logo

Search:

Case Studies Of Industrial Robots

Robots in action can be found everywhere. Robot Manufacturers give examples of robot applications in different industries.

Wittmann, Austria - IFR-Partner

Pallets and Pallet Boxes: The Automation of Agriculturally Used Products

Georg UTZ, a plastics processing group of companies, was founded in the year 1947 as a family business, and is operating as a corporation since 1955. For its Polish subsidiary, UTZ is relying on the established WITTMANN robot technology.

In 2008, the entire Georg UTZ group of companies achieved a turnover of 260 million CHF (Swiss francs). All in all the group is operating about 80 injection molding machines on different locations and at clamping forces of up to 3,500 tons. On location in Poland (subsidiary founded in 1997), plastic parts are produced on five injection molding machines, and eight thermoforming machines. The 80 UTZ employees in Katy Wroclawskie primarily are specialized in the production of workpiece and component carriers for the automotive industry - and the production of solutions in the field of food technology.

In particular pallets and pallet boxes (= "paloxes") are produced, the latter combining the functionalities of pallets and boxes. These are predominantly used in agricultural technology, for instance when transporting or warehousing fruit and vegetables.

A new installation ...

In the year 2008 - to be able to meet the Polish market's increasing demand - this product division needed investment in a new injection molding machine including robot automation. The molding machine comes with a clamping force of 3,200 tons, and it is equipped with two WITTMANN W773 robots.

The production entire system is designed for the effective manufacturing of pallet boxes, and within only one hour it is able to produce either 24 pallet boxes with closed endwalls and closed flooring, or to produce 24 units with perforated parts. The shot weight is about 28 kg, depending on the product type.

... for a new product

The new pallet boxes that are produced on this system are especially designed to meet the Polish market's demands. The concept of these pallet boxes has been developed completely anew, in close collaboration between UTZ and their customers.

Using PP as a material and applying a totally revised product design have made it possible to essentially decrease the part weight. At the same time it has been necessary not to disregard the capacity and stability of the pallet boxes. The products available at that time had a weight of 44 kg and offered a load of four tons at most. The new pallet boxes can deal with a load of three tons at an empty weight of 28 kg. The long lasting experience of UTZ in this field, combined with the results of a detailed market investigation made before in Poland, finally have made possible this new development.

The optimization of the pallet boxes' design resulted in a much better stackability. Zbigniew Putz, Head of the Technical Department at UTZ in Katy Wroclawskie, points out: "Because of the now optimized shape, our product is enabling the user to make stacks of up to five pieces. This means a load of 15 tons for the pallet box at the very bottom.

And exactly this has been a crucial requirement for the new product, because most of the storerooms in Poland are constructed with regard to stacks of five boxes. The pallet boxes with trenches that we now can produce have further advantages.

They are assuring the save handling even of products that are emitting liquids. Before, wooden pallet boxes have caused problems frequently. Not least we are able to offer our products at a better price, due to the decreased material requirements."

The work cell possibilities

The automation solution consists of two WITTMANN W773 robots. One is mounted on the fixed machine platen, and the main axis of the second unit is traversing the moving platen. The decision for WITTMANN robots had many reasons. At first, the flexibility of the two separately operating robots is allowing different approaches for different products.

Wittmann, scheme UTZ Poland1 Fixed plate
2 Adapter
3 Moving plate
4 Short X-Axis
5 Roller conveyor

 

 

 

 

On the one hand, it is possible to work with only one of the robots. This alternative is used when pallet boxes with high capacity (= height) are produced. Very important is the fact, that the robot resting over the moving platen does not handicap the then working robot (which is mounted on the fixed platen by means of an adapter). In principle the installation consists of two autonomously working robot systems that are operating within the same production cell. So on the other hand, it is possible to work with stack molds to simplify the operation of bringing together two different components of one product.

Witmann W773 robotWhen realizing this alternative, each of the two W773 robots is running in one half of the mold, and is removing one of the two components. A basic precondition for this mode of operation has been the strictly seperated configuration of the robots' mountings.

Currently, the use of a stack mold is already tested by producing pallet boxes with movable side parts. The box floor and the side parts are molded simultaneously.

The specifics of the WITTMANN robots

A further important point for the purchase of WITTMANN robots was the broad dimension of the Y-axis stroke. This vertical stroke of 3,600 mm assures that the height of the roller conveyor (where the parts are dropped) has not to be adjusted, not even for parts that are low in height. This means, a removed part can be placed on the same level every time, no matter what its dimensions are. The robot over the moving platen of the machine has been equipped with a shortened X-axis.

Wittmann W773 robots

 

This has made it possible to optimally integrate the entire system (consisting of one injection molding machine and two handling robots) into the overall infrastructure of the production hall.

The integrated rotating A/C servo axis (one module for each of the robots) and a payload of 60 kg for each robot are ensuring the highest flexibility for future projects.

 

 

The WITTMANN partner in Poland

WITTMANN Kunststoffgeräte GmbH and their Polish partner Dopak Sp. z.o.o. have supervised this challenging automation project together. The Polish Dopak company has been selling the WITTMANN products on the local market for a long time.

The new Georg UTZ installation in Katy Wroclawskie has been offered by Dopak as a complete system (machine and robots). This new system at UTZ has started operation in March, 2009.