Non-Contact Transmission of Power & Data on Transfer Rails & Grippers

For press shops utilizing transfer rail systems, fixed sensor connections regularly cause frustration. Cables and contacts are often subject to heavy strain. Cables can wear out and break, damaged pins or mechanical collisions can cause hours of machine downtime, and the replacement of large multi-pin connectors comes at a high cost.

Inductive couplers offer an ideal solution: By using these non-contact, wear-free products you can eliminate pin connections and simplify job changeovers on the press. Inductive couplers transfer signals and power contact-free over an air gap. The quick-disconnect units are easy to use and require no maintenance, enabling you to meet new demands quickly. Mechanical wear is a thing of the past. This increases system availability, reduces cycle time and enhances the flexibility of workflow processes.

Inductive coupling example

Replace pin connections for transfer rails

Typically, two pin-based connectors connect the transfer rail to the transfer system on the press. The connections are on both the feed and exit sides of the rail to the control. If there is any misalignment of the connections, damage regularly occurs. By replacing the connectors with pin-free inductive couplers, the connections are simplified and repair work is minimized. Additionally you don’t have open pins exposed to the environment (dust, water, oil) that can also cause nuisances in the connection process.

Replace pin connections for grippers

To connect the transfer rail on each gripper, normally a pin-based connector is used. As the grippers are changed on each tooling change, the connectors become worn and damaged with regularity. By replacing the pin connector with non-contact inductive couplers, the two sensor signals are maintained but the maintenance of these connections is reduced dramatically. An additional “in-zone signal” verifies that the gripper is installed and connected. This provides assurance during operation.

Inductive couplers offer IO-Link functionality

Inductive coupling with IO-Link technology adds more benefits besides replacing the pin coupling. It allows users to transfer up to 32 bytes of data in addition to power for actuation or sensors. If you connect IO-Link enabled I/O hubs or valve connectors to the remote side, you can also store identification data on the IO-Link hub or valve. When the connection is established, the controller can request the identification data from the tool to ensure that the system is utilizing the correct tool for the upcoming process.

With pin based coupling you needed up to 4-5 seconds to first engage the tool and to mate the two ends of the pin couplers and then request the identification. With inductive couplers, the base only needs to be brought closer to the remote so that you quickly couple and identify the tool before engaging the tool — this takes less than a second. Additionally the base and remote do not need to be well aligned to couple. Misalignment up to 15-20 degrees of angular offset or 2-4 mm of axial offset still provides functionality.

The benefits at a glance

  • Power and signals transfer with pin-less connectivity
  • Reduced downtime due to rail or gripper repair
  • Know that the gripper is present and powered with in-zone signal
  • Inform the controller that the rail has power and connectivity to the sensors

To decide the right coupler for your next application visit www.balluff.com.

 

How RFID Can Push Your Automotive Production Into the Fast Lane

The automotive industry is one of the technological trendsetters in the manufacturing industry. In 1913 Henry Ford invented the assembly line and forever changed automotive production. Now a bit more than a century later the automotive industry is again facing one the biggest innovations in its history.

The complexity of different models and the variety of equipment variations are enormous. This individuality comes with great challenges. The workers in the assembly process are confronted with countless, almost identical components. This requires accurate tracking of all items to avoid mistakes. Safety-relevant components are, therefore, often provided with a barcode that has to be scanned manually.

The major advantages of RFID over barcodes in automotive production

Another technology could relieve employees of this routine task and give them the security of having installed the right parts through automatic testing: RFID. These are the big advantages of RFID over barcodes:

  • While the barcode only contains the information about which type of product it is, the RFID tag provides additional information, such as in which vehicle the car seat is to be installed.
  • While the barcodes have to be read out manually one after the other with a handheld scanner, the RFID tags can all be detected simultaneously and without contact via a scanner – even if the parts are already installed.
  • RFID tags can be used to retrieve information in seconds at any time. During the production process, it can already be checked whether all the required components are installed –  provided they are all equipped with an RFID tag. Without RFID, this was only recorded in the final inspection, using visual inspection and paper list.
  • Additionally, nowadays it is indispensable for the automotive industry to make the production parts traceable and thereby assign them a unique identity. RFID has the advantage that without visual contact or even after a repainting of the component, the information can be easily retrieved. The function is not lost with dirt or oil coverage. Furthermore, tags with special encapsulation can retain their function even under high mechanical, thermal or chemical loads.

How does RFID work?

RFID is the identification of objects by electromagnetic waves.  A reader generates a high-frequency electromagnetic field. If a data carrier (also called “tag”) is brought into the vicinity of the reader, the specific structure of the tag ensures a change in the field and thus transmits individual information about itself – contactless.

