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How to repair the failure of indexable tools of CNC machine tools

Posted by: Chris Na 2021-05-26 Comments Off on How to repair the failure of indexable tools of CNC machine tools

In order to repair damaged tools efficiently and with high quality, advanced cnc machine tools and precision measuring equipment are indispensable. Old-fashioned hand-operated machine tools are far from being able to meet the needs of repairing indexable tools. Then how to repair the failure of indexable tools of cnc machine tools.
In the past, the repair of cutting tools was something that any machine shop could do. Today, this is no longer the case. As the structure of indexable insert-type tools is becoming more and more complex, and the accuracy requirements are getting higher and higher, the mechanical equipment required to repair these tools is usually the same as the equipment required to manufacture new tools. As a result, it has become more difficult for many processing shops to use old-fashioned manual equipment to repair their tools as they did in the past. A hand-repaired tool may look good, but it is difficult to achieve the required cutting performance.
Many companies continue to reduce their own internal machining workshops. The lack of skilled machining personnel makes it difficult to repair tools in the factory. As a result, they need to turn to specialized agencies that can repair tools in accordance with strictly controlled, proven procedures. Repairing the tool in an incorrect way may lead to prolonged tool indexing time and increased tool change frequency, thereby increasing the processing cost-this result is just the opposite of the goal pursued by the processing shop. (Refer to the method of machining threads with multiple tools on CNC machine tools)
Although many tool repair service organizations have invested in advanced CNC machine tools and automation equipment in order to repair complex indexable tools to a “new” state, they still need and believe that all tool repair work can only be relied on. The idea of ​​manual completion—sometimes the repair effect is not ideal—competes with the concept.
Quality issues
The key issue of tool repair is quality cost. The purchase of CNC numerical control machine tools and precision inspection equipment requires a large amount of capital investment, but companies that use these equipment have stated that these advanced equipment are indispensable in order to restore more complex indexable tools to a “new” state.
If a processing shop has tried to repair the tools by hand, and the results are not satisfactory, it may choose to buy new tools. Because the repair quality is not up to standard, many processing shops have given up repairing damaged tools. As a result, they have lost the potential opportunity to save millions of dollars in tool costs.
However, the use of precision test and inspection equipment as a quality assurance tool repair work can extend the service life of indexable tools. For some special tools designed and manufactured for specific processing, repairing damaged tools can save up to 90% of the cost of buying new tools. In addition, since repairing old tools may take less time than producing and delivering new tools, it usually saves a lot of time.
Only a small part of the tools with insert seat is difficult to repair after being damaged, and most of the other indexable tools can be repaired after being damaged. Users often imagine that a tool cannot be repaired, but will eventually be surprised to find that this is not the case. Unrepairable tools generally refer to those with severe cracks running through the entire tool, bending of the tool shaft, or severe deformation. Most indexable tools can be repaired, and can be restored to the initial state multiple times (2-5 times or more, depending on the tool type and usage conditions). Some workshops have adopted 3 cycles of repairing tools as their standard.
Significant improvement
In the past ten years, the processing equipment used by tool manufacturers has improved significantly. High-precision indexable tools using modern tool holder technology put forward higher requirements for its repair work. Precise machining control and more important precision tool inspection are indispensable. In order to completely repair the tool without destroying or sacrificing the original integrity of the steel selected by the tool manufacturer, proper control must be implemented. Changing the integrity of the original tool steel will endanger the cutting performance of the tool, regardless of its accuracy. In the entire tool repair process, the accuracy of the tool and the integrity of the steel must be considered and controlled.
The repair of indexable tools must meet strict accuracy requirements. Taking into account the stricter tolerances of the workpiece, the overall quality and dimensional accuracy of the repaired tool must reach the same or higher level as the workpiece to be processed, which is very important.
Regarding the tolerances of workpieces, machine tool renovation, refurbishment and remanufacturing companies, tool accuracy is very important, because as machine tools become more and more precise, the size and shape tolerances of workpieces are becoming stricter. Nowadays, in many processing workshops, it is commonplace to require cutting tolerances to be maintained at a few tenths of a millimeter, and this level of accuracy was only achieved by grinding in the past.
The success of tool repair usually depends on two key variables: the quality requirements of the workpiece and the number of workpieces that the repaired tool must process. If one of these two variables is very demanding, the processing shop might choose a professional organization with advanced equipment to repair its indexable tools.
