Profit Pointer for Tooling Management & Maintenance Programs
By Robert A. Sladky, Vice President, Tube Mill Engineering, Roll-Kraft Nebraska U.S.A.
A properly employed Tooling Management and maintenance Program will go a long way toward improving your overall performance. The first step is to create individual files for each set of tooling in your shop. These files contain all the necessary information required to maintain your tooling in top condition.
Many shops have a difficult time starting and maintaining a tooling management program; however, it is really not that complicated as you will see as you read through the following steps. Firms that have established such a program have accurate control over their tooling costs and needs. They are able to predict tooling wear and schedule rework and production accordingly. By continually monitoring your tooling with such a program, your tube and pipe production will operate more efficiently at a lower net cost.
II. Starting Your File
A separate file should be set up for every set of tooling in your shop. This is true for partial sets, as well as complete sets. The following items should be
- Prints of the Tooling Setup Chart
- Rework Records
- Rim Clearance Sheets Tooling Inspection Reports
- Rework Cost Record Sheet
- Let’s examine each of these six items to understand their importance in your tooling maintenance program.
III. Prints of the Tooling
Figure 1 is a typical tube roll print. As in any manufacturing operation, the print lists much of the basic information about the process in addition to the dimensional data of the tooling itself. For a particular tubing size, all of the prints, from the entry table to the exit, should be included in the file. The prints will list information that is helpful during setup along with the following: gauge range, rim clearances, tube size, roll width, roll O.D., keyway size, bore size, spacer length and metal line of weld and side rolls. Bearing make and model numbers are also listed if bearings are required on the mill.
IV. Tooling Set Up Chart
Your Setup Chart includes all the specifications required to properly set up your tube mill. Roll-Kraft includes a laminated Setup Chart (see figure 2) with each set of tooling that it supplies. Adjusting your mill according to the data listed on the chart (rim clearance, tube size, spacer length, etc.) will insure that every pass, driven and idle, will properly form the strip as it advances through the mill. Settings, identifications and specifications for auxiliary equipment should also be included on the Setup Chart.
V. Rework Record
This record tells the history of your tooling. The most important data is the tooling size (1) new, (2) before rework and (3) after rework. Figure 3 illustrates a typical rework record as provided by Roll-Kraft. Revisions made to the
tooling will also be recorded on this sheet. This would include such items as replacement of severely damaged rolls, rechroming and side grinding. These modifications will affect the readjustment of the mill when the tooling is reinstalled. The information taken from this record is used to: readjust the mill to maintain the bottom or metal line, make shims for universal stands, lower side roll stands, calculate rpm for mills with multiple drives and make new spacers for rolls that have been side ground.
VI. Rim Clearance Sheets
Record rim clearance before the tube is run out of the mill at the end of every run. By plotting this data on the Rim Clearance Sheet (see Figure 4), you will be able to determine if the set up was maintained through the entire run. As the
tooling wears, you should see an even decrease in rim clearances. If this decrease is not even throughout the mill, one or more passes may be adjusted incorrectly. Studying the data on the rim clearance sheet should enable you to pinpoint the passes where the problems exist. Left uncorrected, tube quality suffers and roll life between reworks is diminished. An additional benefit of this chart is using recorded data to assist in mill set up the next time that particular size of tubing is being run. Simply put, you start up where you left off. If set up was maintained during the last run, the clearances of each pass as recorded can be used for set up thereby saving set up time and reducing expensive scrap.
VII. Tooling Inspection Reports
Another important element of a well managed Tooling Maintenance Program is consistent data from your own tooling inspection. Tooling should be inspected between each run with measurements, notes, and comments recorded on an inspection report similar to that shown in Figure 5. While you can be a thorough as you wish with your inspection, one parameter that must be measured and
recorded is the throat diameter of each roll. As with the rim clearance data, throat diameter measurements can be analyzed to determine whether a particular pass (or passes) is working too much. Throat diameter wear should be progressive, in the same manner as rim clearances. Excessive reduction in throat diameter indicates an overloaded pass. A similar reduction in rim clearance will be seen for that specific pass on the Rim Clearance Sheet as well. Identifying abnormal wear through the use of your Tooling Inspection Reports enables you to confirm and correct problem areas before the next run.
VIII. Rework Cost Record
The final form recommended by ROLL-KRAFT for your Tooling Maintenance Program is the Rework Cost Record (see Figure 6). This form lists which tooling has been reworked, (1) when the rework was done, (2) the footage obtained, and (3) the cost of the rework. Analyzing this data will show you the actual cost of reworking your tooling and allow you to predict product footage and when the tooling will require rework. The Rework Cost Record has many obvious benefits. It will clearly show the additional cost of unexpected rework of overloaded passes. To bring overloaded tooling back to spec requires special rework and increases total cost. Using tooling beyond the recommended rework point not only results in excessive tooling wear and the subsequent increase in special rework costs, it decreases the tooling life. Overloaded tooling adversely affects the quality of the tube and increases the amount of scrap. The data can be further analyzed to determine the actual manufacturing costs per foot of tube. This detailed information is invaluable when establishing budgets and projecting production levels.
A properly organized maintenance file is of the utmost importance in managing your tooling efficiently. When all data is collected and analyzed, it becomes possible to accurately predict rework schedules. This ensures smoother production, faster set up, longer tooling life, a higher quality product and greater cost efficiency. In today’s fast paced global market, keeping pace is an achievement in itself. Implementing a tooling management and maintenance program allows you to step out ahead of your competition and set the pace!