RFID Tag and Reader
Functional principle of an RFID system

Increase process reliability and profitability with RFID

Several thousand parts are needed to build a car. But only those parts that are safety, environmentally or testing relevant get an RFID tag. For example, the motor cabling would get a tag that can be read out automatically. Without RFID a worker would have to manually enter the label in a database and errors can easily arise. RFID detects the part automatically and you don’t have to look for labels in transport boxes, etc.

With RFID you know exactly where a component is located at any time – from the moment of delivery until the belt run of the car. With this information you can react flexibly to changes in the process, such as delays in certain areas, and can reschedule at short notice. In addition, you can always retrieve the current stock and know whether the right component is mounted on the right vehicle. So it can significantly increase process reliability and efficiency. An RFID solution eliminates several manual steps in the documentation per vehicle, and it brings more transparency to the logistics and production processes. That means the effort is reduced and the profitability increases.

The implementation starts with the suppliers

Ideally, the implementation of RFID starts with the automotive suppliers. They attach the RFID tags to their components what allows them to use the technology within their own logistics and manufacturing facilities. On arrival to the car manufacturer, the parts are driven through an RFID gate that reads out the tags automatically and adds the parts to the inventory. If the car leaves the assembly hall after manufacturing you can screen again by the RFID gate. At the push of a button it can show which parts are under the hood.

Automatic configuration with UHF for your convenience

The processes in the automotive industry are versatile, but a broad selection of innovative RFID products can push your automotive production into the fast lane.

For more information on RFID, visit www.balluff.com.

DMC vs. RFID in Manufacturing

The increasing discussions and regulations on complete traceability and reliable identification of products is making identification systems an inevitable part in manufacturing. There are two specific technologies that are very well received: The Data Matrix Code (DMC) and Radio Frequency Identification (RFID).

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One critique of RFID is the market maturity regarding practicability and price-performance ratio is not reached yet. Compare this to DMC; DMC is practical and cost-effective which is an advantage over RFID. In order to choose DMC or RFID for your application, you have to understand the fundamental differences between the two technologies. Both have their advantages and disadvantages, and the wrong decision could have costly consequences. The technology you choose will mainly depend on the object being identified. The decision will be based off of size, shape and the environmental conditions.

A New World of Opportunities with DMC

A Data Matrix Code is a two-dimensional data point pattern that has a variable, rectangular size in the form of a matrix. The matrix consists of symbol elements with a minimum of 10×10 and a maximum of 144×144 . It is a binary code that is interpreted with zeros and ones and can hold up to 1,556 bytes.

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A horizontal and a vertical border describe a corner, which serves as orientation for the reading – called the “Finding Pattern”. On the remaining sides, the border must alternate with light and dark square elements in order to describe the position and size of the matrix structure – the “Alternating Pattern”. The data storage area is inside the symbol.

Advantages of DMC

This machine-readable coding form was invented to encode higher amounts of data in smaller areas compared to 1D code. Camera scanners can already reliably read dot patterns of only 2mm by 2mm. Thus DMC is suitable for very small products or round surfaces where there is little room for marking on the product.

With the technology of DMC you can place a lot of information in a very small area. Article or batch numbers, manufacturing or expiration dates as well as other important manufacturing data can be stored permanently on the work piece across all processing steps.

A particular strength also lies in the fact that the code can be directly applied to a part (without a label) using different printing or embossing methods. It can be needled, lasered or printed with inkjet or thermal transfer printing. It works with various materials: plastics, papers, metals and many more. Since you have to use special cameras to read the DMC, not barcode scanners, they can be read in any orientation (from 0°-360°).

Additionally, the error correction when reading a DMC is very high due to information redundancy and error correction algorithm, even 25-30% contamination or damage of the data field can be fully compensated.

Disadvantages of DMC

As it is not possible to read a DMC with linear barcode scanners, you have to use camera-based image processing systems that are more expensive. In addition, it is imperative that the entire surface (not just a part of it) is decoded, because the arrangement of the modules on the surface determines the contained data. Otherwise you don’t get any valuable information.

Although DMC can accommodate low-contrast printing (20% contrast are sufficient), glossy surfaces are difficult to handle because either the light used by the camera for reading is not optimally reflected or it is too scattered. The angle at which the camera is mounted can also play a role.

Last but not least, the location of the DMC or its attachment determines whether it is readable or not. Unlike RFID, a DMC can only be read with visual contact. A hidden DMC cannot be read by the cameras. Even if there is a line of sight you can read the DMC only within a specific reading distance.

Gain Visibility into the Manufacturing Process with RFID

This technology makes it possible to identify every item that is equipped with an RFID data carrier contactless and unambiguously. An RFID system in manufacturing consists of thousands of data carriers (also called tags or transponders) and a minimum of one read/write device (usually called a reader) with an antenna.

