Automated head wire stringing, termination, and slider bonding suspension assembly with load/unload feature

The invention is a suspension assembly with one or more head wires running across an upper surface of the suspension assembly; a flexure attached to a lower surface of the suspension assembly; a slider attached to a lower surface of the flexure; and a wiring window through which the one or more head wires pass to be attached to the slider. An alternative embodiment of the invention is a suspension assembly with a load/unload feature at a head end of the suspension assembly.

FIELD OF THE INVENTION 
The present invention relates to the field of disk drives, also known as 
direct access storage devices ("DASD"). More particularly, the invention 
pertains to the automated manufacturing of a suspension assembly of a disk 
drive. The suspension assembly includes a load/unload feature. 
BACKGROUND OF THE INVENTION 
One of the key requirements of a computer system is a place to store data. 
Typically computer systems employ a number of storage means to store data. 
One of the places where a computer can store data is in a disk drive which 
is also called a direct access storage device ("DASD"). 
A disk drive or DASD includes several disks which look similar to records 
used on a record play or compact disks which are used in a CD player. The 
disks are stacked on a spindle, much like several 45 rpm records awaiting 
to be played. In a disk drive, however, the disks are mounted to the 
spindle and spaced apart so that the separate disks do not touch each 
other. 
The surface of each disk is uniform in appearance. However, in actuality, 
the surface of each disk is divided into portions where data is stored. 
There are a number of tracks of the disk situated in concentric circles 
like rings on a tree. Compact disks have tracks as do the disks in a disk 
drive. The tracks in either the disk drive or the compact disk essentially 
replace the grooves on a conventional record. Each track in a disk drive 
is further subdivided into a number of sectors which is essentially just 
one section of the circumferential track. 
Disks in a disk drive are made of a variety of materials. Most commonly, 
the disk is made of metal or plastic. The materials from which the disk is 
made determines how data is stored on the disk. A plastic disk, such as 
those used as CDs, stores data using lasers and a laser is used to read 
the data back. Storage of data on a metal disk entails magnetizing 
portions of the disk in a pattern which reflects the data. 
To store data on a metal disk, the metal disk is magnetized. In order to 
magnetize the surface of a disk, a small ceramic block which contains a 
magnetic transducer known as a write head is passed over the surface of 
the disk. More specifically, the write head is flown at a height of 
approximately six millionths of an inch from the surface of the disk and 
is flown over the track as the write head is energized to various states 
causing the track below to be magnetized to represent the data to be 
stored. 
To retrieve data stored on a magnetic disk, a ceramic block which contains 
a read head is flown over the metal disk. The magnetized portions of the 
disk induce a current in the read head. By looking at output from the read 
head, the data can be reconstructed for use by the computer system. 
Typically, the same ceramic block contains both a read head and a write 
head. 
Like a record, both sides of a disk are generally used to store data or 
other information necessary for the operation of the disk drive. Since the 
disks are held in a stack and are spaced apart from one another, both the 
top and the bottom surface of each disk in the stack of disks has a 
ceramic block, also known as a slider, associated with each surface. This 
would be comparable to having a stereo that could play both sides of a 
record at once. In the record analogy, each side would have a stylus which 
played the particular side of the record. 
Disk drives also have something that compares to the tone arm of a stereo 
record player. There are two types of actuators, rotary and linear. Rotary 
disk drives have a tone arm that rotates much like a record player. The 
tone arm of a rotary disk drive, termed a suspension assembly, typically 
has one slider attached at one end. The other end of a suspension assembly 
is attached to a comb-like structure. There is one suspension assembly 
associated with each surface of each disk. The comb-like structure 
facilitates holding the suspension assembly. 
Like a tone arm, the suspension assembly rotates so that the read and write 
heads in the slider which is attached to the suspension assembly can be 
moved to locations over various tracks on the disk. In this way, the write 
heads can be used to magnetize the surface of the disk in a pattern 
representing the data at one of the several track locations or the read 
heads can be used to detect the magnetized pattern on one of the tracks of 
a disk. For example, the needed data may be stored on two different tracks 
on one particular disk, so to read the magnetic representations of data, 
the suspension assembly is rotated from one track to another track. A 
linear disk drive, by contrast, has a linear suspension assembly with a 
suspension assembly similar to that of a rotary disk drive. However, in a 
linear disk drive, instead of repositioning by rotation, repositioning is 
accomplished through linear movement. 
