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Presetting for tool-management systems.

Presetting for tool-management systems

A basic tool-management system should supply proper tools and tool data to appropriate metalworking machines in a timely manner. If we accept this definition, then a tool-preset machine will be the basis of a good system.

Such a machine, at the very least, must provide properly set tooling and accurate tool data to the machines within the tool-management system. In this way, even the simplest presetter enables users to reduce downtime while improving quality.

Preparation

To assist in selection and assembly of the proper size and type of tooling, more advanced preset machines employ CRTs to display descriptions of tool components, crib locations, tool numbers, and programmed tool lengths and diameters. The information can be provided on site at the preset area through hand-carried notes, but it's safer to use floppy disks or a hardwire link to the manufacturing system's host computer.

Once the components are assembled into a complete tool, the preset operator can begin inspection and measuring on the preset machine. The presetter should simulate the tool-holding arrangement of the machine-tool itself, so tools can be examined with consistency.

Transducers and projectors

Vertical and horizontal tool-preset machines should be equipped with measuring systems featuring linear transducers and either a digital readout (DRO) or a tool-presetting software program. The program can store a series of reference-plane coordinates and tool dimensions, and can direct the machine to automatically position the preset axes and turret magazine under a CNC mode. In addition, the measurement system should gage the distance from the spindle or adapter reference points to the tool point in increments of 0.0001".

An optical profile projector on the tool-preset machine magnifies the tool point to allow measurement of tool length and diameter, and allows the operator to inspect the tool point for runout, alignment of cutting edges, and proper nose radii. Additionally, the profile projector guarantees that tool diameters are measured at their maximum diameter and permits the operator to view changes in tool length and diameter during adjustment. The projector can be equipped with a charged-coupled device or photoelectric diodes that provide electronic noncontact measurement of tool length and diameter.

After presetting the tool, the operator can put a label on it for identification. These labels contain tool number, tool dimensions, and other characteristics.

Next, preset tools should be grouped according to an intended operation for a targeted machine tool and transported directly to that machine. Then, the system should transmit data on tool length, diameter, and offsets to the machine by hardcopy listing, tool labels (man readable or bar codes), punch tape, or direct link through an external computer.

Once the tooling has served its intended purpose, or has attained its use life, it should go back to the toolcrib preset area for dismantling, cleaning, resharpening, and preparation for recycling.

Developing a tool-presetting

system

Presetting can be defined as the act of providing a predetermined space relationship between the cutting edge (or edges) of a cutting tool in a reference plane (or planes). Simply stated, tool presetting means setting cutting tools to rough, semi-finish, or, in some cases, finish part dimensions on equipment designed exclusively for setting tools.

A tool-presetting system for complete tool management involves much more than setting tools to proper length and diameter. It should dispatch tool data in a format most acceptable to a particular facility. Because there are so many facilities that use tool-management systems, there are several alternatives available for transmitting tool data from the actual tool-presetting device to the machine tool.

At a beginning level (Level 1), a presetting machine can use a sophisticated DRO. On a higher level (Level 2), it could use an elaborate tool-setting software program to store and access tool data. Each level employs different stages of tool management, and these must be understood to select the correct presetting system.

Level 1 is composed of three stages of sophistication, which you can implement separately or in conjunction with any other stage in this category. Stage 1 consists of a tool-preset machine and a DRO. The DRO should display actual length and diameter in inches and metric units--all selected by simple switches. This setup is enough to provide accurately measured tools on a consistent basis.

Stage 2 is comprised of a tool-preset machine, a DRO, and a printer that produces hardcopy labels to attach directly to the preset tool. The dimensional data on these labels can eliminate human error in reading and recording tool information at the crib as well as the machine tool.

Stage 3 adds a one-way interface to an external computer. The computer then uses the preset data to create files containing tooling coordinates. This plan enables the preset machine and DRO to act as a simple gage and eliminate human error in reading and interpreting dimensional information.

Level 2 has eight stages of sophistication, which, again, you can implement separately or in conjunction with other stages. Stage 1 consists of a preset machine and an advanced tool-presetting software. The software program can store tool records and part lists and also produce detailed tool drawings based on tool dimensions measured by the preset machine. The programs also can determine actual and differential values, thereby eliminating manual calculations.

Stage 2 introduces floppy-disk drive to Stage 1, expanding the memory of the tool-presetting program.

Stage 3 adds a label printer to the setup to create labels with tool-identification number, length values, diameter dimensions, etc. It also produces bar-code labels for reliable data transfer.

Stage 4 enables the tool-preset machine and tool-presetting software to work together and produce a punched tape with tool offsets for any style of machine tool. It eliminates human error during tool-data entry into the machine control.

