DAD3350 US (Ultrasonic Spindle)Dicing with ultrasonic technology has been developed as a new application to support the processing of electronic components (ceramic parts) and optical devices (optical disc parts, optical transmission parts). Using ultrasonic technology will enable the processing of materials such as glass and ceramics, which until now have been difficult to cut with a blade.Issues when processing difficult to cut materialsWhen blade dicing difficult to cut materials such as glass, ceramics, metal and resin, the following issues can occur.1. Process current will increase due to the occurrence of blade glazing*1 and blade loading*2. If process current increases*3, various problems occur such as increased chipping and burring, blade breakage, abnormal blade wear and workpiece burning.a) The grit on the blade tip wears down and new grit does not become exposed. In this situation, the blade can not process normally.b) Workpiece cutting scraps and tape adhesive coat the blade tip and prevent the exposure of the grit. Similar to blade glazing, the blade can not process normally in this situation.c) The process current increases even if finer grit is used or the feed speed is increased. An increase in process current can be confirmed by an increase in the spindle current value.The usable blade variety is limited. Since it is necessary to select a bond that will appropriately wear to prevent blade glazing and loading, it is difficult to use a bond other than a resin. In addition, when selecting a grit size, it is necessary to use a comparatively large grit size from #320 to #600.Dicing with ultrasonic waves has been developed as one countermeasure for blade dicing issues with difficult to cut materials described above.The principle of dicing with ultrasonic technologyWhen dicing with ultrasonic technology, the forward and backward vibration from the ultrasonic wave oscillator, which is installed at the rear of the spindle, converts into a motion that travels through the spindle shaft and blade base, and expands in the blade radial-direction. Due to the vibration conversion principle, it is possible to achieve an ideal vibration direction for processing with ultrasonic waves (Refer to figure 1).

Figure 1: Vibration mechanism of the generated ultrasonic wave

Due to the ultrasonic wave vibration, the dicing blade momentary expands and contracts in the radial-direction and for very small intervals of time the grit repeatedly collides with the workpiece at high speed (Refer to figure 2). As a result, a microscopic fractural layer is generated on the processing surface and this significantly lowers the processing current (Refer to figure 3). Also, due to this ultrasonic wave vibration, the blade痴 cooling capability is greatly improved by the space produced between the blade and workpiece, and this leads to an improvement in process quality and blade life by preventing blade dulling and clogging.

Figure 2: Ultrasonic wave dicing processing mechanism