| 摘要 |
A process for heat element welding thermoplastics with high melting points and/or low viscosity melts involves pressing the sections to be joined on a heating element to remove small surface irregularities, heating the sections to the melting point, removing the heating element and pressing the sections together. A process for heat element welding thermoplastics with high melting points and/or low viscosity melts, e.g. polyamide, involves pressing the sections to be joined on a heating element to remove small surface irregularities, heating the sections to the melting point, removing the heating element and pressing the sections together. The heating element consists of a heated sonotrode, and the sonotrode temperature during the initial surface irregularity removing phase, is below the welding temperature. During the warming phase heat is applied uniformly to the contact surfaces, and then ultrasound is applied during which the sonotrode oscillates. The ultrasound causes the temperature at the contact surfaces to rise to the weld temperature. Amplitude is then increased causing a further temperature rise and reduction in melt viscosity. The sonotrode is then released and the sections are rotated to the weld position and pressed together. |
