United States Patent and Trademark Office has just announced a patent for Apple —— Harvard ultrasonic Bonding of Discrete Plastic Parts to Metal. It's a new combination of technologies apple has developed for portable devices, such as the iPhone, that it hopes will use Ultrasonic welding technology to replace the adhesive and permanently bind the metal and plastic parts of the device together.

Ultrasonic welding is not a new concept and is more reliable than adhesives. But when it comes to combining two completely different materials, such as plastic, the Ultrasonic welding process is difficult. If the design process of the product has to be changed from metal to plastic due to a combination problem, this is not ideal for many very sophisticated portable devices. Apple's idea is to make the surface of the metal bumpy, so that it can better combine the melted plastic material. When the melted plastic material comes into contact with the metal's rough surface, it gradually cools and forms, which is a good fit to the metal surface.

The patented technology can be applied to the external metal parts of the IPHONE and IPAD range as well as the internal plastic parts. It can increase the flexibility and diversity of product design, and the technology of combining metal and plastic can also be used in the production of products. Apple said in its patent filing that the patented technology would facilitate the integration of metal parts in the final stages of assembly.