technique – less thermal deformation – no thermal altered zone
 High advancing speed of the spindle
 Necessary verification steps:
 Mechanical resistance of FS welded joints
 Necessary post treatment for welded zone pickling
 Corrosion resistance of welded zone
 Study of application of the technology to filler housings assembly
 For sperimental activities used butt joints with AISI 304 sheets of th. 2mm
FSW technology application to reduced enclosure
9
SOL. ACIDA VE9

10. NPFP 10
10
SOL. ACIDA VE9 SOL. ACIDA VT70
 Mechanical resistance tests done according to ASTM E8-08
 Tensile strenght equal to base material – 600 Mpa vs. 500-700 MPa of AISI 304
 Post treatment necessary to guarantee oxides removal from welded zone:
 Chemical pickling not enough to remove surface oxides and residual burrs
 Mechanical grinding needed to ensure acceptable roughness
FSW technology application to reduced enclosure

11. NPFP 11
OUTPUT
 FSW welded joint require mandatory mechanical post treatment;
 FSW welded joint (after treatment) shows same mechanichal and chemical resistance as base
material
 At the present time costs related FSW machine availability too high for available budget;
 Corrosion resistance tests done on samples cut from th. 2 mm FS welded sheet in AISI 304,
following same protocol of COP test used for adhesives;
FSW technology application to reduced enclosure

12. NPFP 12
Demonstrator design
 Targeted small size (60 valves) flat water filler machine;
 Demonstrator will consist in the complete joint of two modules of reduced enclosure housings
 Guidelines followed:
 Maximize adhesion surface - by using a proper surface extension the stresses in tension and shear can
be maintained < 1 MPa
 Design joints to make adhesive to be stressed in SHEAR and not in TENSION
 No changes in slope and bending of lower surfaces – all bottom surfaces must be self-draining
(hygienic design)
 No adhesive joint line exposed frontally to COP spraying
GOOD WEAK GOOD WEAK

13. NPFP 13
Demonstrator design
Weld lines to join
housing modules
ROTARY
FIXED
 Assembly interface section
as is today

14. NPFP 14
Demonstrator design
 Addition of sheet elements to realize multiple overlaps (in greed added / modified parts)

15. NPFP 15
Demonstrator design
 Addition of sheet elements to realize multiple overlaps

16. NPFP 16
Demonstrator design
Weld lines to join rotary part sectors
Section view:
Double lap joint
From outside
From inside
 Redesign of rotary part sectors to realize overlap with the following sector

17. NPFP 17
Demonstrator realization
 Demonstrator will consist in 2 modules of fixed part + 2 sectors of rotary part
 Assembly to be performed in Sidel facilities in July 2018 – adhesive supplier will provide
needed adhesive and primer
 Detailed assembly cycle to be defined
(in blue columns to be used as supports)

18. NPFP 18
Participants to this activity
• Alessandro Pirondi, Emanuela Cerri
• Marco martinelli, Filippo Dazzi
Thanks you for your attention!
www.npfp.it