Computerized tool management.
Computerized tool managementTools, gages, and fixtures can add up to a lot of money. Failure to keep tight control over them can cost even more, especially if you own 100,000 tools.
That's about how many tools Textron/Lycoming, Stratford, CT, has when it and the US Army began a $60 million, eight-year program to modernize the 60-year-old plant.
Textron manufacturers sophisticated gas turbine engines for helicopters, commercial aircraft, air-cushioned marine craft, and the Army's M1 Abrams main battle tank. The Army owns the plant, Lycoming operates it.
To handle the "reinvention" of the factory, in 1982 Lycoming set up IREP, an internal Industrial Resources Enhancement Programs organization. The first project IREP tackled was procurement, receiving, and inspection under a program called OMEGA. While this program was being implemented, it began solving tooling problems under TIMS (Tool Inventory Management System).
The tooling problems IREP had to deal with were formidable. In the area of fixtures, the placement of purchase requisitions, tool issues, returns, reworks, and obsoleting was handled manually. That presented a considerable obstacle to the orderly disposition and tracking of equipment.
The area of gages, issues, returns, calibration recalls, reworks, and the retirement of obsolete tools was handled by an outdated DPI data collection system. Reports were generated nightly to reflect the previous day's activity, even though much of that information was needed immediately. As for tracking the location of gages, bin locations were not even entered into the system.
With the aid of several outside computer consultants, IREP developed an on-line system to control these and other activities such as: * Entry of new tools into the system. * Generation of "pick and put" lists. * Issue of move orders to shop, rework, or vendor (by employee badge number, department number, or vendor code). * Tool return (including calibration needs). * Development of user-friendly tool status CRT menus. * Tool usage (a tool/operation cross reference). * Tools needed to make a particular part. * Selection of alternative tooling. * Identification of tools due for recalibration. * Calibration activity. * Collection of tool-maintenance data. * Bin location of every tool (including initial assignment and subsequent changes). * Tool tracking (by employee badge number and department number).
From the beginning, the TIMS system was designed to handle a projected load of 2500 tool transactions per day. The first thing the TIMS managers needed to know was how many tools - both durable (gages and fixtures) and perishable (cutting tools and grinding materials) - they had on hand and what kind they were. The next step was to: 1. Cordon off each manufacturing area in turn (starting with the gear department). 2. Pick up each cutting tool, gage, and fixture; record the tool's serial number; and include a brief description of its function. 3. Check the results against the McCaskey card system that had been used for many years.
The final count showed approximately 80,000 durable tools (65,000 gages and 15,000 fixtures) and 17,000 cutting tools - a total inventory that was about 40,000 less than what was being carried in the inflated McCaskey card system. The end result was the establishment of a database, which they entered into the IBM 3090 mainframe.
Tool location
The computer had stored the entire tool inventory by part number and function, but it had no idea of how to locate the tools. The TIMS managers solved this phase of the problem by moving every tool in the factory into a new system of cribs designed for maximum use and efficiency. These included master cribs for new tools, a gage crib, seven cribs for general production, three satellite cutting-tool cribs near key manufacturing centers, and overflow cribs.
The old system of cluttered racks and bins was replaced by a new, highly organized system of neat cabinets and drawers, with the location of each tool clearly defined and stored in the computer's memory. For example, the listing for a certain plug gage might contain the code F-10-04-032. This tells the crib attendant that the gage can be found in aisle F, cabinet 10, drawer 4, slot 32. In the gage crib alone there are 54,000 such locations, most of them located in four 35-ft x 100-ft storage towers.
This system speeds the production process. The current time from tool request to issue is about 5 min. Under the new system, a machine operator comes to the gage crib with an operation sheet that the crib attendant uses to key in the part number and job lot of the part being run. When the attendant keys in a tool number request, the computer verifies that the number is correct. If it isn't, "Not Found" appears on the screen and a red light goes on. If the tool number is correct, the computer scans the serial numbers of all the gages with that tool number and picks the one with the longest available cycle time.
Once the tools have been located and selected, the computer prints a pick ticket from which the tools are manually collected. The tools are listed in order according to their location in the crib, allowing the kit to be assembled in the shortest possible time.
The efficiency of the TIMS program is event. For example, the computer not only knows all the tools and their locations, it also knows, by checking the part number, what tools and how many of them should be issued for each individual machining operation. For example, if an operator requests six gages when three will do the job, the computer will authorize the issue of only three.
When the attendant returns to the window with the completed kit, the machine operator runs his badge through a terminal, inputting his employee ID and department number into the system and recording possession of the tools. For gages, this operation also starts the clock running as a means of calculating their useful life.
Gage calibration
The system automatically selects gages with the greatest amount of cycle time left. At Lycoming, 180 days between calibrations is considered full cycle. Metrology has established that if a gage is within six days of the 180-day limit and in need of calibration, the system will not permit the issue of the tool. In the same manner, in the case of standard gages (micrometers, dial indicators, and verniers), the system will not allow more than one type of tool to be issued to any one employee. The exception to this rule is that employees may be issued more than one dial indicator. However, no one may be issued more than seven standard gages at a time.
As a further protection against out-of-cycle gages, if a department or individual station continues to hold tools that are past due for calibration, the system will refuse to issue new ones. Any requests for additional tooling is met with a "Cannot issue" on the CRT screen, a situation which will continue until the missing tools are returned for recycling.
The effect of this system can be seen in the decrease in the number of out-of-cycle gages in use on the shop floor. Prior to TIMS, such conditions existed 20 to 30% of the time. In contrast, in one recent three-month period, out-of-cycle conditions were found in only 0.57, 0.48, and 0.66% of the gages in use.
