As Markus Kaffee decided to modernise and expand the production line for folding boxes filled with teabags at Markus Kaffee GmbH & Co. KG in Weyhe near Bremen, this also represented a task for the conveyor equipment. The company has modernised and expanded this production line with a new conveyor and sorting equipment for various assortments of tea that are ultimately supplied to the consumer markets. The conveyor equipment specialist, Transnorm, was responsible for the planning and implementation of this system and installed a conveyor and sorting system that is connected directly with the newly conceived production line that meets the demands of the operator even in terms of maximum levels of reliability and flexibility of use.
Responsible for roasting, packing and preparing coffee for dispatch since 1972, Markus Kaffee GmbH, Weyhe, expanded its range of goods in 1981 and incorporated a comprehensive assortment of different types of tea in its product range. In this manner, the company has ideally supplemented its offering for the consumer markets from its central warehouse in northern Germany while certain European countries are supplied from the facility in Bremen. Therefore, apart from various types of Markus Kaffee coffee and pads, e.g. in the folding box sales unit, there are also teabags – which range from herbal tea to green tea, apple tea, camomile tea or the East Frisian blend – and the Westminster brand also forms part of the product range of the company.
Until recently, various steps of the process (transport, printing, sealing, sorting and saving), up to palletisation) were executed on the production line commissioned in 2004, which was fed from six teabag packing machines, with the teabags already being filled and placed in folding boxes. However, there were enough compelling reasons for not wanting to leave everything to the old production line.
With the decision taken to modernise and expand the existing production line, Markus Kaffee pursued the goal of contributing to the changing purchase behaviour that, among other things, is characterised by the trend of greater product diversity in assorted boxes and, in this context, of achieving a high level of plant and product availability as well as maximum flexibility. Graduate Engineer Harald Stubbemann (Picture 1, left), Works Manager at Markus Kaffee, Bremen: "This demand for the comprehensive retrofit project and the associated strategic plant expansion - apart from the investment in four new packaging machines for teabags - also included their connection to new conveyor and sorting equipment to be designed for the transport of the folding boxes packed with teabags and their supply to the palletising robot. In the process, it was our aim to integrate as many components from the existing system into the new one".
Demanding range of tasks
Based on a comprehensive requirements catalogue, Markus Kaffee floated a tender for the planning and implementation of the project, wherein the order was ultimately awarded to Transnorm System GmbH, Harsum, with which it already had a business partnership spanning several years. Mr. Stubbemann appeared to be convinced of the fact that "…the solution presented shall meet our expectations in terms of performance, flexibility and project execution".
And this is how it was done according to the order issued to Dipl.-Ing. (Graduate Engineer) Uwe Ehlers (Picture 1, right), Sales Manager of the Systems Division at Transnorm, who is responsible for the project. "As requested by the operator, in order to avoid interruptions to the operation of the six machines already available, as the matter was one involving complying with delivery commitments, we have developed a multi-stage concept for the installation and commissioning. Accordingly, the new conveyor and sorting equipment was assembled on a newly erected intermediate level platform (Figure 2) in the reconstructed tea hall for the new production line, before the four new machines were then connected to it".
The basis for this procedure was the exact process description by Markus Kaffee as well as the cooperation with Transnorm based on partnership for the project planning. The clearly defined goal in the process was the optimal arrangement of the ten production machines now and the implementation of efficient processes in order to continue to enable operation by two persons.
The outcome was binding for the conception, design and integration of the conveyor and sorting equipment, which was accommodated on a platform below the hall ceiling for this reason. The connection of the production machines takes place respectively with the help of a vertical conveyor (drag chain conveyor), which accepts the folding boxes directly at the machines, transports them to the platform level and transfers them there to the conveyor and sorting equipment, which then takes over other transport functions and feeds to folding boxes for various handling steps, e.g. turning, aligning, labelling with inkjet printing, before they then proceed to the palletising station.
