This article discusses the elements of smart logistics and investigates how components designed for the rigors of smart logistics at every phase of the logistical supply chain can alleviate problems during manufacturing.

Smart Logistics Whitepaper
Smart Logistics Whitepaper

White Paper from | ROHM

Introduction

The field of logistics continues to evolve rapidly, especially in light of the recent pandemic and the growth of e-commerce. Smart logistics involves the use of technologies such as AI (Artificial Intelligence), automation, IIoT (Industrial Internet of Things), and big data to optimize the mass production and distribution of products. However, for such technologies to be leveraged effectively, certain details must be considered, including elements of smart logistics such as label printer components and optical sensors. Failure to choose the right solution at this level can propagate upward and lead to bottlenecks and downtime at higher levels. 

This article discusses the elements of smart logistics and investigates how components designed for the rigors of smart logistics at every phase of the logistical supply chain can alleviate problems during manufacturing, from goods arriving at the warehouse to production, packaging, and delivery. This whitepaper will also examine the unique requirements for production and detail the component characteristics suitable for the smart logistics lifecycle.

 

Elements of Smart Logistics

Key elements to successful logistics include mobile printers, barcode scanners, LED indicators, and optical sensors. For example, mobile printers must be compact, efficient, durable, and able to provide the right combination of speed and resolution. Two components within a mobile printer that are critical to these requirements are the motor drivers and thermal printheads. 

Motor drivers must provide consistent performance and efficiency, and include protection circuits to support reliability, while printheads determine, to a large degree, the speed and resolution that can be achieved. 

Figure 2. Barcode scanners are an important component in many phases of logistics

 

Barcode scanners, like the one shown above in Fig. 2, are ubiquitous in many phases of smart logistics, from intake through shipping and delivery. Their ability to remain charged for extended periods of time, resistance to damage, and the accuracy with which they scan depends largely on the laser diodes used. LEDs are also heavily used in smart logistics as indicators that provide critical functionality, uptime, and safety. LEDs for indicators must deliver sufficient light while minimizing power demands and costs. 

Smart logistics also involves the use of a warehouse goods management system with a dependable communication standard, one that provides extensive coverage and secure data transmission. Optical sensors must be sensitive and rugged, whether they are found on a conveyor belt in the production area or during shipping where items must be rapidly and safely loaded on trucks. Their failure can result in problematic downtime and damaged goods.

Perhaps the best way to look at the options available for each of these component types is to examine the various phases of smart logistics and how they support critical functions along the logistical supply chain.

 

Arrival Phase

Thermal Printheads

During the arrival phase, registration of incoming goods depends heavily on mobile printers and barcode scanners. For mobile printers, the type of printhead used is essential to both the performance and reliability. 

For example, the wrong choice of substrate can lead to excessive heat generation that can compromise print resolution, especially at high speeds when a resin ribbon is used. Issues with print resolution can ruin the image quality of bar codes, and failures resulting from overheating can occur for both date and barcode printers.

ROHM addresses these issues through the use of a specially designed substrate for high-speed, high-resolution printing as well as a hybrid coating designed to resist both corrosion and abrasion.

Figure 3. ROHM’s KD2002-TQFW00A thermal printhead is designed for high reliability and high currents

 

Thermal printheads for barcode printers include KD2002-TQFW00A and KD2002-RQFW00A (shown in Fig. 3) for high-speed, large-sized label printing. The primary specifications for both are outlined in Table 1. 

Table 1. Comparing the specifications for KD2002-TQFW00A to KD2002-RQFW00A.

 

KD2002-TQFW00A

KD2002-RQFW00A

Print Width (mm)

56

56

Platen Diameter (mm)

20

20

Resolution (dpi)

203

203

Number of Dots

448

448

Supply Voltage

24

24

Resistance Variation (ꭥ)

550

550

Logic Voltage (V)

3.13 to 5.25

3.13 to 5.25

Connector Type

Wire cable

Wire cable

Print Speed (mm/s)

250

300

Abrasion Life (km)

150

150

Pulse Life (million pulses)

100

100

Historical Heat Control

No

Yes

Heat Sink

Yes

Yes

 

Note that the KD2002-RQFW00A includes historical heat control which allows it to control the heat generation time of individual heating elements based on the heat generation history. This makes it better suited for applications that require continuous printing and 24-hour operation. The KD2002-TQFW00A, on the other hand, is well-adapted for printing operations beyond bar codes and works well for outdoor usage.

Thermal printheads for date code printers include the TH3001-2P1W00A and TH3002-2P1W00A, whose specifications are summarized in Table 2 below. Note that both of these printheads can still achieve high-speed printing when scratch-resistant resin-based ink ribbon is used. The major difference is that the TH3001-2P1W00A has historical heat control.