Both the read head and the write head attached to the slider require a pair 
of wires to be attached to the slider itself. Thus, a typical suspension 
assembly has a total of four wires. These wires are very fine and are 
about 0.0014 inches thick, which is about half the thickness of a human 
hair. The wires carry electrical signals. The electrical signals attached 
to the write head are used to store representations of data on one of the 
disk surfaces of the disk drive. The electrical signals attached to the 
read head are used to carry signals representing the data back from one of 
the surfaces of the disk which has data stored on it. A set of wires for 
each read and write head are strung along each of the actuator arms in the 
disk drives. Each set of wires for each of the read heads and write heads 
typically is attached to a flexible cable which allows the suspension 
assembly to move while maintaining electrical connection with each of the 
heads on the slider. 
In the past, attaching the fine wires to the read heads and the write 
heads, stringing the wire along the suspension assembly and attaching the 
wire to the flexible cable has been a very labor intensive process. The 
fine wires were attached to the head and strung along the actuator arm by 
human beings. Much of the work was done under a microscope, especially 
attaching one pair of fine wires to the read head and one pair of fine 
wires to the write head. The pairs of wire were also strung along the 
suspension assembly by humans. Finally, the fine wires are attached to the 
flexible cable by people. 
The past procedure has many shortcomings. Many of the shortcomings stem 
from the labor intensive nature of attaching the wires to the heads and 
flexible cable and stringing the wire along the suspension assembly. 
Basically, the wires are very fine and small and the places to which the 
wires attach on the slider also are very small. The attachment typically 
is done by soldering the ends of the wires to a small pad. This is very 
exacting and detailed work and by its nature is very prone to human error. 
For example, the flexible cable includes pads which are spots on the 
flexible cable to which the ends of the wires from the various heads are 
attached. Since there are so many wires that must be attached to the 
flexible cable, the pads are very small and closely spaced. There are many 
possibilities for error in attaching the wires to the pads on the flexible 
cable. Prior to attaching the wires to the pads on the flexible cable, the 
wires must be sorted. On a disk drive having eight disks there are sixteen 
surfaces most of which have both a read and write head associated 
therewith. Assuming each surface has both a read and a write element and 
four wires. There are 64 very fine wires that must be sorted and attached 
to very small pads. The sorting process is tedious and very prone to 
mistakes. 
Even after successfully sorting the various wires, the wires are soldered 
to pads that are very closely spaced. Attaching the wires is also a source 
of mistakes. It is difficult for a human to consistently apply just the 
right amount of solder to a pad without having it flow to a closely spaced 
adjacent pad. When it does flow to an adjacent pad, a short occurs so the 
electrical signal will not pass through the wires to the write head or 
from the read head. 
The same types of problems occur when attaching the wires to the various 
read heads and write heads on the slider. Problems also occur since the 
work is not done uniformly and with consistency. One person, for example, 
may have a knack for accomplishing the tasks while another may take along 
time to learn the skill. As a result, there are various levels of quality 
from person to person. 
Other problems occur since the wires are so fine. For example, the wires 
can be crimped as it is sorted out which may result in a break in the 
electrical signals to or from the write or read elements on the slider. 
As can be seen, there are many shortcomings associated with a human doing 
the task of attaching the wires to the head, stringing the wires along the 
suspension, twisting the wires for the purpose of noise suppression, 
sorting the wires and attaching them to the flexible cable where the wires 
terminate. This process seems prone to error, especially considering that 
the wires and pads upon which they are attached are very small. Because of 
the difficulty of this process as performed by humans, the time needed is 
high and as a result the labor costs are also high. The cost of the 
suspension assemblies are also increased in that more of the parts may be 
defective when compared to an automated process. Consequently, there is a 
need for a process by which the entire process of stringing the wires 
along the actuator arm, terminating the wires, and bonding of the slider 
to the suspension assembly can be automated. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide an automated method for wiring 
head wires on a suspension assembly. 
It is a further object of the invention to provide a load/unload feature on 
a suspension assembly that has head wires attached by an automated 
process. 
