Barcodes do not have to be introduced, everyone has met them. However, it’s worth mentioning that apart from common EAN store codes, there are also a few other types that support control of all kinds of processes in an enterprise, whether it’s manufacturing, logistics or administration. Thanks to machine-coded data, the information can be conveyed to computer systems quickly and efficiently, while modern barcodes provide instant identification.
fast data reading,
minimization of errors,
easy product marking,
record that is machine and visually readable.
Presently, barcode is the most popular method of automatic identification of goods, logistic units and other objects. It has multiple uses, basically in all branches of economy. Barcodes are used from retail, through wholesale, warehouse management, production processes, quality control, workflow registration, medical and pharmaceutical branch, to transport. Global economy practically doesn’t operate without barcodes, and the benefits they bring cause the increase of competitiveness of enterprises on global market.
Barcodes consist of parallel lines, dark and fair alternatively. In order to make the code maximally useful, keeping basic parameters is required:
the size of module X, i.e. the weight of the thinnest line of the code,
the proportion between thin and wide stripe is a complete iteration of Module X,
high contrast between neighbouring lines,
height of the code,
The best effects are achieved with barcodes printed on allocated devices and when the label is on flat surface. Thanks to intelligent decoders, it is also possible to read codes from curved surfaces, yet, if there is possibility to choose a flat one – it’s worth using.
Exemplary 1D barcodes
Exemplary 1D stacked codes
The basic parameter that characterizes a barcode is symbology. This is the way of using strips (signs) of the code and so-called spaces to encode information. The most popular symbology in 1D codes is EAN-13, EAN-8, Code-128, Code 39, Interleaved 2 of 5, Codabar. They are used according to the requirements of the application.
EAN, GS1 standards
Some uses of barcodes were standardized in world scale. In such cases, it is pointed to a specific symbology (e.g. EAN-8 or EAN-13), or it is recommended to use chosen symbology and reserve some of its structures (e.g. EAN-128, as registered form of Code128). Such standards usually include labeling consumer goods or labeling goods and logistic units in supply chain.
It is essential for standardizing system to be explicit in world scale and thus easily recognized by all units in supply chain on the global market. Such requirements are met by GS1 standard. GS1 unit registers the users of the system, assigns them with numeric resources and shares the rules of the system for users.
IBCS Group members, being a member of this organization, actively participates in standardizing works. It allows us access to up-to-date information about labeling standards and access to professional knowledge to support customers in implementations of automatic identification systems based on barcodes.
Since first barcodes appeared, many possibilities of creating and printing have been developed. A barcode needs specifically determined dimensions and proportions. Other parameters, such as contrast between fair and dark stripes, code modulation, faults etc. are also important. They all affect the quality of the code expressed with different special parameters (decodability, modulation, faults, etc.). The worse the quality, the more difficult (e.g. longer) code read with a scanner.
When it comes to creating barcodes, you can choose from:
label editors with embedded barcode generators,
professional controls that allow embedding barcode generators for created applications,
use of label printers (e.g. by Zebra) with embedded barcode generators,
special TrueType fonts (not recommended because of low quality of generated codes).
Barcodes can be printed virtually on each printing device (inkjet printers, laser printers, dot-matrix printers). However, the best quality (decodability) of the code is achieved when printing on thermal printer. This comes as a result of the type of printing used in these printers. Even in small resolution of 200-300dpi, the quality of the codes is noticeably better than in case of laser printers with higher resolution.
Methods of reading barcodes
To read barcodes, special scanning heads are used. They can cooperate with communication interface (barcode reader) or other device, complementing it with additional functionality ( mobile computers with barcode readers).
The most acknowledged methods of barcode reading are:
CCD line reading – LED diodes are lined alternately with detection diodes – LED diodes generate light, while detection diodes analyze the reflected ray,
laser line reading – laser and a system of mirrors – the laser point is moved with mirror, creating line effect (cross-circular lines or raster when more complex system of mirrors is used), while detection diode analyzes reflected light,
CCD matrix reading – CCD camera takes a ‘photo’, and a special processor analyzes it with special attention to barcodes on it,
digital camera – quite a popular method in the era of smartphones, although fastness of code reading by dedicated applications still remains unsatisfactory.
When reading the code, it is vital to pay attention to possibilities of a given device when it comes to reading symbologies and given code size. For each user, a so-called decode zone diagram is given, which allows to choose a proper reader for each application considering the possibility to read a given code.
2D matrix codes
2D codes are easy to recognize – there are points scattered on a given area that is limited by tags. There are a few standards of coding, their images are significantly different, yet the rule of record and reading remains the same. Thanks to coding in two dimensions (vertical and horizontal), the codes have great capacity, much bigger than barcodes, thanks to which more content can be coded in them. Another advantage of 2D codes is also bigger resistance to damages, dirt or abrasions. Even partially covered codes can still be read by scanners.
2D standard is also supported by GS1 organization which makes DataMatrix codes available to use in logistic chain.