Stage 5 consists of a microchip and read-write device embedded in the body of the tool being measured by the preset machine. The read-write unit reads the microchip and calculates the offsets before writing the updated data back to the microchip. This stage eliminates any visual misreading of tool data by the human eye.

Stage 6 consists of a tool-preset machine, the software program, and an external computer interface that allows two-way communication between the software and the computer. Thus, the computer can send and receive tool records and packages. This stage is beneficial because the external computer sends tool data directly to the machine tool or other area.

Stage 7 provides a turnkey package. It uses a stand-alone IBM PC/XT computer instead of the basic external computer used in Stage 6. This setup permits a self-contained tool-management-software package to communicate with the preset machine and to produce tool drawings, tool-assembly sheets, and setup sheets. The major advance of this stage is the formation of an elaborate tool-management system without the need for a large external computer.

Stage 8 adds a video camera to view the measured tool. The vision system calculates actual length and diameter of tools and eliminates the need for an optical profile projector, providing extremely accurate and reliable dimensional measurements.

The different levels and various stages of presetting systems are designed to meet individual needs within a tool-management system. Each progressing stage or combination of stages reduces the chance of human error while decreasing the time required for the machine tool to receive critical tool-characteristic information.

Automatic tool presetting

In addition to the various levels and stages of tool management that require some form of operator involvement, it is also possible to achieve a completely untended presetting station. For manless operation, a preset machine would have to automatically position the X and Y axes to a predetermined location. Also, it would require a tool-tracking device and a vision system to measure and inspect cutting edges.

Other equipment would include a robotic load and unload unit for positioning tools in preset-machine spindles and removing them upon inspection. Finally, an external computer would act as a communication link between all of the elements of the automatic tool-preset machine.

Total preset automation may be too elaborate for most users, but it illustrates the possibility of maximum efficiency in tool-management systems.

Benefits

CNC machines as standalone units in manufacturing cells or in manufacturing systems are expensive to purchase and operate, but they offer high efficiency, great versatility, and other benefits that are universally recognized. However, these benefits are lost when the machine spindle is idle.

A tool presetting system can improve efficiency of a wide variety of standalone machine tools and NC machining centers. The presetting program can encompass practically all phases of tool preparation, which many times are performed somewhere in the manufacturing arena at the expense of productive machine time.

With emerging trends toward computer-aided manufacturing and flexible manufacturing systems, the role of the presetting machine takes on more importance. Without an effective overall tool-management system, even the most sophisticated manufacturing installation will fail to reach productivity goals.

The integration of the tooling-setup function on line with the machine-communication network is essential for proper use of a precision tool-presetting system. The direct cost benefits of good presetting mated with tool management include reduction of machine downtime, reduction of setup time, elimination of trial cuts, greater tool standardization, better tool-inventory control, and reduction of potential machining errors.

PHOTO : Operator prepares to set drill bits on a Variset vertical two-axis toolsetting gage. Graphic system displays tool layouts, dimensions, and special notes to toolsetting personnel. Photo courtesy Royal Design & Manufacturing Inc.

PHOTO : Tooling Systems Div (DeVlieg) offers all line of presetters including Model PSV-2550 vertical with precision rotary spindle, and Model PSH-3070 horizontal with pneumatic clamping to relieve operator fatigue and ensure consistent tool positioning. TSD offers CATS(TM) Computer Aided Tool Setting software to link the preset machine to machine tools. It stores a variety of tool characteristics and ensures prompt tool placement, reduction of written tool reports, selection of alternative tools, and elimination of obsolete tools. Tool-management systems improve quality of all tools whether they need setting or not. A management system generally monitops every tool going through the "funnel," acting as a manager to keep track of the going and coming of all tools in and out of the crib.

PHOTO : The Firth Set(TM) digital presetter from Teled8ne Firth Sterling comes in three configurations: manual, with Soft Touch(TM) probe; visual, with camera-enhanced vision system; and computer enhanced, with special optics and software to create, store, and retrieve graphic colored tool overlays. Command Corp. International's tool holder presetter adjusts diameter at any height, length at any point on the diameter, length and diameter simultaneously, and tool runout.

PHOTO : DeVlieg (TSD) Model PSV-200 vertical preset ma hine has two-axis digital readout and 3" optical profile projector that magnifies tool point 20 times. No 50 tapered spindle locates and orients tools ranging to 18" length and 15" dia.

PHOTO : Operator sets inserts on milling cutter using Royal Design's Variset 2 HP Series horizontal two-axis toolsetting gage.
COPYRIGHT 1989 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Author:Brunette, Michael R.
Publication:Tooling & Production
Date:Jun 1, 1989
Words:1807
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