Table 2. Comparing the specifications for TH3001-2P1W00A to TH3002-2P1W00A.

 

TH3001-2P1W00A

TH3002-2P1W00A 

Print Width (mm)

31.99

53.312

Platen Diameter (mm)

50

50

Resolution (dpi)

305

305

Number of Dots

384

640

Supply Voltage

24

24

Resistance Variation (ꭥ)

570

570

Logic Voltage (V)

4.75 to 5.25

4.75 to 5.25

Connector Type

Wire cable

Wire cable

Print Speed (mm/s)

1,000

1,000

Heat Historical Control

Yes

No

Heat Sink

Yes

Yes

 

Motor Drivers

A mobile printer is only as good as the motor driver. A printer that keeps jamming or cannot consistently feed paper can lead to frustration for users and a reduction in productivity. The same is true when printheads require constant adjustment and alignment. When slowdowns occur at arrival, it propagates throughout the remaining logistics phases. 

 

NEED INFORMATION ON RECOMMENDED MOTOR DRIVERS TO HIGHLIGHT 

Barcode Scanners

Barcode scanners are also a key tool during the arrival phase of smart logistics. Their reliability, accuracy, and power consumption depend heavily on the laser diodes used. In addition, these diodes must exhibit the ability to resist localized heat generation and overcurrent damage from static electricity. One approach to preventing the issues with static electricity and heat generation is the use of an end-face window structure.

Laser diodes for barcode scanners must be sensitive with excellent temperature characteristics along with high COD (Catastrophic Optical Damage) and ESD (Electrostatic Discharge) resistance. At the same time, all of the components that make up the barcode scanner must make efficient use of power to maximize the time between charges, which can depend heavily on stabilized temperature. 

Figure 4. ROHM’s RLD65 Series of laser diodes is well known for their reliability and durability

An example of a diode meeting these requirements is ROHM’s RLD65 Series of 650nm red single-mode laser diode shown in Figure 4. Its basic optical specifications are outlined in Table 3 below. ROHM diodes offer excellent reliability and provide a range of outputs to fit a variety of product needs.

 

Table 3. Optical specifications for the RLD65 series of laser diode for barcode scanners.

 

RLD65NZX2

RLD65PZX2

RLD65PZX3

Typical Wavelength (nm)

658

658

658

Optical Output (mW)

5

5

10

Typical Parallel Beam Divergence (degrees)

8.5

8.5

8.5

Typical Perpendicular Beam Divergence (degrees)

28

28

28

Parallel Beam Tolerance (degrees)

+/- 4

+/- 4

+/- 4

Perpendicular Beam Tolerance (degrees)

+/- 4

+/- 4

+/- 4

Emission Point Accuracy (𝝁m)

+/- 100

+/- 100

+/- 100

Efficiency

0.6

0.6

0.6

Equivalent Circuit

 

Production Phase

Thermal Printheads for Mobile Printers

The production phase of smart logistics also requires mobile printers, primarily for product labels that contain an increasing amount of information. For example, recent changes to food labeling laws require more information to be included to support traceability and provide detailed nutritional information, which can be challenging for labeling food that is not necessarily mass-produced. QR codes are also becoming increasingly common and require high-definition printing to be properly recognized by camera technology. And all of these features must be present along with high reliability.

Thermal printheads for label printers include products such as KD-TQFW and KD-RQFW, already discussed in the previous section on the Arrival Phase in Table 1.

 

Optical Sensors

A variety of optical sensors are used in logistics, and like so many of the components that make up smart logistics, they must be reliable and efficient. These optical sensors include infrared LEDs, transmission photointerrupters, and reflective type phototransistors.

Figure 5. The ultra-miniature SMD type photointerrupter shown here is just one of many options available from ROHM

 

Highly reliable, highly sensitive phototransistors are paired with infrared LEDs in pairs in compact precision instruments. Transmission type photointerrupters, such as the one shown in Fig. 5, are effective optical switches for detecting the presence or absence of an object by intercepting light. They are often implemented for determining the speed of rotation or position of an object. Reflective type phototransistors are used to determine the existence/absence of an object by detecting the light it reflects.

 

Warehouse Phase

Warehouse Goods Management

Smart logistics also requires a comprehensive warehouse goods management system. Goods management systems must be able to do the following:

  • Facilitate the easy collection and sharing of data

  • Provide sufficient coverage

  • Consume minimal power

  • Support robust security

  • Comply with international standards

Wi-SUN (Wireless Smart Utility Network) uses multi-hop networks to provide superior coverage transmission distance while consuming minimal power. It addresses security by implementing the IEEE802.11/11i/EAP-TLS/AES standard and is fully compliant with relevant international standards. Wi-SUN is easy to install and provides highly reliable data collection. An example of such a network is shown in Fig. 6.

