How to make a continuous drive for reducing setup times and batch sizes more effective in complex systems?

Lean manufacturing considers setup time and batch size as two major contributors of waste in production and therefore, it emphasizes on reduction of both  for production operations as much as possible in order to improve flow and throughput and reduce lead times and inventory. In fact, a relentless drive for reduction in setup times and batch sizes "wherever possible" seems to be an important objective in lean manufacturing. But, how effective and acceptable is this drive as such in a complex system when we do not know in advance the marginal benefit from any reduction in setup time or batch size?

In a general production system, the overall marginal benefit of certain reduction in setup time for any specific operation may depend on many factors including the existing level of the setup time and the magnitude of reduction. The same is true with respect to batch size. The marginal benefit may sometimes be insignificant causing a disappointment to the people involved. There will be a risk of such disappointment unless we know in advance the marginal benefits from reduction in setup times and batch sizes. But, lean manufacturing apparently offers no powerful mechanism to accurately assess in advance such marginal benefits for a general production system.

With reliable, advance assessment of marginal benefits from reduction in setup times and batch sizes, production people can proceed with the above said drive more confidently. It is possible to make such assessment in many systems using simple calculations. In some complex systems, material for any product may flow piece by piece at some work centers and in terms of batches at some other work centers with the possibility of batch size varying with work center. In such systems, it is not always easy to quantify the impact of any reduction in setup time or batch size for an operation of a product on the overall production performance. It is also not easy to determine an optimal production run for given demand rates of products unless there is a common pace maker in the system for all products. Accurate and advance assessment of the above said marginal benefits in such systems require more rigorous calculations which are currently not available in lean manufacturing methodology. Very often, senior management gets the blame for failure of lean manufacturing in the company. They are accused of not giving full support to lean manufacturing efforts. In my opinion, senior managers will have more confidence in efforts for reducing setup times and batch sizes based on reliable and advance assessment of marginal benefits.

An effective approach to making those calculations is discrete event simulation of production system. Popular simulation software can help with this assessment but they need development of a right simulation model (within the software) for a complex production system. Skills for developing simulation models of production and for using simulation software are usually not available in many industries. However, factory people can easily run simple and straightforward software tools like Velflow

for the same purpose without any skills for model development and without any experience with simulation software.

For a continuous drive for reducing setup times and batch sizes,  the use of simple calculations for assessing the marginal benefits in advance is more effective than the absence of any calculations  Although it is rational to look for effective use of simple calculations in support of the drive, simple but rigorous software tools like Velflow can greatly support the drive in some complex production systems. Velflow is more appropriate for production systems in which (1) each product passes through an operations sequence that may vary with product, (2) there may be several alternative resources (with the same or different calendars) for an operation, (3) material flow at a work center may be piece-by-piece or batch wise and (4) order quantity may be small or large.

It is rational to adopt simple and effective solutions for any problem.  However,  it is also rational to take a close look at any advanced solution that is fairly simple to use and promising to be more effective and rewarding.