The invention is a suspension assembly with one or more head wires running 
across an upper surface of the suspension assembly; a flexure attached to 
a lower surface of the suspension assembly; a slider attached to a lower 
surface of the flexure; and a wiring window through which the one or more 
head wires pass to be attached to the slider. Also claimed is a suspension 
assembly with a load/unload feature at a head end of the suspension 
assembly. Also claimed is a method for automated wiring of a suspension 
assembly comprising positioning the suspension assembly on a tool block 
and securing the head wires; rotating the suspension assembly vertical to 
the plane of the tool block and placing the slider in a slider nest; 
bonding the head wires to the slider and cutting off the excess wires; 
placing epoxy on the slider then returning the suspension assembly 
parallel to the plane of the tool block; and bonding the slider to the 
flexure with the epoxy. 
It is an advantage of the invention that an automated method is provided to 
wire the head wires on a suspension assembly. 
It is a further advantage of the invention that a wiring window is used to 
permit bending of the wires down under the load beam of the suspension 
assembly to be attached to the slider. 
It is a further advantage of the invention that a suspension assembly 
manufactured with an automated wiring process has a load/unload feature 
for removing the slider from a disk in a disk drive when the disk drive is 
not operational.

DETAILED DESCRIPTION OF THE INVENTION 
The invention relates to an article of manufacture known as a suspension 
assembly used in a disk drive and method for producing same. The invention 
can best be understood by reference to the drawings. 
FIG. 1 is a top view of a disk drive 10 showing the suspension assembly 12 
of the present invention. Also shown is a sample disk 14 on which 
information is stored that needs to be accessed by an information handling 
system (i.e., computer, not shown). Also shown is the casing 16 
surrounding and protecting the disk 14 and the suspension assembly 12. 
Although a rotary suspension assembly is shown, the invention applies to 
linear suspension assembly drives as well. 
FIG. 2 is a top view diagram of the suspension assembly 12 of the present 
invention. FIG. 2 shows the overall design of the disclosed suspension 
assembly 12. The suspension assembly 12 consists of a slider 30 which is 
bonded to a flexure 20. The slider 30 rests underneath the flexure 20. The 
slider 30, thus, is not shown in the top view of FIG. 2. The slider 30 is 
shown in the side view of FIG. 3. The flexure 20 provides the slider 30 
with appropriate pitch and roll stiffness which is important in accurately 
reading and writing information to and from a disk. As discussed in the 
background section, the slider 30 is used to read or write information 
from or to the disk 14 in a disk drive 10. The flexure 20 is welded onto a 
load beam 21. The load beam 21 provides the appropriate vertical load for 
optimal operation of the suspension assembly 12. A gimbling dimple 40 
(shown in FIG. 4) to the slider 30 is attached to an arm 22. Head wires 23 
are routed on top of the suspension assembly 12. The head wires 23 are 
contained within the height of the bent flanges 44 running along each edge 
of the load beam 21 for wire protection and z-height control. Two head 
wires 23 are connected to the read head on the slider 30 and two head 
wires 23 are connected to the write head on the slider 30. 
The load/unload feature 24 is a lever which is used to load the slider 30 
onto the disk 14 when the disk drive 10 is operational and to lift the 
slider 30 away from the disk 14 when the disk drive 10 is shut down. 
Removing the slider 30 away from the disk when not in use protects the 
disk 14 from being damaged by the slider 30 due to shock loading. 
A key aspect of the invention is that the load/unload feature 24 is 
available on a suspension assembly 12 that has been produced by automated 
manufacturing. Near the tip of the assembly 12, there is a unique wiring 
window 25. The wiring window 25 exposes the front end of the slider 30 to 
which the wire termination pads 60 are attached. It is this wiring window 
25 that enables the wiring, termination of the head wires 25 and bonding 
of the slider 30 to the flexure 20 to be automated. Also shown in FIG. 2 
are various glue dots 26 that relieve the stress on the head wires. 
FIG. 3 is a side view diagram of a suspension assembly with load/unload 
feature of the present invention. FIG. 3 shows the arm 22, the load beam 
21, the flexure 20, and the head wires 23. Also shown is the slider 30 and 
the load/unload feature 24. The load/unload feature 24, as indicated in 
FIG. 3, moves up and down in the y-direction. When the disk drive 10 is 
operational, the load/unload feature 24 is down and the slider 30 is on 
the disk 14. When the disk drive 10 is not operational, the load/unload 
feature 24 is up and the slider 30 is lifted away from the disk 14. 