Figure 6. An illustration of how Wi-SUN achieves excellent performance and coverage

 

One of the integral components in setting up Wi-SUN for a facility is a wireless communication module, such as the BP35C5 available from ROHM. This Wi-SUN FAN-certified module features an ultra-compact (15.0mm x 19.0mm) design and supports mesh networks of up to 1,000 units (making it ideal for large infrastructures). Additional features include channel hopping capability at high data rates and an integrated software stack.

 

Thermal Printheads

Inventory management also requires printers that provide excellent image quality for barcodes and QR codes and can print on a variety of label surfaces, including RFID tags. The requirements for these printheads vary according to the application. Table 4 below summarizes three printhead options from ROHM.

 

Table 4. Printhead options for mobile printers used in warehouses.

 

KR2002-D06N10A

KA2002-FB20A

KD2002-D5JX20A

Goal

Low consumption, excellent efficiency

Small size

High-speed (1.5 x standard model)

Print Width (mm)

48

48

56

Platen Diameter (mm)

8

8

20

Resolution (dpi)

203

203

203

Number of Dots

384

384

448

Supply Voltage

3.6

7.2

12

Resistance Variation (ꭥ)

80

176

210

Logic Voltage (V)

2.7 - 5.5

2.7 - 5.5

2.7 - 5.5

Print Speed (mm/s)

100

100

150

Heat Sink

No

No

No

 

Indicator LEDs

Indicators are an important part of automation and inventory management, often as part of HMIs (Human-Machine Interfaces). LED indicator lights must provide a variety of features related to color, brightness, luminosity, and power requirements. 

Recommended ROHM LED indicator lights include mono-color types such as the SMLD1 and CSL09 series along with RGB multi-color variants. The SMLD1 product line consists of general-purpose compact LEDs measuring just 1.6 x 0.8mm with a thickness of 0.55 mm. They are available in a range of colors and luminosities. The CSL09 series consists of high brightness LEDs with the same footprint as the SMLD1 and a thickness of 1.4 mm.  This series is also available in low, medium, and high luminosities. They are ideal for applications where power savings and lower costs are desired. Furthermore, ROHM offers multi-color LEDs with built-in red, green, and blue chips that allow users to select their preferred color.

 

Optical Sensors

In systems for advanced inventory management, optical sensors are often used to detect the presence/absence of goods on shelves. For this purpose, ROHM recommends the reflective type light sensor RPR-0521RS, which can detect up to 100 mm in distance. It can even cancel out ambient light noise, such as the sun or indoor lighting, enabling more accurate object detection.

 

Shipment and Packaging

Thermal Printheads for Labels

The shipping phase of logistics management involves label printing, and as with the other printers discussed so far, requires high speeds and resolutions. ROHM thermal print heads for mobile shipping label printers include the KD2002-TQFW00A and KD2002-RQFW00A, whose specifications and features are outlined in Table 1. Both printheads provide the accuracy and resolution needed for barcodes and the reliability necessary to prevent bottlenecking in this phase.

 

Delivery

Mobile Printers

The delivery phase of smart logistics also requires mobile printers that are not only durable but can also remain charged for an extended period of time. For mobile delivery printing, a recommended thermal printhead is the KR2002D06N10A, shown in Figure 7. Its specifications and features are listed in Table 5 below. Note the low power consumption and excellent efficiency that contribute to extended operating time between charges.

Figure 7. ROHM’s KR2002D06N10A thermal printhead for mobile printers work extremely well  for delivery applications.


Table 5. Printhead options for mobile printers used in the delivery phase.

 

KR2002-D06N10A

Goal

Low consumption, excellent efficiency

Print Width (mm)

48

Platen Diameter (mm)

8

Resolution (dpi)

203

Number of Dots

384

Supply Voltage

3.6

Resistance Variation (ꭥ)

80

Logic Voltage (V)

2.7 - 5.5

Print Speed (mm/s)

100

Heat Sink

No

 

Barcode Scanners

The needs for portable barcode scanners in the delivery phase are the same as those used during the arrival phase. They have similar requirements for the laser diodes along with an emphasis on efficiency to achieve acceptable times between charges.

 

ROHM Solutions for Smart Logistics

ROHM offers a broad array of solutions for smart logistics applications, including digitization, IIoT, and Warehouse 4.0. Our catalog includes thermal printheads and motor drivers with options suitable for all phases of logistics, whether the need is high speed, high resolution, high efficiency, or a combination. We also provide indicator LEDs for everything from automation to HMIs. Our LEDs for barcode scanners have been designed for optimum performance in terms of accuracy, alignment, and power consumption. And we have the wireless modules needed to implement Wi-SUN in your facility as an effective warehouse goods management system.

 
The content & opinions in this article are the author’s and do not necessarily represent the views of ManufacturingTomorrow

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