Measurement and Test requirements

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					HDD Test and Handling


             School of Mechanical Engineering
                        Institute of Engineering
            Suranaree University of Technology
Measurement and Test requirements

   Disc Balance
   Acoustic
   Leak test
Measurement and Test requirements

ฮาร์ดดิสก์ถูกออกแบบให้ทางานตามข้อกาหนดทางเทคนิคต่างๆ เช่น
 shock, vibration, temperature, humidity,
   altitude และ magnetic field
 ถูกป้องกันจาก ESD

 Breathing hole บน top cover จะต้องไม่ถูกสิ่งของหรือวัสดุ
   อื่นมาปิดไว้
 ไม่มีแรงภายนอกมากระทา หรือกดต่อฮาร์ดดิสก์
 ขนาดของกระแสและกาลังไฟฟ้าที่ป้อนให้กับฮาร์ดดิสก์อยู่ในพิกัดที่
   เหมาะสม
Measurement and Test requirements
ฮาร์ดดิสก์ถูกออกแบบให้ทางานตามข้อกาหนดทางเทคนิคต่างๆ(ต่อ)
 ฮาร์ดดิสก์ถูกต่อลงดินผ่านสกรูที่ใช้ยึดฮาร์ดดิสก์เข้ากับสิ่งที่ถูกติดตั้ง

 สกรูที่ใช้ถูกขันยึดด้วยแรงบิดที่กาหนด ความลึกที่กาหนด

 Interface เหมาะสม เช่น SATA

 Power-off sequence ของฮาร์ดดิสก์ถูกกาหนดแล้วตาม
   “Required power-off sequence.”
Measurement and Test requirements

   Disc Balance
   Acoustic
   Leak test
Disk Balance

                  A disk drive recording
                   device comprises at
                   least two platters for
                   storing magnetic
                   recording data and a
                   spindle motor rotating
                   at high speed for
                   mounting the platters.
Disk Balance

   The disk drive is assembled by using pushing
    devices to push the platters toward the center of the
    spindle motor in respective directions to bring a
    portion of an inside circumference of a concentric
    center hole of each of the platters in contact with an
    outer circumference of the spindle motor so that the
    center of gravity of each platter coincides with a
    center axis of the spindle motor.
Disk Balance

                  Method for balancing a
                   rotating assembly
                   using eccentric rings
                   (United States Patent
                   6947253)
Measurement and Test requirements

   Disc Balance
   Acoustic
   Leak test
Acoustic

Sound power level
 Measurements are to be taken in accordance
  with ISO 7779.
 The mean of the sample of 40 drives is to be
  less than the typical value.
   Each drive is to be less than the maximum
    value.
    Acoustic
   The sound power in
    dB converted from
    Watts as follows:

    Ten times the common
    logarithm of the ratio of
    the acoustic power to the
    reference sound power,
    10-12 W or 1 pW.


   The symbol is LW
Acoustic

   The criteria of A-weighted sound power level
    are described below.
Acoustic

   The background power
    levels are to be recorded.
   Sound power tests are to
    be conducted with the
    drive supported by
    spacers so that the lower
    surface of the drive be
    located 25±3 mm above
    from the chamber floor.
    No sound absorbing
    material shall be used.
Acoustic
The acoustical characteristics of the disk
  drive are measured under the following
  conditions.
 Idle mode - Power on, disks spinning, track
  following, unit ready to receive and
  respond to control line commands.
 Operating mode - Continuous random
  cylinder selection and seek operation of
  actuator with a dwell time at each cylinder.
Measurement and Test requirements

   Disc Balance
   Acoustic
   Leak test
Leak Test

   It is air leak test when air pressure is applied
    into the HDD cavity.
   It indicate HDD seal performance.
Electrostatic Discharge (ESD)

Electrostatic discharge (ESD) is the sudden
and momentary electric current that flows
between two objects at different electrical
potentials (such as ground). The term is usually
used in the electronics and other industries to
describe momentary unwanted currents that may
cause damage to electronic equipment.
Type of ESD Damage

   Upset Failure
   Catastrophic Failure
Upset Failure

 Upset failures occur when an electrostatic
 discharge has caused a current flow that is
 not significant enough to cause total failure,
 but in use may intermittently result in gate
 leakage causing software malfunction or
 incorrect storage of information.
Catastrophic Failure

   Direct catastrophic failures occur when a
    component is damaged to the point where it no
    longer functions correctly.
   Latent catastrophic failures occur when ESD
    weakens a component to the point where it still
    functions correctly during testing, but
    subsequent minor electrical overstresses or
    power surges during normal operation of the
    equipment cause the component to fail.
ESD Test Models

   Human-Body Model (HBM)
   Machine Model (MM)
   Charged-Device Model(CDM)
Human-Body Model (HBM)
The HBM was developed to simulate the action of a human
body discharging accumulated static charge through a device
to ground, and employs a series RC network consisting of a
100-pF capacitor and a 1500-Ω resistor.


