Article written by Steve Langford
VP, Engineering Services
Cardinal Scale Manufacturing Co.
Whoever said “a scale is your cash register” knew what they were talking about. A truck scale serves to make sure that you get what you pay for when buying raw materials as well as making sure that you receive proper payment for your products. An accurate scale is not only necessary to maintain profitability but to comply with weights and measures laws. For most of us, the purchase of a truck scale is a major investment and, when you consider its use, it only makes sense to make sure the scale continues to do its job and to help maximize your profits.
Perhaps the best advice to ensure that your truck scales continue to meet your expectations is to be proactive. Don’t wait until your scale is out of calibration before calling your service company. Have your scale’s calibration checked at regular intervals. How often? How long can you go with an inaccurate scale causing you to pay for material you don’t get or to give product away? At a minimum, a truck scale’s calibration should be checked by a reputable scale service company at least once every six months. Between calibration checks, keep an eye on the readings to make sure that the readings stay within the ballpark and are not obviously wrong. If there’s any question, call your scale service company. It’s better to spend a few dollars verifying the calibration of your scale than to loose thousands or more with an inaccurate scale.
Truck scales are designed to maintain calibration, within predefined limits, over a range of temperatures but calibration can vary from winter to summer. If you are in an area subject to temperature extremes, it is a good idea to schedule the calibration of your scale to coincide with the temperature extremes. Granted, the scale may still be in calibration and only slightly high or low but, the greater the number of weighing operations, the greater the influence on your bottom line. Keep in mind that you are obligated to keep the calibration as close to a zero error as reasonably possible so that the scale favors neither the buyer nor the seller. Why would an honest business owner want it any other way?
While scale calibration requires the use of calibrated test weights and therefore the services of a scale service company, there are things that you can do yourself to keep your scale profitable. Perhaps the most simple and most often overlooked is cleaning the scale. When we say clean, we mean cleaning not only the scale platform but also beneath the scale. Dirt, sand, snow or debris can accumulate beneath the scale weighbridge structure and, if not removed on a regular basis, can eventually cause weight errors and even contribute to corrosion. The best thing to do is to not let it get to that state. Clean beneath your scale at regular intervals removing all foreign material. This is a good time to check for the start of any corrosion and, if any is found, apply paint or some anti-corrosive compound to keep it in check. Pressure washers are often used to clean beneath a scale but, if you choose to use one, make certain not to direct the spray on load cells and load cell junction boxes. While normally that would not be a problem, it’s probably best not to tempt fate if you don’t have to. While you’re at it, make certain that the drain(s) in the foundation are clear and free flowing so that a sudden downpour doesn’t flood your foundation. How often should you clean your scale? That depends on your application and where the scale is installed. Once a year in some applications is plenty while once a day in others may not be enough. Once you’ve cleaned it a few times, you will get a feel for how often it needs attention. Whatever you do, don’t put it off.
Now that you’ve got your scale clean and calibrated, that’s it, right? Unfortunately, no. Many of the causes of inaccurate weights and therefore detrimental to profits is operating the scale incorrectly. You might think that, but you’d be wrong. Fortunately, most of the things to watch out for when operating the scale are pretty simple. First, make certain that the scale is on zero before placing a truck on the scale platform. Any departure from zero will have a direct effect on the final weight. Most truck scale weight indicators are equipped with auto zero tracking and pushbutton zero making it easy to keep the scale at zero but, sometimes, these features give a false sense of security. Whoever operates your scale should be in the habit of always checking the scale’s weight display before allowing the driver to pull the truck onto the scale. If the driver pulls on the scale platform before you have verified that the weight display is at zero, make them pull off the scale. Granted, you won’t make many friends doing this but then you’ll be assured that an off-zero reading won’t be stealing your profits.
Another thing to keep aware of when weighing trucks coming into and then leaving your place of business is to know whether the driver was in or out of the cab when the weight reading was recorded. A simple thing but one that can catch you if you aren’t keeping watch. One thing that helps is to have a box on your weigh ticket to check if the driver is in or out of the cab. That way you will be reminded to keep track of the driver.
Still another source of operational error is failure to keep an accurate and current tare weight value for the truck and trailer if you are using stored tare values to calculate the net weight. Studies in the past have shown that errors in tare weight can easily account for the lion’s share of weight errors. Newer weight indicators automatically clear stored tare weight values after a certain period of time but don’t depend on that. Make sure that any stored weight values for the weight of the tractor unit and the unloaded trailer are accurate and current. Also make sure that the tare weight of the trailer used is actually the same trailer that is sitting on your scale platform.
Yet another, and one that may be all too obvious, is to make sure that the weight units are always correctly set. Most weight indicators have a units key to toggle between various units of weight. Accidentally pressing the units key can change the display from pounds to kilograms cutting the value in half. Sure, the weight units is displayed and printed but you, the operator, have to make sure that you have it correctly selected and don’t ignore it.
Make sure that personnel around the scale do not step onto the scale platform while you are conducting a weighing operation. You could suddenly find the weight off by a couple hundred pounds if one of your workers happens to step onto the platform as you perform the weighing operation. Granted, this is another one of those “duh” sources of error but, believe me, it happens and it is up to you as the scale owner and operator to keep an eye out for just such errors.
Maintaining calibration, keeping your scale clean and in good repair and watching out for operational errors can help ensure that you keep your truck scale on track for a record year of profits. As the television commercial says “It’s just common sense”.