Modular Smart Design of Tuber Washing Lines

Abstract

Tummers Food Processing Solutions is an internationally operating company based in the Netherlands, that sells factory lines for processing tuberous products like potatoes. Before being processed into various products, the incoming tuber batches are always washed and cleaned from waste particles like clods, stones and haulm. For this purpose washing lines consisting out of different machines are used. Every processing application, customer and kind of input product results in different requirements regarding the machines, options and their configuration. Currently for every customer a tailor made machine line is designed, consisting out of customised machines based on the expertise of the corresponding sales agent and the engineer that designs the machines. This results in individually designed machines, friction between different departments and mistakes in drawings, parts lists, manufacturing, documentation and others. Once installed on site, the machine line is controlled by machine operators that keep the factory operational but are not optimising the performance and efficiency of the machine line nor conduct preventive maintenance. To tackle both the issues on the company and the customer side, the strategy for designing these tuber washing lines has to be turned into adaptive machine line design. Adaptive machine line design is a combination of modular design and smart factory engineering. Machine lines are customer specifically configured out of standardised modules and controlled by smart systems to optimize performance and efficiency and predict maintenance.

Because potatoes are by far the most commonly processed product, followed up by carrots, this research focusses on potato washing lines with some specific side notes for processing carrots. Based on sales records and customer preferences, a set of standardised machine models and options is defined as the machine portfolio. This portfolio consists out of ten different machines, each available in different sizes, with waste and product streams to different directions and other standardised options. A jigsaw puzzle model can be made where this machine portfolio is build up as a set of puzzle pieces. For every different application a set of these puzzle pieces can be chosen from the portfolio and connected in different configurations. To determine which machines with which options to choose from the portfolio in which order, a model can be used. This model is based on a set of input- output relations and first set up as a decision scheme after which it is modeled in LabView as a basic machine line configurator. The model is then used to configure machine lines for five different examples. Each example is an existing order with differences in customer specific wishes, input and output characteristics and boundary conditions regarding factory layout and peripheral equipment. With help of these five examples the model is iteratively checked and improved after which the amount of customer specific engineering is determined that still needs to be performed after standardising of the machines.

A first layer of a Digital Twin for smart control of the washing line is designed. This control strategy is based on the Key Performance Indicators of the washing line and their relations between them. Based on open or closed loop control, a set of control schemes is created for each machine that requires smart control.

A thorough analysis of the costs and benefits of implementing a modular design strategy for the tuber washing lines shows that huge amounts of man hours can be saved after implementation. Next to these savings in labour, less mistakes will be made in the design and manufacturing of the machines which improves the professional image of the company and lowers friction between different departments and stress on the workfloor. Due to significant savings in replacing wear sensitive parts, reduced factory downtime, loss of product in waste streams and reduced operator wadges, installing a system for smart control can easily be earned back in the first year of operations. All and all changing the design strategy for tuber washing lines to adaptive machine line design is very promising for both the machine line manufacturer as for the customer.