Typical Tests Performed By CETR Olympus Tribometers

 

1. Basic Start-Stop Test on the Disk Landing Zone

2. Start-Stop Test with Periodic Head Seeking

3. Continuous-Seeking Test

4. Continuous-Dwell-Flying Test

5. Park-Stiction Test

6. Fly-Stiction Test

7. Dynamic Load-Unload Test

8. Load-Unload Tests at Different Disk Speeds

9. Combination of the Load-Unload and Seeking Test

10. Simultaneous Measurement of the Dynamic Gram-Load and Friction Force

11. Magnetic Signal Degradation during Start-Stop Test

 

In all these tests, Olympus HDI Tribometers can measure all or some of the following parameters:


• Stiction and Friction

• Normal Load (so-called head gram-load)

• Acoustic Emission (AE) from the Head-Disk Interface

• Magnetic Signal Amplitude (TAA)

• Thermal Asperities (TA)

 

1. Basic Start-Stop Test on the Disk Landing Zone

This is the most basic test. The final disk RPM and durations of the acceleration and deceleration are chosen by user. The breakaway stiction of the head is measured, along with the takeoff friction during acceleration, landing friction during deceleration, takeoff and landing velocities. This can verify the effects over time, of repeat power cycles on the disk and head surfaces.

 

  Friction

   Acoustic Emission

 

 

2. Start-Stop Test with Periodic Head Seeking Between Any Disk Radii During A Flying Part of the CSS-Cycle

This provides the same data as in the basic start/stop testing, however the sweeping action allows the head to pick up and redistribute lubricants and other organics on the disk surface. Changes in the take-off time and stiction values are used as an indicator.

 

 

 

 

3. Continuous-Seeking Test, When Head Is Seeking, Either  in Random or Sweep Mode, Between Any Disk Radii

Continuous seeking or sweeping tests show the long term effect of head motions on the disk and head surfaces. Continuous head movement allows the lubricant and other organics to migrate over time and effect both the durability and stiction in the head-disk interface.

 

 

 

4. Continuous-Dwell-Flying, When Head Is Flying Over The Same Disk Radius For An Extended Time

Dwelling at a specified radius shows the effects of the head flying over the same radius for extended periods. Disk burnishing, debris formation, lubricant pick up by the slider, and other running-in processes can sometimes lead to disk wear instead of a nice surface smoothening.

 

 

5. Park-Stiction Test When Head Is Resting On The Disk  For An Extended Time, Then Disk Starts and The  Breakaway Stiction Is Measured

Following many of the previous tests, the disk is stopped for extended periods. This allows the head to settle onto the disk and the lubricant with organics and moisture forms menisci between head and disk asperities. This can cause high stiction and take off velocity during the following startup of the disk.

 

 

6. Fly-Stiction Test, Which Incorporates Some CSS, Some Continuous-Flying, Some Continuous-Seeking, and Some Park-Stiction Some Continuous-Flying, Some Continuous-Seeking,  and Some Park-Stiction

 

 

7. Dynamic Load-Unload Test, When Head Is Continuously Loaded From and Unloaded To An Off-Disk Ramp

Ramp load testing is designed to examine the characteristics of the slider loading onto a spinning disk. The AE (Acoustic Emission) can be monitored to provide useful information as to the amount of contact made as well as the subsequent flight characteristics. Information regarding the behavior of the suspension during load and unload can also be gathered during these tests. Optional is a strain arm designed to measure friction force in the radial direction when the head loads and unloads.

 

 

8. Load-Unload Tests Using Different Disk Speeds At The Moment Of Loading, To Optimize The Load-Unload Dynamics

As in standard ramp load testing, this is used to determine the characteristics of the head disk interface during load and unload. The enhancement here is that the speed of the disk at time of contact as well as the speed of the strain arm can be adjusted to optimize both of them.

 

 

 

9. Combination of the Load-Unload and Seeking Test,  Which Monitors the Dynamics of the Head During Both Load-Unload and Seeking Over the Disk Surface

This test shows the characteristics of the head load and unload functions, as well as the performance of the slider during subsequent sweeping. It allows to optimize the head-disk interface for drives with ramp loading.

 

 

10. Simultaneous Measurement of the Normal (Gram-Load) and Friction Forces Using Proprietary  2-Dimensional Force Gauge

 

The CETR 2-Dimensional friction gauge allows simultaneous and truly independent measurements of the dynamic gram load and the friction force during both start/stop and load/unload tests. This produces accurate and continuous measurements of the real coefficient of friction.
 

 

 

11. Magnetic Signal Degradation During Start-Stop Test

This test includes measurements of both the friction and stiction characteristics and the magnetic signal characteristics at each start-stop cycle. The track average amplitude of the magnetic signal may show the onset of degradation of head or disk surfaces earlier than the strain-gauge signal