2D codes are very useful in case of labeling small products, on which traditional 1D codes simply wouldn’t fit.
DPM (Direct Part Marking)
Direct Part Marking is creating permanent label on the surface of the product, with help of e.g. laser etching. It provides better identification of products and tracking individual components in difficult industrial conditions in comparison with standard barcode labels.
DPM technology proves its efficiency in conditions such as extreme temperatures, fire and ice, oil, water and sand, where traditional labels stand no chances. DPM codes are as resistant as the material they are put on – thanks to this technology, the producer can be sure that the code will last as long as the product.
DPM read solutions offer numerous benefits:
DPM technology is integrated with existing, tested solutions dedicated to difficult environments, which leads to significant reduction of the price of devices,
the possibility to read DPM markings with a resistant mobile terminal,
no-contact read, greater depth of field and DPM codes read in different angles,
reading codes from different surfaces with no additional light,
the possibility of automatic differentiation between 1D and 2D codes,
marking small details, small printing area.
DPM solutions have been available for many years, yet high price of efficient hand scanners adapted to mark reading was the obstacle.
Identification and tracking in chain supply process
The possibility of complex product tracking is becoming more important for producers and suppliers. More and more branches are implementing DPM technology. They include automotive, aircraft and space, electronics, mining, petroleum and chemicals, medical, as well as governments all over the world.
In automotive and aircraft, DPM is used in processes that prevent errors and during product withdrawal. Effective marking enables producers to track and trace components in whole chain supply.
Electronic companies maximize space on printed cards and reduce costs through laser etching of small data codes instead of using bigger labels. In petroleum branch, DPM is used to ensure liability with rules, safety supervision and asset management.
Medical equipment producers use DPM to mark surgical instruments in order to track and trace them in operation theaters and during sterilization.
Better quality management
When many products are assembled on one line, fast and accurate identification of parts is the key factor. Zebra DPM devices allow to read DPM codes from metal, glass and plastic parts and products on each stage of production – and in the whole supply chain. It allows for easier identification of faulty parts (or batches of parts) and their precise exchange. It means less losses and lower costs of customer complaints service and warranty commitments.
DPM technology allows to mark small details, from products to tools. The main advantage, just like in case of 2D matrix codes, is high resistance to dirt and damage, even if the surface is partly damaged, the DPM code will still be read well by an allocated device. In case of DPM codes, the use of special barcode readers, optimized for DPM is required. All DPM readers can read codes generated by label printers, as well as the ones obtained from ink and laser printers and inkjets.
Voice systems are solutions, in which the exchange of data between the system and the operator is conveyed via voice commands, without the need of entering data with keyboard or scanner and reading commands from the screen.
Voice systems advantages
error reduction from 4-6 for 1000 positions to pick (for traditional scanning systems) to <1,
increasing productiveness by 10-15% by accelerating operation time,
shortening worker’s training – simplicity of the process,
better work ergonomics and safety – hands are free from terminal/scanner.
Voice systems are a technology that is complementary to popular solutions used in warehouse, such as barcodes or RFID. They can simplify and accelerate warehouse operations, where time ratio of data processing (data reading and entering) to productive time (physical implementation of the task) is high.
Such situation happens with e.g. picking. That is why voice systems are mostly used in this process (42% of systems), and they are referred to as pick-by-voice systems.
The advantages of voice technology in comparison to traditional methods can be also seen in other processes , such as restocking, transfer or even entry. There are warehouses where voice systems are the only solution, but there are some where voice systems are used only in chosen areas, while other operations are conducted traditionally. It is worth remembering to conduct a meticulous and thorough ROI analysis and take it into account when deciding which technology and in which processes will bring most benefits. Thanks to its advantages (error reduction and productivity increase), voice systems allow to gain significant savings of time and assets in chosen logistic processes. High efficiency of the system guarantees fast return of investment.
The main information carrier in voice systems are voice messages sent between the operator and WMS.
An exemplary picking process of given goods in warehouse looks as follows:
the operator receives a message with information about the zone and location number,
the operator confirms arriving in the right zone by reading a location control number,
the system sends a message of quantity/weight that has to be picked,
the operator loads goods and confirms loaded quantity and weight.
Main elements of voice systems are:
interface between voice system and WMS,
portable voice terminal (mobile computer),
managing application (console).
The main role of the interface is data exchange between voice system and WMS of ordered tasks, their status, etc.
Portable terminal is used to convert text messages send by voice system to sound and to convert operator’s voice messages to text. Devices dedicated for voice systems, such as Honeywell Talkman or standard portable scanners (mobile computers) with dedicated software and equipment can be used as terminals.
A vital element of voice system is a set of special headphones, adjusted to operator’s needs. They are highly resistant when it comes to mechanics and environmental conditions and have high quality microphones. They are able to filter noise in such a way so that distortions arising during conversion of sound to text, caused by outer disruptions, are excluded.
