Automation boosts vertical injection machine quality

The prime aim of the automation of vertical injection machine systems is not to save high labour costs but to ensure high process and product quality, says Engel. Nowadays, handling devices and robots are “run-of-the-mill” equipment in the manufacturing industry.

In an vertical injection machine shop, for example, the manual placing and removal of inserts is the exception rather than the rule, and the same goes for the feeding of moulded parts to downstream finishing stations.The prime aim of automation is not, however, to save “high labour costs” but, rather, to ensure high process and product quality, this being an absolute prerequisite in a modern production facility.

Handling devices and robots operate in an exactly reproducible rhythm, and at extremely high speeds and round the clock.Besides vertical injection machine machines, Engel also offers matching automation systems – from the simple handling device to the complex production cell incorporating product-specific downstream finishing stations.Since all system units are produced by Engel, the responsibility for everything, including CE conformity, rests entirely with Engel.Engel automation, whether standard or special, partial or complete, permits reproducibility to the highest standard.

Continuous growth from the very beginning Engel has been involved in automation technology since the 70s (at that time it was still the parent company Engel Maschinenbau), beginning with simple pneumatic devices for assisting the demoulding operation.By the middle of the 80s, Engel was already developing servo-actuated handling devices and was soon to lead the way in this particular field.By channelling its automation activities into Engel Automatisierungstechnik GmbH, which was founded in Steyr in 1985, Engel simply surged forward technologically.The Steyr production facility commenced operations at the beginning of 1986, with only 20 employees, and grew continuously over the following ten years.

With a production volume of barely 500 units per year, the company was soon “bursting at the seams” and the building of a new production facility at nearby Dietach began in 1996.This new facility, with 7,500 my production space combined with the very latest in process-oriented logistics, as well as 2,500 my office space, commenced production at the end of 1997.After the first year, its 120 employees had already built as many as 650 robots and handling devices.Only two years later, in the business year 2000/2001, the company’s work force of 210 employees realized a total production volume of 1000 robots and handling devices.This “magic” number was achieved two years sooner than originally planned, for Engel had set itself a period of five years for this growth target.Indeed, annual growth rates averaging 25 percent testify to the widespread preference for Engel robotic systems.

For Engel, automation is an essential element of modern vertical injection machine machine production.Indeed, it is becoming an increasingly indispensable means of meeting customer requirements.The robot production facility at Dietach has all the necessary means for experimental set-ups and feasibility tests, robot acceptance tests, with or without machines and/or moulds, acceptance tests for complex automation systems with vertical injection machine machines (up to 3,000kN clamping force) and moulds under actual production conditions, and prototype production.

However, in consequence of such rapid and extremely positive development, the originally planned reserves of production and office space are now virtually exhausted, meaning that extensions to this relatively young production facility are already in the decision pipeline.Fortunately, there is still ample room for expansion at the Dietach site.In parallel with the company’s developments and activities in Austria, robot production for the North American market was already transferred in 1995 to a newly acquired production facility located in immediate proximity to Engel’s vertical injection machine machine factory at Guelph, Ontario/Canada.

Last year, with a work force of 55 employees working on a floor area of 4000m2, this new facility manufactured as many as 250 handling devices and robots.While the basic design work for all robotic systems is handled by the Austrian company, all customer-specific adaptations and options are realized on the spot by the Canadian facility.Together, the production facilities in Canada and Austria plan to manufacture a total of 1,500 handling devices and robots in the present business year. Engel robots – the ultimate in modularity Today, every handling system, whether it is a single-axis sprue removal device or a complex ERC (Engel Robot Controlled) parts removal system, is modularized down to the smallest detail, permitting rapid and flexible adaptation to individual automation requirements.

Theoretically, the available modules can be combined to produce as many as ten million individual system variants.The modular system on which Engel robots are based has been developed consistently and is now in its fifth generation, the so-called E Series.The smallest E Series robot – designed for machines with clamping forces ranging from 400 to 6,000kN – made its d?but at K 98.The medium-sized version (2,500 to 18,000kN) has meanwhile gone into production as well.The largest member of the E Series family of robots, designed for vertical injection machine machines with clamping forces ranging from 13,000 to 55,000kN, will be presented at K 2001.The E Series thus covers the entire range of vertical injection machine machine capacities currently available on the market.

