How to repair the indexable tool failure of CNC machine tools

In order to repair damaged tools efficiently and with high quality, advanced CNC machine tools and precision measuring equipment are essential. Old-fashioned manual machine tools are no longer sufficient to repair indexable tools. Then how to repair the indexable tool failure of CNC machine tools.

In the past, repair of cutting tools was something that any machining shop could do. This is no longer the case. As the structure of indexable blade tools becomes more complex and the accuracy requirements are higher and higher, the machinery and equipment required to repair these tools are usually the same as those required to make new tools. As a result, it has become more difficult for many machining shops to repair their own tools with older manual equipment, as in the past. Manually repaired tools may look good, but it is difficult to achieve the required cutting performance.

Many companies continue to reduce their internal machining workshops, and the lack of skilled machining personnel makes it difficult to repair tools inside the factory. As a result, they need to rely on specialized agencies that can repair tools in accordance with tightly controlled and proven procedures. Repairing a tool incorrectly can result in longer tool indexing times and higher tool changes, which increases machining costs—a result that is exactly the opposite of what the machining shop is pursuing. (Refer to the method of machining multiple threads of CNC machine tools)

Although in order to restore complex indexable tools to a "new look" state, many tool repair service agencies have invested in advanced CNC machine tools and automation equipment, but they still need to maintain that all tool repair work can only rely on The idea of doing it by hand-sometimes the repair is not ideal-fights.

Quality issues

The key issue for tool repair is quality cost. Purchasing CNC machine tools and precision inspection equipment requires a lot of capital investment, but companies using these equipment have stated that in order to restore more complex indexable tools to a "new look", these advanced equipment are essential.

If a machining shop has tried to repair the tool by hand and the result is not satisfactory, it may choose to buy a new tool. Many repair shops have abandoned repairing damaged tools due to substandard repair quality, and 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 can extend the life of indexable tools. For some special tools designed and manufactured for a specific process, repairing damaged tools can save up to 90% of the cost of buying new tools. In addition, it can often save a lot of time because repairing old tools can take less time than producing and delivering new ones.

Only a small number of tools with insert holders are difficult to repair after being damaged, and most other indexable tools can be repaired after being damaged. Users often assume that a tool cannot be repaired, and they will be surprised to find out that this is not the case. Generally, tools that cannot be repaired refer to those tools that have severe cracks throughout the tool, the shank being bent, or severely deformed. Most indexable tools can be repaired and can be restored to their original state multiple times (2-5 times or more, depending on the tool type and usage conditions). Some machining shops have used the repair tool cycle 3 times as their own standard.

Significant improvement

The machining equipment used by tool manufacturers has improved significantly over the past decade. High-precision indexable tools with modern shank technology place higher demands on their repair work. Precise machining control and more important precision tool inspection are essential. In order to completely repair the tool without destroying or sacrificing the original integrity of the steel chosen by the tool manufacturer, proper control must also be implemented. Changing the integrity of the original tool steel will endanger the cutting performance of the tool, regardless of its accuracy. Throughout the tool repair process, the precision of the tool and the integrity of the steel must be considered and controlled.

The repair of indexable tools must meet strict precision requirements. Considering stricter workpiece tolerances, it is important that the repaired tool has the same overall quality and dimensional accuracy as the workpiece being processed or higher.

Regarding the tolerances of workpieces, machine tool renovation, refurbishment and remanufacturing companies, tool accuracy is of paramount importance, because as machine tools become more sophisticated, the size and shape tolerances of workpieces are becoming more and more stringent. Nowadays, in many processing workshops, it is common to require tolerances for cutting operations to a few tenths of a millimeter, and this level of accuracy used to be achieved only by grinding.

The success of a tool repair usually depends on two key variables: the quality requirements of the workpiece and the number of workpieces that the tool must process after the repair. If one of these two variables is demanding, the machining shop should probably choose a professional agency with advanced equipment to repair its indexable tools.

