Correctly calibrated weights indicate precise results and will reduce the probability of any errors in weight measurement which otherwise could cause disastrous results. Calibration is in fact an investment that builds up the confidence for a user. Using non-calibrated equipment can lead to issues in production and quality.

Over a period of time due to repeated usage the accuracy of balances and scales become less reliable. This is due to normal wear and tear caused by regular usage and external factors such as mechanical shocks or detrimental environments. Such a situation could lead to degradation or deterioration over a period of time.

But if such equipment’s are maintained with regular calibration in combination with frequent maintenance this would enhance the life of a balance / scale and its weighing accuracy.


What is Mass Calibration?

Calibration is a quantitative comparison with a standard to check the accuracy of an instrument/weight. Calibration of weight/mass is a procedure by which a licensed technician uses a known calibrated reference mass, to check and adjust the reading of a mechanical or electronic weighing system.

Initially the display indicator must show zero when there is no weight on the scale. When a known weight is applied, it must display the correct amount of applied weight within the given tolerance limit.  Tolerance limit is the difference between the measured value (the reading) and the true value (the reference weight).

After mass calibration procedure, a certificate is provided with necessary values which would classify if the equipment adheres to the tolerance limits.

Why Should Mass/Balance be calibrated?

When any equipment has not been calibrated or certified would you be sure regarding the weight it displays – by no means. The calibration of a Balance or Scale is essential to achieve accurate weighing results.

Benefits of the Mass Calibration.:

  • Traceability: The unbroken chain of calibrations contributing to the uncertainity
  • Reliable & Precise Measurements: Maintaining accurate weight measurements with clarity
  • Cost Savings: Reliable quality of measurement reduces waste, rework or product recall. Also you could avoid Penalties, Legal action & Customer complaints
  • Compliance: This ensures that your company adheres to all relevant National & International standards.
  • Early Detection of Ageing: Every equipment ages over time and its components may sustain mechanical stress, wear and tear. Mass calibration uncertainty or Drift cannot be eliminated but it can be detected through periodic calibration.
  • Process and profit improvement: Regular calibration ensures correct results within defined tolerances thereby improving processes and ultimately increasing profits.
  • Brand Image: A genuine brand image is maintained by providing accurate product data to customers

How often Mass/Weight Calibration to be carried out?

People assume that the validity of calibration of scales/balances is for a year. But this is wrong as calibration is not proportional to time factor or even usage pattern. Calibration intervals are defined on a risk-based methodology. For example what is the probability of something going wrong and what would be its impact?

Higher the impact and more disastrous the consequences corresponds to higher risk therefore this correlates a shorter calibration interval. But for low impact and low probability of consequences the risk is low, thereby calibration interval can be extended.

What are the risks of not calibrating?

Not calibrating could have dreadful consequences. Hidden costs and risks involved using un-calibrated balance or scale could have terrible results on the long run. Using non-calibrated equipment can lead to issues such as:

  • Unscheduled downtime
  • inferior product quality
  • process and audit issues
  • product rework and recalls

Environmental changes & location can also lead to undetected drift or increase in random errors which lower performance. Different balances will react differently to a change in location & environment.

A less-sensitive balance, for example with 1 gm accuracy may not be able to measure a change in gravity when it is moved from one location to another. But sensitive balances, such as those found in laboratories, will easily display the difference in gravitational forces and will detect small differences of change in location. Not calibrating regularly can cause changes to a balance calibration/reading. Periodically scheduled calibration along with routine testing is the optimal manner to reduce calibration-related risks.

Which tolerances apply to Mass calibration?

Tolerances determine whether a balance or scale behaves judiciously to meet a particular set of process requirements. Tolerances indicate whether to Pass/Fail statement for an instrument. There are 3 main categories for this: Legal tolerance, Manufacturer Tolerance & Process Tolerance.

Legal Tolerance: Legal tolerances are specified by OIML R-111/ OIML R76/1 or NIST guidelines to assess legal for trade requirements. These tolerances are quite large and easily met with laboratory balances, or while weighing at the lower end of a measurement range.

Manufacturer tolerance: It ensure that equipment meets manufacturer specifications. Manufacturer tolerances do not consider user specific process requirements and are therefore unsuitable for improving the weighing process.

Process tolerances: Specific process tolerances defined by the user, support process improvements and savings on material, waste and rework.

Difference between mass calibration and mass adjustment:

There is an important difference between Calibration & Adjustment but these terms often confuse most people. During mass calibration, weights are compared to specified measurement standards. During this process the accuracy of test weights can be determined. Adjustments can be made to instruments to bring the reading within set tolerances. Or then we have the option to replace the test weights with more accurate ones.

