Thus, this flow is organized by smoothed period batch control, adjusting the starting times of production of each batch smoothly along the time scale through the working week.. Informati
Trang 1• Plating cell: The connectors are plated in a centralized process which represents a bottleneck in
the production flow Thus, this flow is organized by smoothed period batch control, adjusting the
starting times of production of each batch smoothly along the time scale through the working week
Information and Control
Based on this concept of factory planning, information flow and control have to change in this factory
in comparison to traditional production planning practices The planning scenario is as follows: The
material manager receives all orders from customers He identifies the product families and sorts them
by groups The resulting job list is transferred to the cells via the computer network Subsequently, an
operations list is scheduled with assistance by the computer system and/or manually Basic rules for an
optimized sequence of orders are available in the cell software
Once the load is in the range of 100%, the cell members microschedule the operations list They check
and adjust all the used data, paying special attention to the setup times These times are important for
small- to medium-sized batch production because they reduce the utilization times of the machinery
Once the operator thinks that he has found the best sequence, he simulates it on the computer
The material manager at the factory level does not control the decisions in the cell His task is the
balancing of orders between the available cells; if a cell rejects a planned job, he would have to find a
different cell to do the job
Shop Floor Tasks
According to this cell-based production concept, there are many new tasks which have to be performed
by the cell team on the shop floor The team working in the cell may have to perform the following tasks
on the shop floor:
• Planning the work for the week
• Preparing the work and setting the machines
• Producing the different parts
• Quality and performance control
• Management of tools, raw materials, etc
• Maintenance and minor repairs of machine tools
Thus, the strategy aims at giving shop floor personnel an increasing degree of responsibility — not
only for technical aspects of production, but also for organizational and planning tasks This strategy
is at present being implemented on a large scale all over Europe, characterized by its enterprisewide
introduction
Workflows for Shop Floor PPC
The Concept of Workflows
This example has shown that a procedural and top-down control perspective does not fit in with the
concept of today’s flexible cell-based manufacturing organizations Therefore, a new concept is needed
for looking at production planning and control (PPC) across the plant: e.g., linking the different
pro-duction cells as customer–supplier chains This concept is called workflow A workflow, similar to
activities in coordination and control, is a unit of work that happens repeatedly in an organization of
work However, there is a difference from traditional control concepts; in workflow concepts, processes
get completed that are related to, or result in, customer satisfaction In fact, every workflow has a customer
who may be an external customer of the company or another workgroup or individual within the
organization (an internal customer) The resulting enterprise model sees the entire organization as a
chain of customers and suppliers, starting from the external customer (market), through the front-office
units, to the internal production cells and to other back offices and service departments [4]
© 2001 by CRC Press LLC