Optimize your production schedules by minimizing machine changeovers


Reducing machine setup time is crucial for supply chain planners or schedulers in some industries. In fact, utilizing the same resource (machine) to manufacture different products requires a changeover. It means interrupting work-in-progress, allocate time and resources to proceed to the change while keeping an attentive eye on the impact that this will occasion on subsequent operations.

Improving resources utilization brings in many benefits to your process and business:

  • Faster changeovers and production pace
  • Shorter lead times
  • Smoother manufacturing flows
  • Higher margins
  • Faster deliveries
  • Better competitiveness and customer satisfaction.

So let us not wait and dive right into the subject.

Sequence-dependent setup times

When you’re facing sequence-dependent setup times, you’re adding a layer of complexity on top of the original challenge. In addition to dealing with variable lead time and setup time for each job — which already requires complex planning — you deal with variable setup time calculated from which job was performed just before. If two jobs in queue require minimal changes, then the setup time is lesser. If those two jobs differ greatly, the setup time rises accordingly.

For example, your factory owes 3 tanks containing wood paint. Switching from red to black takes 3 days. Switching back from black to red takes only one day because cleaning the black painting away is much easier than removing the red particles. Which means that you have to regroup as many red items as possible before the switch while taking into account different changeover durations.

This is a challenge in many industries: paper, container/bottle, plastic/injection molding, chemicals, pharmaceuticals, food processing, metal processing, printing, etc.

To tackle these complex planning issues, frePPLe uses a feature called setup matrix. This allows you to define the changeover time from one machine configuration to another machine configuration.

For instance, a pharma company would need to adjust changeovers depending on the types of pills, flavors, and packaging sizes.

The art and science of planning with setup matrices

As a planner, you’ll also want to find the right balance between reducing changeovers while keeping your inventory levels under control. Overstocking in order to reduce machine setup time can cause an increase in inventory cost, which you want to avoid. You can adjust that in frePPLe by defining precise machine setup time windows adapted to your particular business needs.

Here is what your plan looks like before applying the setup matrix rules. This plan has both a high changeover cost but a minimal inventory cost.

And this is how it looks like after optimization. Demand is now produced in very large batches. This results in a minimal changeover cost but large inventory costs.
Finally, by reducing the batch size window, we obtain a plan that reduces the changeover cost while avoiding excessive inventories. Finding the correct balance is the art and science of planning with setup matrices.

Some frePPLe customers use this feature to optimize their production planning daily. Camunacavi operators have considerably improved machine setup times when manufacturing industrial cables presenting diverse properties (read the full case study) and Elcam Medical has applied the same principle to its injection molding process (read the full case study).


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