In this paper “The real strategies in shoe manufacturing” we take a look at the reality of a
Mexican industry dedicated to shoe manufacturing, with the intention of showing the lack of
professional techniques that take place not only in the company studied, which affect the
efficiency of the business.
THE REAL STRATEGIES IN SHOE MANUFACTURING
Nowadays there are many different approaches and methodologies that can be used for industrial
systems’ optimization and analysis. Among these techniques are the ones for production and
inventory management and industrial plant distribution, which are mainly used for reducing the
company’s cost. According to APICS Dictionary, ...view middle of the document...
This is why they base their production rate and inventory levels on
intuition, with the objective of avoiding stock-outs during the demand period. This leads them to
have problems; not only with their efficiency but also with their inventories (large quantities of
shoes stuck or lack of them for an uncertain period of time). A complex analysis was made in
order to understand how the company’s procedures could be improved.
How they work
Zebra Shoes produces approximately 6,500 pairs of shoes per week. They use the
following raw materials for the manufacturing: polyvinyl chloride (PVC), fabric, shoelaces and
iron holes. The company uses a chase strategy for purchasing raw materials; this means that
purchasing varies to meet demand. Usually they get 1.5 ton of PVC, 400 m2 of fabric, 91 boxes
of shoelaces (each box has 72 pairs of shoelaces) and 130 000 pieces of iron holes.
The way that Zebra Shoes keeps its warehouse is not well planned. They don’t have a specific
order for raw materials nor finished products. This isn’t only a space optimization problem but
also an ergonomic and time issue. Workers have an active movement inside the factory and it’s
difficult because of the lack of free space to walk. In addition they don’t always reach the
shelves properly and have to carry ladders from one place to another; and even worst, sometimes
they use the pile of bags or boxes as stairs. These obstacles create a waste of time which affects
the factory’s efficiency.
Actual warehouse distribution
SUGGESTIONS FOR IMPROVEMENT
There are some mathematical methods used to optimize the size of inventory and orders. One of
them is EOQ model that assumes instantaneous production (it may be a purchase), a
deterministic and constant demand. This model will be used in this study to determine the
optimal quantity because it allows analyzing singly every raw material. Its graphic behavior
shows that the inventory will be decreasing on time and when the product is over you must buy
more material. In the case of Zebra Shoes this EOQ model applies perfectly because providers
deliver products at the moment of purchase.
Inventory versus time in the EOQ model
On the other hand, Zebra Shoes is a producer and it must be able to reach its clients full
satisfaction; this means having on time, on place and quantity required. Nowadays, the company
has some difficulties in completing an order because sometimes they only use one injection
machine and this affects its relationship with clients. Therefore the importance of having a
production policy, during this analysis the authors have considered a production rate of only one
machine and a EPQ model is going to be used. This model fits with the behavior of the
company because the demand remains constant, but in this case we are considering a production
rate (units produced per year).
Optimal quantities of shoes to produce
Considering a constant and uniform...