Comparison Of Newly Developed Ultrasonic Welder To .
COMPARISON OF SERVO-DRIVEN ULTRASONIC WELDER TO STANDARDPNEUMATIC ULTRASONIC WELDERMiranda Marcus, Paul Golko, Steve Lester, Leo KlinsteinDukane Corporation – Intelligent Assembly SolutionsAbstractUltrasonic welding is one of the most widely usedprocesses for bonding polymers, valued for its speed,flexibility, and low cost. Recently there has been a call formore controlled and consistent welding processes,especially in the medical field. Dukane has worked tomeet this demand through the development of a new iQseries Servo-Driven Ultrasonic Welder with MeltMatch technology.Careful comparison, detailed here, has shown that theservo-driven welder can provide more consistent resultsthan the standard pneumatic welder can. The newlydeveloped welder also offers a number of user friendlyergonomic features, superior Graphic User Interface withEthernet connectivity (iQ Explorer) as well as moreaccurate process control capabilities.IntroductionAlthough ultrasonic welding was first developed over45 years ago (1), and has been widely used in the industryfor over 25 years (2), there have been few fundamentaldesign changes in the process. Ultrasonic welders havelong been a popular choice for joining thermoplastics inthe industry due to several factors.The equipment is compact, easy to incorporate intoautomation (3), and economical. Additionally, ultrasonicwelders can produce welds that are high quality (4) in ashort cycle time. The greatest advantage of ultrasonicwelding, however, is the ability to use very precise processcontrol (5).Ultrasonic welding can be defined as the “joining [ ]of thermoplastics through the use of heat generated fromhigh frequency mechanical motion (6).“ This end isachieved through the use of a generator, transducer,booster, and horn (6). The generator converts standard linepower into high frequency AC voltage that is then passedthrough the transducer (1).The transducer consists of piezo-electric ceramics thatexpand and contract at the same frequency as the currentwhen alternating voltage is applied to each side of theceramics (7). This sinusoidal mechanical vibration is thenpassed through the booster and horn into the part (1).As the vibrations travel through the part, they generateintermolecular friction at the joint interface, which createsmelt and lead to molecular bonding (6). The amplitude ofthe wave can be increased or decreased by changing thebooster gain ratio (7).This process depends on several important factors toobtain a robust weld: amplitude, weld time, weld pressure,weld speed, hold time and hold pressure are a few of themost important factors (1). Dukane’s iQ Servo Welderallows novel ways to control these welding parameters.Weld and hold speed, pressure, time, and distance areinterdependent factors that can not be easily correlatedusing a standard pneumatic welder. The use of a servodriven ultrasonic welder, however, offers shorter controlsystem acting times, allowing faster application of weldpressure (8) and greater control of the welding process.Previous studies have demonstrated that a constantvelocity, such as can be obtained using a servo-drivenprocess, provide increased weld strength, reduced standarddeviation, and a generally more robust process (9). Aservo-driven weld process provides a constant velocityduring the weld, a dynamic applied force, and precisedistance control.As early as 1980, research has shown that the weldingpressure has a significant effect on weld strength whenusing ultrasonic welding (2). The application of a staticforce has long been used to provide good contact betweenthe horn and parts for improved energy transfer and topromote flow of the energy director (10). Research hassuggested, however that a dynamic force can producegreater weld strength when properly applied (11). Forceprofiling, generally decreasing the weld pressure during theweld, has been shown to maximize weld strength whilesimultaneously decreasing weld cycle time (1).Velocity of the weld has historically been moredifficult to control than weld pressure, but previous studieshave indicated that weld speed has a significant effect onultrasonic welding results (12). It has also been shownthat, when a constant force is applied, the welding speedvaries depending on the type of polymer used.Specifically, it has been found that semi-crystallinepolymers have a faster welding speed than amorphouspolymers. This is due to their different melt properties;semi-crystalline thermoplastics have an absolute meltingtemperature while amorphous thermoplastics have agradual melting temperature (9). Thus, the use of a servodriven welder presents an unprecedented opportunity tomatch the weld velocity to the natural melting properties ofthe material being welded through the used ofMeltMatch technology.The iQ Servo-Driven Ultrasonic Welder also offerssignificantly more precise control of weld distance. This isANTEC 2009 / 1714
