Volume 6 Issue 7 July 2005
And the Wheels in the Bearing
Go Round and Round
by Al Simone
I am an avid SCUBA diver. On every dive, I don my gear and jump into the ocean looking forward to the shipwreck I may see or wildlife I may encounter. But there is a lot to think about before I even get in the water. The equipment I’m wearing is designed to support my life (which is important to say the least) with possible drastic consequences to me if it fails.
Even though the equipment you use in your plant is not supporting your life, it is supporting your livelihood, from the floor production worker up to the owner. The equipment you use and maintain is just as important to your business as your raw materials.
With this importance in mind, do you really understand what is going on inside your machines as they each trudge tirelessly throughout the day? Let’s look at a small slice in the life of a machine and learn how much work is being performed.
A Practical Example in the Plant
In this example, we will assume that the machine has a motor and that it is operating a conveyer system. (We’ll also need to know some nitty-gritty numbers that we’ll use in a minute.) The rollers on the conveyer are two inches in diameter, and have ball bearings with an inside diameter of half an inch and an outside diameter of one inch.
The ball diameter inside the bearing is a quarter-inch. We’ll also assume that the motor has the same bearings as the roller, and that the motor is operating at a speed of 1,725 rotations per minute (rpm). The motor is connected to a 30-to-1 gear box (for every 30 turns of the motor, the conveyer roller turns once) and the gear box is connected to the conveyer roller by a four-foot chain wrapped around two four-inch diameter sprockets. Got it?
It’s 7 a.m. and the first shift arrives, and the equipment is turned on. The motor is powered up and the conveyer starts to move your product down the assembly line. After the first minute of production, the motor has turned 1,725 times, the ball in the ball bearing has rotated 862.5 times, and the output shaft on the gear box has rotated 57.5 times. This has caused the chain sprocket to rotate 57.5 times and the chain to move approximately 60 feet, and the conveyer roller to turn 57.5 times causing the conveyer to travel approximately 30 feet. All this in the first minute of the day!
By the end of the shift (eight hours later), the motor has turned 828,000 times, the ball bearing has rotated 414,000 times, the output shaft on the gear box has rotated 27,600 times along with the chain sprockets, the chain has moved 14,400 feet, the conveyer roller has turned 13,800 times and the conveyer has traveled 7,200 feet.
As you can see, a significant amount of movement, motion and work is being performed by this single machine every single day, and what I have described is a simplistic system which is not even working at a significant production speed. On many machines, normal production speeds can easily quadruple these numbers.
What does this mean to you? That taking care of and maintaining your equipment on a regular schedule is extremely important, because neglecting your equipment for even a short period of time can result in premature failure of the system, and most likely loss of production and income.
Sharpening your Tools
This reminds me of a story about an apprentice butcher who was eager to please his boss. He worked hard the first day and cut 500 pounds of beef. The next day he worked just as hard and only cut 300 pounds of beef. The third day, he felt as though he had worked twice as hard yet only cut 150 pounds of beef. When his boss saw how much he did on the third day, the boss asked him if he had sharpened his knife. The apprentice looked at him and said, “But I have been too busy cutting all this meat to sharpen my knife!”
Sometimes you have to take time to sharpen your knife to keep production at its peak.
Al Simone serves as president/owner for Spadix Technologies in Middlesex, N.J.
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