Change tool structure

Changing the tool structure makes it possible for tool repair to save more costs. A development trend of cutting processing is the use of multifunctional composite tools that can reduce processing time and reduce the number of tool changes, such as multi-diameter plunge milling cutters. Since compound tools are often dedicated tools and new tools are more expensive to purchase than standard single-function tools, machining shops are more enthusiastic about repairing such tools.

The skills of tool repairers are just as important as the equipment they use. Tools must be repaired by a technically qualified mechanic who can properly use the appropriate machining and inspection equipment. However, whether the tool needs to be repaired on a CNC machine tool depends on 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 skills and experience of the mechanic, all these factors together determine whether the tool should be repaired manually or on a CNC machine. Many high-volume parts are processed on automated equipment. In such a process system, if a tool fails, a large number of workpieces will be scrapped at a rapid rate. The more automated the process, the more reliable each component of the process must be. Of course, knives are also one of these components. Indexable tools that do not meet technical requirements will wear faster.

In high-productivity machining, due to the irregular or inconsistent chip load of one blade and the next, indexable tools with substandard quality will fail more quickly. If the tool does not run properly because it is not repaired properly, some blades will cut a larger diameter than others, and more material will be removed per revolution than other blades. Leigh pointed out, "All these issues will shorten the blade life. In any process, especially in high-speed, automated processing, this will quickly consume a large number of carbide inserts, not to mention the increased downtime required to solve the problem and replace the blade. . "

Meticulous plan

The best results can only be achieved if the tool repair work is carefully organized and made part of the shop system. This plan includes the collection, distribution of tools and training of operators.

For example, a large aircraft manufacturer has implemented an indexable tool (drill, milling cutter, and tool chuck) repair program. The part manufacturer should have a comprehensive plan to ensure that all repairable tools are repaired to maximize tool cost savings.

Although the most important reason to repair a tool is to save money, the most important goal pursued when repairing a tool is quality. Generally, the cost of a restored indexable tool is 50% -85% lower than buying a new tool, but this cost saving is meaningless if the cutting performance of the repaired tool does not reach the level of the new tool . In fact, if a repaired tool fails early or is not repaired to the correct size and accuracy, the ultimate cost may be higher than buying a new tool.

Lean Repair

Global competition and lean production are the two main driving forces for tool repair. A few years ago, it was more common for worn tools to be discarded in machining shops, and repairs could save about 50% in costs compared to buying new tools. Adopt the recommendation of the tool repair company-the tool is recycled 3 times after repair.

To carry out tool repair work, we must first develop a tool recycling system covering the entire plant. Tool repair companies can provide a variety of services to facilitate the implementation of the repair process. For example, we can provide off-site inventory management of tool recycling bins, shipping containers and recycled tools. A machining shop considering a tool repair plan should also carefully review the repair equipment it intends to use.

Depending on the type and complexity of the tool, it may be necessary to mark the repaired tool. The tool repair company should also provide a quality inspection certificate for the repaired tool. This requires proper inspection equipment and fixtures, as well as a mechanic with extensive knowledge of 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 inspection procedures. A quality-assured tool repair shop requires sophisticated equipment, regular fixtures, and trained operators. Understanding the accuracy requirements of the tool and maintaining the integrity of the tool material are critical to the repair process.

Inspection is particularly important for the repair of certain tools. For example, an American car manufacturer uses a special indexable tool chuck to machine certain parts. This imported chuck is expensive, requires high precision, and has a long lead time for ordering new chucks. Carbide Tool Services has developed a repair program for these tool chucks, which now saves users more than $ 200,000 in tool costs each year.

All tool repair services are not set in stone. Even if your machining shop has had an unpleasant experience with tool repairs in the past, now again consider how to carry out tool repair work-including field visits to potential tool repair service providers-may still Significant. Expensive indexable tools are important to the success of the process, so they cannot be entrusted to anyone.