Wednesday, February 8, 2012

Tool management

Tool management is needed in the metalworking so that the information regarding the tools on hand, can be uniformly organized and integrated in the manufacturing environment and process flow. The information is stored in a database and is registered and applied using the tool management software. The tool data management consists of specific data fields, graphics and parameters which are essential in production, as opposed to a solution for the management of the general production equipment.

Unlike hand tools, a tool in the CNC-production is composed of several parts. Putting the parts together accurately into an assembly is a requirement in order to achieve error-free production.

Processing a part with the CNC machine (machining operation) requires several tool assemblies, which are documented in a list. Each component, each assembly and each list has an identification under which the specifications are found. The tool management is divided into the documentation of the tools (master data) and the logistics (transaction data). The documentation includes, at the very least, all information needed for a trouble-free and a comprehensible production process. Moreover, spare parts, experiences in production and the corresponding data can be managed. Several functions are available to manage, process, print and combine with other applications.

The logistics deal with demand planning, supplies and the location of the tools. This includes, on one hand, the location in the warehouse and the purchasing of individual parts with the corresponding consumption report. On the other hand, it also allows the planning and coordination of the movements of the assemblies within the shop floor.

Master Data of Tools

The master data describes the tools with regards to the geometric characteristics, the composition and the usage. The information is divided into the actual description of the tool (specifications), the work instructions for use through people and the description for the use through machines (Instruction set). The master data describes the tool in its qualitative aspects, but does not provide quantities and locations.

Components


Outline sample for chamfer tools.

The components are individual parts, which can be combined into an assembly. Components are purchased as a unit and stored in tool release. There is a distinction between cutting components (ex.:collets) and non-cutting components (ex.:collets ). Cutting components are worn out during use and therefore must be purchased and replaced periodically. Non-cutting components are practical unlimited in use. They are often acquired together with a new tool machine. Clamping equipments are handled like non-cutting components.

  • The header data is uniformly structured and contains information such as name, supplier's product code, and a unique item number. Each component is assigned to a specific tool type, which defines the number and description of the required data fields. Each component is also linked to a tool category that belongs to a user specific tree structure, which serves to find the tools according to their technical criteria without indicating the number.
  • The descriptive data (geometrical value) vary depending on the type of tool. The data fields are specified in the class list of characteristics. The meaning of the geometrical data fields is illustrated in diagrams and pictures. The DIN 4000 recommends diagrams and pictures for their explanation. Varying graphics for different functions are stored either in the database, or on the components through data links.
DXF according ISG/BMG Standard.

*Generally, there are four types of graphic illustrations:

  1. 2D drawings, for example, in DXF format according to the ISG/BMG standard for geometrical information,
  2. PDF data of the tool manufacturer as a data sheet with exploded view,
  3. 3D data (ex.: STEP or STL) for the use in CAM systems,
  4. Photos (ex.: JPG) as graphical information
  • Cutting data (speed and feed) is stored for the cutting components for optimal chipping efficiency. The different data for varying materials and processing methods, number of revolutions, progressive feed, cooling and production method.

Tool Assemblies

The tool assembly is built out of several components. The component at the rear end must fit to be connect the machine tool , and the cutting component is found on the other end (ex.: drill or insert). Varying components are used intermediately (ex.: extension, collets) in order to reach the desired geometry of the assembly. The documentation of the assembly describes how the components need to be assembled, in order to ensure that the applied geometry in the CAM system matches that of the real tools in the CNC machine.

  • The header data contains information such as identification, a specific number and the allotted tool class.
  • The geometric fields are computed directly through the data of the applied components. Adjustable tools (ex.: fine drill tools with adjustable diameter) are stored in addition to the data of the assembly.
  • The assembly instructions contain the bill of material as well as the data for the parts assembly that is important for the specific assembly (ex.: adjusting tolerance + 0.03/-0.01 mm).
  • The nominal values for the presetting serve as a default in the measuring process with a tool presetting machine. The exact position at the tool and the measuring method can be specified, in addition to the nominal values of the geometry, so that, for example, the left or right corner has to be measured for a grooving tool.
  • The cutting data is typically used for the cutting components as a recommendation for the assembly. This can be adjusted to the specific situation for the assembly. The specifications are continually improved with the help of the practical experience in the factory and are automatically made available for the NC programming in the CAM system.

