A lab balance can be a big investment so it’s likely something you don’t want to have to replace often. Plus, the wrong measurements could spell trouble for virtually any application, so it’s important that your machine is used and maintained properly to ensure it works as it should.
Thankfully, there are certain steps you can take to help make sure your machine has a long life and that your balance readings are accurate:
1. Position your unit correctly
2. Let it warm up
3. Don’t overload the balance
4. Clean the unit regularly
5. Calibrate it often
In this post, we’ll look at each of these in turn, so you’ll be able to confidently use your balance.
1. Position Your Unit Correctly
The position of your unit is important to help ensure you get an accurate reading. It should always be on a flat, stable surface and should be adjusted such that it is level.
It should also be placed away from draft sources such as frequently opened doors and air vents, and any vibrating equipment.
It’s probably not a good idea to try to weigh something while that printer is running.
Once a unit has been calibrated, it shouldn’t be moved. If you do have to move it to another spot or adjust the feet to level it, you should calibrate it again.
Aside from those factors, the balance needs to be in a non-harsh environment. For example, extreme hot or cold, high humidity, or lots of dust can affect the balance mechanisms and throw off readings.
It’s a good idea to check that the unit is level each time you use it, especially if you’re sharing the machine with others in the lab.
2. Let It Warm Up
Are you in the habit of turning off your machine each day? If so, bear in mind that after you turn it back on, it’s not a good idea to try to use it immediately. The electronics need a little time to warm up before you’ll get an accurate reading.
3. Don’t Overload the Balance
Overloading a balance will often give you an error, so you’ll know when it’s happening and likely won’t get any reading at all. But don’t use this as a guide. Overloading a balance by too much can cause permanent damage to the delicate internal mechanisms. Similarly, you shouldn’t leave your weighed items on the balance for prolonged periods of time.
Analytical balances like Shimadzu ATX224, Wensar MAB220T,METTLER TOLEDO ME 204 are especially delicate and shouldn’t be overloaded.
You should also be mindful when handling or storing the balance so that there’s not too much pressure is applied to it. For example, in storage, there definitely shouldn't be other items placed on top of it.
In general, balances should be handled with care. Although they may look like fairly robust units, their mechanisms can be easily damaged.
4. Clean the Unit Regularly
When cleaning and maintaining any piece of lab equipment, it’s important to follow the notes provided in the manufacturer’s guide. In most cases, you should be wiping the balance clean after each use. Even a tiny amount of debris can affect the accuracy of the balance. Remember to wipe gently so that you don’t apply too much pressure to the balance.
If you have loose debris of dust on the balance it can be tempting to blow it away, but this could cause it to end up in the balance mechanisms. A tissue is a better option. For other substances, a mild cleaning agent should do the job, but avoid anything abrasive. If you’re using a liquid such as ethanol, spray it onto a cloth first, not directly onto the balance.
For more thorough cleaning, you can remove the pan and clean it separately. This way you avoid the potential of putting too much pressure on the plate and damaging the machine. Check your balance manual to find out what cleaning agents should or shouldn’t be used.
5. Calibrate It Often
If your unit comes with an internal calibration feature, then calibration will be less of a concern. For example, AG Pro Precision Balances come with internal calibration as standard and Ohaus Adventurer Precision Balances have the option of internal or external.
Even so, you should still check at scheduled intervals with certified calibration weights. One of the most important things to bear in mind is that you should store and handle calibration weights properly to avoid them getting dirty or damaged.
Troemner Cal-Paks™ and OIML Precision Weight Sets come with a neat case to keep them protected from dust and debris.
They should also be handled with a forceps where applicable. For larger weights that can’t be held with a forceps, clean gloves should be used to avoid oil from your hands transferring onto the weight.
Troemner Analytical Precision Weights come with a forceps for handling.
Aside from calibrating yourself, you may want to have a company come in and calibrate your machine. This can be done as part of a service. Balances should be serviced and calibrated on at least an annual basis. This can change depending on your application, industry regulations, and the environment. For example, for improved accuracy, you may need to calibrate weekly or even daily.
Other times to calibrate would be when the machine is first installed or if the readings seem to be inconsistent. Keeping a calibration and service log of this and other machines in the lab will help you stay on top of things.