very important as the residual melt layer thickness isdirectly related to weld strength (8). In fact, the collapsedistance of the weld was identified nearly ten years ago asthe most dominant factor affecting weld strength (13).One of the most persistent problems preventing easyand even more wide spread use of the ultrasonic welding asa joining method is the difficulty of finding an optimumwelding parameter set (8). The development of a newservo-driven welder is an important step to ease theprocess of weld application set-up by providing superiorprocess control.Multiple testing stages were implemented to fullycompare the two welders. First, three hundred parts werewelded on each welder. These samples were run usingoptimized parameters on the pneumatic welder and theclosest matching parameters on the servo welder. Both theweld strength and the collapse distance were measured forthese trials. Collapse distance was measured by using adrop gauge to measure the height of the parts before andafter welding. A gauge reliability and reproducibilityexperiment was run on this measurement process to ensurerepeatable results. The settings used for these tests areshown below in Table 1.Table 1: Weld Parameters for 300 sample runExperimentationWeldHoldTriggerForce Distance Speed Pressure Distance Speed PressureServo ExperimentationDue to the fundamental difference between the newDukane Servo-Driven Ultrasonic Welder and the standardpneumatic-driven ultrasonic welder, a whole new approachto welding had to be implemented. In order to discover theeffect of the newly available operating parameters,extensive experimentation had to be completed.These trials were completed using the AWS standardI-Beam welding test specimen for thermoplastics. Figure 1shows a simplified drawing of this design. ABS waschosen for these initial experiments for its ease ofweldability. A custom fixture and horn, and EDM‘d pulltesting apparatus were manufactured specifically for theseexperiments, as shown in Figure 2.The first concern was to determine the repeatability ofthe servo motor. Therefore, three consecutive parts werewelded and their weld speed graphed in the first trial.Further tests investigated constant velocity at varyingspeeds, rising velocity, and falling velocity to determinetheir effect on weld strength.Also studied was the effect of pre-loading the parts;every previous trial used a pre-trigger. Each of thesesubsequent experiments were completed using both theshear and energy director joint. Additional processoptimization was later completed using polycarbonateround parts. The focus of these later runs was to reducestandard deviation. A simplified drawing of the part usedfor these trials is shown in Figure 3.Servo vs. Pneumatic ComparisonAll comparative testing was performed using the newDukane iQ series Servo-Driven Ultrasonic Welder withMeltMatch technology and the standard Dukanepneumatic welder. Testing was performed using the sametransducer, booster, and generator with both presses tominimize variation.These tests were done using the AWS standard I-Beamwelding test specimen for thermoplastics, with a shear joint(Figure 1). The material chosen for these tests waspolycarbonate. The same fixturing was used as isdocumented in Figure 2.1715 / ANTEC 24.5kPa-Pneumatic 133.40.762-241.30.127-275.8After this, a follow-up experiment was run with fiftyparts welded on each machine. For this second set, thesame basic parameters were used for the pneumatic welder,but optimized settings were used for the servo. The settingsused for these tests are shown below in Table 2.Table 2: Weld Parameters for Follow-Up TrialsWeldHoldTriggerForce Distance Speed Pressure Distance Speed 9-0.12724.5-Pneumatic 133.40.762-206.80.127-275.8Results and DiscussionServo Parameter OptimizationThe first trial set showed excellent repeatability of theservo motor. These results are graphed in Figure 4. Thetime vs. distance curves for three welds at the samesettings are virtually identical.This result is veryimportant as it demonstrates consistency of the Dukane iQServo-Driven Ultrasonic Welder. Once this is established,subsequent efforts can be focused on using the newfeatures made available by this machine to improve weldquality and repeatability.Figure 5 shows the time vs. distance and power curvefor the speed profiling experiment using the shear jointsamples. It was demonstrated that increasing speed resultedin the greatest weld strength for the shear joint, whiledecreasing speed resulted in the greatest weld strength forthe energy director joint. Table 3 below shows averageweld strength for each speed profile tested.
