KST5a STacKer for all reaSonS

Case Study

The TaSK

When the American fast-food chains moved into Eu-rope they brought the hamburger bun business with them. Bakeries which were especially built for produc-ing these buns introduced the hamburger bun plastic crates – bun crates – in a 540 x 640 format together with the corresponding packaging technology. These new crates were not typical for Europe and were only used for the exchange of goods between bun bakeries and the fast-food restaurants for which these baker-ies were producing exclusively during the first years. But fluctuations in sales, due for example to the BSE crises, as well as regional changes, forced the bun

bakeries to greater flexibility regarding their sales mar-kets. As a result they conquered supermarket shelves. For this purpose new packaging was introduced as well as different pallet formats, such as industry and half pallets, for the export to other European coun-tries. Today, besides packaging with a return system of plastic bun crates, there are one-way (dispos-able) crates made of carton. In addition to the typical sealed “American Case” crates there are • nestable stacking crates in 540 x 640 format for industry pallets

Case Study KST5

• carton crates in 400 x 600 format for Euro pallets• carton half crates in 400 x 300 format for Euro pallets and• carton crates in 500 x 600 format for industry pallets

And just about every supermarket has its own prefer-ences.

The challenge

These new packaging formats presented different technological challenges than the original American Cases had. Many of the American machine suppliers could not handle them and could not find an acceptable solution. With the introduction of articulated arm robots in the foodstuffs packaging industry many machinery installers attempted to automate the stacking of crates with grippers. Here it was necessary to be able to place the crates with grippers as a complete layer and at the same time guarantee the interlocking of the stack cor-ners – a difficult task with damaged reusable crates and cartons. The tolerances of the different crate dimen-sions also proved to be a special challenge for design-ers. Added to that the handling capacities and cycle output of articulated arm robots is limited.

One solution was pre-stacking the crates with the help of small stackers. This made it possible for the gripper to take 3 or 4 layers in one cycle and thus attain the required speed. But current customer demands can no longer be met with this trick. Today robots must be able to manage layers with 30 crates – this is the maximum truck loading height – and at the same time operate with a minimum of energy requirements. The implemented installation controls must also be simple and easy to use.

The SoluTion

With the KST5 Langhammer developed a stacker that, besides a high performance of 23 crates per minute, can manage any stacking height. This machine safely stacks plastic as well as carton crates - and without damaging them.

Changeovers from one format to another are no longer time consuming as all 4 sides can be changed as to length and width automatically at the touch of a button: a format change “on the fly”! 30 seconds are all that are required for a quick and easy changeover to bun crates. The operator need only place small form adapter plates onto the corner cylinders. Tools are not required - mag-nets hold the adapters in position.

A turning station positioned in front of the stacker rec-ognizes from which direction the nestable plastic crates are coming from. Two spring fingers take over the align-ment in the alternate right/left position.

The stack lift is based on module belt technology. This ensures a firm base for every product – regardless of whether it is a flat carton or a crate with feet. As soon as 4 stacks of a packaging unit have been stacked these frequency controlled module belts move them to the stack palletizer PA14. This chooses the corresponding pallet according to the stack format from the dispenser and palletizes up to 100 pallets an hour – regardless of the format.

The BenefiTS

Over against robot solutions used till now the KST5 stacker has many advantages:

Downtimes for gripper changes and stockage of differ-ent gripper types for the various case formats fall away. In contrast to articulated arm robots the KST5 has no difficulties with the product crate orientation. It stacks any number of the currently in trend half crates – from 1 to 30 crates per carrier are possible – even odd number

layer amounts. This was not possible for the competi-tion’s original pre-stacker system which could only pre-stack 2 or 3 layers. A pallet change does not affect the stacking performance or cause a process disruption. In addition the narrow KST5 and PA14 footprint solution requires less space than the expansive robot solution.

The Siemens controls on the basis of SPS-S7-300-DP are intuitive in their operation and require no extra train-ing. An additional advantage: the maintenance of this energy saving stacker can be carried out by company own employees – independently of the supplier.

There is no source dependency as to acquiring spare parts. Special parts are not required. Access is easy and when doing maintenance work only the one line being worked on needs to be shut down.

Summary

The narrow Case Stacker KST5 connected to the PA14 palletizer and Siemens controls is an economic and maintenance-friendly alternative to articulated arm robots when stacking bun packages.

Langhammer GmbHSiemensstraße 267304 Eisenberg · DeutschlandTel. +49 6351 900-0Fax +49 6351 900-180www.langhammer.deinfo@langhammer.de

Case Study KST5

Technical DaTa

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Transport goods: plastic crates L x B 300 x 400 mm to 550 x 650 mm

Stacking height: 1 to 30 crates per stack

Stacking speed: 1200 crates / h per stacker

Palletizing speed: 100 pallets / h

Pallet format: Duesseldorfer Half, Euro or industry pallets 800 x 600, 800 x 1200 and 1000 x 1200 mm