Hot Pin Pull Method New Test Procedure for the Adhesion Measurement for 3D-MID HARTING Mitronics Christian Goth in cooperation with: FAPS Thomas Kuhn, Gerald Gion, Jörg Franke 11 th International Congress MID 2014 Fuerth, Germany 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 1/20
Content HARTING AG in Biel, Switzerland Adhesion measurement for 3D-MID Test method hot pin pull Results of basic investigations Size of test structures Temperature profile Wetting of test structures Integration into series production Conclusion 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 2/20
HARTING AG, Biel, Switzerland HARTING Mitronics since 2003 we serve customer globally from our competence center in Switzerland with 50 employees whole MID process chain under one roof strengths: development and manufacturing services for individual 3D-MID components TS 16949 certified Target markets automotive lighting (interior, rear) automotive sensor and actuator industrial medical 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 3/20
Our 3D-MID serial applications in HARTING Mitronics target markets Automotive Medical Sensors Industry Others 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 4/20
From idea to serial production all manufacturing steps from one partner Development Tool shop Molding Laser structuring Inspection/Qualification Assembly Plating Cleaning 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 5/20
Influences to the adhesion force Design material Injection molding Handling geometry layout compound filler additive molding direction parameter gate damage contamination Metallization Cleaning process Laser structuring /activation Stress during lifetime thickness deposition rate ultrasonic water jet CO 2 snow jet frequency/ velocity/power hatch thermal chemical mechanical Packaging Adhesion measurement glueing/soldering wire bonding flip-chip people method 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 6/20
Conventional test methods Tensile force Adhesive/ solder joint Metallization Pull-off test F ten Pull-off tool Pin/Rivet Surface A Shear test electronic components Shear chisel Shear force F s Component Solder joint Metallization Shear test conductor track Shear chisel Shear force F s Metallization Source: HSG-IMAT, H. Willeck, Dissertation Chisel Conductor material with flake surface A Metallization Micro chisel F p Direction of substrate movement Tensil force F ten Peel test Tensile force Pull-off hook Eyelet Metallization with width b Solder/adhesive Direction of substrate movement Cross cut test/tape test GTO GT1 GT2 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 7/20
Conventional test methods Pull-off test Shear test electronic components Shear test conductor track Tensile force Adhesive/ solder joint F ten Pull-off tool Pin/Rivet Shear chisel Shear force Component Solder joint Shear chisel Shear force Metallization Surface A Metallization F s Metallization F s Micro chisel Peel test Cross cut test/tape test Chisel Conductor material with flake surface A Metallization F p Tensil force F ten Tensile force Pull-off hook Eyelet Metallization with width b Solder/adhesive GTO GT2 GT4 Direction of substrate movement Direction of substrate movement 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 8/20
New test method Hot Pin Pull Adhesion testing system Measuring head and copper pin with test substrate and solder paste Test equipment micro-material testing system 4000Plus Nordson DAGE copper pins are available with a tip radius of 100 µm, 300 µm or 450 µm in tinned or untinned versions New measuring head a special heatable cartridge can be programmed to apply a time-temperature reflow profile 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 9/20
Functional principal and test procedure Preparation manual insertion of copper pins with a diameter of 900 µm pin is held by a spring-loaded mechanism F ten Pin positioning with motorized axes (x,y,z) tinned pin: directly on the plain test structure untinned pin: into dispensed solder paste F T T F Soldering process pin temperature ramps up according to the defined temperature profile and is soldered to the metallized test structure cooling is achieved by pulsing compressed air along the pin and onto the test sample Measurement defined test temperature is reached: clamping mechanism to fix the pin automatically pull-off process and recording of force cross section after soldering w/o pull-off 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 10/20
Size of test structures Limited flexibility with standard tests shear test: limited by the pad dimensions / respectively component size pull-off test: requires test circles with a minimum diameter of 3.0 mm 0.6 0.7 0.8 0.9 1,0 1,1 Investigations: test circles with a diameter from 0.6 to 1.1 mm / from 1.1 to 3.0 mm this means areas from 0.28 mm 2 to 7.07 mm 2 material Vestamid HTplus TGP 3586 adaption of solder paste volume and temperature profile (1.3, 1.5, 1.9 and 3.0 mm) constraint of the test: entirely removed metallization and completely wetted pads 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 11/20
