What are the differences between conveyor scales and checkweighers?
Let’s first describe a checkweigher; a checkweigher is a scale that allows you to set a target weight for a product often referred to as the “Accept range”. Other ranges can include “Over,” “Under,” “Accept Over” and “Accept Under.”
The accept range is generally a very small range where the target weight was almost perfectly hit. The accept over and accept under ranges refer to a product whose weight just slightly missed the target weight but is still acceptable enough to pass inspection. The over and under ranges are set to where a product is too far off of the target range to pass inspection at all, and will need to be reworked.
Checkweighers are available in two very different styles; the first is a “static” scale where an operator will have to place each individual product on a scale, the scales controller will then indicate to the scale operator what range the product fell into, often times with the use of a series of red, yellow, and green lights.
The second type is an “automatic checkweigher.” With an automatic checkweigher the products are conveyed across a series of conveyor belts and the weight is automatically collected with
An automatic checkweigher offers distinct advantages over the static checkweigher. Mainly it can be very cost effective, it also reduces the chance for unintentional human error, as well as removing the possibility of an operator having a bad day and letting their attitude enter into their decision making process.
Additionally, this type of automated system can also keep track of production data by keeping track of the total numbers of packages that fell into each of the ranges.
Now that you have a good understanding of what a checkweigher is we can look at what a conveyor scale is.
A conveyor scale is a component to be used in some sort of system, it’s essentially a scale with a conveyor mounted to it, and some sort of a controller to gather the weighing information.
The only thing the conveyor scale really does with this weight information is to send it to a controller that controls a larger system.
A checkweigher is a good example of one of these systems; another would be a sortation system where products need to be sorted according to weight so that a decision can be made as to how to process each particular product that goes across the scale based on its weight. A final example would be a box labeling system that would apply a net weight label.