Wafers for the world - Robust lead screw linear system for extracting paper ice cream cones
 

Profile

• What was needed: drylin linear axes with lead screw drive
• Requirements: The plant is exposed to humidity, exhaust fumes, high temperatures, high levels of wafer dust and abrasive salts and sugars. At the same time, trouble-free functioning in three-shift operation seven days a week must be guaranteed.
• Industry: Food industry
• Success for the customer: The drylin lead screw linear technology is a solution that is as simple as it is reliable. The linear bearings are maintenance-free, cost-effective and versatile, as well as FDA-compliant depending on the material selected. As they are completely lubrication-free,  product contamination is excluded. Friction and wear have been optimised due to their tribological properties, which has a positive effect on the operating times of the machine.

A number of tribo-optimised plain bearings are used in the baking plants. They meet the high demands, free of lubricants.

Problem

The baking process of a standard wafer for industrial ice cream production is always the same. It is baked in an oven in the flat state, fed to a winding station and rolled up whilst it is still warm. Subsequently, further transport takes place via a link chain conveyor to the cooling tower, before the wafer is provided with a paper bag in the assembly area. The filling with ice cream takes place in a later process. To meet the high performance requirements, the process takes place in several stages. It must be guaranteed that only one bag is fed, otherwise it would cause problems during filling. If a customer has various paper bag sizes, the system needs to be continually readjusted.
The wafer baking systems are distinguished by very high capacities as well as flexibility during changeover. They are used worldwide. Heat, fumes, wafer dust and moisture make high demands on the machine elements that must carry on functioning properly in the long term. Only in this way can the national and international customers be guaranteed smooth holding times and minimum service intervals.
 
A clear requirement of the linear unit is the reproducibility of the extraction process. The system is usually in three-shift operations, seven days a week. They only stand still for a few hours for cleaning. The external conditions on site are demanding. Ambient temperatures of around 50°C may prevail there. Then there is the ubiquitous wafer dust. It is tacky due to the sugar content and the residual moisture. Moreover, there are customers who add flavour-enhancing salt to the product. Both salt and sugar are extremely abrasive. Baking plants for industrial ice cream wafers are also often provided with gluing devices, to glue the bag and wafer together with a sugar solution. They may squirt but nevertheless must not affect the separation process.
 

Solution

Simple, robust and efficient: these are the characteristics of this lubrication-free linear system which is used in an industrial wafer baking system. It proves its efficiency in the assembling area during the separation and feeding of paper ice cream cones. This leads to very high cycle rates on the one hand, and on the other, influences adverse ambient conditions of all components. Tribo-optimised, high-performance polymers from igus GmbH ensure long-term stable conditions, so that the running performance of the system rises constantly.
 
For its modular baking systems the special machine constructor has been relying on lubrication-free bearing technology from igus for many years. It is maintenance-free, cost-effective and versatile. The challenges of the customers have always continued to rise over time. In its plants for the fully automated production of wafers, hardly any off-the-shelf solutions have been used, but customised solutions that have been found partly from the standard range of the tribo-polymer specialists.
 
Plain bearings made of high-performance polymers for the food and packaging environment are FDA-compliant depending on the choice of materials. Product contamination by an additional active lubricant is excluded. Friction and wear have been optimised due to their tribological properties, which has a positive effect on the operating times of the machine. Even regular cleaning with aggressive media doesn't present any problems.
 
Various approaches were pursued and finally a simple but reliable system solution was chosen that can be adjusted manually by the user. In a wafer baking line that is being delivered to Korea, two parallel systems have to be adjusted simultaneously over a length of almost one metre. The two lead screws are coupled via a helical bevel gear wheel on one side. Due to the low loads a shaft construction for support could be dispensed with. The aluminium guide tube guides the inner-lying stainless steel lead screw. The material combination withstands the adverse ambient conditions. There is also a position indicator and a hand wheel. The whole system is maintenance-free. And due to the absence of lubrication, contact with food is safe.

Adjustment and format adjustment of a prism beam in the stripping station of ice cream cones.

Position adjustment of dough spray tube with a clearance-adjustable lead screw linear system.

Safety hood adjustment with maintenance-free hybrid bearings for the lowest adjustment forces.