Robotic control

Packaging Professional magazine
,
21 Jan 2012
yoghurt cartons on production line

The introduction of robotics is key to lowering production costs and
increasing efficiency, yet the UK has been slow on the uptake. Keith
Thornhill from Siemens outlines how centralised control is the next
stage in packaging development.

Automation systems that are both cost-effective and high-performance are key requirements for manufacturers across industry. Indeed, with an ever-increasing focus on the flexibility and efficiency of production lines, both original equipment manufacturers (OEMs) and end-users are under constant pressure to stay ahead of the technological game.

In the food industry, food safety and sustainability have been the driving force behind a culture change towards the use of automation. Safety concerns have driven a significant proportion of the investments made in the past decade. Everything from raw materials to finished stock is tracked and traced. Metal detectors, and more recently X-ray units, are being used to guarantee non-contamination. Sensor and vision technology is being deployed to reject defective items to ensure product quality.

While most robotic applications have been post packaging, and mainly in the area of palletisation, removal of human contact with food during processes is steadily becoming part of the cost rationalisation for upstream use investment. The problem is that the UK has traditionally been slow to accept automation and robotics, considering this technology to be both expensive and inflexible. Although the use of robotics is just one of many indicators of levels of automation, it is one that is measurable.

The International Federation of Robotics reported in 2010 that Germany had an installed base of 144,100 industrial robots, Italy 62,200, France 34,100 and Spain 28,800 and the UK just 13,900. However, the signs are encouraging, indicating the UK is prepared to increase its adoption of automation now it has a greater understanding of the many benefits the technology can deliver.

Food and beverage

A 2011 report from the British Automation and Robot Association that included 40 robotics manufacturers and automation companies showed clear growth in this sector, with sales 24% higher than 2010 – against a background of 205% growth in the food and beverage industry since 2005.

There has never been a better time to allow automation to solve the business requirements of safety, sustainability, manufacturing efficiency and inflexibility. Increasingly, production lines need to respond rapidly to changes in consumer demand. Integral to their ability to meet these expectations is the need to minimise the time involved to transfer raw material into a finished, packaged product and also to run multi-product formats on the same line.

This requires machines that are capable of performing not only with greater control but at much higher speeds. With the advent of software modularisation and intelligent networks, production lines can be changed at the push of a button and multi-packaging formats achieved by plugging in different machine options to include for example, foil and tray and cardboard packaging to be run on the same line.



Motion control is becoming a key factor in these developments, as it is only through the replacement of fixed mechanical linkages with servo motors that the production line can automatically configure to run multi-product formats.

For many years, robotics technology has only been used on high-margin products and highly productive environments involving the use of expensive and inflexible robot controllers. Some of these standard robots, which were designed around the automotive industry, are now finding their way into the food and beverage sector.

This evolution has sparked off new ways of automating handling. A robot designed to lift many kilogrammes in a car plant is typically over-engineered for the types of payloads in a food factory. This has an impact on the operational costs and flexibility of the installation, hence the need to design a handling solution specific to the task.

Handle with care

There are several ways to pick and place an object, and orientate into the correct location. Therefore, to optimise the design particular dynamics need to be taken into consideration, including production throughput, product form factor, mass, stability and texture. The space envelope will then be key to tailoring the specialised mechanical kinematics that include portal, delta, articulated, gantry and scara. Performance optimisation will, in turn, result in efficient energy consumption to control the servo motors. One example is the delta robots being used to place meat on skewers, portion lines of dough to form bread rolls that have a precise weight and cut pretzels.

Gripper technology is a further important consideration for successful automation. The more fragile and slippery the product, the greater the challenge to hold it throughout the process without damage or misplacement.

Vision systems are often used for high speed applications where the pick-up location is a variable, and the location of the exact position of the product is important. The position coordinates are relayed to the control system to move the axis to a position so the end effecter can grip the product. The same process is then applied to the placement of the product in the correct location. In the past, this process was so high-speed that it had to be operated via a bespoke black box robot controller, which resulted in inflexibility and supportability issues.

However, developments in processor power, drive and servo motor performance and miniaturisation have meant that robotic control can now be integrated into standard equipment, resulting in an immediate and significant impact of reducing costs and increasing serviceability and flexibility. The processing power of standard motion controllers has made the key number crunching requirements of calculating the interpolation position of the axes in moving positions a reality.

User-friendly programme

Some of the user-friendly programming and configuration available on the dedicated robot controllers are now also offered on standard motion controllers. The many Delta 3 demonstrations on display at drives exhibitions prove the extent of the technology and market requirement for it.

However, the really significant benefit to an end-user is that high performance pick and place solutions can be integrated with other axes to control upstream and downstream conveyors and functions, as well as networking horizontally and vertically to other processes, maximising operational efficiency. A fully integrated automation strategy can include the robot as part of the production jigsaw that needs to be completed to fully optimise packaging lines. The latest solutions have been developed to include standard function blocks that are designed specifically to control kinematics and produce robotic control.

A high-performance multi-axis machine controller at the centre of the machine architecture allows operators to control multiple machine functions from a single central control point. For example, the two machines usually required to place a product into a carton via a robotic top loader are the carton erector with a smart infeed system and a robotic pick and place unit. However, there are systems where the robotic element is crucial – essentially creating a single fully integrated machine out of the two. The networking capabilities of the individual components of the machine, together with vertical and horizontal networking, can monitor the energy andefficiency information at line-side or remotely.

This type of control was instrumental in the design of an automated line capable of packing a variety of food products into stick packs – sachets containing single portions. This comprised modules to shape and heat-seal the packs, proportion different sized sachets, an integrated weighing zone, pick and place into cartons, and a chain conveyor to supply the empty cartons and transport the filled ones to the sealing area.

This development will improve production lines across a broad range of industries. The single network control will allow faster throughput and greater line flexibility while the elimination of specialised robotic control will reduce costs significantly. If accepted by the packaging community in the UK, these systems have the potential to make the country’s packing sector more competitive so it can catch up with the rest of Europe.

Further information

Alison Vasey, Tel: 0161 446 6656 Email: Alison.vasey@siemens.com Website: www.siemens.co.uk