On the one hand, the highest priority for machines in food production is their robustness; on the other, they must be easy to clean. To ensure that germs have no chance at all, very strong cleaning agents and lots of water are usually used. They must not have any influence on machine availability in the long term. In this aggressive environment lubrication-free polymer plain bearings prove themselves, which reliably and permanently withstand all adversities.
"We are almost exclusively active in special purpose machine construction," says Simone Singer from the sales and marketing department of the company Singer & Sohn GmbH in Berching, Upper Palatinate. "And the proximity to the Bratwurst metropolis of Nuremberg means that our machines are frequently used in sausage and meat production. We see ourselves as problem solvers for our customers, who generally want to automate work processes with tailor-made systems in order, among other things, to be able to continuously comply with the strict hygiene guidelines. “
In the food processing industry it is very important to find a robust and above all easy to clean bearing. Special cleaning agents are used, which can damage the plain bearings. The bearings that come in direct contact with food must be compliant with FDA or EU 10/2011.
With the materials iglidur A180 and J it is possible to respond to the different requirements of the application. The material A180 offers good resistance as well as FDA conformity. With iglidur J a low coefficient of friction can be achieved, enabling easy and quiet adjustment. In addition, the bearings made of both materials are maintenance-free and lubrication-free. This saves lubricant costs and protects food from contamination.
Dieter Koller, Head of Design: "Our range of machines is characterised by the fact that it is particularly reliable, durable and robust. This is particularly important in the food sector, since on the one hand they are often operated by unskilled employees. On the other hand, their service life must be right. The market is highly competitive. Under no circumstances should unnecessary service and maintenance times be incurred. “
Founded in 1978 as a contract manufacturer, the family-run company with its approximately 38 highly qualified employees today focuses on the design and construction of conveyor systems and special machines, which are primarily used in the food and beverage industry, but occasionally also in chemical and pharmaceutical applications.
"With us, every detail is right. From simple conveyor belts to highly complex machines - we plan, produce, supply and install economical systems that are now proving their efficiency all over the world," says Dieter Koller. "Everything up to the service comes from one source. “
Whether transport lines for batter and bakery products, scales, cutting plants, automatic production lines for meat loaf or brushing plants for salami sticks: these are always customer-specific products made entirely of stainless steel. "The material guarantees durable and hygienic operation," says Simone Singer. "And all machine elements must also be matched to this. “
At the Anuga FoodTec, the special machine manufacturer has now presented a sausage chain cutting machine 'OptiCUT SI-1000', which has aroused lively interest. "This development arose from the demand of a customer who wanted to significantly reduce manual labour in his production for reasons of hygiene, among others. " Whereas in the past the employees used to cut the sausage by hand with a kind of razor blade, a machine now takes over this part. Although the employees wear protective suits as a matter of course, it was impossible to avoid touching the food and possibly contaminating it.
In addition, the manual work always resulted in different lengths of the sausage, which created an uneven appearance. "And that can no longer be communicated to the food trade in this day and age," the head of design addresses another aspect..
The operation of the machine is simple. The smoke sticks with the sausage chains are removed from the cooking or smoking trolley by an operator, placed on the sausage separating machine and then automatically run into the system. Inside, the sausages are fixed, spread and separated at the bottom. The smoke sticks run out again on the opposite side of the plant and can again be removed by an operator or automatically fed to the next production process by continued material handling.
"In food production, lubricants are absolutely frowned upon," Dieter Koller clarifies. "Again, the risk of product contamination is far too great. " For this reason, the special machine manufacturer has been working with the company igus® GmbH, Cologne, for many years. Basically, lubrication-free polymer plain bearings and a large number of other plastic products are used in the entire product range. They are usually available from stock and help to reduce maintenance intervals, lower costs and increase service life.
In the sausage chain cutting machine, robust drylin linear guides and trapezoidal lead screws as well as corrosion-free igubal fixed flange bearings also prove their versatility. All supplied parts are designed for direct contact with food. In addition, durable polymer energy supply systems provide the necessary power supply.
"We used to install needle roller bearings," the head of design looks back. "They proved unsuccessful in the harsh operating and cleaning environment. They are very sensitive in that the bearings had to be replaced as soon as a few drops of water penetrated through the seal during cleaning. This was too costly in the long run. In contrast, we are very satisfied with the current solution right from the start. The plastic machine elements, on the contrary, are characterised by a low level of water absorption and are resistant to chemicals. “
The development of the sausage cutting machine 'OptiCUT SI-1000' was based on the specialist's wide experience in the construction of customer-specific models. In the area of the spreading mechanism, a drylin® W single rail guide made of stainless steel with sliding elements made of iglidur® J is used in the sausage chain cutting machine.
Besides extremely insensitive linear guides with JUM liners, plain bearings made of the material iglidur® P210 are also used in the knife edge deflections. They serve as anti-rotation feature and thus ensure high availability. Due to thermal stability and total moisture absorption, the P materials are among the most dimensionally stable under varying environmental conditions. They are recommended for rotation movements for medium to high loads. "Especially in this area, we tested a number of plastics in our machines over the years before we found the right solution now," Dieter Koller looks back.
"Although our machines prove themselves mainly in the meat industry, our transport systems can also be used in large bakeries, for example. Depending on the place of use, the cleaning procedures differ, as do the external conditions. It can get very hot around the ovens. In addition, the rollers of the conveyor belts travel up to 80 m/min. It has taken some time to find a material for all requirements. “
The plain bearing material P210 is now used so frequently that the investment in an in-house tool paid off. The wall thicknesses have been increased from the standard 1 mm to 3 mm so that the service life and runtimes are even better for the customers. "In this way we can guarantee long runtimes over the long term. “
In addition, the machine is equipped with cost-effective EFSM fixed flange bearings for the pivot cylinders. Even the hatch of the switch cabinet is equipped with a plastic plain bearing, which ensures that it opens and closes permanently and quietly. A hexagonal guide with iglidur® J is also available as a special part. For further requirements of the end users especially in the food sector, such as even higher resistance to temperature or chemicals or FDA conformity, the liners made of the different J materials can be easily replaced at any time with liners made of iglidur® A180. This is a proven FDA-compliant material that is suitable for applications with low to medium loads in direct contact with food and moisture.
"Basically, we try to supply solutions from our extensive modular system," explains Bernhard Hofstetter, the technical sales consultant in charge of bearing technology. "However, if this does not work, we are able to provide samples or special parts from batch size 1 in order to offer our customers the best solution. “
The sausage cutting machine will be used by the end user at least five days a week for three shifts at a time. It is cleaned once a day. This mainly affects the parts in contact with the product. But splash water also gets onto the camera or the integrated operating terminal. "All interior and exterior areas must be able to withstand wet conditions and cleaning chemicals," points out Dieter Koller once again. "It must be ensured that, during ongoing operation, malfunctions or unintended shutdowns do not occur under any circumstances “
The special machine manufacturer relies on maintenance-free and lubrication-free polymer plain and spherical bearings and linear technology in its entire range of machines and systems. They are economical, easy to install and work in harmony with stainless steel. The collaboration between the two companies works well. "When we decided on the new material, for example, we were given 50 bearings in advance to put them through their paces. The result has convinced us so much that we do not want to do without them today," Dieter Koller concludes. "And since we can predominantly fall back on standard parts, we are also on the safe side in terms of business management. “