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Process automation in glass cutting — the potential of robotic technology

Robots appear in any science fiction story. For many, they are synonymous with technical progress. In glass cutting, however, they are seldom used — even though in the automotive industry, for example, they were first introduced in 1961. Looking for the reasons for this — and where they can be found.

Automation of the processes

“In the glass industry, there has always been the goal to automate — with or without robots — in order to improve cycle times and cutting quality,” says HEGLA CEO Manfred Vollbracht. However, even before comparatively expensive robotics technology arose, there was already a growth trend, and it continues today: “During cutting, uniform material flow at a steady speed can mainly be achieved if the glass consistently stays on the line and handling is reduced to a minimum.” In addition to cost considerations, this is why HEGLA strives to integrate processes on the cutting line and to introduce suitable automation there.

Robotless Strategy

When they were introduced to the market, for example, automatic edge stripping and the system-controlled film peeling device were ahead of their time. While previously the production process had to be interrupted and the work done by the operator, these functions have since been integrated into cutting as a sub-process. “Contributing to the success of these solutions,” continues Vollbracht, “is that no expensive multi-axis robotics have to be installed — the cutting system’s existing controls, drive technology and sensors can largely used.” For example, an X/Y crusher and a Tracon glass sheet turning device added to the blanking line ensures that the glass stays on the cutting line even after scoring. The system breaks off, turns and further separates the glass sheets.

SortJet, developed by HEGLA for online production, shows the extensive possibilities and high flexibility of this robotless strategy. Transfer of glass between cutting and insulation production is fully automated, the material flow is improved and additional potential is created for use of the glass. The glass flows continuously. There is no damage from manual handling.

Establishing beyond window glass production

While use of industrial robots for producing insulation glass promises no further advantages at current sheet sizes, beyond window glass production, this technology can show its real strengths. “Robots have established themselves in series cutting of automotive and furniture glass, and for general home appliances,” Vollbracht adds. Especially at the end of these cutting lines, HEGLA has installed many robots, because here, with their high load-bearing capacity, great speeds and precise positioning, they are an attractive alternative to conventional solutions. Because the glass sizes are similar, the robot can work with just one tool, and even when the glass is moving through quickly, it can unstack the blanks as required and provide them for further processing. An operator would soon reach his physical limits if he had to perform at the same rate for cutting glass doors or shower stalls. The risk of damaged glass would also be comparatively higher.

Mobile robotics solutions provide additional possibilities

Robots can be used even if cutting is not done in large series or similar sizes. This is especially true when the glass is mainly provided to processing lines further along and doesn’t have to be sorted by the same strict criteria as in insulation glass production. Then, even if the panes are heavy, a robot can automatically place them on one or more racks. This solution’s technical advantage over humans isn’t just a matter of performance. Using robots also improves safety and reduces injury to the operator. For best use of placement positions, glass panes can also be stacked side by side or one above the other on the same rack, depending on the application. For cutting that requires a large number of placement locations, HEGLA has already developed and implemented robotic solutions. A robot with an automatically changing tool (suction frame) offers additional possibilities when there are a lot of types of glass.

Consideration of robotics in the general context

“Robotic technology should be considered for every application and in general context,” Vollbracht stresses. For example, in the automotive industry and series production, robotically controlled unstacking can reduce cycle times so much that faster processes have to be designed for transporting the glass and replacing the racks, just to prevent interruptions. Here, rotary platforms with multiple frame positions are one way to take the filled block of glass out of the robot’s reach as fast as possible and to provide an empty one just as fast.

“Which application an industrial robot is right for, and whether there is a technically simpler solution, depends on the individual case,” Vollbracht is convinced. “Robots have established themselves in many fields and will go farther as the market develops.”

Further information:

HEGLA
GmbH & Co. KG
Industriestraße 21
D - 37688 Beverungen

Telefon:+ 49 (0) 52 73/ 9 05-0
Telefax:+ 49 (0) 52 73/ 9 05-2 55
E-Mail: info(at)hegla.de
Internet: www.hegla.de

Figure 1: High speeds and high load capacity make a robot ideal for unstacking glass when cutting series of the same or similar sizes.

Figure 2: To protect the coating, here the glass is removed by combing. Unstacking is done on a rotary rack. The glass can be stacked side by side or one above the other, as needed.

Figure 3: Robotic technology can even deal with changing glass types and sizes. For more unstacking options, the robot is installed mobilely. It can be guided on the floor (as shown) or hanging, depending on need.