FIG. 4 is an expanded view of the head end of FIG. 2. FIG. 4 shows the load 
beam 21 with the head wires 23 running across the top. The flexure 20 is 
underneath the load beam 21 and is therefore shown by dashed lines. A 
gimbling dimple 40 to the slider 30 is welded to the load beam 21. The 
function of the gimbling dimple 40 is to allow the slider 30 to rotate 
freely in the x-, y-, and z-direction as it moves across the disk 14. A 
large glue dot 42 is shown. The glue dot 42 is used to relieve the stress 
and tension on the head wires. Also shown is the wiring window 25 which 
permits automated wiring and termination of the head wires 23 as further 
described below. Finally, at the end of the load beam 21 is the 
load/unload feature 24. The bent flanges 44 serve to stiffen the 
suspension load beam 21 to increase the natural frequencies. 
FIG. 5 is an expanded side view diagram of the head end of FIG. 3. FIG. 5 
shows the bent flanges 44 of the load beam 21. Running down the middle of 
the load beam 21 are the head wires 23. The head wires 23 in FIG. 5 are 
dashed since from the side they cannot actually be seen due to the 
upturned bent flanges 44 of the load beam 21. FIG. 5 shows the slider 30 
which is attached to the lower portion of the flexure 20. FIG. 5 shows for 
the first time detail of the termination point 50 of the head wires 23. 
FIG. 5 makes it clear that the head wires 23 are bent down through the 
wiring window 25 and around the flexure 20 and affixed to the edge of the 
slider 30. Not shown here are the wire termination pads 60 on the side of 
the slider 30 to which the head wires 23 are attached. Also shown is the 
load/unload feature 24. 
FIG. 6 is a front view diagram of the suspension assembly 12 of the present 
invention. FIG. 6 shows the bent flanges 44 running along the edges of the 
load beam 21. Also shown is the glue dot 42 that relieves the stress and 
tension on the head wires 23. FIG. 6 shows in detail the termination point 
50 of the head wires 23 as they bend down through the wiring window 25 
(not labeled on this diagram) at the end of the flexure 20 and are 
attached to the wire termination pads 60 at the edge of the slider 30. 
FIGS. 7 through 12 show how this suspension assembly 12 design accomplishes 
the automation of head wire 23 routing, head wire 23 termination, and 
bonding of the slider 30 to the flexure 20. 
FIG. 7 shows a top view of the suspension assembly 12 positioned on a 
rotatable portion of a tool block 70. The suspension assembly 12 is 
clamped to the tool block with clamp 71. Head wires 23 are routed on the 
suspension assembly 12 by a robot (not shown) or other automated means. 
The head wires 23 are precisely positioned on the suspension assembly 12 
by two sets of wire routing pins 72 and 73 on either end of the suspension 
assembly 12. The head wires 23 are then strain relieved by glue dot 42 on 
the suspension assembly 12. Also shown in FIG. 7 is the slider nest 74 
which is used to hold the slider for termination of the head wire 23 and 
for bonding of the slider 30 to the flexure 20. 
FIGS. 8 through 12 show a cross-sectional view through part of the 
suspension assembly 12 and the tool block 70. FIGS. 8 through 12 are drawn 
in chronological order to show the process flow of the automated routing 
of the head wires 23, termination of the head wires 23, and bonding of the 
slider 30 to the flexure 20 processes of the present invention. 
FIG. 8 shows a side view of the routed and strain relieved head wires 23 on 
the suspension assembly 12. FIG. 8 shows a sample glue dot 42 that is used 
to relieve the strain on the head wires 23. This Figure also shows part of 
the slider nest 74 which will be used to hold the slider 30 for 
termination of the head wires 23 and bonding of the slider 30 to the 
flexure 20 later in the process. Also shown in FIG. 8 are the bent flanges 
44 along the sides of the load beam 21; the flexure 20 and load/unload 
feature 24. The wiring window 25 is important in the process of 
terminating the head wires 23. 
After the head wires 23 are strung and strain relieved, the part of the 
tool block 70 which holds the suspension assembly 12 is rotated ninety 
degrees clockwise around a predetermined center of rotation 90 on the tool 
block 70 as shown in FIG. 9. The suspension assembly 12 is then 
perpendicular to the tool block 70. The slider 30 can be rotated to 
achieve the same result, but the preferred way is to rotate the suspension 
assembly 12 for process compatibility reasons. The slider 30 is then 
placed into the slider nest 74. As shown in FIG. 9, the slider nest 74 
does not rotate with the suspension assembly 12. The wire termination pads 
60 on the edge of the slider 30 are lined up with the head wires 23 and 
the head wires 23 are ready for termination at this point. 
