By: Arthur Cooper
Submitted: 2010-12-29 19:43:36 | Word Count: 664
Regular platform scale calibration is a necessity for any business that relies on measurement accuracy to perform its daily operations, whether it’s a manufacturing, water treatment, shipping, farming, or food service business. The following is a general guideline to help you make the most of the delicate procedure for calibrating a platform scale:
1. Always be sure to place the scale on a completely flat surface, otherwise the scale will still not read accurately after all your efforts.
2. It should not be close to any vibrating machinery.
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3. Make sure that the conditions for the procedure are between 65 and 85 degrees Fahrenheit.
4. Do not try to calibrate it if the environmental humidity is outside of 40% ( /- 10%).
5. Make sure no magnetic devices such as cell phones or radios are near the scale when you are calibrating, as they will cause the reading to become erratic.
6. Consult the NIST (National Institute of Standards and Technology) guidelines for the technical details you need to familiarize yourself with before you begin.
7. Tare the scale so the display reads all zeros all the way across.
8. Place an apropriate calibration weight on the scale. You can purchase calibration weights from the manufacturer.
9. If any readings are out of the parameters called for on the scales requirements, take the calibration records to your quality assurance manager for review and recording. Your QA manager can take the necessary steps to make sure that the scale conforms to ISO 9001 requirements.
You should also keep the following in a calibration record to ensure regular and consistent calibration of all your platform scales:
1. Calibration record number
2. Name and manufacturer of scale
3. Location of scale
4. Scale number
5. Scale calibration procedure number
6. Name of weights and weight identification numbers
7. Due date for next calibration
8. Temperature and humidity log
Also Remember:
No calibration procedure can be more accurate than the test weights themselves. For extremely precise calibration, handle the test weights very carefully, with rubber gloves and/or tweezers.
Even the oils or acids present on your skin can etch material from a weight and throw off its true weight value. Be sure to store the weights in their padded case when they arent in use. Corroded or damaged weights are going to be almost worthless for an accurate calibration procedure with close-tolerance requirements.
Different platform scales will also have different processes for calibration. For NIST and ISO 9001 compliance, careful record-keeping is essential. Keep a master list of all calibrated scales, and record what actions are taken when an instrument or scale is found to be out of calibration.
Determine how to identify defective standards, cover the handling and storage of weights, and be absolutely sure to discuss the process of handling lost standards and out-of-calibration instruments. This should put you in good shape in case of an ISO 9001 audit.
Most scales can be accurately and quickly calibrated using test weights. Whether you need to maintain ISO 9001 or NIST compliance or not, it’s always a good idea to bear the general guidelines in mind when embarking on a procedure, and to keep a record of past calibrations along with the platform scale.
