Salad days for WITNESS at Bakkavor

Advanced automated predictive simulation tools from Lanner have been used by Bakkavor’s Delicatessen business to ensure that an increase in the range and quantity of products does not compromise the ability to deliver finished product on time. WITNESS Simulation software was used to create a predictive digital twin that could justify the correct capital expenditure, and avoid costly investment in unnecessary equipment.

Background

The Delicatessen business produces premium salads and snacks for supermarket chains in the UK. The business has grown rapidly since 1996, with huge flexibility in production. This flexibility can be a double edged sword as it means a large variety of complex products are made, but packing runs may be relatively short.

The business process encompasses cooking for pasta and potatoes, roasting vegetables, slicing and dicing salad vegetables, blending mayonnaise and spices into dressings then mixing all these together to produce batches of the finished product. Batches are packed into varying size containers depending on whether they are to be used on self serve deli counters or sold as individual pre-packed meals.

Throughout the process there are strict technical constraints controlling life of the ingredients and batch temperature in chill stores. Segregation is also essential to prevent cross contamination of nut and non-nut, vegetarian and non-vegetarian, protein and non-protein, organic and non-organic, cooked and raw produce. There is a delicate balance to strike between preparing large batch sizes to minimise changeovers and a large number of small batches to ensure that mixes are not short of ingredients.

The Bakkavor Delicatessen management team recognised that whilst the range and complexity of products continues to grow, the short lead time and commitment to supply customers on time would not change. Also, changes to one area of the process may have unknown knock–on effects elsewhere – a need had already been identified to introduce automated filling to some of the packing lines. It was difficult to predict whether the increased capacity in filling due to automation could be utilised because this would inherently increase the demand on the preparation areas.

It was also apparent that the size of the chill stores would potentially constrain the throughput. Estimates had been made as to the required size of the chills, but there was some nervousness about committing to make the changes requiring moving walls, air conditioning ducts and drainage sites without being certain that the sizes were right.

In order to ensure that all relevant factors were taken into account when deciding the strategy to handle the growing complexity, a digital twin, created using Lanner's WITNESS simulation software, was used for scenario planning and to facilitate the investigation.

Lanner’s professional services team were commissioned to produce a simulation model that would allow Bakkavor staff (who are not simulation experts) to: establish the plant capacity under different schedules; investigate work centre utilisation; identify bottlenecks and propose alternative strategies; predict the storage requirements; evaluate changes in batch sizes and scheduling rules; provide an on-going means of evaluating schedules. Input from the required staff within the business was invaluable in producing an accurate representation of the whole process. Timings, priorities and routes all came from the people dealing with products on a daily basis.

The required packing schedule and data for a large number of SKUs and over 200 raw materials and intermediate products was fully contained in a Microsoft Excel spreadsheet so that all process and Bill of Materials data could be entered by a user not familiar with WITNESS modelling.

The model was used to quantify the benefits of a number of proposed investments and run with the demand at its anticipated peak.

Results

The findings from the project confirmed that the proposed changes to the chill stores would have the capacity to cope with peak demand. The justification provided by the model resulted in the sign-off of the works by the General Manager of the Delicatessen factory.

The added benefit of the model was to allow creative, innovative thinking to be tested out without disturbing the day-to-day running of the business.

In addition, the model provides an ongoing means of evaluating schedules using alternative process arrangements – all under the control of Bakkavor staff who are best placed to identify improvement opportunities.