Table 3: Speed Profiling Weld Strength ResultsSpeed Profiling Weld Strength Results (N)#123Ave.Shear Jointfor the energy director joint with increasing load, as shownin Table 5 below.Energy e 5: Pre-Loading Weld Strength ResultsPre-Load Weld Strength Results (N)#12This information indicates a fundamental difference inthe melting characteristics of the two joint designs thatshould be noted. Falling weld speed creates forcedcompression of the shear joint which could prevent meltinitiation at the surface and allow less heat in the joint,leading to fracture instead of welding. Rising weld speed,on the other hand, would cause a slow initiation of melt,allowing plenty of heat to dissipate into the shear, and thena fast push through the joint. This phenomenon likelyexplains why falling speed led to the lowest strength withthe shear joint, while rising speed led to the highest.The energy director joint, however, would reactdifferently to the speed profiling. A rising speed may notachieve the same level of melt initiation with the smallercontact area of an energy director. Then the parts arequickly propelled together, squeezing out the melt ratherthan mixing it between the two parts. A falling speed onthe other hand causes quick melt initiation, for which thesmall contact area of the energy director is better equipped.Then the parts are slowly compressed, allowing more timefor melt mixing at the joint, for a stronger weld.Figure 6 shows the time vs. distance and power curvesfor the speed variation experiments using the energydirector samples. It was demonstrated that slower speedresulted in the greatest weld strength for both joint designs.Table 4 below shows average weld strength for each speedmagnitude tested. It is unsurprising that slower speedsresulted in greater strength as this allows more time formelt to form.Table 4: Speed Variation Weld Strength Results3Ave.Shear Joint240 N378 N98 N240 N378 se results are most likely due to the differentamount of initial contact area for each part. The shear hasgreater initial contact area, and therefore benefits frommore compression prior to welding, allowing the surfaceasperities over the large surface area to be brought intomore intimate contact. On the other hand, the energydirector provides a very small initial contact area; greaterpre-loading is not necessary and may lead to flattening ofthe peak.Experimentation with the round parts using theDukane iQ Servo-Driven Ultrasonic Welder resulted in astandard deviation of 1.9% of the weld strength at theoptimum weld parameters. Figure 8 shows the effect ofweld speed and amplitude on standard deviation for asample set of ten to fifteen parts. Decreasing weld speedand amplitude were found to decrease the standarddeviation, while weld distance and hold distance had noindependent effect.Servo vs. Pneumatic ComparisonIn the initial run of three hundred I-Beam parts, thepneumatic and servo welders produced very similar results.Samples welded with the servo welder, however, showedslightly greater weld strength and lower standard deviationof that weld strength and the collapse distance, as shownon Table 6 below.Table 6: Comparison of 300 Sample RunSpeed Variation Weld Strength Results (N)#123Ave.Shear JointEnergy Director98 NCollapse (mm)Energy 256527583198258928481775299827312501552672334519A graph of time vs. distance and power when preloading of the parts was implemented is shown in Figure 7.Pre-loading the parts consists of applying force to the IBeam before triggering the ultrasonic vibration. Using thisfeature was found to increase weld strength for the shearjoint with increased load, while decreasing weld strengthStrength iation (%)3.7%3.4%14.2%14.0%The follow-up experiment results showed that theparts welded with the servo achieved greater weld strength,lower standard deviation in the collapse distance, andequivalent standard deviation of the weld strength to theparts welded with the pneumatic welder. This is due tooptimization of the servo welding parameters that was laterimplemented.Approximating the pneumatic processprevents full realization of the potential of the iQ Servo-ANTEC 2009 / 1716
