Weighing balances need regular calibration if they are to provide you with accurate and consistent readings. Without calibration, the readings you take from a weighing scale are always uncertain and that can significantly affect your quality of work in industries like material research, clinical research, manufacturing, and chemical analysis.

This blog sheds some light on why keeping your weighing scales calibrated is extremely important. This information will help you understand how regular calibration can enhance the performance of your weighing balance and finally, you will also learn some useful tips for the calibration of weighing balance in general so keep on reading till the end.

• What is Weighing Scale Calibration?
• The Importance of Weighing Balance Calibration
• The Procedure for Weighing Balance Calibration 
• Pre-Calibration Processes
• Tests for Weighing Scale Calibration
• Repeatability Test
• Linearity Test
• Eccentricity Test

What is Weighing Scale Calibration?

Weighing scale calibration is a process carried out under control conditions to find the relationship between the values of quantities using measurement to that of the corresponding values according to previously set standards.

In a typical weighing balance calibration sop, the standard output and accuracy are already known. This allows you to compare these measurements with those of the instrument that you need to calibrate.

In simple words, the calibration of weighing scales deals with figuring out the relationship between a known value and the measured value. This gives you an understanding of the behavior of your scale which you can use later to increase the accuracy of your measurements.

The Importance of Weighing Balance Calibration

The calibration of weighing balance is the only way you can get reliable outcomes in routine weighing applications. For calibrating any scale, you can go with internal or external calibration.

In most cases, however, it is external calibration with a standard known weight that gives you greater accuracy. The internal calibration is done by the electronic scale itself which you cannot always trust.

Following are a few points that show how important weighing balance calibration is

• A calibrated scale gives you accurate weight measurements and that reduces the risks of waste, product recalls, and rework saving you a lot of costs.
• Calibration of weighing balances allows you to ensure compliance and to do well in external or internal audits.
• Periodic calibration allows you to assess the performance of your scales to figure out wear and tear caused by mechanical stress.
• Calibration increases measurement reliability and usability.
• Regular calibration improves processes which also leads to increased profits.

The Procedure for Weighing Balance Calibration 

Calibrating a weighing scale is not as difficult as it sounds. With just a little practice you can easily do it on your own.

Following are a few things that you will need before you start the calibration process.

You need to have a complete understanding of your weighing balance operation. You also need to arrange precise standard weights whose values are known. Once you get these things down you can move on to the pre-calibration phase.

Pre-Calibration Processes

Pre-calibration involves warming up your weighing balance for the time given in the operating manual. As a rule of thumb, you can do it for 30 to 60 minutes before starting the calibration.

Another important step is to place the standard weights as close to the weighing balances as possible while it warms up. This will establish a thermal equilibrium which enhances calibration accuracy.

Tests for Weighing Scale Calibration

No matter whether you are thinking of buying a personal weighing scale or a commercial one, you can follow the tips given below to calibrate it with ease.

1. Repeatability Test

This test involves the assessment of the ability of a weighing balance to produce the same results over and over again when the same load is used. You need two weights one of full and one of half the capacity of the weighing balance to perform this test.

Here are the steps you need to follow:

• Warm up the balance and make sure the display shows zero.
• Place the full capacity weight on the scale and note the reading when the display is stable.
• Then remove the weight, let the display return to zero, and note down the return zero display.
• Repeat this process 5 to 10 times and find out the standard deviation.
• You can also find the repeatability at half load by repeating the same steps as above.
• If two times the standard deviation you just calculated divided by the smallest net weight does not exceed 0.10%, the repeatability of your scale is satisfactory.

2. Linearity Test

The purpose of this test is to determine the difference between the actual mass and the measured value by the scale. To do this, you need to place calibrated weights of known value successively on the scale and note the difference between the actual and observed values.

Following are the steps you need to follow to perform this test:

• Put a known mass of approximately one-tenth of the weighing range of the balance on the scale and note down the reading.
• Remove the weight and then place it back and again note down the new reading. Take an average of the two readings.
• Remove the weight and note the zero indication. This gives you the zero load value.
• Repeat the same process with all the other weights until you have reached the maximum capacity of the balance.
• To find the linear correction, use the formula

Standard Mass Value – (average observed value – average zero value)      

• You can add this correction to the given mass to find the correct weight of the object placed on the pan.

3. Eccentricity Test

This error arises due to the off-center positioning of the weighing balance pan. To conduct this test, a load of one-third or half of the maximum capacity of the balance is used. As a rule of thumb, you can use a weight whose surface area is one-third and half of the pan.

Before conducting the test, mark five points on the pan one in the center and one on each of the four corners.

Following are the steps you need to follow

• Ensure the balance shows zero reading and then place the weight in the center position. Note the reading and then remove the weight.
• Now place the same weight on the remaining four positions and note down the corresponding readings.
• Now place the weight in the center position again and take a second observation.
• Then again place the weight at four corners and take the readings.
• Finally, place the weight again at the center for the third observation. 
• Then calculate the average for all corner locations and subtract these values from the central location value.
• If the maximum difference between any location is within the specified limit your balance has passed this test.

Conclusion

The calibration of weighing scales allows researchers to improve their experimental outcomes and businesses to deliver quality products consistently. Apart from that, it is through calibration that businesses can ensure compliance with industry regulations by delivering quality goods and services every single time.

Regular calibration not only enhances the performance of your weighing balance but also ensures it lasts you for years to come without any considerable difference in output quality.

Visit Eagle Scales right now to get our fully calibrated premium quality weighing balances and scales both for personal and commercial applications.