There are generally two ways of automatically filling containers in modern industry: filling by volume and filling by weight.
Most filling machines are volumetric in nature, meaning that they output a fixed volume of product into each package or container that they fill. A machine filling by mass would have some sort of scale component, so it is able to weigh and output at a fixed weight. An example of this would be our Net Weight Filler systems. They use a hopper scale system to output an ideal weight into each container.
Ideally, you would want a system that fills by mass because most consumer products (in the case of food at least), are measured or sold by weight. Unfortunately, filling by mass can be very difficult with certain types of filling where a scale would not work well. An example of this is with the machines that fill the packages for beef chubs. They use pressure to extrude a certain volume of product into each plastic wrapping.
While many of these machines are good at staying at a fairly constant volume, correct weight is still not insured because of density. This often depends on how tightly packed a product is. For example, with any product in small pieces, filling by volume to reach net weight might not have the intended effect every time. If product doesn’t settle ideally into gaps and pockets in a package, the net weight of that package might be different than other packages of the same product.
The question then is how you eliminate the problem of products not meeting their intended weight. When combined with an in-motion checkweigher, there is a very intuitive answer to this issue.
If volumetric filling machines aren’t quite hitting the net weight mark for you, you can try running them over an in-motion checkweigher after they are output. You can set up the checkweigher so that it can reject these products and notify you to possibly adjust your filling machine.
An even more automatic option could be possible too. By combining the checkweigher and filling machine, you make it possible to make automatic adjustments to output. If the checkweigher system starts receiving a trend of out-of-weight products it can send an automatic voltage signal to the filling machine which can increase or decrease its output to bring the weight trend back into spec.
A solution like this could apply to a great variety of products and a number of industries. Whether you are dealing with beverages, food products, or even something like small toys or parts, an in-motion checkweigher might help you with an efficient resolution to your out-of-weight product woes.
Learn more about our In-Motion checkweighers.
Recently, we were called into a potential customer’s plant to help them look for a solution to a problem that was causing them to lose a lot of production.
This customer was running two different production lines through a small corridor with a checkweigher set up on each line that would reject any of the boxes that were out of weight range. Seemingly, the majority of these boxes were falling out of the acceptable weight range. This made the people at these two stations very busy, and it created a large bottleneck.
The boxes that were going across these scales were being filled by an automatic filling machine in a different area of the plant that was a fair distance away. This was only compounding the problem because the filling machines were so far away that it took a long time for the scale operator to relay a message to the filling machine operator that a problem existed with the amount being output. Even when the filling machine operator made an adjustment, it would take a long time for those adjusted boxes to get to the scale.
What we proposed to solve these problems was the installation of an in-motion checkweigher directly after each filling machine that would be capable of sending feedback to the filling machines when the tolerances were getting close to out–of-range. This would allow the filling machine to continuously self-adjust to changing product characteristics.
They admitted that they had thought of placing a checkweigher closer to the filling machines before but could not find a layout that would work. We showed them that by using one of our custom-designed checkweighers designed for their specific needs, we would be able to make the system fit with minimal modifications to the existing environment.
Learn more about In-Motion Checkweighers.
People sometimes confuse conveyor scales with in-motion checkweighers. They are very different instruments with different uses. Here are some comparisons and contrasts.
An in-motion checkweigher looks at singulated units of one product ID at a time, compares the weight of each unit to the acceptable weight range for that product ID, and diverts the units that are outside of the pre-determined acceptable weight parameters that are stored in its controller.
There are many methods available for diverting or rejecting items that are out of tolerance.
An in-motion checkweigher might also be asked to send a signal that would make an adjustment to a system that is feeding product to the checkweigher, based on whether products are trending heavy or light. A filling or portioning system could be told to increase or decrease the weight and/or size of products that it sends down the line.
An in-motion checkweigher can be equipped to accumulate data for statistical analysis of product variations and weight ranges.
In-motion checkweighers are often used for quality control purposes to ensure that customers are not getting less than they are paying for and that the company is not eating up profits by giving away product.
Another common use of in-motion checkweighers is as a counting scale to make sure the right number of certain items are contained in packages, boxes, or cases.
An in-motion checkweigher should have three distant conveyor sections. It should have an in-feed conveyor, a conveyor scale, and an exit conveyor. The exit conveyor will usually have some type of divert or reject mechanism.
A conveyor scale measures the weight of each separately spaced item that is conveyed across it. It can send each weighment to peripheral devices, such as label printers or a host computer system. It does not compare those weights to any stored parameters. A conveyor scale can handle chaotic flows of many different products at a time, as long as those products fall within the conveyor scale’s designed weight capacity.
A conveyor scale can be asked to accumulate information such as the number of items weighed during a period of time and the total weight of those items.
Uses for a conveyor scale can be net weight labeling and measuring production levels.
We make both types of scales and our ability to customize them will make sure that yours is optimized for your application.
Learn more about In-Motion Checkweighers.
A customer recently asked how much it costs to replace a load cell in our WeighMore® in-motion checkweigher. My answer: it costs a few hundred dollars. The precise figure can vary a little depending on a couple of specifications.
He was quite surprised because he has an in-motion checkweigher manufactured by another company that is on a tray pack production line. A replacement load cell for that checkweigher costs several thousand dollars. To make matters worse, he said it takes about six weeks to receive the replacement load cell after ordering it.
My customer said he replaces the load cell in that checkweigher once a year because it fails due to water damage despite being rated for wash down environments.
I gave my customer some numbers to consider. His tray pack line needed a load cell set to a capacity of 10 lbs. At 2,000 divisions he could checkweigh to a sensitivity of 0.005 lbs. The WeighMore® in motion checkweigher easily provides that performance level.
The next numbers he looked at were the prices on the quotes for a new WeighMore® in-motion checkweigher scale compared to the other manufacturer. The WeighMore® was nearly half the price.
Next, he compared the carrying cost of keeping a spare load cell on hand to prevent down time.
His conclusion was the same as an increasing number of people’s. The WeighMore® in-motion checkweigher costs less to purchase, less to maintain, and delivers the performance that today’s plants need.
Learn more about our Dynamic Checkweighers.
Recently, we assisted a meat processing facility with just this dilemma. They have an excellent work force and were doing an outstanding job of manually weighing each piece of meat prior to packaging because the end customer required tight weight constraints on different cuts of meat on separate processing runs. A factor radically affecting the end customer’s weight constraints was the injection of a specific marinating liquid. With the company’s excellence in product and production came additional contracts and increased demand.
The problem was how to increase the output without increasing the workforce. The need was to utilize the existing excellent workforce and workspace. The solution was to remove the time consuming segment of manually checkweighing each piece prior to packaging and to replace it with automated checkweighing.
To accomplish this activity, we designed and incorporated our checkweigher with sortation diverts to operate and sort according to prescribed and changeable settings. Adjustable speed of infeed conveyors and other actions, provide necessary product singulation for fast and accurate product checkweighing. Thus, people that were doing the checkweighing and packaging can now assist others and concentrate completely on packaging actions. The product that is diverted by the prescribed weight settings is subsequently reprocessed accordingly.
As designed, our system more than doubles the output of the high quality product while meeting the accuracy constraints as required by the end customers. Our customer is happy to be achieving their goal of increased output while utilizing the same work force in the work space available.
Learn more about our Dynamic Checkweighers.