Miniature Ball Bearings Contribute Big To Modern Manufacturing
But first, let’s define our terms. A miniature ball bearing is the smallest size commercially available as a ball bearing, with an outer diameter less than 1″ (20 mm), ranging on down to miniature bearings as small as 1/10″ (2.5 mm, 2.5/1000 of a meter). Scientific research facilities have created bearings in the micrometer (one-millionth of a meter!) range, but we’ll get to that later.
Ball bearings in the 1″ to .1″ range are perfect for precision applications that require many functioning mechanical parts within a small space. Such bearings can be made of carbon steel, chromium steel or stainless steel — stainless steel provides the greatest corrosion resistance.
Industries that make extensive use of these commercial miniature ball bearings include:
– food processing
– semi-conductor manufacturing
Some of the actual products that make use of miniature ball bearings are:
– food washers
– fishing reels
– miniature slot cars
– high precision watches
– radio-control trucks
– power tools
– machine tools
– auxiliary generators
– air blowers
– control actuators
– vacuum pumps
– x-ray machines
– dental drills
– yo-yo bearings
– go carts
Let’s take a look at the future.
Micro-Electro-Mechanical-Systems, called MEMS, are millimeter-scale devices, on the scale of a grain of rice, that mimic larger devices. Over the last few years, tiny turbines have been built in research labs that generate several watts of power on a continuous basis. Such devices will become an alternative to batteries in handheld electronic devices. And, because mechanical movement is involved, micro-miniature ball bearings at scales never before imagined, must be designed, made, and tested.
In 1997, a millimeter-size jet engine was built using stainless steel ball bearings 285 micrometers, or about 1/100″, in diameter — the smallest ball bearings in the world at that time. Upon testing, the engine produced a thrust-to-weight ratio ten times better than a full-size engine! Put a thousand or ten thousand of these tiny jet engines together under the control of a computer, and you’d have a power source that, though tiny, would still be powerful enough to lift considerable weight.
Most MEMS are created by a photo-lithography process, and it was difficult to incorporate metallic balls, even tiny ones, into MEMS devices. However, etching techniques were developed in the early 2000s that create a silicon trace to encase ball bearings as small as 150 micrometers, the size of dust particles. Though done in a lab, this process seems to be easily scalable to commercial manufacturing processes.
These proof-of-concept experiments in labs worldwide will soon lead to commercial manufacture of miniature motors and generators that can be fit into other larger devices as power supplies. Injectable pumps could be built to float along the bloodstream to allow efficient dispensing of drug dosages. The military is particularly interested in micro-power generators and tiny rotating sensor arrays that could be incorporated into a soldier’s clothing.
So, because these MEMS devices depend so much on tiny ball bearings, the ball bearing industry will soon progress from miniature ball bearings to the micro-miniature — who knows what devices will spring forth from that endeavor?