The reader generates a weak electromagnetic field via its antenna. If you bring a tag into this magnetic field, the microchip of the tag is supplied with energy and can send data (without contact) to the reader or store new information on the chip. If the tag leaves the magnetic field, the connection to the reader breaks off and the chip is inactive again. The stored data will remain in the tag memory.

RFID tags are available in many different designs, it can be just a simple adhesive tag but also a hard tag as a disc, bolt or glass tag. Only a few millimeter tags can be used for tool identification and very large transponders for container identification.

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Advantages of RFID

An RFID tag has 3 main advantages:

  • The tag can be read or written contactlessly without visual contact to the reader
  • The tag has almost unlimited rewritability
  • Several tags can be read simultaneously (multitag/bulk reading)

These features open up completely new possibilities that DMC cannot provide. If the RFID tag is integrated in a pallet or tool and you can’t even see it, it can still be identified. RFID tags can also be read with the greatest possible contamination as no visual contact is needed. With the rewritability of the tags you have the chance to change, delete or supplement the data on the chip – at any time.

Once an RFID system is integrated into a process, the system can be run with just minimal human participation. For a new order, the new information is written automatically on the tag. This can be up to 128 kbyte of data on a single tag. The detection of RFID-equipped parts happens within less than a second, much faster than using a barcode. This leads to reduced administrative errors, increased transparency and significant increase of speed.

With RFID, even after a post-treatment, parts can be tracked down for a lifetime. Every production step can be documented, read and written directly on the RFID tag in or on the part. To avoid security issues, data can be encrypted, password protected or set to include a “kill” feature to remove data permanently.

Disadvantages of RFID

RFID also has some disadvantages. Depending on the used frequency, physical conditions are often the reason for issues. For example, metal containers or contents made of metal can create problems or even non-readings as metals reflect and shield. Products with a high proportion of water absorb radio waves and it could cause the reader to not detect certain objects.

Another sore point is the cost. RFID tags are always more expensive than a DMC because even with a large amount, the integrated antenna and the transponder must be paid. However, with having almost unlimited read and write capabilities, the higher initial acquisition costs pay off over the time with tens of thousands of uses of the tags – at least with closed-loop applications.

Different frequencies for different applications

There are 3 established radio frequency ranges that have specific characteristics:

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The application determines which frequency you should choose. As Low Frequency (LF) systems only have a moderate sensitivity for potential metallic reflections they are designed for applications where the tag has to be mounted flush in metal, for example, with tool identification. High Frequency (HF) systems score with a high transmission speed for large volumes of data and are therefore ideal for work in progress (WIP) applications. High reading ranges make Ultra High Frequency (UHF) very attractive when the plant or process does not allow a close proximity between reader and tag, RFID tags on various positions on an item can be read with just a single UHF antenna. As all tags can be read out almost simultaneously in the read range of a reader, UHF systems are ideal for detecting complete pallet loads.

Main Differences Between DMC and RFID Tags

Here is an overview of the most important differences between Data Matrix Code and RFID:

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Which Option is Better for Your Application?

Ultimately, the decision to opt for one or the other technology is always a case-by-case decision. Here are some fundamental questions you can ask yourself in order to choose the right one:

  • Will the marked object be reused or will it be lost at the end of the processing chain? → closed-loop application = RFID, open loop application = DMC
  • Is there only a one-time marking or a repeated writing/ change of the stored data needed within the processing chain? → One-time marking = DMC,  rewriting = RFID
  • How big are the detection distances? → Short = DMC, large = RFID
  • What about the data volume on the object? → Low = DMC, high = RFID
  • Should process data be stored on the object? → Yes = RFID, no = DMC
  • What about the processing speed? Not relevant = DMC, high = RFID
  • What about the lighting conditions and contrasts? → Good = DMC, bad = RFID
  • How big is the space available for the marking? → Small = DMC, sufficient = RFID
  • Is the direct line of sight to the object difficult? → Yes = RFID, no = DMC
  • Are there potential sources of interference like dirt or damage? → Yes = RFID, no = DMC
  • Are there potential sources of interference like metals or liquids? → Yes = DMC, no = RFID

It’s Not Always About “Either/Or”

DMC and RFID do not necessarily have to compete. Sometimes it may be beneficial to have a combination of both technologies. An example of a combination solution is an RFID label with a printed DMC. While the DMC can be read directly on the object with a scanner, the RFID tag fulfills further tasks. Thanks to the special technology, goods can be identified even when packaged. In addition, all relevant process data can be stored on the RFID data carrier and offer added value throughout the value chain.

To learn more about RFID technology, please visit www.balluff.com.