Ultrasonic welding

Patent metadata

Field	Value
Publication number	US-9333704-B2
Application number	US-201313842626-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Sep 17, 2012
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

The described embodiments relate generally to ultrasonic welding and more particularly to performing an ultrasonic welding operation while rotating one part relative to a mating part. A non-uniform energy director can be disposed along a mating surface of a first part. The energy director can maintain a constant cross-sectional area while having a smaller height near a pivot point for the rotation and a larger height away from the pivot point. The varying height of the energy director can allow the tip of the energy director to come in contact with a second part rotating relative to the first part at approximately the same time during the ultrasonic welding process.

First claim

What is claimed is:

1. A method for ultrasonically welding a first part to a second part, comprising: forming an energy director on a surface of the first part configured to mate with the second part, wherein the energy director has a non-uniform cross-section; and applying a vibrational energy to the energy director while rotating the second part relative to the first part;
wherein a height of the non-uniform cross-section increases proportional to a distance from an axis of rotation for the second part, the increase in height being configured to allow an entirety of the energy director to contact a mating surface on the second part while applying the vibrational energy.

2. The method as recited in claim 1 , wherein the non-uniform cross-section of the energy director maintains a constant cross-sectional area.

3. The method as recited in claim 2 , wherein the non-uniform cross-section of the energy director has a triangular shape.

4. The method as recited in claim 3 , wherein a product of a base of the triangular cross-section and a height of the triangular cross-section remains constant throughout the energy director.

5. The method as recited in claim 2 , wherein the non-uniform cross-section has a rectangular shape.

6. The method as recited in claim 1 , wherein the first part and the second part are made from a same material.

7. The method as recited in claim 6 , wherein the first part and the second part are made from a polycarbonate material.

8. The method as recited in claim 7 , wherein the energy director is integrally formed with the first part.

9. The method as recited in claim 1 , wherein the vibrational energy is applied to an outer surface of the first part using an ultrasonic welding horn.

10. The method as recited in claim 1 , wherein the first part is an AC inlet and the second part is a housing for a power adapter.

11. A system for ultrasonically welding a first part to a second part while rotating the second part relative to the first part, the system comprising:
a transducer coupled to a welding horn, wherein the transducer is capable of generating vibrational energy and transmitting the vibrational energy through the welding horn to the first part;
a vertical press coupled to the transducer and capable of adjusting a vertical position of the transducer and welding horn;
a fixture for holding the second part, wherein the fixture is rotatably coupled to a structural support by a rotation servo; and
a controller electrically coupled to the rotation servo, wherein the controller automatically controls a speed and angle of rotation of the second part during an ultrasonic welding process.

12. The system as recited in claim 11 , wherein the speed an angle of rotation are configured to allow a non-uniform energy director disposed on the first part to uniformly come into contact with a mating surface on the second part.

13. The system as recited in claim 12 , wherein the controller is electrically coupled to the transducer and automatically controls an amplitude and frequency of the vibrational energy.

14. The system as recited in claim 13 , wherein the controller is electrically coupled to the vertical press and automatically controls a vertical position of the transducer and welding horn.

15. The system as recited in claim 14 , further comprising at least one sensor capable of sensing a position and orientation of the second part, wherein the at least one sensor is electrically coupled to the controller and provides positional data to the controller.

16. A method for ultrasonically welding two parts together while allowing the parts to rotate relative to each other during the welding process, the method comprising:
receiving a first part formed from a thermoplastic material;
forming a second part including at least one energy director disposed on a surface configured to mate with the first part, wherein the at least one energy director maintains an approximately constant cross-sectional area while having a varied height, the varied height configured to allow the first and second parts to come into contact by rotating along an axis;
orienting an upper surface of the second part to be parallel to and in contact with a welding horn, wherein the welding horn is configured to deliver vibrations sufficient to melt the energy director during an ultrasonic welding process;
rotating the first part relative to the second part during the ultrasonic welding process, wherein the rotation allows all areas of the at least one energy director to come into contact with the first part simultaneously; and
continuing to rotate the first part until the mating surfaces of the first and second parts are approximately parallel and the at least one energy director melts, forming a weld between the first and second parts.

17. The method as recited in claim 16 , wherein height of the at least one energy director is lower near the point of rotation than the height of the at least one energy director is furthest from the point of rotation.

18. The method as recited in claim 16 , wherein the profile of the at least one energy director is triangular along the varied height.

19. The method as recited in claim 16 , wherein the second part is formed from a thermoplastic material.

20. The method as recited in claim 16 , wherein the at least one energy director is integrally formed with the second part.

Assignees

• Apple Inc

Inventors

• Bolanos Gerardo Salas
• Lancaster-Larocque Simon R
• Dolci Dominic E
• Lozano Cesar
• Smeenge James G

Classifications

• H05K5/10

  comprising several parts forming a closed casing · CPC title

• B29C66/71

  characterised by the composition of the plastics material of the parts to be joined (welding bar compositions B29C65/125) · CPC title

• B29K2069/00

  Use of PC, i.e. polycarbonates {or derivatives thereof}, as moulding material · CPC title

• B29C66/9674

  involving special data outputs, e.g. special data display means (B29C66/8748 takes precedence) · CPC title

• B29C66/9241

  by controlling or regulating the pressure, the force or the mechanical power · CPC title