Bar code Scanners should be cleaned

The number of bar code laser scanners in industrial environments is increasing. Especially in distribution centres where they are used in packing stations, sorting systems, with entrance control, delivery control or with picking stations. These laser scanners collect data for the Warehouse Management System but when they are dirty, they don’t collect anything and this happens faster as one expects.

Not only the scan head

Most users expect the scan head – the eye that spreads the laser beam and receives the reflection – the first to be dirty. This expectation looks to be logic because dust in the air always seeks objects like a beamer to adjust to. So everybody cleans on a regular basis the glass hoods of laser scanners. What indeed is needed in industrial environments, where a lot of fine dust is circulating. Look around you and see how much paper is used with packing stations in production lines! So non reading bar code scanners cause problems to organisations. Especially in distribution centres and production environments. When the laser scanner doesn’t identify a pallet label, box label etc., the efficiency in processes decreases in no time. An occasional 'no read' could be a signal of a bad printed bar code or having too far of a distance for scanning, but when a whole series of goods are not identified, it looks like something else is going on. In that case you have to stop the processes to analyse the problem before eliminating it. “Analysing and eliminating can be a huge problem when a scanner is polluted inside”, Onno Walda, managing director of Walda Impuls in the Dutch city of Arnhem says. Walda is acquainted with the phenomenon and being as well a bar code equipment supplier as thé maintenance organisation for a.o. Accu Sort scanning systems, he knows that just outside cleaning of a scanner isn’t enough. He knows also that scanners and in particular laser scanners get polluted inside. And he knows how this can lead to great problems in working processes because cleaning of the inside of a bar code laser scanner is not easy. “It can take several hours to clean the moving parts inside a laser bar code scanner”, he says. Many times when there are more than one scanner involved cleaning even might take several days. Which means that all the processes are stopped during that period.

The problem: the moving parts

The main problem are the moving parts. Laser scanners have rotating mirrors to catch the reflecting light from the bar code. “This rotating element moves the air inside the scanner’s housing and moving air fills itself with dust. Don’t think that your laser scanner, having a so called dust free housing, will be really dust free”, Onno Walda says. No housing with the possibility to be opened really is completely dust free. So slowly but inevitable a thin layer of dust will cover the mirror, which decreases the readability of the scanner. This defines the problem. A laser scanner though is a tiny instrument and its internal elements even are smaller. “Indeed a laser scanner has very tiny and vulnerable elements”, Onno Walda confirms. And according to his knowledge the cleaning of these tiny parts demand most of the cleaning time. “Meaning that it might take several days before a complex scanning installation is in action again”, he says. There are however possibilities to avoid long downtimes. “Some companies buy a double system”, Onno says. Meaning that two scanners are mounted next to each other. One in reserve and one operational of which the reserve one takes over when the other one gives too many ‘no reads’. But this kind of double installed systems are very expensive and therefor Onno Walda has another solution. This time to provide pollution. “It is possible to give scanners periodical service and cleaning them by that occasion. For example during holiday periods or by taking a full service contract with your supplier or a specialised maintenance company”, he suggests. This means that once or twice a year, on the moment it suites you, this specialist gives service to your scanners including cleaning en in case of need also revitalising. “They can measure the reading capacity and tell you the enduring life time of the scanner”, Onno Walda explains. “Of course you can incorporate in this kind of contract all costs including transportation, inspection, cleaning and revitalising as well as man costs. You even can incorporate free changing of spare parts because of your monthly contract contribution”, he says. A contract like this can also incorporate fast reactions with complaints or operational failures. “Some companies incorporate in their service contracts the possibility to solve a scanner failure within 4 hours”, Onno Walda gives as an example. Also reaction times of maximum 8 hours after reporting the failure are possible as well as other kinds of solutions. Walda says that these kind of reaction times really can be realised when there is a repeating service cycle according to this scanner. “The serviceman is familiar with the scanner because of his service tasks”, he says. It means that this particular scanner quickly can be operational again because of the knowledge of the repairman.

CCD Scanning systems

CCD scanning systems – because of the absence of moving parts less sensitive for pollution – can also get a kind of service. These systems are specifically sensible for no reads because of bad printed bar and two dimensional code symbols. “The serviceman often can find out by remote problem analysing the non reading reasons”, Walda knows. In that case an advise by e-mail, telephone or resetting the system by remote meanings makes it often possible to eliminate the failure within a few minutes. It is this possibility to log in into the end users computer system by the service organisation that helps decreasing service and repair times. Especially for CCD scanning systems. For laser scanners this kind of solution is alas not possible. Laser scanners just need cleaning of the internal parts in time. Pre planned maintenance therefor seems to be the best approach.

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