To make a transducer by painstakingly micro-machining a brittle block of ceramic material can take many hours of work, though.

换能器需要用到陶瓷材料，而精密地加工一块精细陶瓷材料就要耗费几个小时工作时间。

To do all this, though, you need a device called a transducer.

但完成该过程，你不能缺少一台叫做‘换能器'设备。

Transducers are made from arrays of tiny piezoelectric structures that convert electrical signals into ultrasound waves by vibrating at an appropriate frequency.

换能器是由具有‘'效应一系列敏感元件机构组成。敏感元件机构通过‘定频'震荡将信号转换成超声波。

However GE, a large American conglomerate, is now proposing to make ultrasound transducers by " additive" manufacturing—or three-dimensional printing, as it is also known.

而GE作为美国一个庞大业集团正考虑采用‘对比添加'加工流程（或者又称大家所熟悉‘3D印刷'）来加工超声波换能器。

The GE process for making a transducer begins by spreading onto the print table a thin layer of ceramic slurry containing a light-sensitive polymer.

GE对加工换能器方法是首先在印刷台上撒上薄薄一层陶瓷粘土，其中混入一种光敏聚合体。

The waves are then reflected back from areas where there is a change in density and on their return the transducer works in reverse, producing a signal which the scanner can process into a digital image.

超声波会从密度发生变化介质反射回来，这时换能器会反向操作产生信号，再过扫描器处理，最后进行数字成像。