Industrial-grade Fixed-mount ID Reader and Verifier In-Sight ID readers eliminate the need for costly peripheral devices, reducing the overall cost of implementing a reading application. Fixed-mount readers are used to identify parts that are handled and moved automatically by conveyor, indexer or robot.

SEATTLE, Wash - March 7, 2005 - Jobwerx News - Tracking a part for life. Cost effective vision-based code readers offer numerous advantages. In-Sight ID readers facilitate part traceability and process control.

Manufacturers in many industries, including automotive, electronics, medical, pharmaceutical, consumer products, food, beverage, and aerospace, are under pressure to track parts and components from cradle to grave. To address full cycle traceability some manufacturing engineers are marking 2D codes directly on parts. Direct part marking identification (DPMI) offers numerous advantages.

Low contrast codes, variations in part surfaces, partial damage to codes from process and environmental conditions have created difficulties in high rate reading of DPMI. Thanks to advances in power of digital signal processors, imaging sensors and decoding algorithms, cost-effective vision-based code readers are now available.

There are some important factors that engineers should consider when implementing DPMI:

• Code selection
• Data coding
• Marking processes
• Mark Placement
• Verification
• Reading systems
• Connectivity

CODE SELECTION
Automotive, aerospace and electronics manufacturers have adopted 2D code standards and formats to meet their application needs. Typically, it makes sense to follow industry-specific guidelines, But, when there is no specific standard, Data Matrix ECC200 is recommended.

This ANSI code standard is the most widely supported for DPMI applications involving metal, glass, ceramic and plastic materials. This code is in the public domain, so marking and reading equipment suppliers have invested significant resources to improve the performance of ECC200 supporting tools.

DATA ENCODING
The Data Matrix code offers a number of advantages for DPMI applications, including small size and high date encoding capacity. Data encoding refers to the amount of information that is stored within the matrix when the Data Matrix code is generated. When trying to comply with code size with an industry specification, and application specification will define the size that is needed for compliance. Decisions about what information to encode are typically driven by company specifications and the requirements of the traceability project.

The available space on the part must also be considered. Limited space may require the Data Matrix code be used as a license plate to simply identify the part, reducing the amount of data encoded and size of the code. In this case, a centralized database containing manufacturing and historical data referring to the part is updated as the part is identified during manufacturing and supply chain processes.

MARKING PROCESS
The choice of marking process is typically incorporated into the component design. The primary methods used to produce machine-readable symbols for DPMI include dot peening, laser marking, electromechanical etching and ink-jet printing. Other considerations include surface texture and the amount of data to be encoded on each part, in addition to the available space and location of the mark on the part.

MARK PLACEMENT
The location of the code on the part can directly impact the readability of the code. The location should be clearly visible throughout the manufacturing process and it is best to mark on a flat surface on the part as well as a prominent position that can be easily viewed by the reader.

Clarity around the zone and the location of the reader, located away from electrical noise sources are important. Care must be taken when selecting a location for a cylindrical part. Surface curvature can distort the code and make illumination difficult. 16 percent of the diameter or 5 percent of the circumference is recommended.

VERIFICATION
To ensure that the marking equipment is applying a mark that will produce the highest read rates, a code verification system that includes lighting, optics, camera and software should be implemented at the marking station. This reduces non-conformance and the associate costs of rejected parts due to unreadable codes.

A verification system will immediately detect a problem with the marking process that could be due to poor fixturing of the part, damage to the machine, such as a broken tip on a dot peen machine, or incorrect setting during part changeover. Additionally, a code verification system can provide feedback on the marking process that can be used in preventive maintenance.

READING SYSTEM
There are three types of readers for DPMI: Fixed-mount readers, presentation readers, and handhelds.

Fixed-mount readers are used to identify parts that are moved automatically by conveyor, indexer, or robot. Typically, fully automated manufacturing lines, such as those found in electronics and automotive manufacturing use fixed-mount readers.

The advantage of a fixed-mount reader without an integrate light source is that it can be mounted in varying working distances from the part. Fixed mount readers can be easily set up, viewed and maintained over an Ethernet network to the general manufacturing control system for efficiency.

Similar to a fixed-mount reader a presentation reader is mounted in a fixed-position; however it operates in a continuous reading cycle, automatically performing the decoding task once the operator places the part in front of the reader. Presentation readers provide a fast way of reading part codes in areas where parts are handled manually. And, as more and more code readers used throughout the manufacturing process, it becomes important to have a centralized way of managing them. The reader should allow engineers to manage and control vision activity over the network from remote locations in the plant and beyond.

CONNECTIVITY
With handheld readers, connectivity methods depend on whether the reader is tethered with a cord of cordless. Tethered readers often communicate the read result through what is called a keyboard wedge interface, which eliminates the keystrokes of a keyboard making integration to a PC very simple. Alternatively, communications can be made over an RS232-C interface. A cordless handheld reader uses wireless technology, such as Bluetooth, to communicate to the base PC station or other controller.

Haven't found what you're looking for? Try 'Search' powered by : For more information stop by and visit- Cognex Corporation

Click here to view more current news articles