The role of the spindle motor plays in the operation of a hard disk drive is of great importance. The main concern for many people, especially when looking at hard disks to use in a RAID is how fast the platters will spin, with faster considered the best choice as access speeds are usually faster. The spindle motor plays a crucial part in the successful operation of a disk drive, as it ensures the platters spin at the correct speed continuously with absolute precision, while avoiding any flutter in the platters which might cause the read/write to impact with them. Any consideration is that the drive should produce the lowest sound possible for the given drive speed.
If the spindle motor is unable to maintain the correct speed continuously or the spindle losses alignment, it may result in vibrations, which could lead to catastrophic failure. Any fluctuation in the rotational speed of the platters may cause read errors, while the resulting vibrations will cause extra noise and could result in the platters starting to oscillate due to resonance. If a resonant oscillation occurs it can easily result in the read/write heads contacting the magnetic recording media, destroying the heads and recorded data at the same time.
Ball Bearing Spindle Motors
Up until the early 2000’s, the bearing used in the majority of hard disk drives contained a set of ball bearings, which ensured that the platter remained centrally located while acting as a support for the spindle motor. It was soon apparent that another technology was required as the use of ball bearings had a number of limitations holding back the industry from creating the disks of a large enough capacity which were suitable for all market sectors, in particular enterprise storage.
Not only does this technology produce a lot of noise through physical contact, which causes heat to build up resulting in overheating, it also limits the speed at which the drive can reliably spin. If the bearing overheats the most likely outcome is for the lubricants to evaporate in a process known as outgassing, at which point the motor may seize up. The friction resulting from the physical contact will in spite of the lubrication, will over time cause the ball bearings to wear out, which limits their lifetime.
No matter how perfectly the ball bearings are manufactured, they will always have some imperfections, which will result in the spindle motor fluctuating while it rotates. This fluctuation limits the height at which the read/write heads fly above the platters which limits the capacity of the drive. By overcoming this limitation, the read/write heads can fly at a height lower than the platters, which allows for higher recording density.
Fluid Bearing a Solution
Fluid bearings allow the limitations ball bearing technology imposed on hard disk drive capacities. It allows for drives of a higher capacity, produce less noise with a much increase reliability. Fluid bearings are create using a small quantity of lubricant which is sealed with a high precision machined housing and often referred to a liquid bearing.
The use of fluid within the bearing removes the physical contact which reduces the vibration whereby the platters spin with significantly reduced levels of vibration. Any imperfections within the machined housing cause less problems than those caused by ball bearings. Noise is greatly reduced due to the fluid acting as a sound damper.
Fluid Bearings and Data Recovery
Impact events such as dropping an external drive or a laptop containing a drive with fluid bearings will often cause less damage than those using ball bearing technology. Impact events are still likely to cause damage to the spindle motor, which will need to be replaced by a professional data recovery company.
If you suspect that the drive has suffered an impact incident or the spindle motor is not operating correctly, it should be powered down immediately. Any attempt to turn on a drive which has been dropped or has a damaged motor spindle, could lead to head crash as the result of the read/write heads impacting with the surface of the disk platters. Once powered down, the drive should be sent to a professional data recovery company, such a DiskEng who have extensive experience in rebuilding drives and recovering data from drives which have suffered motor spindle failures.