Ultrasonic welding or cutting

Citation

(2000), "Ultrasonic welding or cutting", Assembly Automation, Vol. 20 No. 2. https://doi.org/10.1108/aa.2000.03320bad.009

Ultrasonic welding or cutting

Ultrasonic welding or cutting

Keywords: Welding, Ultrasonic

Applicant: SCA Hygiene Products AB (SE)Patent number: US5985065Publication date: 16 November 1999Title: Method of welding or cutting material ultrasonically

The present invention provides an apparatus and a method of welding or cutting a moving web of material transversely to its movement direction with the aid of ultrasonic means. According to a first embodiment of the invention, an abutment surface of essentially constant size is obtained during the entire welding or cutting procedure, therewith avoiding various technical problems relating to power outtake and punctiform wear. This is achieved by positioning an ultrasonic horn obliquely to the web of material to be worked, and by positioning a cylinder carrying ultrasonic anvil surfaces with its rotational axis parallel with the longitudinal axis of the horn, such that the web will travel between them. The anvil surface extends helically on the cylinder. The pitch of the helix is adapted so that the abutment surface between horn and helically extending anvil will move successively along the entire length of the horn as the cylinder rotates with a peripheral speed which is adapted so that the speed of the anvil surface at the welding point will coincide with movement of the web. By adapting the obliqueness of the ultrasonic horn and cylinder to the direction of movement of the web, and by selecting a commensurate pitch with regard to the helically extending anvil surface, the desired weld or cut can be made transversely to the movement direction of the web. In a second embodiment of the invention which is primarily intended to enable the speed of the web to be increased, the anvil is undoubtedly slightly helical, but constant contact between horn and anvil is not necessary.