DETROIT-Needles and thread are becoming materials of the past in many shops that make plastic auto parts as ultrasonic welding takes over more tasks. And the technique often is used to join dissimilar materials. Equipment makers say users are welding a diversity of materials in efforts to cut production times and manufacturing costs.
Examples include: film to textiles; fabric to plastic armrests and other interior panels; and even shredded cotton-rag and polyester-rag insulation pads to polypropylene and ABS door panels, says Doug Robertson, director of worldwide automotive sales for Dukane Corp.'s Ultrasonic Division, based in St. Charles, Ill.
Even as changes come in the materials being welded, more of the welding is being done on a continuous basis rather than a piece at a time, he said at the recent SAE International Congress & Exposition in Detroit.
Continuous processing is being made possible by dramatic improvements in equipment and controls, Robertson said.
``The industry is using very sophisticated active controls with equipment networking,'' he said. Data acquisition relates to statistical process control and allows manufacturers ``to grab parameters like temperatures, energy, weld distance and peak power. It all helps produce quality product with assurance.''
In Danbury, Conn., Branson Ultrasonics Corp. said its newest equipment adds a new dimension to the control picture because it can increase or decrease amplitude instantaneous-ly during the weld cycle.
``That means the best ampli-tude for each phase of a weld can be used instead of just one amplitude for an entire cycle,'' said Bonnie Stephens, manager of marketing communications.
She said benefits of amplitude control include fewer rejects, greater consistency, stronger welds and better appearance.
In addition to thread and needle, ultrasonic welding can replaces vibration welding, heat staking, mechanical fasteners, glue, and staples. Robertson said the technique can be used to cut, seal and attach plastics. As designers change shapes, such as making auto interiors smoother with rounded contours, even automated welding equipment can accommodate the changes.
