Reducing the cost of automation:Andy Parker-Bates and John Hill of the Automation Group of Parker Hannifin discuss the latest modular automation technology

Assembly Automation

ISSN: 0144-5154

Article publication date: 20 April 2010



(2010), "Reducing the cost of automation:Andy Parker-Bates and John Hill of the Automation Group of Parker Hannifin discuss the latest modular automation technology", Assembly Automation, Vol. 30 No. 2.



Emerald Group Publishing Limited

Copyright © 2010, Emerald Group Publishing Limited

Reducing the cost of automation:Andy Parker-Bates and John Hill of the Automation Group of Parker Hannifin discuss the latest modular automation technology

Article Type: Mini features From: Assembly Automation, Volume 30, Issue 2

For many companies in the manufacturing and processing sectors, the goal of total automation represents something of a Holy Grail: it is desirable but is often only achievable at a cost that outweighs the benefits. As a result, it is rare to find fully automated production operations, especially in smaller or lower volume manufacturing; here, it is generally easier either to use unskilled, low wage staff, or to develop in-house mechanical or electronic handling systems that are built from standard parts, sourced from different suppliers and combined with bespoke engineered components.

For many companies with manufacturing and assembly operations, the key issue has to be a clear cost-justification for any investment in automation technology. Cost is generally associated with the purchase price of hardware, the labour required to design and build each system, downtime while an existing line is being replaced or upgraded, plus ongoing maintenance and operating requirements. Balanced against this are the benefits, which typically include improved workflow, greater productivity, better product quality and lower labour and long-term operating costs.

The good news is that if full or partial automation of a production process has been identified as the way forward, then there is now a wide range of modular automation products that can be used by both OEMs and production engineers in end use applications, to simplify design and build, with lower construction and ongoing operational costs.

These products are typically based on conventional pneumatic and linear motion devices that have been reengineered as modular and easily interconnected components; although simple in concept, they can offer the levels of performance and functionality that are required to develop and cost-justify the most complex of automation systems.

Linear technology

Modular linear products can generally be subdivided into: handling mechanics, such as industrial servo drives, electric cylinders and belt-driven actuators; and precision mechanics, including iron core and iron-less linear servo motors and packaged linear actuators capable of delivering sub-micron accuracies.

Common throughout is the approach taken by modular product manufacturers of introducing products that are, as far as possible, plug-and-play devices, often being supplied with all cabling and interface options ready to connect direct to higher level drives and controllers. Perhaps, as importantly, most manufacturers now offer an extremely wide range of modular products direct from their catalogues, so there is ample opportunity to source exactly the component parts needed with minimal lead time; similarly, some manufacturers such as Parker Hannifin have the ability to supply and support a complete set of parts, including linear devices, drives, controllers and HMI against single catalogue part numbers, simplifying ordering still further.

In terms of the latest technology, products for handling mechanics now include devices such as integrated linear tables, with ballscrew or linear motor drives, built from modular components and supplied with encoders, brakes, cable sets and limit switches, for constructing one-, two- and three-axis systems. Further developments include modular Electro Thrust Actuators, belt-driven actuators and linear motors.

Electro Trust actuators are compact devices that use a high-precision ballscrew, operated either directly by an inline motor, or indirectly via a toothed belt from a motor mounted to the body of the actuator, to drive a piston and rod assembly. This self-contained system effectively integrates three otherwise independent components into a single unit, complete with all connections and mounting points, which is capable of producing variable levels of force – to around 44,500 N – at high speed and with excellent levels of accuracy and repeatability, typically to within plus or minus 0.01 mm, with backlash of just 0.02 mm when used with an inline drive.

Perhaps, as importantly, these devices are available in a wide range of standard ISO sizes from M05 to M50; these match conventional pneumatics sizing and highlight the fact that the actuators can be used alongside or instead of pneumatic cylinders.

Similarly, robust, modular belt-driven actuators, available in a wide range of standard sizes and with a choice of bearing mechanisms, mounting and connection options, enable complex multi-axis machine systems to be developed quickly and at relatively low cost, without the need for specialised engineering, prototyping or testing.

For precision-handling applications, linear servo motors using ironless or iron-core technology also offer machine builders extensive options, as they can provide an efficient alternative to the traditional method of combining a rotary servo motor and actuator or ballscrew to produce linear motion. In addition to reducing the number of parts required, linear servo motors do not suffer from the same level of frictional and coupling losses between components, and can provide exceptionally high levels of accuracy and repeatability from a single, integrated unit.