FIG. 10 shows the head wires 23 are then terminated onto the termination 
pads 60 with an ultrasonic bonding tool 100. The bonding tool 100 pushes 
the head wires 23 through the wiring window 25 and makes contact with the 
termination pads 60 on the slider 30. The head wires 23 are then 
ultrasonically bonded to the termination pads 60. After ultrasonic 
bonding, excess head wires 23 are then cut off. 
As shown in FIG. 11, epoxy 110 is dispensed onto the slider 30 for bonding 
of the slider 30 to the flexure 20. The suspension assembly 12 is then 
rotated counter-clockwise as shown in FIG. 11 until the assembly once 
again sits parallel to the tool block 70. As the suspension is rotated, 
the head wires 23 are being constrained on one side by a glue dot 42 and 
on the other side by the wire termination pads 60 on the slider 30. A 
ninety degree bent loop 112 is formed on the head wires 23. The shape and 
dimension of the loop 112 is determined by the location of the center of 
rotation 90 of the suspension assembly 12. 
As the suspension assembly 12 is rotated back to the horizontal position, 
the flexure 20 is compressed slightly by the slider 30. Since epoxy 110 
has been dispensed onto the slider 30 earlier as part of step 4, the epoxy 
110 is spread between the flexure 20 and the slider 30. The epoxy 110 is 
then cured and the slider 30 is bonded onto the flexure 20 as shown in 
FIG. 12. 
FIG. 13 is a flowchart of the method of the automated process to wire a 
suspension assembly 12 with load/unload feature 24 in accordance with the 
present invention. FIG. 13 summarizes the steps in the process shown in 
FIGS. 8 through 12. As shown in FIG. 13, the first step in the process is 
to place the suspension assembly 12 on a rotatable portion of a tool block 
70 and secure it. The flexure 20 is placed over a depression in the 
rotatable portion of the tool block 70 called the slider nest 74. The 
suspension assembly 12 is secured to the tool block by clamps 71. The 
initial wiring of the head wires 23 is completed in step 1 by securing the 
four head wires 23 around wiring pins 73, then down the center of the 
suspension assembly 12 where the head wires 23 are supported by the glue 
dots, such as glue dot 42. The head wires then are secured at the head end 
of the suspension assembly 12 by further wiring pins 72. The first step is 
further described in FIGS. 7 and 8 and the accompanying text. 
In the second step, the suspension assembly 12, together with the rotatable 
portion of the tool block 70 is rotated ninety degrees clockwise until the 
suspension assembly 12 is perpendicular to the plane of the tool block 70. 
The slider nest 74 remains in the same plane as the tool block 70. In step 
2, the slider 30 is inserted into the slider nest 74. The slider 30, at 
the time of insertion, already has wire termination pads 60 which are 
aligned with the head wires 23 as the slider 30 is inserted into the 
slider nest 74. The second step is further described in FIG. 9 and the 
accompanying text. 
In the third step, the head wires 23 are terminated onto the wire 
termination pad 60 on the end of the slider 30. The head wires 23 are 
terminated using an ultrasonic bonding tool 100. The bonding tool 100 
pushes the wires 23 down around the edge of the flexure 20 and through the 
wiring window 25 until the wires make contact with the wire termination 
pads 60. The wires 23 are then ultrasonically bonded to the wire 
termination pads 60, with one wire 23 attached to each of the four wire 
termination pads 60. The excess wire 23 that extends beyond the wire 
termination pads 60 is then cut off and discarded. The third step of the 
process is further described in FIG. 10 and the accompanying text. 
In the fourth step, epoxy 110 is placed on top of the slider 30. The 
suspension assembly 12 then is rotated back to once again lie parallel to 
the took block 70. The head wires 23 are constrained by a glue dot 42 and 
by the termination pads 60 on the slider 30. A ninety-degree bent loop 112 
is formed by the head wires 23 as the rotation is carried out. Step four 
is further described in FIG. 11 and the accompanying text. 
In the fifth step, the slider 30 is bonded to the flexure 20 by the epoxy 
110. Step five is further described in FIG. 12 and the accompanying text.