There are many steps in building a single hard disk drive (HDD) that require fluid dispensing. Hard disk drives continue to shrink the available space for sub-components in order to maximize storage capacity within the external package designs and demand increased drive reliability to meet industry requirements for dependability of stored data in network environments. This in turn has led to multi-stage head gimbals and increased requirements for underfill dispensing to PCBs and flexible circuits. From piezo crystal attachment in head gimbals to final package assembly gasketing, Nordson ASYMTEK has been a trusted development partner for HDD manufacturers in providing precision fluid dispensers to meet the challenging demands of throughout the multiple stages of product manufacturing.
Examples of HDD manufacturing steps utilizing Nordson ASYMTEK fluid dispensers:
Piezo Attachment for Double-Stage Actuator Assembly
Current head gimbal assemblies require multi-stage actuators in order to increase read/write speeds of hard drives and shrink the sizes of the storage bits/sectors. The most common application in the market today is the Dual-Stage Actuator (DSA). A DSA assembly includes two piezo attachments and interconnections to the piezo. Nordson ASYMTEK provides the dispenser system to dispense die attach material on the assembly and to dispense conductive paste on the piezo for the interconnections. These dispensing applications need precise location accuracy because the DSA is quite small. Our dispensing platforms provide the accuracy as well as the operational speed for high-volume production.
Underfill dispensing for flip chip on flex circuit board
Nordson ASYMTEK is a world leader in supplying equipment for encapsulation and underfill on PCBs and flexible circuits. Precise motion controls allow underfill to be dispensed without bridging critical gaps, for example, as small as 1mm between dies. Jet dispensing on non-rigid, flexible circuits is the preferred assembly method because of the insensitivity to the dispense gap between the substrate and the jet. Thus, the dispenser can move to the dispense position faster and therefore have higher throughput than traditional needle dispensing.
Head Stack Assembly
For gimbal or head stack assembly, small dots of silver epoxy are used to electrically ground flex circuits to gimbal arms. Silver lines can also be dispensed to make electrical connections to MEMS actuators on heads. Nordson ASYMTEK has equipment from simple bench-top automation to high-speed, automated dispensing systems, capable of jetting dots of silver epoxy at rates of 50,000 dph.