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Issue link: http://pty.epubxp.com/i/827817
Initial Setup Inspect Part Process Validation Underwelded? Overwelded? Increase Pressure/ Downspeed, Energy, Amplitude Decrease Pressure/ Downspeed, Energy, Amplitude— Amplitude Profile? Changing to titanium horns with wear- resistant surfaces (carbide or titanium nitride, for example) is recommended. For fixturing, steel or hardened stainless steel is recommended. PART CONFIGURATION & TROUBLESHOOTING Having everything else right—equipment, materials, and process—won't mean much if the parts you're attempting to weld are not properly designed. But rather than try to review all of the details of a good part design here, let's focus instead on some of the basic causes of improper part design: • Lack of clearly defined project or applica- tion goals. Many application projects expe- rience difficulties when there is a "moving target" for testing and acceptance. For example, will the application require a drop test? A pressure test? And if so, at what values? These values are essential to pro- ceed effectively with the design of a sealing joint. Generally, acceptance criteria need early consideration and decision making if a design is to proceed smoothly. • Lack of understanding about the best joint types for particular applications. Sub- optimal joint designs often occur when a principal designer, who may only have a marginal understanding of plastics joining processes, moves a project forward only to find that an incorrect decision has been made and that part joint and weld charac- teristics haven't been properly considered. Often, such findings are made only after significant investment (mold completion, part production, and initial weld trials) has already been made. Once again, key part- and weld-related considerations (weld flash control and sealing type—hermetic, struc- tural, or both) ought to be determined early in the project. Collaboration with an ultrasonic- welding engineer in the initial stages of a project can help to identify key part criteria, better educate designers, and help to mini- mize or at least illuminate possible risks. FIG 5 The Pellbow® – to optimize your conveying system Better systems for brilliant products and higher margins. Learn more: www.pelletroncorp.com Better systems for brilliant products and higher margins. Better systems for brilliant products and higher margins. Reduced dust + No streamers = Less maintenance and production costs www.pelletroncorp.com www.pelletroncorp.com and production costs After setup, conduct an initial weld. If the weld fails inspection due to "under welding" (e.g., incomplete weld or inadequate weld depth), an increase in pressure/down speed, energy, or amplitude is probably needed. If the part is "over welded" (e.g. excessive weld depth) a decrease in the same parameters, or a diagnostic display of the weld amplitude, may be needed to identify the problem and bring the weld into specification. Overview of Troubleshooting/Parameter Adjustment Process 60 JUNE 2017 Plastics Technology PTonline.com Trouble shoot ing