Bin location
One menu on the crib attendant's CRT is the free-form crib bin maintenance screen. The supervisor uses this screen to create exact bin locations for all durable tooling.
After bin locations have been established, the tools are given a home through a tool-bin-assignment screen on the CRT. If locations are created, but no tools are assigned to them, the system will display the word "vacant," along with the size of the vacancy.
Tool tracking
Durable tools can be tracked through all stages of their lives, with the system showing tools issued to employees, departments, individual stations, vendors, and repair or calibration areas. The system is also linked to OMEGA, where purchase requisition and purchase order information on tooling can be obtained without leaving TIMS and logging into OMEGA. A batch report entitled "Received in OMEGA, not in TIMS" is printed daily and distributed to the tool cribs that might be looking for missing material.
Many tools in the system have duplicates. Each tool, however, has its own serial number which makes it unique to the TIMS database. The tool number can be keyed in the tool inquiry function of the system, and all serial numbers associated with the tool can be viewed simultaneously. If a tool has, for example, ten duplicates, but only #6 is in question, the operator keys in the tool number and "6" to receive information on the status of that individual item.
The ability to track tools once issued to an employee, department, or vendor is a widely used feature of the system. By entering an employee's clock number, all the tool numbers charged that person can be displayed. The same is true of departments. When the department number is keyed in, an alphabetical listing in produced of all tools and serials charged to that department. The same is true of vendors and the repair, inspection, and calibration departments.
Another widely used, on-line feature is a display of all information on the tools in the database. The TIMS system allows operators to know where a tool is at any given moment, whether it's in a crib, in transit, in manufacturing, and even what it's being used for.
Control of perishable tools
The TIMS system is designed to allocate perishable tools for distribution to all satellite cribs based on inventory levels on hand and each crib's "min/max" level. It is also programmed to search the regrind crib for all tools to be distributed to the satellites. This ensures maximum use of all perishable tools and reduces the need to draw new, expensive tools from the master cribs.
Whenever a crib falls below its minimum for any tool, an order is automatically generated to allocate tools from the storage cribs. Should the storage cribs be temporarily out of stock, the order will remain open until new stock is received or the order is cancelled. When new tooling is received by the master crib, all outstanding orders are automatically filled and transferred to the requesting cribs.
Inventory levels are adjusted by TIMS if receipt quantities do not match the OMEGA-generated received quantity. A discrepancy report is automatically generated each time an inventory imbalance occurs. The report "Received in OMEGA, not in TIMS" notifies tooling supervision whenever stock is received by the dock. Expeditors are notified and the tools are delivered to their proper areas as quickly as possible.
All returns of perishable tooling flow through the regrind crib where attendants acknowledge the return of used or excess tools from the production floor. The system automatically prints out a transfer ticket to the cuttergrind inspection department where the tools will be inspected for conformity, and either reground and returned to the crib for use, or scrapped and deleted from inventory balances.
The transfer ticket produced by the regrind crib when tools are returned is the "put list" for cuttergrind. It lists the sending crib number, tool number, tool description, transfer quantity, and the transfer-to-crib number. Tools are stored in the cuttergrind storage crib until they are either resharpened or scrapped by supervision.
Storing perishables
Perishable tools are assigned to multiple cribs or satellite cribs according to a set of predetermined rules. The tool number must be logged in a master crib before it is allowed to be entered in any other crib. In addition, it must have a primary location within a crib before it can be assigned to an overflow crib.
Here again, locations which have been established and do not have tools assigned show up as vacant. This allows tooling supervision to assign tools to the best possible locations by scanning on-line for available vacancies.
Once min/max levels for all perishable tools have been established, the system automates future calculations of the min/max by accumulating at least six-months history of tool usage and reevaluating the history of min/max levels monthly. The new min/max figures are compared to those existing. If the new figures vary from the originals by more than 15%, the change is recorded and printed out for action. Tool Acquisition and Records uses a special report, "Perishable Tools At or Below Min," on a daily basis to maintain proper inventory levels.
Tooling requirements are forecast by the company's Master Planning and Control System, whereby part numbers and manufacturing operations are broken down by tooling requirements. These tools are ordered in advance and leadtimes are provided for all tools being delivered to the company, which avoids having material on the production floor without the cutting tools.
Inventory levels
All inventory levels are controlled by bin location. The system is set up for two bin locations per tool number, one being the primary location, the other being the overflow location. Balances are determined by the sum of both.
Inactive or obsolete tools are tracked according to last usage dates. A report called "Inactive Perishable Tools" lists tool number, description, last issue date, and current quantity on-hand for all tools not used for 1 to 2 years, 3 to 5 years, and over 5 years.
Abnormal usage of perishable tools is detected by variation in tool usage versus the scheduled allotment of tools. Cost center managers also receive reports of such variances. These reports list the badge number of the employee drawing the tools, along with the part and the operation worked on.
A well-planned inventory control system is essential for any company dealing with a large number of tools. Lycoming qualifies as such a company. For example, TIMS will print out the total number of almost anything it deals with. When asked recently how many active production gages it had stored in its memory, it printed out a number . . . 76,350.
PHOTO : In Lycoming gage crib, narrow aisle reach trucks fill, pick, and put orders in four 35-ft x 100-ft storage towers.
PHOTO : Training sessions are held regularly in TIMS operation, showing its interfaces with Lycoming's other data systems.
PHOTO : TIMS allows system managers to track all tools, gages, and fixtures anywhere in the 1.5 million sq ft plant.
PHOTO : When filling cutting-tool requests, TIMS computer first scans for tools in the regrind crib, reducing the need to draw new tools from master cribs.
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| Author: | Picozzi, Dexter A. |
|---|---|
| Publication: | Tooling & Production |
| Date: | Sep 1, 1990 |
| Words: | 2405 |
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