Size of test structures 25 20 Adhesion in N/mm 2 15 10 5 at least 10 measurements per specified value 0 0,6 0,7 0,8 0,9 1 1,1 1,3 1,5 1,7 1,9 2,1 2,3 2,5 3 Pad diameter in mm Hot pin pull test can be performed with pad diameters up to 3.0 mm with increasing pad diameter the adhesion in N/mm 2 decreases standard deviation is relatively low compared to the conventionally used test methods shear test: approx. 20 %, conventional pull-off test: > 20 % further optimization of temperature profile and solder paste volume is possible current recommendation for a test geometry: circle with a diameter of 1.0 mm 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 12/20
Temperature Temperature profile Further influencing factor: temperature profile to solder the pin to the test pad adherent connection without change in the composite Necessary peak temperature and temperature profile? 180 T3 T4 Test conditions material Vectra E840i LDS C 120 90 60 30 0 T1 T2 0 10 20 30 40 50 s 70 Time test circles with a diameter of 1.0 mm temperature profile adapted to the reflow soldering profile recommendation solder paste (SnBi), melting point 137 C T5 T6 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 13/20
Adhesion in N/mm² Temperature profile 10 8 6 4 at least 8 measurements per specified value 2 0 170 210 250 290 330 Peak temperature in C Temperature profile influences the adhesion strength increase of peak temperature decrease of the determined adhesion strength pre-damage of the metal-plastic composite due to high temperatures temperature profile should basically be defined as soft as possible effect depends on the substrate material 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 14/20
Wetting of test structures Test structure is not completely wetted with solder a: metallization is usually just partly pulled off the substrate b: even if the complete metallization is removed not reproducible influences Complete wetting of the test structure with solder c: metallization is pulled off completely from the substrate required for reproducible testing with the hot pin pull method a not completely wetted b not completely wetted c completely wetted 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 15/20
Integration into series production Important topic: integration of the test method into series production series product parts w/o any further modification of the layout and w/o additional test structures ideally: there is an insulated pad defined size of removed metallization optional: the test pad/conductor track must be isolated (e.g. solder resist, cutting) Investigations with 3D-MID position sensor for adaptive speed control size of the pad is 3.06 mm 2 (corresponding to a circle with a diameter of approx. 2 mm) material Vectra E840i LDS for this test series : the whole metallization was removed in 100 % of the tested pads (20 values) mean 4.86 N/mm 2, minimum of 3.90 N/mm 2, standard deviation below 10 % material was released with the metallization typical of LCP 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 16/20
Integration into series production Variation of laser power material Stanyl ForTii NC1119B laser power 7, 8, 9, 10 Watt test structure: circles with diameter of 1 mm on serial 3D part Adhesion in N/mm 2 20 18 16 14 12 10 8 6 4 2 0 16,53 17,01 15,20 15,35 7 8 9 10 Power in W at least 9 measurements per specified value Resolution of test method is sensitive enough for detecting process changes 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 17/20
Conclusion Fundamental topics of the hot pin pull test with the focus on the method itself. The investigations confirm that the hot pin pull method is an easy test procedure to determine the adhesion of metal coatings on thermoplastic materials: for all investigated test configurations the whole metallization was released test results show a low standard deviation below 10 % different pad sizes are possible current recommendation for a test geometry: circle with a diameter of 1.0 mm temperature profile should basically be defined as low as possible for reproducible test conditions: test should be proceeded with completely wetted structures the hot pin pull test allows the direct use of serial parts resolution of test method is sensitive enough for detecting process changes To establish the hot pin pull method as a standard testing method for 3D-MID defined parameters are necessary, e.g.: machine parameters (e. g. take-off speed) test geometries (e.g. 1.0 mm circles) amount of solder paste (related to the test pad) temperature profile (related to the test pad and amount of solder paste) 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 18/20
Special thanks to FAPS, University of Erlangen-Nuremberg Thomas Kuhn, Gerald Gion, Johannes Hörber DAGE Nordson Corporation Armin Struwe 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 19/20
christian.goth@harting.com 2014-09-25 Hot Pin Pull Method Adhesion Test for 3D-MID Dr. Christian Goth HARTING Mitronics 20/20