Tool lists / manufacturing operation

The tool list includes all tool assemblies that are needed for a machining operation. It will be printed as picking list and is used for commissioning and providing advises for the assembly setup. Often there are instructions and information contained therein that are not directly related to the tools (e.g. clamping, clamping fixtures, the name of the NC program, etc.) to ensure that all documents for an operation can be viewed together.

  • The header data include information such as name, unique identification and the allocation to the right machines. As identification is used e.g. the combination of "part number + operation". Instead of the part number, the drawing number can be used.
  • The list of assemblies contains all the assemblies needed for the operation, along with the designated pocket in the machine (T number, Turret). That list also includes those requirements for the assembly, valid for this specific operation only (such as minimum cutting length). The assemblies are listed in the order in which they are used in the NC program.
  • The print edition (picking list) is used for the picking of components and assembly of the complete tools in the tool output. It includes the necessary components and their storage location and the important geometric details and tolerances of the complete tool.

Auxiliary Tables

Match conditions for tool components.

In addition to the actual tool data, auxiliary data tables simplify the data acquisition, using values selected from a table instead of having to collect them. Compared to a manual input, this ensures a more comfortable and consistent data collection.

  • On both sides of a component match conditions indicated the geometric condition another component must meet to be connected. If a component has on the right side matching conditions such as a next component on the left side, the two can be assembled. The use of match conditions makes searching matching components easier and more secure. When entering the component into the database, for both sides the right match conditions are selected from a table.
  • A list of the work materials is required for the assignment of the cutting conditions. Different qualities and additional terms for the materials are also contained in the list, and extended by the individual designations as used by the respective enterprise.
  • The tool classification is used to organize the tools in technical terms. All tools assigned to the same tool class are suitable for the same task, but they have different sizes. The tool classes are organized in a tree, which is adapted and expanded by the user.
  • The tool types with the corresponding images describe the required geometric values and where they are measured. Each tool type is assigned to a class list of characteristics that define the data fields of the components.
  • The locations are used in order to specify the location of the assemblies and components in logistics. They are a reflection of the manufacturing environment and include all stands where tools and equipment could stay. They are divided into storage locations, intermediate locations, preparation- and production units (machines). Several locations are grouped into departments. The locations themselves can be divided into individual places. The level of detail and depth of the structure are defined only as far as the logistcal aspects are actually necessary.
  • The cost centers are used in logistics to evaluate the use of tools in different departments (e.g. turning). With the removal of a component from the storage, an indication is specified at the cost center it relates to. The cost centersof the tool management must be adjusted with those in the PPS system.

Transaction Data (logistics) of Tools

Tool Components on stock.

Logistic is concerned with the inventory, the storage areas and the purchasing of tools. Within the logistics, there is a differentiation between the components and the assemblies. The components themselves have a differentiation between internal material flow and purchasing goods from external suppliers (stock control).

Stock control of Components

The logistics of the components includes primarily the inventory management, the planning of requirements and the monitoring of the minimum stock level. When reaching the minimum level, the tool management triggers a procurement process, which is handled by the Purchasing Department, with the ERP system. The logistic of the tool management uses a workplace-tuned user interface and has interfaces to storage systems and other facilities within the shop floor. Requirement for coordinated inventory of components is a central organization of the tools in which all components of a production unit are stored at one location, and each withdrawal is recorded reliably.
In-house logistics of Components

In-house logistics is mainly interested in what place a wanted component currently is, and at what cost center it was consumed. This method only consumes wear parts (cutting), the other components (holders, clamping devices) are only be moved between toolroom, storage places, and machine tool. The booking of the components at the individual cost centers and locations occurs simultaneously with withdraw / restore in the toolroom. The preparation of tools and resources is triggered by a production order. It refers to a tool list in the master data, in which all required components are listed. Prior to the usage in the machine tool, the components are assembled, according to the specifications and work instructions in the tool list. When scheduling the production orders, for each component will be checked if the available inventory is sufficient to assemble the tools required.

