Integrated tool management: bridging the gap between process engineering and shop floor activities can bring about a "deproliferation" of cutting tools

Modern Machine Shop, Nov, 2002 by Goetz Marczinski

In general, cutting tools account for about 3 to 5 percent of total manufacturing cost. By itself, this level of expense may not be enough to attract the attention of top management at major manufacturing companies. However, activity-based costing has tended to reveal that the cost involved in the sourcing and replenishment process can exceed the purchase value of tools -- an insight that has led many manufacturers to switch to full-service supply. Also, there is the painful irony that even though $50,000 worth of cutting tools may be tied up per manufacturing line or flexible cell, stock-outs are still a recurring problem. Many facilities have looked to shopfloor tool management to help address this problem.

But there is only so much that can be done at the shopfloor level. To look to the shop floor for the solution to these problems is to take for granted the tool as it was released from engineering, and treat tool management as merely a logistics and delivery challenge. The flaw in this thinking is revealed when one considers the sources of the inefficiencies that the shop floor confronts. These sources include...

* The large number of distinct components the shop floor must manage.

* The variety of obviously redundant tooling from multiple sources.

* The differing tool layouts.

* The error-prone nature of entering tool data into shopfloor systems.

What this list suggests is that many of the decisions affecting the difficulty of tool management have already been made before any physical tool comes into play. In fact, close to 70 percent of the difficulty in shopfloor tool management is created in engineering. Here the tool layout is fixed, and so are the supplier and the operation. Thus 70 percent of the life cycle cost of the tooling is fixed as well.

A concept called integrated tool management allows for the fact that a cutting tool, over the course of its lifetime, changes from an engineering item to a logistics item. During engineering, tooling is an area for process innovation. During the manufacturing cycle, tooling becomes a productivity driver for the machine tools.

Both of these separate realms can optimize their own flow of information. However, these areas typically don't view one another as customers. Engineering has no means to provide value-added service to manufacturing, and manufacturing has no means to channel its experience and requirements back to engineering. Providing these means--and therefore the integration--is the mission of integrated tool management.

Integration Issues

Usually the tool layout is the handover document transferred from engineering to the shop floor. A tool layout captures the tool information in the language of engineering, consisting of drawings, bills of material and parameter lists. A single tool layout refers to a single tool assembly for a certain operation performed with a specific spindle on a specific machine tool. The layout documents the components of the tool assembly, including spare parts. On average, 30 to 50 tool assemblies are assigned to a machine tool in engine manufacture, with each assembly including some 230 to 350 components. Tooling engineers undertake great effort to document all of these components, and yet the effort is often of little value for downstream activities.

From the tool layout, machine operators and purchasing personnel (or a full service supplier) pick relevant information for their own downstream systems. Most of the information needed for these systems is not available in digital form, so information has to be obtained and keyed in at various stages. Here are some examples:

* Procurement generates tool packages--that is, bills of material used to generate purchase orders.

* Shopfloor tool management assigns storage IDs to populate the inventory management system. Also, tool management adds the distinctions of perishable versus durable tool components and returnable versus non-returnable tooling.

* The tool crib physically assembles the tool according to the tool layout and performs presetting. Correction values are sent to the NC control.

* The tool crib inspects returned tool assemblies and generates failure reports.

* On-site cost reduction teams improve cycle times--changing speed and feed rate or calling for alternate tooling--and thereby change the tool specification, creating the need for a new release from engineering.

Now consider what effort is involved in these activities. Lost time can be attributed to these factors:

* Tool search and legacy case studies. Including communication with tool suppliers and machine tool companies, this work alone can consume up to 50 percent of the tooling group's time.

* Generating tooling packages. This takes approximately 3 days per package, with each package addressing one particular spindle.

* Populating downstream systems. At a rate of about 2 minutes per item, this translates to about 500 hours for the average of 15,000 tool items per transmission plant. For an engine plant, the figure is approximately 200 hours.