First conclusion
Calibration cycles are not a fixed number of years, but rather a control item that can be explained by data.
There is no single correct answer regarding calibration cycles. What's important is determining a cycle that your company can explain, based on factors such as frequency of use, operating environment, required accuracy, past calibration results, and the potential impact of any deviations.
- Don't make decisions based solely on the practices of your predecessor.
- When implementing a new system, first establish a provisional cycle.
- Record the calibration results each time.
- Record the basis for the review in a ledger.
Chapter 1
1. What is a calibration cycle?
The calibration cycle is the interval between calibrations, set to periodically check whether a measuring instrument maintains the required accuracy. A calibration certificate is a record of the instrument's condition at the time of issuance, not an expiration date itself. Therefore, it's essential to design the next calibration check schedule yourself.
JCSS may include periodic recommendations on calibration certificates and labels only with the customer's agreement. However, these are merely recommendations and do not automatically determine the next due date.
Calibration, inspection, and adjustment have different roles.
| Item | Role | Points to look at |
|---|---|---|
| Calibration | Check for deviations by comparing with the standard. | display value, difference, uncertainty, record |
| Inspection | Check if it is working correctly. | Appearance, operation, presence of abnormalities |
| Adjustment | Adjust display and output as needed. | Changes before and after adjustment, and whether recalibration is necessary. |
The basic process involves first checking the current state through calibration, and then determining whether adjustment, repair, or replacement is necessary based on the results.
Chapter 2
2. Why do so many people struggle with the proofreading cycle?
The reason is simple: setting the cycle is a trade-off between "cost" and "risk." Shorter cycles provide greater peace of mind, but increase costs and downtime. Longer cycles reduce costs, but increase the risk of continuing to use the system in an inaccurate state.
Too short a cycle
Calibration costs and downtime will increase. If the calibration time is too short, it will only increase load on the staff.
Too long a cycle
This increases the likelihood of continued use in a misaligned state, which could lead to quality defects and customer complaints.
Unexplainable in the audit
"That's how it was done by my predecessor" is not sufficient evidence. Records and a logical explanation of the decision-making process are necessary.
Immediately after introducing new measuring equipment, it's practical to tentatively adopt the manufacturer's recommended or standard cycle, and then review it based on your own data.
Chapter 3
3. Five criteria for determining the calibration cycle
In practice, it's fundamental to consider the following five perspectives together. Instead of making a decision based on just one of them, a comprehensive assessment is necessary.
| perspective | Content to watch | Influence on the cycle |
|---|---|---|
| Frequency of use | Do you use it every day, or a few times a month? | The more frequently you use it, the shorter you can make it. |
| Operating environment | High temperature, high humidity, vibration, dust, presence of dew condensation | The harsher the environment, the faster we want to see change. |
| Required accuracy | Is it used for determining pass/fail status, or as a reference value? | The more important something is, the stricter the management. |
| Past calibration results | The magnitude of the discrepancy, the trend, and the presence or absence of outliers. | If it remains stable, it will be a factor in considering an extension. |
| Impact | How far will the ripple effect extend if it is misaligned? | The greater the impact, the more appropriate it tends to be to shorten the duration. |
The way thermometers and temperature sensors display data varies depending on whether they are contact-type or non-contact-type. Contact-type thermometers are susceptible to installation conditions and deterioration, while non-contact-type thermometers are easily affected by emissivity, optics contamination, distance, and field of field of view. Therefore, even though they are all called "thermometers," their cycles are not uniform.
