Piezo-Actuator Cartridge for Guzik V2002 Spinstand

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  • Typical Non-Repeatable Run-Out (NRRO) 0.35-0.60 nm (0.014-0.024 µInch)*, 1sigma
  • Servo Bandwidth 2-3 kHz
  • Improved Test Time
  • Estimated Spinstand Capability 420-720 kTPI

The new generation of Guzik cartridges** is equipped with Piezo actuator to achieve higher servo closed loop bandwidth. The typical bandwidth is in the range of 2-3 kHz. This allows for non-repeatable run-out reduction down to 0.35-0.60 nm (0.014-0.024 µInch)*, 1sigma. The higher servo bandwidth also improves seek time, which leads to test time improvement for several tests.

TPI Capability

The TPI capability of a tester is normally calculated such that the error of the measurement does not exceed some percentage of the magnetic head Track Size. One of the recommended criteria is that 1sigma of NRRO does not exceed 1% of the Track Size. Based on this criteria the 0.35-0.60 nm (0.014-0.024 µInch) would be 1% of the 1.4-2.4 µInch wide head, which means that the V2002 tester capability with Piezo-Actuator Cartridge is 420-720 kTPI.

Non-Repeatable Run-Out Improvement

The figures below illustrate the NRRO 0.35-0.60 nm (0.014-0.024 µInch) with Piezo-Actuator Cartridge. The data was measured using 7200 RPM product.

Figure 1: Position Error Signal at ID

Figure 2: Position Error Signal at OD

The Figure 3 below compares V2002 spinstand performance in three configurations:

  • With the Regular Cartridge. Standard bandwidth servo loop is enabled, using the main piezo actuator of V2002 spinstand.
  • With the new Piezo-Actuator Cartridge. Standard bandwidth servo loop is enabled, using the main piezo actuator of V2002 spinstand. The piezo actuator on the cartridge is not used.
  • With the new Piezo-Actuator Cartridge. High-bandwidth servo loop is enabled, using the piezo actuator on the cartridge.

The Piezo-Actuator Cartridge and the Regular Cartridge are interchageable on the same spinstand without need to realign the spinstand.

Figure 3: Cartridge Comparison

When you use the new Piezo-Actuator Cartridge and enable the high-bandwidth servo loop, you will typically get 35-45% improvement in NRRO, shown in green.

The figure above also shows that the new Piezo-Actuator Cartridge is a more stable platform comparing to Regular Cartridge. It delivers 15-20% better NRRO results, shown in blue, even if you do not enable the high-bandwidth servo loop using the piezo on the cartridge.

Test Time Improvement

When the high-bandwidth servo loop using the Piezo-Actuator Cartridge is enabled, the parametric tests may run up to 5-10% faster compared to the regular servo mode. Guzik is working on further improvement of test time.

System Requirements

The following test system components are required:

1. Guzik V2002 spinstand requires the following components:

  • Head Loading Mechanism upgraded with piezo-actuator cartridge interface
  • Control Interface board P/N 321850
  • Combloader Interface board P/N 324250 or 328390

2. Spinstand Control Box requires the following boards:

  • Servo Driver 5 board P/N 330880 (revision B)
  • Servo Controller 5 board P/N 330890 (any revision)

3. Guzik RWA-2000 series with the following servo revision:

  • Servo Revision 3, or
  • Servo Revision 4

4. It is recommended that your RWA-2000 series has RWA Control 2 Board P/N 325800***.

5. WITE32 Software Revision 4.00 or later.

For compatibility verification and upgrade quotation please send RWA and Spinstand EEPROM Dump information to support@guzik.com.

* Typical value. Measurement results may vary for different head types.

** Patent Pending

*** If your RWA has an older RWA Control Board P/N 306180, you will not be able to use the Enhanced Performance Mode 2 (Partial Revolution ) with the high number of sectors required for Piezo Actuator Cartridge.