Driven Ultrasonic Welder with MeltMatch technology.In these follow-up experiments, the welder was optimizedtaking into account its unique parameters to increase weldstrength and repeatability.Figure 9 shows the collapse distance and power overthe time of the weld for the weakest, strongest, and averageweld strength as welded by the servo welder. Figure 10shows the same for the pneumatic welder.Figure 11 shows the relationship between weldstrength and collapse distance for parts welded by bothwelders. It is interesting to note here that the collapsedistance of the pneumatic welder shows a general positivecorrelation to weld strength, as is typically reported. Thistrend is not the same, however, with the servo welder.This is a great indication of the primary differencebetween the two welders. The pneumatic welder relies ona static pressure to compress the two parts, collapsedistance is based on the amount of melt that is formed andpushed out of the way. Greater collapse means more meltand causes greater strength. The servo welder, on the otherhand, will collapse the parts at the same speed, and to thesame distance, whether or not there is melt being produced.Therefore, collapse distance cannot be the same indicatorof weld strength as it has historically been when using thestandard pneumatic welder.Table 7, below, shows the results of this lastexperiment in terms of average weld strength and standarddeviation obtained with each welder. Here it is obviousthat when the servo welder is optimized using its specialfeatures, such as MeltMatch , instead of approximating apneumatic weld, greater weld strength and more repeatablecollapse distance can be achieved.While the data below shows a small decrease instandard deviation with the pneumatic welder, thedifference is not statistically significant. It was notedduring pull testing that AWS I-Beam samples would oftenbreak on one side first, then this crack would propagatethrough the weld in a shear mode. This phenomenon islikely the cause of much of the variation of weld strengthin these results. It was later determined that round partscould eliminate this effect, and this led to our experimentswith them as described in the previous section.AcknowledgmentsWe wish to thank Héctor Dilán of HDI Inc for his helpwith initial testing.We are grateful to Alex Savitski of Baxter Healthcarefor providing test samples.References1.2.3.4.5.6.7.Table 7: Servo v. Pneumatic Weld ResultsCollapse (mm)Ultrasonic Welder with MeltMatch technology cangenerate greater weld strength and more consistentcollapse distance than the standard pneumatic welder,when optimized weld parameters are used on both welders.Second, the new servo-driven ultrasonic welder offers avast array of new possibilities for the future of plasticwelding.With the new Dukane iQ Servo-Driven UltrasonicWelder, greater control of ultrasonics welding is possible,allowing a level of consistency that has never before beenreached.Many new research opportunities have been opened upby the development of this new equipment. One of themost promising avenues to explore is the possibility ofadjusting the servo welder speed profile to match thenatural melt layer formation in the part. It would also beinformative to pursue the further comparison of thepneumatic to the servo welder using the round parts, toimprove repeatability of the weld strength results.Strength iation (%)3.9%1.1%19%20.5%8.9.10.11.Conclusions and Future Work12.Two important conclusions can be drawn from theseexperiments. First, the new Dukane iQ Servo-Driven13.1717 / ANTEC 2009Handbook of Plastics Joining – A Practical Guide,Plastics Design Library, USA (1997).Frankel, E.J. and K.K. Wang. Polymer Engineeringand Science, 20, p. 396-401 (1980).Stokes, Vijay K. Polymer Engineering and Science,29, p. 1310-1324 (1989).Liu, Shih-Jung, Wen-Fei Lin, Bo-Chien Chang, GwoMei Wu. Antec Conference, (2000).Park, Joon. Antec Conference, (2002).Guide to Ultrasonic Plastics Assembly, DukaneCorporation, USA (1995).Rotheiser, Jordan. Joining of Plastics – Handbook , Ohio (1999).Haberstroh, Prof. Dr.-Ing. Edmund and Dipl.-Ing. KaiKuhlman. Antec Conference, p. 43-46 (2004).Holt, Ken. Antec Conference, p. 2860-2864 (2005).Benatar, Avraham and Zhang Cheng. PolymerEngineering and Science, 29, p. 1699-1704 (1989).Van Wijk, H., G.A. Luiten, P.G. Van Engen and C.J.Nonhop. Polymer Engineering and Science, 36, p.1165-1176 (1996).Dilán, Héctor, Ken Holt, and Gregorio Velez. AntecConference, p. 47-51 (2004).Park, Joon and Jim Liddy. Antec Conference, (2000).
