Metal Detector Videos
Why inline inspection equipment
The concept of quality assurance (QA) says that machines and processes must be designed so that they cannot make a bad, out of specification, product. This is fine in theory but nothing is ever perfect. Quality control (QC) inspects products with inspection equipment after they are made to try to catch any bad ones. In the past QC relied on inspection of representative samples at various stages.
There are a number of一世nline inspection processeswhich inspect 100% of products on the line using inspection equipment, rejecting any out of specification product. This paper will discuss some of them.
Machine vision inspection equipment means using an automated system to replace human visual inspection. Some systems do this using photoeyes. For example to detect a missing cap, label or other component. In general when we speak of machine vision, we mean camera based inspection equipment. These take a picture of the element of interest then process the image in a computer to determine whether the element is within specification.
Common elements inspected include missing components, presence and correctness of lot and date codes, label skew, cracked glass and much more.
Most machine vision systems inspect 2 dimensionally, meaning they can only see what is on the surface, They cannot detect, for example, a tablet with the back half missing. Several companies in recent years have begun offering 3D vision systems that may be useful in these applications. It is still a new technology with limited applications so this whitepaper will focus on 2D systems.
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Metal can get into your product at many points in the process. It may come with the raw material, it may be a screw or nut on a filling machine, it can be chips caused by maladjusted mixing blade making contact with each other. The customer doesn’t care where it came from, they just do not want it in the product.
Inline metal detectors can detect ferrous and non-ferrous metal in your product at particle sizes down to 1mm and smaller depending on product and application.
Metal detectors come in various configurations. One common configuration is show where the detector is mounted on a conveyor. Metal detectors can also be mounted vertically, for example on the infeed to a vertical form-fill-seal bagging machine. The detector is mounted between the filler discharge and the forming chute. Product being fed to the bag passes through the metal detector. If metal is detected, the bag is rejected.
Sensitivity of metal detectors is, in part, a function of the aperture size. The bigger the aperture, the less sensitive they will be. For best results metal detectors should be sized as small as possible while still allowing free flow of product.
Metal detectors detect all metal passing through them. The foil security lining on a bottle cap. Foil wrapping will trigger them. One area to note is the conveyor. Conveyors passing through a metal detector must be non-metallic. Most chain conveyors use metal pins to connect the links. Chains with non-metallic links are are available. If a belt conveyor is used, vulcanized splices are recommended. If this is not possible, be sure to use a plastic splice to avoid triggering the detector.
消费者有权安全产品,免费的contamination. Producers have an obligation to provide it to them. Ideally, packaging and processing lines should be designed, validated and operated so that they cannot produce a defect product. Inline inspection verifies that they do not. Metal detectors are a valuable tool in the quality toolbox.
检查员, as their name says check the weight of packages. This is useful for verifying the proper amount of product in the package, the proper number of finished packages in a sealed case or for determining the weight of variable packages such as trays of chicken parts. They can even be used to calculate things like shipping charges on random packages.
Most checkweighers are gross checkweighers. They only weigh the finished package. If a bottle is supposed to contain 12 ounces of candy, the total weight of the package might be 14 ounces including bottle and cap. The assumption is that the weight of the bottle and cap is constant and, if the gross weight is 14 ounces, the net weight will be 12 ounces.
This may not be good enough for some applications. An expensive product my require a high degree of precision. If the product is in a glass bottle, the bottle weight may vary more than the permissible variation in fill. The solution for this is net checkweighing. This requires 2 checkweighers. The first weighs the empty bottle and records the tare weight. After filling the bottle is reweighed, the tare subtracted and the net weight verified.
The typical checkweigher weighs the package in motion and consists of 3 conveyors, though sometimes only 2 are used. The infeed conveyor is used to time the package onto the weighing conveyor and assure that only one package is weighed at a time. The weighing conveyor, sometimes a pair of side gripping belts, is mounted on a load cell. As the package crosses the conveyor, the weight is taken, verified, and recorded. The third, discharge conveyor, rejects the over/underweight package.
一些应用程序,鸡肉部分,托运人s in a distribution center are two examples, do not classify packages as in or out of spec. Rather, they weigh the package and use this information to print a label with the package weight. In some instances, they may calculate the price and print that as well.
Whatever your process, whatever your package, you need inline, 100% verification to assure the perfect product ships to your customer. Checkweighers from Frain help make sure you achieve that.
But what do you do when you want to detect bone fragments in a hamburger patty or mix or glass chips in mayonnaise? Both hamburger and mayonnaise are so no camera can “see” any contamination. Glass and bone are non-metallic so they won’t be picked up by a metal detector.
X-rays can be thought of as analogous to light. A burst of x-ray is passed through the product onto a receptive surface on the other side. This used to be a photographic film but is now a digital media which allows instant, computerized analysis. Passage of the x-ray is partially blocked by areas of higher density in the product. Blockage is proportional to the density so that a bone chip will show up on the media as a dark spot. The hamburger or mayonnaise, of lesser density will show up on the media as a lighter color.
We’ve been conditioned to think of x-rays as dangerous to be around. Like any industrial machine, x-ray inspection machines can be dangerous if not handled properly. If handled properly, they are no more dangerous than any other machine. Do not let unfounded fears prevent you from adding this valuable tool to your line.
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