Stepped sonotrode and anvil energy director grids for narrow/complex ultrasonic welds of improved durability

摘要

A sonotrode and anvil are adapted for ultrasonic welding of work pieces, to produce a narrower weld region that exhibits greater durability, permitting use of less material per package. The horn-to-anvil contact is through a plurality of energy directors arranged into a three-dimensional grid pattern to be capable of distributed vibration-transmissive contact. The energy directors include a series of plateau surfaces regularly spaced apart in a first direction, and in a second direction that is orthogonal to the first direction, to form the grid pattern. The energy directors of the horn are configured to interlock with the energy directors of the anvil. The rectangular-shaped plateaus are spaced apart by angled side-surfaces that form valleys. A stepped transition to a corresponding region of reduced height for the energy directors of the sonotrode and anvil may form a cosmetic seal region with a lesser integrity, in addition to the main barrier seal.

主权项

1. A horn and anvil combination, said horn and anvil combination configured for use in ultrasonic welding of thin work pieces, for improved integrity in the packaging of solids and liquids with narrow welds:
said horn comprising:
a plurality of energy directors being spaced in a first direction and in a second direction to form a pattern, each of said plurality of energy directors comprising a shaped plateau surface with each side of said shaped plateau surface configured to transition into an angled side surface; each said angled side surface of each said plateau surface being connected with another side surface of an adjacent plateau surface, except at an outer periphery of said horn; said anvil comprising:
a plurality of energy directors being spaced in a first direction and in a second direction to form a pattern, each of said plurality of energy directors comprising a shaped plateau surface with each side of said shaped plateau surface configured to transition into an angled side surface; each said angled side surface of each said plateau surface being connected with another side surface of an adjacent plateau surface, except at an outer periphery of said anvil;and wherein said energy directors of said horn and said energy directors of said anvil are configured for alignment, whereby said side surfaces of said horn plateaus interlock with said side surfaces of said anvil plateaus in a pattern, in both said first direction and said second direction.