Collapse Distance (mm)Repeatability of Servo Welder0.090.080.070.060.050.040.030.020.01000.02 0.03 0.05 0.06 0.08 0.09 0.11 0.12 0.14 0.15Time (sec)Figure 4: Repeatability of Servo MotorShear JointConstantConstant1.30Figure 1: AWS I-Beam Welding Test Specimen 01500.80Power (W)Distance (mm)1.101000.70500.600.500.00 0.050.100.15 0.200.25 0.300.350.400.4500.50 0.55Time (sec)Figure 5: Speed Profiling with Shear JointEnergy Director2.54 mm/s2.54 mm/s0.73.81 mm/s3.81 mm/s1.27 mm/s1.27 mm/s1000900Distance (mm)0.68007000.56005000.4400Power (W)Figure 2: Horn, Fixture, Pull-testing 5Time (sec)Figure 6: Speed Variation with Energy DirectorFigure 3: Round PartsANTEC 2009 / 1718
Shear Joint1.3Pneumatic240 N240 N378 N378 N3001.001.22500.91500.81000.7Distance (mm)2001Power (W)Distance 05250.604500.503750.403000.30
Careful comparison, detailed here, has shown that the servo-driven welder can provide more consistent results than the standard pneumatic welder can. The newly developed welder also offers a number of user friendly e
Ultrasonic distance meter can be used to measure distance without contact, which is the use of ultrasonic wave at 40 KHz for distance measurement. The ultrasonic distance meter employs an ultrasonic module that consists of an ultrasonic transmitter and receiver, along with an ATMEGA 328microcontroller.
ultrasonic as significantly more aggressive ultrasonic cavitation within the ultrasonic tank, resulting in faster and more efficient cleaning in reduced time. (It should be noted that the vast majority of the ultrasonics produced by the various competitive ultrasonic manufacturers utilize the older non-sweep ultrasonic technology which can be seen
Ultrasonic testing was done prior to mechanical testing to eliminate concerns about damage occurring in the sample which would affect the ultrasonic measurements. An ultrasonic transducer was placed on the broad surface of the flat plate so that wave propagation would be in the c-axis direction. An ultrasonic signal was passed through the sample.Cited by: 3Publish Year: 1999Author: M. L. Kaforey, C. W. D
Dec 12, 2008 · OLYMPUS XMS-310 ULTRASONIC TRANDSDUCER Our system also contained an ultrasonic transducer, which was provided to us by Honeywell FM&T. They gave us the Olympus XMS-310 Ultrasonic Transducer as that is what they are using for their testing procedure. The ultrasonic transducer must maintai
the ultrasonic gas flowmeters' measurement range is less than 30m/s. This paper mainly considers the application of the ultrasonic flowmeter for high-speed gas flow mea-surement. At first, the ultrasonic propagation characteris - tics in the high-speed gas medium are analyzed, then, the effects of the flow rate on nonlinear ultrasonic .
1.1 Ultrasonic metal spot welding In ultrasonic metal spot welding, two (or more) metallic partners are joined in a discrete area. It is the most relevant ultrasonic welding technology in power electronics appli-cations, other ultrasonic welding technologies join plastic parts and/or form continuous joints.
foils welding, copper cable bonding, and ultrasonic processing of liquids. The aim of the paper is to present a novel design of an ultrasonic welding generator. 2. Ultrasonic welding machine. Example of an ultrasonic welding machine is presented in Figure 1. Fig. 1. Ultrasonic welding machine.
Ultrasonic welding machines for plastic parts Company foundation Ultrasonic generators Company Development Ultrasonic Welding Technology Foundation of Herrmann Ultrasonics Co. Ltd. China DIALOG process visualization 1961 1969191 1984 1989 2000 2011 1965 1973 1994 Marketability ULTRALINE First digital ultrasonic generator