Calibration: “Mass Calibration is carried out under specified conditions by comparing the test weight/scale/balance against a known standard or mass value”. Mass calibration standards and mass calibration factors are responsible for the accuracy of equipment.

Adjustment:The calibration of a balance or scale indicates how an instrument behaves. While adjustment of the device changes its behaviour. A give set of operations is carried out on a measuring system so that it provides prescribed indications corresponding to given values of a quantity to be measured. Therefore, adjusting a balance or scale means modifying its indications in such a way that it  allows them to correspond – as much as possible – to the quantified value of the measurement standards applied.

Is measurement of uncertainty so important?

Absolutely!! Calibration of an equipment without measuring its uncertainty is meaningless. Measurement uncertainty is critical to risk assessment and decision making. Organizations make decisions on a daily basis based on reports containing quantitative measurement data. If measurement results are not accurate, then the risk of failure increases.

Measurement uncertainty is an integral part of any calibration; it is the quantified doubt about the result of a measurement. If not reported in the certificate, calibration is incomplete.

How do I ensure accurate /safe weighing results?

The accuracy and precision of a result is dependent on how reliable the weighing system is. Accurate & safe weighing range is determined by following parameters:

  • Regular calibration of an equipment
  • The safety factor applied according to the process
  • Ensuring appropriate environment
  • Handling of weights properly
  • Storing weights in the right manner

Take measurement of samples appropriately to gather accurate results which are a sum of several key service activities. Routine testing, in addition to calibration, can satisfactorily improve the accuracy of a balance or scale. While calibration is performed by authorized service technicians, routine testing is executed by the end user.

Correct way to handle test weights:

Proper handling of test weights is vital to ensure accuracy of the weights on the long-run. Having accurate test weights is essential for calibration and routine testing of balances and scales. Weights are frequently used and are important for testing/calibrating of scales and balances.

Actions that keep weights in perfect and accurate condition are:

  • Do not touch weights with bare hands, wear approved gloves
  • Store weights in original packaging
  • Store weights near to the balance
  • Ensure to use non-magnetic and non-abrasive tweezers
  • Handle with care
  • Clean according to OIML/ASTM recommendations
  • Use specialized handles for heavier weights
  • Inspect for damage prior to use

This will help you to avoid weighing errors and costs associated with rework, waste disposal, and product recall.

Is Routine testing necessary between calibration intervals?

With routine testing you can enhance the performance of your balance and ensure consistency in the quality of your products. While calibration is performed by authorized service technicians, routine testing is executed by the end user. Routine testing helps in early identification of potential balance irregularities in the weighing process requirements. If performed frequently, out-of-tolerance status can be detected before any tragedy occurs.



    Sushma Industries Provide E1, E2, F1 & F2 class Weight Calibration.

    Sushma Mass Calibration Laboratory has been constructed in conformation to strict environmental guidelines. In order to maintain a strictly controlled environment, Mass Calibration Laboratory has been designed and constructed within a building. The climate in the Mass Calibration Laboratory is strictly monitored and controlled using necessary systems.

    Our Mass Calibration Lab is equipped with marble tables for lab comparators thereby reducing vibrations totally. With traceability to SI units through NPL and ISO-9001-compliant calibrations, Sushma’s accredited mass calibration capabilities conforms to the most stringent quality requirements. Our quick turnaround time and our competitive pricing further set us apart from other OEMs.

    Mass calibration services are accredited by ISO 17025. Calibration results are traceable to NIST/NPL-UK/PTB.

    Our services are timely, accurate and easy-to-read Calibration Certificate with a full report of all processes carried out and results. When a calibrated instrument is due for re-calibration, we shall keep you informed via a reminder notice.

    Following Mass equipment can be calibrated at our facility:

    1. Mass Weights 1gm – 2kg: Using E0 & E1 class weight & balance/comparator of readability 0.0001mg/0.001mg/0.01mg/0.01mg & 5mg readability calibration of weights of class E1 accuracy & coarser as per OIML R-111
    2. Mass Weights 2kg – 20kg: Using E2 Class weights & balance/comparator of readability 0.1mg & 5mg readability calibration of weights of class F1 accuracy & coarser as per OIML R-111
    3. Weighing Scale & Balance:
    • Electronic balances 2gm – 2kg: Using E2 & F1 Class weights calibration of electronic weighing balance & comparator of Class I & Coarser as per OIML R-76-1
    • Weighing Balance Upto 75kg: Using electronic weighing balance and comparator of class II & coarser as per OIML R-76-1

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