Robolink & Injection Molding Machine

Plastics industry: Automated parts handling for efficient injection molding machines

Whereas employees used to have to place ice scrapers in an injection molding machine hundreds of times per shift, this monotonous task is now performed by a low-cost robot. It is so cost-effective and easy to operate that the investment in automated parts handling pays for itself after just four months.

Monday morning, start of shift at a manufacturer of ice scrapers. An employee places twenty blanks in a magazine and starts the BOY 35 EVV, an injection molding machine that overmolds the scrapers with a lip made of thermoplastic elastomer (TPE). What follows is an example of part handling automation in the plastics industry. robolink, a four-axis robotic arm from Cologne-based plastics specialist igus, grips a blank with a vacuum end effector. The arm then moves to the overmolding machine. The highlight: there are also suction cups on the back of the end effector. This allows the arm to pick up a finished overmolded ice scraper, then turn 180 degrees and place the next blank - with a repeat accuracy of 0.8 millimeters. Removal and loading thus take place in a single motion cycle. And that saves time. The robot arm then places the finished ice scraper on a conveyor belt.

The solution for automated parts handling on an injection molding machine was on display for the first time at Fakuma 2018, the International Trade Fair for Plastics Processing in Friedrichshafen. "The topic of automation is growing strongly in the plastics industry," says Bernd Fischer, division manager for application technology and service at Dr. BOY, a company based in Rhineland-Palatinate, Germany, specializing in the development of injection molding machines since 1968. "Unlike a few years ago, more and more machines are leaving our factory automated today." Before this automation phase, workers had to insert blanks into the machine by hand. Hundreds of times per shift. A monotonous job that is inefficient, tiring and error-prone.

Automated parts handling: payback after approx. four months

Packaging, technical parts, semi-finished products and consumer goods: The plastics processing industry is one of the most important sectors of the German economy. According to the German Plastics Processing Industry Association (Gesamtverband Kunststoffverarbeitende Industrie - GKV), more than 330,000 employees, mainly from small and medium-sized enterprises, generate annual sales of over 65 billion euros. However, this balance sheet is no reason to rest on one's laurels. After all, the sector is going through a transformation phase - just like most other industries. Cost pressure is increasing. And topics such as automation and Industry 4.0 are becoming a competitive factor.

"However, many companies shy away from the topic of automation because they fear investment costs of several hundred thousand euros," says Norman Franke, Head of Automation Injection Molding at igus. "Yet today, thanks to low-cost robotics, it is easily possible to automate monotonous and dangerous processes at low cost and low risk. For example, the robolink robot arm with 5-DOF costs from 3,845 euros - a fraction of the price of conventional industrial robots." The reason for the low cost: Many components of the robotic arm, such as bearings and gears, are not made of metal but of high-performance plastic.

"The investment can pay for itself after just four months," Fischer emphasizes. This is because employees now only have to spend ten percent of their working time on parts handling - namely refilling ice scraper blanks into a magazine from which the robot arm serves itself.

Robot can also be operated by IT laymen

Low-cost robotics is not only comparatively inexpensive to purchase, but also to operate. That starts with operation. "Many companies fear that they will have to spend a lot of money on IT experts to program the robotic arm," says Fischer. "But in fact, after a training period of just a few hours, it's possible even for IT laypeople to define motion sequences." This is made possible by software from Commonplace Robotics, whose origins go back to adult education.

At its heart: a 3D simulation of the robot arm. A Digital Twin of the real robot. Instead of programming, employees define the start and target positions of the arm with mouse clicks. The software calculates the motion paths automatically. It is also possible to insert your own 3D objects. The matching robot controller, integrated in a control cabinet as a DIN rail version, takes care of controlling the stepper motors - and communicates with the controller of the connective injection molding machine via EUROMAP interface. "We have designed the operation of the system so intuitively that the need for IT specialists is reduced to a minimum," emphasizes Fischer. "This saves costs and counteracts the problem of a shortage of skilled workers, which also affects the plastics processing industry."

Reduced need for maintenance technicians

Since the bearings of the robot arm are made of high-performance plastic and not metal, dry running is possible without lubricants. The lightweight plastic components also reduce energy consumption - another savings factor in times of rising energy costs. Last but not least, the automation does not even require additional space. "The automation of parts handling takes place within the 1.67 square meter footprint of the compact insert molding machine. The company does not have to provide additional space. The low-cost robot, the parts magazine and the conveyor belt are positioned on the free machine table of the injection molding machine to save space."

Low-cost automation of injection molding machines faces a hungry market, Fischer is convinced. He says the solution is particularly suitable for machines with longer cycles. "For cycle times of more than 30 seconds, it makes economic sense for companies to automate part handling with low-cost robotics." For faster machines, on the other hand, robolink is too slow, he said. The robotic arm moves at a maximum speed of 0.25 meters per second and manages seven picks per minute.

Driving automation forward: Online platform RBTX bundles expertise of several manufacturers

If companies like the automated parts handling, they have the option of expanding the automation. This is where RBTX comes in, an online marketplace where manufacturers of low-cost robotics pool their products and expertise. Companies put together automation solutions with the help of a configurator. Robots from igus, for example, provide the basic electro-mechanical framework - including Cartesian robots, jointed-arm robots and delta robots. They can be combined with components from various manufacturers, including vision systems, grippers, interactive software, power electronics, motors, sensors and control systems. Nasty surprises regarding compatibility are ruled out. "To ensure that even small medium-sized companies can make the low-risk leap into the automation age, engineers have already combined and tested all the components," says Franke. "This ensures smooth interaction. Companies can conveniently put together solutions and get started right away."

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