The modular robots of the E Series afford the plastics processor a great many advantages which, when added together, mean “more output for less money”: higher speeds and acceleration rates with standard versions, various selectable levels of performance for digital drive systems, extended maintenance intervals and greater ease of servicing (through permanent lubrication of the rack-and-pinion drives, the use of low-maintenance linear guides, the use of plug-in limit switches etc.), digital monitoring of the vacuum system for the suction grippers (with display and control elements), increased number of optional additional modules, and, last but not least, availability at an even lower price than that of the previous series (approx.10 to 15% depending on the actual equipment fitted).

Robot control systems – intelligent automation The user-beneficial integration of machine and robot control systems has been one of the main objectives of Engel Automatisierungstechnik GmbH ever since it was founded.Engel’s “intelligent” robotic systems have been constantly developed and improved.

The many improvements achieved in recent years include: the faster synchronization of robot and machine movements – without any additional hardware – through the use of internal bus connections between the respective control systems, new features for easier operation and programming using menu and teach-in modes, extended integrated safety functions.

Since the launching of Engel’s stand-alone robot control system at K 98, the sale of robots for other makes of vertical injection machine machine has increased considerably.Like the “integrated version” (joint operation of the machine and robot control systems via the machine’s VDU), the stand-alone control system is equipped with a high-capacity RISC processor and communicates with the digital drive system and the sensors and actuators of the robot via a CAN bus.From “high speed” to “low price” Depending on the application, the ERC Series robots are capable of minimizing demoulding times to 0.7 seconds and the total cycle time to around 4 seconds.For standard applications, such speeds are really exceptional, but when it comes to using machines for special, fast-cycling applications (e.g thin-wall packaging containers), even these speeds are too slow.For such high-speed applications, Engel has developed special ERS Type high-speed robots which have already proved themselves in actual practice many times over.

This high-speed version permits robot movement speeds of up to 8m/s and an acceleration of up to 150m/sec2 – that’s 15 times faster than acceleration due to gravity! However, fast speeds and acceleration rates alone do not suffice to achieve extremely fast cycling times.Just as important is the optimum co-ordination of the vertical injection machine machine, the injection mould and the robot.The process of “tuning” these three system components even involves optimizing the software running times for the individual program sequences.This facility is a performance feature which distinguishes Engel systems from those of its competitors.

ERS high-speed demoulding robots operate so fast that it is possible to achieve a total cycle time of only 2 sec and demoulding times of less than 0.3 sec (the shortest demoulding time achieved so far is 0.235 sec!).Not every application calls for a high-end robotic system.

For demoulding injection moulded parts and depositing them on a conveyor belt, the handling devices of the ER-HLi Series represent a low-cost, integrated means of automation, especially in conjunction with Engel tiebarless machines with clamping forces ranging from 200 to 6,000kN.This compact demoulding robot can be optionally mounted on the moving platen or on the stationary platen.The parts are deposited on the machine’s own integrated conveyor belt behind the safety guard, whereby the area around the mould remains readily accessible, as the conveyor belt can be pushed aside whenever necessary.The compact design of the system not only permits short robot movements and hence short cycle times but also minimizes the required floor space for the production machine.The integration of the robot control into the machine’s control system makes for optimum ease and reliability of operation.

From the robot to the tray server “Never lose the orientation of a part” is one of the fundamental principles of automation technology.Consequently, many production facilities make use of special transport containers and systems.Widespread use is made of thermoformed plastic trays, especially for parts such as mobile telephone housings and components.The injection moulded parts are deposited, temporarily stored and then transported in these trays for further finishing and assembly (e.g fitting of electronic components).For this special logistics application, Engel has extended its product range to include, among other things, the so-called tray server.

Moreover, the tray server takes up a minimum of floor space and, thanks to its integration into the production machine (both into the actual machine and into its control system), affords optimum ease and reliability of operation.Robots and gripper components on-line Delivery at extremely short notice is becoming an increasingly important factor in the automation field.

With a view to shortening delivery times, Engel is currently planning an Internet Ordering vertical injection machine System which will ensure the fastest possible delivery of robots and gripper components to customers in any part of the world.

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