Must-Read for Manufacturers Troubled by Machining Errors From Chips! Preventing Chip Entanglement to Improve Machining Accuracy and Productivity

Chips Are Just Scraps but So Much More

Chips (swarf) are an inevitable part of cutting. Chips are fine metal shavings removed from material during cutting.

At first glance, chips may just seem like waste material, but they are an important element that significantly affects machining quality and efficiency. Depending on the shape of the chips and how they are discharged, problems such as a rough machined surface and shortened tool life can occur.

In addition, chips can enter the machine tool, creating a machine breakdown or lowering machining accuracy. Chips can also pose a safety risk to the machine tool operator.

While chips cannot be avoided during the cutting process, it is important to understand the nature of chips and how to take appropriate measures. Taking measures to deal with chips rather than treating them as just scraps will lead to safer and more efficient machining.

Machining Problems Due to Chips

Chips that occur during the cutting process can result in a variety of machining problems. This section explains typical chip problems and their effects.

Chips Wrapping Around Tools

When chips become entangled in a tool, it can create problems such as a rough machined surface and tool chipping. In particular, during deep hole drilling and machining of difficult-to-cut material, chips can be difficult to remove and become wrapped around the tool.

When chips become wrapped around the tool, it reduces the tool sharpness and worsens the roughness of the machined surface. In addition, chips adhering to the tool can damage the tool and cause chipping. Tool damage will lead to reduced machining accuracy and significantly reduce productivity.

Chip Entanglement During Tool Change

On machine tools equipped with an Automatic Tool Changer (ATC), chips can become entangled between the tool holder and spindle.

Chip entanglement can increase tool runout and significantly reduce machining accuracy. Even the slightest tool runout is not tolerated during boring and other hole machining that requires accuracy.

Chip entanglement may occur more easily depending on cutting conditions and the machining program. A large amount of chips will occur during high-speed, high-feed rough machining, and the risk of chip entanglement increases for programs with frequent tool changes.

Tool runout due to chip entanglement can lead to machining errors, reduced tool life, and even tool damage.

Chip Clogging in the Workpiece

If chips clog in the workpiece, it can cause problems such as errors in the dimensional accuracy and damage to the surface of the workpiece. For box-shaped and bowl-shaped workpieces as well as hole machining,chips can be difficult to remove and are prone to clogging.

When chips become clogged, it reduces the tool sharpness, affecting the machined surface roughness. In addition, when chips get caught between the workpiece and tool, it can create errors in the dimensional accuracy. Forcibly removing clogged chips can damage the surface of the workpiece, so it is important to take appropriate measures.

Heightened Occupational Safety Risk for Operators

Because chips can be sharp and hot, the occupational safety risk to operators cannot be ignored. If chips generated during cutting scatter and come into contact with the operator's eyes or skin, it can lead to a risk of serious injury.

The work of removing chips from a machine itself is dangerous. Removing chips manually poses a risk of cutting or burning the hands.

It is possible to determine how hot chips are according to their color (interference color).

[Color of chip by cutting point temperature (when cutting stainless steel)]
Light yellow: 300°C
Brown: 350°C
Purple: 400°C
Violet: 450°C
Dark blue: 530°C
Light blue: 600°C or higher

To prevent occupational accidents during cutting, it is essential to use a safety cover that prevents chip scattering and wear appropriate protective equipment. It is also necessary to remove chips in a safe manner.

Handling Machining Problems Caused by Chips

It is important to take appropriate measures to prevent machining problems due to chips. This section introduces troubleshooting measures from the two perspectives of dealing with chips around tools and workpieces and dealing with chip entanglement.

Adjusting the Tool Environment

To prevent chip problems, it is essential to set the appropriate cutting conditions.

[Examples of cutting conditions that can affect chip discharge]

• Cutting speed
• Feed rate
• Cutting Depth
• Tool type (hardness and use of chip breaker, etc.)
• Coolant supply amount
• Cutting path

By optimizing these cutting conditions, you can control the shape of the chips.

In general, fine chips are more easily discharged and are less likely to cause machining problems. Each tool manufacturer provides the recommended cutting speed, feed rate, cutting depth, and other parameters according to the workpiece material to maximize the effectiveness of the tool. It is important to fine-tune the cutting conditions based on the recommended conditions for optimal chip control.

Ensuring sufficient supply of coolant (cutting oil) to the machining point is also key. Coolant allows for quick discharge of chips from the cut part while cooling and lubricating the tool. This improves chip evacuation and prevents chips from sticking to or welding onto the tool.

Appropriate coolant management is essential for improving cutting performance and protecting the machine. Regularly check the coolant concentration, pH, purification status, and other parameters to stabilize the machining quality and reduce damage to the machine tools.

Using the Chip Detection Function

Utilizing the machine tool's built-in function can be effective in preventing problems of chips getting caught between the tool holder and spindle.

Machine tools equipped with a chip detection function can detect chip entanglement automatically to prevent problems from occurring. This function detects chip entanglement at the production start-up stage and stops machining, thereby preventing damage to the tool and the outflow of defects.

While there are not many machine tool models with this chip detection function, they are gradually becoming more popular. In high-accuracy machining and machining of difficult-to-cut materials, in particular, problems due to chip entanglement can easily occur, so using a chip detection function in these processes is very meaningful.

Brother Machining Centers Help Prevent Machining Errors

Certain models^* in the Brother's CNC-D00 series of machining centers come standard with the chip detection function.
*Models with the chip detection function as standard: S300Xd2, S500Xd2, S700Xd2, U500Xd2, M300Xd1, and W1000Xd2

The Brother chip detection function can monitor load fluctuations during tool changes without using a sensor. If a chip gets caught between the tool holder and spindle, the load behaves differently than normal. The CNC-D00 series uses software to analyze these load fluctuations and determine the presence of chip entanglement.

If chip entanglement is detected, the machine stops machining automatically. The operator removes the chip, checks the tool status, and resumes machining. By detecting chip entanglement at an early stage, it is possible to prevent tool damage and machining errors to ensure high machining quality.

Conventionally, it is possible to attach a dedicated machine sensor to the machine tool to detect chip entanglement. However, this requires additional installation work.

In contrast, the Brother chip detection function can be used without any additional installation work. In addition, our machine tools are equipped with maintenance functions such as machining load monitoring. With numerous features to prevent potential problems in daily production, our machine tools ensure improved productivity in manufacturing environments.

Taking Measures Against Chips to Improve Productivity

It is important to take measures against chips in the cutting process to improve machining quality and productivity. Chips can cause a variety of problems including machining errors, a longer cycle time, and reduced tool life.

To effectively manage chips, companies must accurately understand their causes and take appropriate measures, such as optimizing cutting conditions and utilizing chip detection functions.

I encourage you to take thorough measures against chips to improve productivity and machining quality.