Change the tool structure
Changing the tool structure makes it possible to save more costs for tool repair. One of the development trends of cutting is to use multi-functional composite tools that can shorten the processing time and reduce the number of tool changes, such as multi-diameter plunge milling cutters. Because composite tools are often dedicated tools, and the price of buying new tools is more expensive than single-function standard tools, processing shops are more enthusiastic about repairing such tools.
The skills of tool repairers are as important as the equipment they use. The tool must be repaired by a mechanic who has the technical qualifications and can correctly use the appropriate processing and testing equipment. However, whether it is necessary to repair the tool on the CNC machine tool, the decisive factor is the complexity of the tool and the number of tools that need to be repaired.
high-speed scrap
The batch size, the complexity of the tool, the skill and experience of the mechanic, all these factors together determine whether the tool should be repaired by hand or the tool should be repaired on a CNC machine tool. Many mass-produced parts are processed on automated equipment. In this process system, if there is a problem with the tool, a large number of workpieces will be scrapped at a very fast speed. The higher the degree of automation of the process, the more reliable each component of the process must be. Of course, the tool is also one of these components. Indexable tools that do not meet the technical requirements will wear out more quickly.
In high-productivity machining, due to irregular or inconsistent chip loads between one insert and the next, indexable tools that are not up to the standard will fail more quickly. If the tool does not function properly due to incorrect repair, some blades will cut a larger diameter than others, and cut more material per revolution than others. Leigh pointed out, “All these problems will shorten the life of the blade. In any machining, especially in high-speed, automated machining, this will quickly consume a large number of carbide blades, not to mention the increased downtime required to solve the problem and replace the blade. .”
careful plan
The best results can only be obtained by carefully organizing tool repair work and making it a part of the workshop system. This plan includes tool collection, distribution and operator training.
For example, a large aircraft manufacturer implemented a repair plan for indexable tools (drills, milling cutters, and tool chucks). Parts manufacturers should develop a comprehensive plan to ensure that all tools that can be repaired are repaired, thereby minimizing tool costs.
Although the most important reason for repairing tools is to save money, the most important goal pursued when repairing tools is quality. Usually, the cost of a repaired indexable tool is 50%-85% lower than the purchase of a new tool, but if the cutting performance of the repaired tool is not up to the level of the new tool, this cost saving is meaningless . In fact, if a repaired tool fails prematurely, or is not repaired to the correct size and accuracy, then the final cost may be higher than buying a new tool.
Lean Repair
Global competition and lean production are the two major driving factors for tool repair. A few years ago, the phenomenon of scrapping worn tools in processing workshops was more common. Compared with buying new tools, repairing tools can save about 50% of the cost. Adopt the suggestion of the tool repair company-the tool will be used 3 times after being repaired.
To carry out tool repair work, we must first develop a tool recovery system covering the entire plant. Tool repair companies can provide various services to make the execution of the repair process more convenient. For example, we can provide tool recovery boxes, shipping containers and off-site inventory management of recovered tools. Workshops that are considering developing a tool repair plan should also carefully examine the repair equipment they intend to use.
Depending on the type and complexity of the tool, it may be necessary to mark the repaired tool with a mark. The tool repair company should also provide a quality inspection certificate for the repaired tool. This requires appropriate testing equipment and fixtures, as well as a machinist with extensive knowledge of the various indexable tools on the market.
A tool repair workshop should also pass ISO certification and be able to implement precise quality control, including management of related technical documents and testing procedures. A tool repair workshop that can guarantee quality requires sophisticated equipment, formal fixtures and well-trained operators. Understanding the accuracy requirements of the tool and maintaining the integrity of the tool material are critical to the repair process.
For the repair of certain tools, inspection is particularly important. For example, an American car manufacturer uses a special indexable tool chuck to machine certain parts. This kind of imported chuck is expensive, requires high precision, and the lead time for ordering a new chuck is very long. Carbide Tool Service has developed a repair plan for these tool chucks, which can now save users more than $200,000 in tool costs each year.
All tool repair services are not set in stone. Even if your workshop has had unpleasant experiences in tool repair in the past, now again consider how to carry out tool repair work-including on-site visits to potential tool repair service providers-maybe still Significant. Expensive indexable tools are critical to the success or failure of machining, so they should not be entrusted to anyone.

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