In-house logistics of Assemblies

tool Assemblies loaded.

The assemblies are built from components, and after usage usually disassembled into components and restored again. From an assembly, multiple copies can be assembled simultaneously, if the components are available in sufficient numbers. The logistic of assemblies refers to the condition and location of these copies.

Each copy of an assembly can typically be in three various states:

  • not yet assembled (the components are available as individual parts)
  • Assembled in the intermediate storage (e.g. on a shelf)
  • assembled on the CNC machine

When scheduling a production order, the relevant, for the work required assemblies are known, based on the tool list. Also, known is which assemblies, required for the machining process, are already located on the machine tool. The necessary, but not yet available assemblies are calculated and printed in a net loading list. They either have to be assembled or removed from the intermediate storage. With a coordinated logistic of the assemblies it is possible to reduce the time required for providing and replacement of assemblies at the machine.

Integration of Tool Data

The tool management serves to guarantee an efficient and faultless order processing in the manufacture. Existing knowledge is made generally available and the guidelines stated in the master data are noticed. The integration of tool data enables other applications to use the tool data which is maintained with the tool management. Thereby, the applications either fall back on the tool management's database, or the data will be replaced by the interfaces. Especially in CNC manufacturing where several persons are involved in the production process the integration avoids faults, delays and multiple data recordings. As follows you will find a short description of some of the respective connections between the most important applications and the tool management.

PDM (documentation)

In the PDM system every product's work plan is saved which comprises the CAD Models, the description of the working steps and the list of the needed equipment. The detailed description of the equipment themselves takes place in the tool management because the PDM system does not offer functions and data fields do describe them in detail. It typically offers links to external data. If a product is to be produced, a production order will be generated with the ERP system which comprises the link to the work plan stored in the PDM system. The needed resources such as NC programs, tools, and instructions will be requested in the production from the tool management. Integration means to guarantee the availability of the actual information in the tool management system mentioned in the PDM system. The basic objective for integration is a systematic numbering of the documents and resources.
ERP (purchase)

The ERP system plans raw material, consumable items and other resources. It is closely connected with the PDM system and assumes the tasks of the materials management and logistics. Related to the tools, this concerns the consumable components (cutting items). If the inventory of the components is conducted with the tool management system, purchase orders will be transmitted as purchase requisitions to the ERP system which assumes the actual order. This requires that the products are registered in both systems with the same number. Additionally all internal stock movements of the tool components for the costing can be handed over to the ERP system with the integration.
CAM

With the CAM system the G-Code commands (NC program) for the CNC machine are generated. Geometry, description and cutting conditions of the assemblies are selected and received directly from the tool management database. This ensures that all tools used are documented and consistent with the reality in the workshop. From the CAM system, all tools used in an NC program are automatically saved as tool list in the tool management. This ensures the correct use and equipment of the tools during the preparation of the working process.
Storage systems

Besides the conventional tool cabinets, storage systems which provide the operator with the shelf containing the desired product are often used. The relationship between the item number and the storage place is saved in the tool management. When booking a tool removal in the logistics area of the tool management the storage system is operated automatically. Alternatively, the assignment of storage locations can be configured in the storage system. The removal is then performed on the storage system and the inventory change is transmitted to the tool management.
Presetting

At the processing to the tools' positioning the CNC machine needs their exact measurements. Therefore, the length and diameter of the complete tools must be entered when inserting them in the machine. These setting values of the tools can be measured with an external pre-setter. Convenient pre-setters assume the nominal values, tolerances and designation from the tool management and pass the measured actual values directly to the control of the CNC machine. The integration of the tool management with the pre-setters takes place in the exchange format of the respective equipment manufacturers and also includes the graphics and information about the method of measurement.
Tool catalogues

To reduce the cost of the initial data acquisition of the components in the tool management solution, tool manufacturers provide the data and graphics in appropriately conditioned form. For the technical data of the tools, the DIN 4000 and the ISO 13399 exchange format are currently used. Wherever required, the 2D graphics are provided in accordance with the ISG / BMG DXF standard. For 3D graphics a standard is not defined yet. Normally, STL and STEP format are offered and axis position is chosen according to the application on the machine.