Chapter 4
4. Guidelines for Calibration Cycles by Measuring Instrument Type
While these are merely general guidelines, the following cycles are often adopted in practice. It is essential to adjust them according to your company's working conditions and past data.
| Measuring instrument type | Cycle guideline | supplement |
|---|---|---|
| Calipers, micrometers, and other general-purpose measuring instruments | 6 months to 1 year | In environments with high usage frequency, the setting may be shortened. |
| Torque wrench | 3-6 months | This equipment is susceptible to the effects of usage frequency and load conditions. |
| Electrical measuring instruments | 1年 | This is a widely used guideline, but it can vary depending on the application. |
| Thermometers and temperature sensors | Around 1 year | Whether it's contact-based or non-contact depends greatly on environmental conditions. |
In the case of temperature sensors, the way degradation is observed differs depending on whether it's a thermocouple, resistance thermometer, or radiation thermometer. It's important not to rely solely on a guideline table, but to consider the type of equipment and on-site conditions separately.
Chapter 5
5. How to think about extending or shortening the period
When extending
This explanation assumes that the calibration results from the past few trials have been consistent and that the usage environment and methods have not changed. I will explain using data from multiple trials, not based on subjective feelings.
When shortening
Typical changes include failures or significant discrepancies, stricter working conditions, or being used in critical process.
If a decision is made to shorten the cycle, it may be necessary to check the impact on products and process previously measured with that instrument. It is important to operate the system by checking not only the cycle but also the scope of the impact.
Chapter 6
6. Practical Flowchart for Determining the Calibration Cycle
- We will conduct an inventory of our current equipment and organize the frequency of use, environment, and importance of each measuring instrument we possess.
- For newly installed machines, the manufacturer's recommended cycle will be used as a provisional setting, while for existing machines, the current cycle will be used as the basis.
- We record the results of each calibration and the trend of the deviations, creating a system where changes can be seen.
- Based on the accumulated data, we will decide whether to extend, maintain, or shorten the cycle, and the rationale for this decision will be recorded in the management regulations.
By following this process, you can shift from a "vague, yearly" cycle to a "well-founded cycle."
Chapter 7
7. Things to organize before consulting about proofreading
When reviewing cycles internally or consulting with external parties, having the following information will help the process move more quickly.
| Check items | Things to organize |
|---|---|
| Measuring Instrument | Type, model, serial number, measurement range |
| working conditions | Frequency of use, operating environment, installation location, temperature range |
| Calibration results | Discrepancies, outliers, and failures in the most recent few data points. |
| Required accuracy | Quality assurance, audit compliance, internal standards, supplier requirements |
| Impact | Scope of impact in the event of a malfunction |
| Certificate Requirements | Calibration certificate, traceability, and JCSS requirements |
Why not review your calibration cycle based on the actual conditions of each piece of equipment?
The better we understand the on-site conditions, the more specific the required calibration cycle and certificate requirements will become. Please consult with us after organizing information about the intended use, installation environment, and past data.
Consult about calibrationSummary
The calibration cycle can only be determined after establishing justifications that can be explained during an audit.
Calibration cycles are not determined by a single set number of years dictated by laws or standards. It is important to consider usage frequency, operating environment, required accuracy, past results, and impact, and then define a calibration cycle that can be explained within your own company.
In particular, the approach to thermometers and temperature sensors changes depending on whether they are contact-type or non-contact-type, and in what environment they are used. First, establishing a provisional cycle, accumulating records, and creating a process for reviewing them based on evidence is effective for both audit compliance and on-site operations.
FAQ
FAQ
Q. Is there a correct answer for the calibration cycle?
A. There is no single correct answer. It is determined based on the frequency of use, the environment in which it is used, the required accuracy, past calibration results, and the degree of impact.
Q. Does JCSS calibration also determine the period?
A. It's not determined automatically. It can only be listed as a recommendation if there is an agreement with the customer.
Q. Is it okay to extend the calibration cycle?
A. If past data is stable and working conditions haven't changed, we can consider it. Multiple records are required.
Q. What would you think if your work failed the calibration stage?
A. We will review the possibility that the cycle was too long and consider environmental changes. If necessary, we will also consider checking the impact on past measurements.
Q. How should I consider the period of a temperature sensor?
A. It varies depending on whether it's a contact or non-contact type, the operating temperature range, the installation environment, and the surface condition. It's not uniform for each model.
Reference information