Packaged linear actuators, normally supplied completely assembled and tested with linear bearings, drive screw, thrust bearings, motor mount, coupling and motor, are designed for quick installation. Again, these standard devices minimise assembly time and cost for machine builders and offer a wide range of options, including a choice of stroke lengths from 25 mm through to 20 m; previously, these large sizes would have only have been available as a special build option but are increasingly becoming seen as standard catalogue parts.

Pneumatic modularity

Despite the growing popularity of linear motion technology, there are still many applications where pneumatics offer considerable advantages. For example, on automotive spot welding lines where there are brief but extremely high spikes in electromagnetic energy, pneumatic logic control provides a safe but efficient method of positioning robotic welding heads. The same is true in semi-conductor manufacturing applications, where pneumatic actuators and vacuum end effectors play an important role; while in the food sector, where aggressive cleaning chemicals are often used as part of washdown procedures, specially developed pneumatics cylinders and valves designed to the extremely strict hygiene requirements demanded by the industry play a crucial and widespread role in processing and packaging machinery.

Modularity of design and interchangeably of components is an important consideration for pneumatic companies when considering new products. Increasingly, special purpose machine manufacturers are keen to maximise their investment and simplify their supply chain by being able easily to reconfigure machines to suit several customers and their varying applications. The ability to field-configure valve islands without returning the product the factory is a great advantage and one which is fully exploited by products such as Parker’s Moduflex valve system.

In this system, the ultra lightweight valve slices can be assembled into valve islands, which are themselves light enough to be positioned on the actuator, shortening pipe lines and reducing response times but which may be reconfigured with additional valve slices to accommodate developments in the application in the field in minutes.

A recently launched valve system Isys Micro from Parker highlights this point, as it uses centralised plug-in valve islands constructed from a sequence of individual modules or sub-bases. These are quick to assemble and integrate all air and electrical connections, which can easily be extended on a common bus. Each module incorporates four solenoid valves, providing up to eight functions, with compressed air ports being either front or bottom mounted and grouped together for ease of installation. Fieldbus, Ethernet and Isysnet protocols are featured as standard, with a single communications module being able to support up to 63 I/O modules and 256 inputs and outputs.

The idea of using a common base or mounting block that can easily be extended is also used in the current general of FRL products, which are designed to be quick and easy to snap together using specially designed fasteners. These allow combinations of components to be assembled without the use of tools, in less than half the time needed for conventional FRL systems, and eliminate the need for extra items such as pipe connectors; also, since the individual components mount directly face-to-face without intermediate blocks, the system produces exceptionally compact assemblies, while enabling individual parts to be easily removed or exchanged, greatly facilitating maintenance.

The modular concept has been carried forward by the industry as a whole in the promotion of the ISO mounting standard for pneumatic cylinders. ISO standards 6431 and 6432 regulate the mounting dimensions of pneumatic cylinders making interchangeability between competing manufacturers a market reality for customers. This has led to main pneumatic companies to offer more and more integrated functions in ISO actuators to maintain their edge, and this is predicted to continue as field bus communication and remote plc control becomes the norm throughout the automation sector.

Design considerations

Although the latest generation of modular automation systems has been developed to make it as simple as possible to construct machine systems quickly and efficiently using standard catalogue parts, there will still be instances where engineers need to work closely with system integrators or component manufacturers to ensure that optimum benefit is derived from modular automaton technology.

Ideally, the best partner is one that is capable of offering a complete end-to-end product solution, as this will improve the efficiency of product and system integration, helping to shorten development and build times still further.

This is an important factor and should not be overlooked. Bear in mind that a manufacturer that concentrates solely on drives and controllers will not necessarily have the expertise to advise on mechanical handling elements, while a supplier of linear motion devices is unlikely to have the level of programming knowledge to configure drive systems accurately.

By comparison, working with a manufacturer that has a full product offering enables design engineers to concentrate on the mechanical functionality or work-handling ability of each machine system. Engineers can then work outwards to create the complementary electronic drive, monitoring and control infrastructure that maximises overall machine performance and reliability, safe in the knowledge that at all stages the component parts used will interface effectively.

Component manufacturers are often keen to increase the value they provide to customers, and for the OEM or end-user this can make a significant impact on the reduction of both costs and build time. For example, manufacturers now offer design and assembly of sub-systems, or the collation of a number of interconnected parts into a single pack for delivery to line-side under a single catalogue number to simplify ordering and machine build.

Productivity and profitability

Ultimately, automating production operations, either in part or in full, has to be cost-justified. In many instances, however, this can be a simple decision, especially if a structured and carefully planned approach is taken to machine upgrades or refurbishment, if a suitable partner is found and if use is made of modular automation products and systems. Used correctly, these devices can produce a rapid return on investment for OEMs, system integrators and end-users alike, delivering improved machine performance and functionality, with greater productivity and profitability.

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