The role of the console is to supervise the session and store so-called profile users, on the basis of which the system learns to recognize their voice.
Vision systems, thanks to perfectly refined techniques of image analysis, are a great alternative to product identification by 1D or 2D barcodes. Vision heads assess the product according to criteria introduced by designers, controlling all essential qualities of the product. Image carries definitely more information than a barcode, allowing to get more specific information about the detail that is being checked.
This solution is used in practically all branches of economy. It allows not only for identification, but also control of all features of the product, e.g. dimensions, correctness, filling. Vision systems are based on comparison of the current image with a pre-defined pattern. By setting tolerance range for particular aberrations, it is easy to detect correctness of detail montage and eliminate products that do not fulfill the norms. Efficiency of these systems does not slow down manufacturing, while fastness, precision of reading and assessment of production is very high.
The additional advantage of vision system is the possibility to read barcodes at the same time, which makes this solution perfect for replacing barcode readers.
RFID (Radio Frequency Identification)
RFID (Radio Frequency Identification) technology is a way of coding information in electronic label that consists of processor and antenna. Such information can be read with radio waves without the need of line of sight between the scanner and the label.
fast identification of elements of a logistic unit (pallet, multipack) without the need to unpack it,
large data capacity,
the possibility to modify data on different stages of supply chain,
the possibility to re-use the label repeatedly.
RFID extends the use of automatic identification system, completing barcode technology where it was not possible to be used before. The interest of biggest retail chains and logistic companies in RFID and creating EPC standard makes this technology even more popular, which makes the group of those interested in implementing technology in their enterprises bigger.
RFID can bring real benefits wherever:
barcode is not accessible to read,
time and work input limit is needed in the process of reading information about the product,
allocation of the product is difficult to achieve (e.g. pallet or other logistic unit has to be unpacked),
storing information on the product, not in database is required.
RFID systems can be used in any sector of economy, some of the benefits of RIFD are:
increase of stock availability (right goods in right time),
acceleration of processes (release, acceptance, stocktaking, POS),
instant location of product,
the possibility to control chain supply,
better protection from theft,
identification of fake products,
reduction of inventory balance,
identification of components,
fast and thorough stocktaking,
transport and logistics:
faster delivery and customer service,
the possibility of full co-operation with recipients already using this technology,
increasing service range,
better protection from theft,
automation of processes of loading and unloading,
better process development,
minimization of picking errors,
flow control in real time,
automated and correct picking,
libraries, cashless payments and others:
fast and efficient stocktaking,
fast location of the product.
RFID technology uses low power radio signals to exchange data between transponder (RFID tag) and decoder/interrogator (scanner). RFID scanners can read and process even hundreds of tags within reach.
RFID tag consists of processor (IC) and antenna (usually layered on insulator). Data is saved in IC cache memory and transmitted with antenna. The speed and range of transmission depend on the frequency, antenna size, radiation power and signal interference. RFID tags are available in RO (read only), RW (read and write) and WORM (write once, read many) configuration.
In passive systems (the most popular), the scanner emits energy that is used to power the processer on the tag and enables data transmission and read through modulation of the signal sent by the scanner. In active systems, radio tag is equipped with an inbuilt accumulator that powers the processor. Thanks to such a solution, there is a possibility to increase the distance between the scanner and RFID tag significantly.
RFID tags can be mounted on different devices. They can be:
integrated with mobile terminals,
mounted as control gates,
mounted on forklift, e.g..
RFID technology can operate in following frequency ranges:
low frequency (LF) – 125 kHz, typical range approximately 0,5m,
high frequency (HF) – 13,56 MHz, typical range approximately 1m,
ultra-high frequency (UHF) – 865-869,85 MHz (Europe), 902-928 MHz (USA), typical range approximately 1-3m (when using amplified antennas even up to 6m),
microwave – 2,4 GHz.
Different frequencies are used in different applications. Because of possibilities and standards that have been developed over time, RFID systems in HF and UHF technology gained the biggest popularity in logistics.
Radio tags usually come in two forms:
RFID tag – a form of tag mounted on appropriate ground and usually in a protective cover. Such tags are mostly used in places where great resistance to mechanics, environment and chemicals is vital,
‘smart label’ tag – a form of tag where RFID transponder (inlay) is ‘built in’ a paper tag ready to print. Such tags can be printed in special printers that enable programming with print (e.g. Zebra Technologies printers). This is an easy and safe solution that carries information in a form that is easy to read (description), to be machine decoded (barcode) and by radio (transponder).
RFID is a stable technology that brings proven business benefits. It should be taken into consideration wherever increasing efficiency, limiting losses or improving service is vital. Considering the fact that RFID tags are re-used many times, do not require ‘eye contact’ with the scanner, can be read and written, they will be even cheaper than barcode technology in many cases, as work input and use of consumables is limited. The benefits of RFID should therefore be considered in the long term, not on the basic of mere comparison of label and scanner prices.