Storage systems

Besides the conventional tool cabinets, storage systems which provide the operator with the shelf containing the desired product are often used. The relationship between the item number and the storage place is saved in the tool management. When booking a tool removal in the logistics area of the tool management the storage system is operated automatically. Alternatively, the assignment of storage locations can be configured in the storage system. The removal is then performed on the storage system and the inventory change is transmitted to the tool management.

Presetting

At the processing to the tools' positioning the CNC machine needs their exact measurements. Therefore, the length and diameter of the complete tools must be entered when inserting them in the machine. These setting values of the tools can be measured with an external pre-setter. Convenient pre-setters assume the nominal values, tolerances and designation from the tool management and pass the measured actual values directly to the control of the CNC machine. The integration of the tool management with the pre-setters takes place in the exchange format of the respective equipment manufacturers and also includes the graphics and information about the method of measurement.

Tool catalogues

To reduce the cost of the initial data acquisition of the components in the tool management solution, tool manufacturers provide the data and graphics in appropriately conditioned form. For the technical data of the tools, the DIN 4000 and the ISO 13399 exchange format are currently used. Wherever required, the 2D graphics are provided in accordance with the ISG / BMG DXF standard. For 3D graphics a standard is not defined yet. Normally, STL and STEP format are offered and axis position is chosen according to the application on the machine.

Motivation for Tool Management

Utilization of New Technologies

Rising demands in design und quality, combined with time and cost pressures, force companies to permanently invest in more efficient equipment and procedures. Modern CNC-Machines (i.e. Mill-Turn-Machines) are highly productive, however they are very demanding in terms of preparation and application. A prerequisite for the successful use of new technologies is therefore the simultaneous adaptation of the organization together with the opportunity to include the storage und retrieval of necessary operational information. The additionally required knowledge can subsequently be included in the operational procedures and made available for each necessary task. This avoids the situation that instructions allocated regarding equipment and tooling are flawed or incomplete resulting in the interruption of the production.

Supplying the Right Information

Newly Purchased equipment is supplied with specific information for its usage (i.e. cutting data with tools). This Information is however found in the supplier specific (i.e. maximum allowed diameter of a fine boring tool). Before the new acquisition can be utilized, the data must be integrated in the company orientated specific task format. (i.e. The exact setup values for a required fine boring tool). Furthermore, this information must be made available to all participating work areas. (i.e. the exact adjusted diameter must be made known to the NC programming and tool store departments). Processed company information is then made available as general or as specific part data instructions (i.e. appropriate cutting values for a particular tools usage with a specified material) and must be managed and integrated within a workflow to prevent valuable production capacity is lost or tool life is reduced due to unsuitable cutting data.

Make Information Available.

Tool and production data is managed within a company database and in a specific format. For this purpose a software application is utilized so that information can be accessed across all departments and be accessed and used by different people without repeatedly registering duplicate data. So that the data can be utilized by various other software applications (i.e. CAM-Systems, tool pre-setters, shop floor logistics), suitable interfaces are integrated to secure a smooth, seamless workflow. Central data management reduces errors and stoppages in production.

Planning and Preparation

To plan a machine schedule and preparing tools for a night shift, purchasing consumable articles or a decision for a new requisition requires the necessary sufficient information. The structured administration of all data pertaining to tools makes it possible to access pertinent information and relevant data within a short term.

Necessity of a solution

The importance of exchanging information between operational areas varies according to each type of company. Generally it can be said, that missing or unclear information means that sources of errors are made transparent through loss of capacity, delays and inefficient work flow. Manual interfaces and information passed on by word of mouth are without doubt potential error sources and obstacles for new employees. The more people that are involved in the production process; the necessity and importance of binding instructions and clear cut procedures become clearer. Activities that are to be frequently carried out must of organized just as efficiently as a seldom duty. Especially important are binding specifications that are involved in complex working situations to reduce the chance of machine damages as well as the risks involved with defective deliveries.

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