Belt instead of rollers (pulleys)…
The folding boxes, based on their low weight and the instability of the shape, are extraordinarily demanding transport goods, which represents a concern in relation to the transport on the conveyor equipment (Picture 3). In addition, the boxes are not flat on the bottom side but a little bulgy. This is why they lie virtually only in one line. At this juncture, based on their low weight but with the requirement of being carried away with certainty, roller conveyor equipment cannot be used here for this purpose. Mr. Ehlers: “This is why we omitted using rollers and instead opted for belt conveyor equipment, which ensures that the folding boxes are carried away easily both on the straight route as well as in a curve and enables gentle and safe transport. The reason is that even the passage of a folding box past a curve is an absolutely critical moment".
… and an inductive pusher, instead of compressed air
Sorting folding boxes means the "trigger" for changing over from parallel conveyor routes to those arranged next to one another and feeding the folding boxes to the palletising station took place on the old production line with the help of compressed air. Mr. Stubbemann: "We wanted to move away from this technique in the new system. The reason being on the one hand that compressed air is expensive as a medium, and on the other hand, while operating the pneumatic valves, a small amount of tea powder always gets swirled up and is then contained in the ambient air based on the production and also gets deposited on the machines and units. This in turn leads to greater wear and an increased need for the maintenance of the respective components. We wanted to eliminate this by using another technique".
With the solution developed and implemented by Transnorm - inductive acting pushers (Picture 4) - the air is no longer swirled up and therefore the vulnerability of the corresponding components is also noticeably reduced. Moreover, maximum sorting performance is achieved with the pushers.
Know-how and practical experience were also called for as far as the lateral guidance of the folding boxes was concerned, which are transported, rotated, turned around, sealed and labelled with the help of inkjet printing with important information and data for the manufacturer and consumer, e.g. the expiry date and batch number, in order to be ultimately fed to the palletising robot. Based on the degree of complexity and the fact that the guide rails cannot be constructed in detail on the "drawing board", the task faced by the installation team of Transnorm was primarily one of adapting the guides of the boxes during installation on-site on the platform in order to ensure smooth and trouble-free material flow. Mr. Ehlers "That was highly demanding and it could be seen how important knowledge, experience and even the gut feeling of our technicians are for the processes and the sensitivity of the folding boxes as transport goods".
Peculiarities of the controller
An important starting point for the conception or adaptation of the already existing system controller was the demand from Markus Kaffee for greater diversity and therefore product variety in the assortment boxes. Mr. Stubbemann: "We would like to operate the lines both independently as well as to be able to interlink them with one another. This flexibility enables us to work with all ten machines that we have operating at present - for example, to handle only one product or even to consolidate folding boxes of different sizes on both parts of the overall system".
In this context, the controller manages tasks such as ejecting the desired folding boxes from the product flow as well as consolidating the sorted products with a performance of more than 6,000 boxes per hour and to feed them to the palletising station. Mr. Ehlers: "There are diverse controller-specific functions that needed to be taken into consideration at the planning stage for the function of consolidating each individual folding box in the correct sequence and orientation for the palletising station".
And one must not forget the provisions prescribed by legislation and to be complied with for tracking foodstuffs, which are mapped efficiently in the controller.
If you wish to get to the bottom of the reasons for the expansion project at Markus Kaffee, then this is best done via the arguments put forth by Mr. Stubbemann for greater efficiency, the system in operation since 2004 and the demand of the customers for even greater product diversity in assortment boxes.
For Transnorm, after being awarded the order and intensive planning, it was a project with a focus on connecting four new and six already existing production machines to a new conveyor and sorting equipment, with the help of which the ambitious goals regarding flexibility and performance could be achieved. In addition, Transnorm could build the system in a highly compact form, which resulted in considerable space saving and enabled the optimally efficient arrangement of the production machines.
An additional aspect from the cost perspective for Mr. Stubbemann: "Approximately 30% of the existing Transnorm system could be taken over and integrated into the new conveyor and sorting system for folding boxes after appropriate preparation and conceptual redesign".
A special challenge of the expansion project for Mr. Ehlers turned out to be, among other things, the organisation of the assembly and commissioning. "In order not to interrupt the production at any time, we carried out the pending assembly work and commissioning in close coordination with the production management during on-going operations" he stated.