   R=1 MΩ    R=1.5 kΩ
              C= 100 pF




                          MR
 Machine Model (MM)
The MM simulates a machine discharging accumulated static
charge through a device to ground. It comprises a series RC
network of a 200-pF capacitor, and nominal series resistance of
less than 1 ohm. The output waveform usually is described in
terms of peak current and oscillating frequency for a given
discharge voltage.
                                       R=1 MΩ       RL=1 Ω




                                                   C= 200 pF
                                                               MR
Charged-Device Model(CDM)
The CDM simulates charging/discharging events that
occur in production equipment and processes. Potential
for CDM ESD events occur when there is metal-to-metal
contact in manufacturing.
Controlling ESD

   Dissipate and Grounding
   Isolation
   Prevention
Dissipate and Grounding

Human Suit
Machine
Tools
Working Area


 Grounding is a means of draining the static
 charges present on your body, by use of a
 personal grounding device or a wrist strap.
Isolation

Isolation can also be accomplished by keeping
charge generating materials away from working
area
       plastic bags

       cellophane tape

       paper work

       common untreated plastic materials

       styrofoam cups
Isolation

 duringstorage and transportation
  packing of components and assemblies to

   protect static charges cannot penetrate
  containers made of conductive materials or

   have a conductive layer.
Prevention of ESD
   Never enter an ESD-sensitive area without
    taking the proper precautions.
   Test ground devices for correct operation on
    a daily basis.
   Open ESD-sensitive items only at a static-
    safe workstation.
   Always keep your workstation clean and
    clear of unnecessary material, particularly
    common plastics.
Prevention of ESD

   Place ESD-sensitive items on a dissipative
    surface, not on top of a blueprint or other
    paperwork.
   Return ESD-sensitive items to their ESD-
    protective containers when not actively working
    with the items.
   Do not hold ESD-sensitive items against your
    clothing. Even if you are wearing a wrist strap,
    your body is grounded but your clothes are not!
ESD Environment

 Temperature 19-25 C
 Relative humidity 40-60%

 Dust (Cleanroom Technology)
HDD Handling
Hard disk drives (HDD) can be critically damaged by
static electricity, shock, vibration and other factors.
Therefore, the proper handling of HDD in appropriate
environment to ensure their reliability is important.


•   General instructions
•   Handling of the package
•   Storage and handling after unpacking
•   Assembly and testing
General instructions


                         ✓
 1. Wear a wrist strap
    when handling HDD




                         ✓
 2. Places HDD on a
    static-free place
General instructions

 3. Do not carry two or
    more HDD with one
    stacked on top of
                              ✗
    another



                              ✗
 4. Do not leave HDD in
    a vertical position
    without putting it in a
    container
General instructions


                       ✗
5. Do not let HDD
   bump against one
   another




 6. Do not drop HDD    ✗
Handling of the Package

                          ✓
 1. Use a packaging
    box exclusively
    prepared for the
    HDD




  ✗
Handling of the Package

 2. Do not drop the
    packaging box
                          ✗

                          ✗
 3. Do not step on the
    packaging box
Handling of the Package

 4. Take care when
    stacking packages.
    The number of
    packages that can
    be stacked is limited   ✗
    follows the
    instructions (except
    when they are
    palletized)
Storage and Handling after Unpacking

 1. Do not leave HDD in
    environment with
    extremely high/low
    temperature or with
    in an excessive
                                ✗
    humidity
Storage and Handling after Unpacking
 2. If the HDD in
    unpacked when its
    temperature is lower
    than room
    temperature, wait
                                 ✓
    until the HDD
    temperature is as
    warm as the room
    temperature to
    avoid dew
    condensation
Storage and Handling after Unpacking

 3. When placing HDD
    temporarily in the
    case after
    unpacking, put it in
    antistatic and shock
    absorbing material
    at the bottom and all


                             ✓
    four inner side of the
    case
Storage and Handling after Unpacking

 4. Put a shock
    absorbing mat and
    antistatic mat on the
    desk where HDD is
    to be handle (the
    antistatic should be
    on the top)


                            ✓
Storage and Handling after Unpacking

 5. Putting the HDD on
    the top of the shield
    bag will not protect
                                ✗
    the adverse effect of
    static electricity
    discharge
Storage and Handling after Unpacking

 6. When carry the
    HDD contained in a
    case, make sure
    that the case is not
    exposed to any
    shock and vibration


                           !
Assembly and Testing

 1. When carrying HDD
    on a cart or belt
                              ✗
    conveyor, take
    appropriate
    measures to protect
    them from shock
    and vibration

                          ✗
Assembly and Testing

 2. Mounting and tools
   • Use low impact
     screwdriver
   • Follow tightening
     torque requirements
   • Recommended plane
     level for mounting

                           !
Assembly and Testing


                                   !
 3. Powering off; the disk
    continues rotating under its
    own inertia for about 30
    seconds. After the test is
    completed and power is
    turned off, wait until the
    disk comes to a complete
    stop before disconnecting
    the cable and moving the
    HDD
Q&A