Barcode labels are being increasingly sought in harsh environments for applications like systems integration projects where they have as yet not been used. With new inventions in the world of scanning technology with progressive symbologies and techniques, a lot more information can be stored in barcodes to meet the needs of users. Barcodes are expected to hold more information and deliver results without any errors or failure as applications become increasingly demanding.
The success of a barcode labeling system is dependent on a series of factors. It is important to evaluate and define the environment in which the barcode label is to be used, how the data will be collected, the worst kind of conditions in which the barcode labels will be tested, and also review the proposed procedures for data collection. Should the barcode label fail during any of these checks, it reveals the failure of the data collection link. This will necessitate reverting to the manual collection of data, a waste of time, effort and money and will also bring down employee morale. Therefore, it is important to carry out a few checks discussed below:
Elements To Be Tested
- Heat/Cold - Barcode labels use mainly thermoplastic material including pressure-sensitive adhesives and plastic. Adhesives react to high heat by softening and loosing their strength to join two sides. Thus the adhesive, no matter how thin the layer, will ooze out and the label will slip, or sag if applied to a cylindrical surface. Often the size of the label also gets distorted along with the barcode printed on it. This will render the barcode defective and lead to an incorrect reading of the barcode. Direct thermal face labels are also sensitive to heat and sunlight. Thermal transfer ink softens and is prone to leaking when exposed to extreme heat. The maximum damage is done when the labels are exposed to heat continuously for extended periods of time. This would stress the labels far more than a short exposure to heat. Therefore it is better to state the maximum temperature the labels can be exposed to and are resistant till. Cold conditions may either refer to the surface temperature being low where the barcode label is being applied or when the barcode label faces heat or cold as is typically found in cryogenic environments. When a label is applied at room temperature to a cold surface a difference in the two temperatures will make the label lose its heat and also its attaching ability, leading to the overall bond with the surface getting affected. Adhesives are generally weakened if not completely destroyed by extreme cold conditions. For this, Freezer grade adhesive labels, also called low-temperature adhesives must be used. These are found on food items needing to be stored in cooler environments where temperatures are maintained at around 10 degrees F or less, and the adhesive strength is ensured at this level of temperature.
- Bright Lights- Bright lights or the reflection of morning sunlight can blind people for a few seconds. Similarly scanners can be blinded by lights bouncing off a label surface. For this reason labels come with a matte surface to minimize this reflection of light. The scanning is additionally helped by the angle of the scan. Scanning problems can be further minimized by making the lights in the scan room dim. Or some kind of shades can also serve the purpose.
- Extending label life- The life ofa barcode label can be extended considerably if over and above the use of outdoor materials like polyester along with acrylic adhesives, the labels are also laminated with UV screens. The consequence will be durable exteriors that will also benefit from with ways and means to minimize direct sunlight.
- High abrasion applications- In certain applications chances of abrasions on labels are high. In such cases metal barcode labels may be used. Various types of durable labels are available with films like polyester, Teflon, polypropylene, tedlar, kapton and polyamides that prove to be the bets protectors in the harshest external environments.
- Moisture and humidity- It is very common to have labels exposed to moisture or humidity or even a wet environment. A film with over lamination can help to protect the label that may otherwise end with distorted print, delaminating and loss of the adhesive coating that makes it stick. Labels adequately protected and coated with these can stay immersed in water also and not get damaged. Special adhesives are available that get added strength when soaked in water.
- Solvent resistance- Solvent resistance needs to be verified by checking the label edges. Some solvents do not affect the laminated surface of the label but the face stock and the adhesive used may get spoilt with the solvent solution used for cleaning purposes.
- Grease, oil and grime- A frequently observed problem is faced while attaching a barcode label to an oily surface that is inevitably slippery. The adhesive tends to absorb the oil and lose its stickiness. The solution is to apply the label after cleaning the top surface.
- Chemicals- All labeled surfaces come in contact with some types of chemicals, mostly found in cleaning solutions. The alkaline base and the moisture will both have a damaging effect on the label. Lamination may protect the labels and a prior testing of the labels to the potential solvents they may be exposed will prevent scanning problems later.
- Adhesive problems- Often, the adhesive on the label joins it to only a part of the item surface. This could be because the pressure-sensitive adhesive has not been spread evenly. The problem gets further aggravated in textured or uneven surfaces. The only solution is to ensure that a specific amount of the heavy adhesive is applied. Only if the fluid thickness is adequate will the label stick to up to 90% of the surface. Low surface energy plastics are also responsible for adhesive ineffectiveness. The solution is having the manufacturer detail the specifications of adhesives required for sticking to plastic surfaces.
- Matching Scanners- The scanner must always match the barcode. All scanners have near and far points depending upon the distance at which they can scan best. Long-range scanners thus are meant for scanning from around 40ft as required in warehouse applications, and would prove to be ineffective in scanning from a close range. The material of the label also determines the effectiveness of the scanner.
- Barcode Symbology- The symbology for the barcodes in question can be specified either by the customer or the industry it is meant for. The latest barcode scanners can read multiple symbologies and are auto-discriminating. 2D and RFID are leading symbologies for barcodes today. But a less dynamic approach for deciding symbologies is preferable for best results.
- Barcode density for space limitations- The electronics and telecommunications industries require information barcodes that are compact and space saving. Miniature labels require barcodes that fit in while also storing all the required information. The new barcode scanners have to be able to scan these high-density barcodes flawlessly.
- Barcode Verification - becomes important especially in applications where they are printed on site. This will prevent penalties for barcodes that cannot be scanned at retail of commercial outlets. Appropriate verification equipment comes in handy for this purpose and fits into the organization’s quality control system.
- Proper training of staff for skill development - The proper use of systems and the latest technologies being developed is possible only by training the staff and helping them become efficient in every part of the system. This helps in improving the effectiveness of the program.
Once all these checks and tests for barcode labels are put into place, and effective corrective measures taken, all barcodes will be successfully scanned and excellent results will become a normal routine.
by Neil Jones
Neil Jones has been involved in the barcoding and data capture industry since 1997. In that period he has owned and run several successful businesses in his field of expertise. With his latest business venture emobilescan.co.uk he has broadened his focus to encompass fully integrated RFID systems along with smart card and HID technology.
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