Hard Disk Drive 3D Model , structure and Functioning

Hello everyone, Welcome to Data Empires. Friends, I believe that you all might have seen the hard disk. When we open the top cover of the hard disk, we can see the internal mechanical structure of the hard disk. Here we can see ribbon cables, head, platter, spindle motor, slider, actuator, magnets, and head parking area inside it. In this video blog of Mechanical Data Recovery structure, we are trying to describe the internal structure, media-level components, and the functioning of all these components of the hard disk in detail via 3d model.

There are plenty of mechanical components engaged in a hard disk. The main components are the platter, head, spindle motor, air circulation filter, magnets, slider, preamplifier, breathing hole, and breathing filter. Now, we will discuss all these components in detail.


Our First Mechanical Component will be the Platter. The platter is a circular disk, on which the data is stored. Generally, in the 2.5-inch hard disk, the platter is made up of glass, and in the 3.5-inch hard disks, the platter is made up of aluminum. Track, sectors, and clusters are already defined on the platter. Data is stored on this track and sectors, and it defines the address of the data.

When reading and writing are done on the platter, the data is searched by these addresses. There is a layer of Ferro-magnetic material on the platter. Data is stored on the same magnetic material. Any hard disk can have one or more platter, which is mounted on the spindle motor. On every side of the platter, ahead is provided to read and write the stored data. Here, in this image, we can see the type of platter visible, and how more than one platter is fixed on the assembly.

Read/write head

Our second main component will be the read and write head. Head is the smallest part of the hard disk .Head slides on the platter and it reads and writes the store data on the magnetic part of the platter. On any hard disk, a head is placed on every side of the platter, to read and write the stored data. A maximum of 2 heads can work on a single platter. A slider is also attached to the head. A lead wire carries the signal from the head. All of these assemblies are fixed on a head arm.

Spindle Motor

Our next component will be the Spindle Motor. Every hard disk contains a spindle motor. This spindle motor rotates at a constant speed, which is also defined as the RPM of that hard disk. Hard disk can function properly because of the rotation of spindle motor at a constant speed. The platter is mounted on this motor, which also rotates the platter. Bearings are used for the smooth rotation of the spindle motor.


The next mechanical component is Magnet. A very strong magnet is attached to the actuator coil section of the hard disk. This magnet is used to develop electromagnetic environments. Some hard disk models have a head stack stopper attached with the magnet that controls the movement of the head. The magnets inside the hard disk are very important components, as it works to develop magnetic field over the actuator coil.


Our Next Mechanical Component is the Slider. The slider is a black-colored component, which is connected to the head. The surface of the slider is aerodynamic, and it works to keep the head on the platter in the air. When the platter rotates, the air pressure develops inside the hard disk. Due to the aerodynamic design of the slider, it floats in the air and will not let the head and plate touch each other. The distance between the head and platter is approximately 3 to 5 nanometers, which is called Flying Height. This slider maintains the Flying Height. If the dust particle enters into the hard disk and, if the dust particle comes between the slider and the platter, then the slider and even the platter may get damaged. That is why the repairing of hard disk requires a class hundred cleanroom.


Now, let us discuss another component, called Preamplifier. The preamplifier is an I C that controls the incoming signals from the head and provides strength to the communication between the head and the PCB. When the headworks as read and write, the signal strength generated is very low. These signals are so fragile that, the signals cannot even reach the PCB from the head. To achieve this, the preamplifier has to be installed in the hard disk. Preamplifier boosts the signal strength. Here, in this image, we can see the preamplifier, which is connected by the head directly through the lead wire.

Recirculation filter

Our Next Component will be the Recirculation filter. Clean air is required for the hard disk to work properly. When hard disk runs continuously, small particles of metal and oil are formed inside the hard disk. It is very important to clean these particles immediately. For this, the recirculation filter is attached to the hard disk. This filter absorbs dust and oil particles and keeps the inside air clean.

Breathing hole and breathing filters

The last mechanical components are breathing holes and breathing filters. When we discussed the structure of the hard disk previously, we have mentioned the breathing hole. Every hard disk has a breathing hole on its outer body. There’s a myth among many people that the inside of the hard disk is a vacuum. But the myth is wrong. To maintaining the air pressure and temperature inside the hard drive, dust-free and clean air is required. For this reason, we have to use the breathing holes in the hard disk. The breathing filter is attached to the breathing hole. The breathing filter keeps the air clean coming inside from dust and moisture. Due to this, the air coming inside the hard disk will be absolutely dust-free, and the mechanical components of the hard disk will not get damaged.