Updated: Oct 22, 2020
Test weights are an important component in a quality system to make precise measurements. To establish whether a balance is meeting process tolerance requirements, it's essential to properly handle test weights. Incorrect handling of weights can instantly hamper their accuracy and change their conventional mass value (CMV). Here are 5 tips on how to correctly handle test weights.
1. Always use tweezers, weight forks, or gloves -It's important to never touch test weights with bare hands as heat, grease, and dirt can transfer from fingers to the weight. Use tweezers, weight forks, or gloves instead. Make sure the tweezers are Teflon tipped or plastic.
2. Be careful when picking up and placing weights-Make sure you always pick up and place weights since sliding weights removes mass. If using a cloth, use designated laboratory-grade, lint-free cloth. Alternatives are dusting the weight with a bellows blower or using a soft, weight-specific brush. Don't use any chemicals!
3. Avoid temperature drift -Allow weights to acclimatize or reach temperature equilibrium near the balance with which they will be used. This will eliminate any temperature drift during testing. Keep the weight close to the balance and its approved container. Don't leave the weight box sitting with the lid open in order to avoid knocking container over.
4. Keep weights away from magnetic sources - Always keep your test weights away from magnetic sources, such as stir plates or other electrical equipment with a magnet or motor. Magnetized objects can change the properties of the weight, also distorting the indicated weight from the way cell, increasing the repeatability error.
5. Don’t set weights on the bench - If performing a repeatability test, don't set weights on the bench between weighing as lab dust, dirt, and debris may be present.
Incorporating routine visual inspections into the staff’s normal routine can help catch evidence of mishandling. In the event weight is dropped, it must be recalibrated. Contact Custom Calibration to find the best balance calibration service. Follow the shared tips to keep weights in class until their next calibration is due.