Rugged lead screw linear system for extracting paper from 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 capacities of the wafer baking systems of Walterwerk Kiel GmbH & Co. KG are constantly increasing and, depending on the machine size, range from 3,000 to 19,000 standard wafers per hour.
The baking process of a standard wafer for industrial ice cream production is always the same: it is baked flat in the oven, fed to a wrapping station and rolled up while still warm. The wafer is then transported via a conveyor belt to the cooling tower before the wafer is provided with a paper bag in the assembly area. Only then is it filled with ice cream. It must be guaranteed that only one bag is fed, otherwise it would cause problems during filling. With different paper bag sizes, the system must always be readjusted.
And it is precisely in this section, the assembly area for separating and feeding paper bags, that linear bearings are used. They guarantee the format adjustment in the removal station and have to meet high demands in the process: Operation in the plant is sometimes characterised by high humidity and exhaust fumes. In addition, temperatures of around 50°C sometimes prevail in combination with the ubiquitous, sticky wafer dust. Sugar as well as partially used salt are extremely abrasive. And a sugar solution used in gluing equipment, which additionally glues the cone and wafer, must not influence the separation process despite possible splashing. Under these conditions, all machine components must function trouble-free in a three-shift operation seven days a week in order to guarantee national and international customers uninterrupted service life and minimum service intervals.
Due to the high requirements, Walterwerk Kiel was looking for a fully harnessed, complete solution from a single source.

Solution

Walterwerk Kiel GmbH & Co. KG pursued various approaches as a solution for format adjustment and finally decided on a simple as well as reliable system solution that can be adjusted manually by the user. To be more precise, the special machine constructor has been using lubrication-free plain bearing technology in their modular baking systems for format adjustment for many years now. The drylin lead screw unit used is maintenance-free, cost-effective and versatile. Plain bearings made of high-performance plastics for the food and packaging environment are FDA-compliant depending on the choice of material. 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 does not pose any problems for them.
The special machine manufacturer obtained the complete lead screw unit harnessed as a system. Doing this has been agreeable not only for the technical parameters that are exclusively designed for the local requirements, but also for the business operation.
For example, in a wafer baking system being delivered to Korea, two parallel systems had to be simultaneously adjustable 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.