Burr is an unintended metal "Kaeri" generated in the cutting process. If Burris left as it is, it will hinder the assembly between parts, or the parts will not move smoothly, causing problems in the next step, so it is processed that suppresses the occurrence of burrs and surely burrs. Is indispensable. In this article, I will explain the causes of Burrthat cannot be avoided by cutting processing and the countermeasures.
Burris a stuck out of the work left out and cut powder. It is no exaggeration to say that it will always occur from large burrs to small burrs in cutting processing. Burris roughly classified as "Poasonbali" and "Roll -Obali" from the occurrence process.
Poisson burr is a burr at the start and processing of cutting. When the tool bite into the work, a part of the work that could not be shaved was pushed outward and generated. At the start of cutting, the poresonBurris called "entrybali", and the poresonBurrgenerated on the side during processing is also called "sidal". In general, it is smaller than rollover.
Roll -over is a burr at the end of the cutting. When the tool leaves the work, a part of the cut powder that could not be shaved is pushed out in the cut direction. Generally, it is larger than Poasonbali.
Burrcauses serious trouble in metal processing. The following tasks caused by Burrinclude: Dropping processing accuracy Dropping product life and outflow of defective products Worker's injury
Balinese occurrence leads to a decrease in processing accuracy. In addition to the dimensional error when the parts are measured by the burrs, the bite of burrs into jigs such as the vise or clamp can cause the processing surface to be tilted and cause poor processing. Furthermore, if the existence of burrs at the time of assembly and the burrs are peeled off and between parts, the accuracy of assembly will deteriorate. Tools for drills and end mills are cut, but if the tool edges have burrs, they will not become sharp edges. Therefore, burrs must be removed as soon as possible.
If you incorporate it into a product without noticing Bali, it will cause a decrease in product life and the outflow of defective products. Machine parts may cause various problems, such as poor assembly and sliding, causing failures, and short circuits occur in electrical parts.
A sharp burr also leads to an injury to workers. If you leave the burrs to the assembly process, it is dangerous because it causes the worker's injury. It is important to pay attention to the handling of the work of Bali, as it can lead to injuries during work transportation and setup. In addition, although there is a risk that the end user will be injured by Burras well as workers, this is a serious problem related to the Product Liability Law.
Burris transformed and generated by a part of work and powder.
The work cannot be cut, and it is plastic deformed by being pushed in with a tool and turns into burrs. (Plastic deformation: The deformed metal does not return to the original)
The work escapes from the tool and changes to Burrdue to elastic deformation. (Elastic deformation: A state in which a deformed metal is about to return)
If the toughness (stickiness) of the work is high and the cut powder cannot be cut, the part of it will be pushed out of the work and it will change to Bali.
In order to prevent the occurrence of burr, it is essential to select tools and review the processing process.
We will review the selection of tools, such as the sharpness and strength of the tools, and take measures to prevent them. As for the tools, it is basically to select conditions in which the shearing angle (disconnection) angle is increased, such as increasing the scooping corner, making the edge of the blade sharp, using cutting oil to reduce the scooped surface friction coefficient. However, it is important to note that simply sharpening the tools will cause strength problems.
Selecting a large square and sharp tools to prevent the occurrence of burrs. Generally, the larger the square, the thinner the soybeans, making it harder to generate burrs. Early tool replacement and tool management are important, as the blade tip is worn and the sharpness falls, so early tool replacement and tool management.
Select a strong tool and keep the cutting edge sharp to prevent the occurrence of burrs. Hard tools such as carbide and ceramic tools are effective. If the strength of the tool is higher than the need, it is important to use the tools depending on the material.
We will review the processing process such as burr off and cutting paths. If it is a processing of its own product, it is also important to assume a shape that is difficult to get Burrfrom the design stage.
Remove the burrs issued by rough work by finishing. In the finishing process, the cutting conditions are reduced and the process is used as a burr off. In continuous processing using a machining center or the like, you can prevent the outflow of products with bars in the next process by using a brush and dedicated cutter.
In order to make it easier to take burrs in the later process, consider the direction of cutting the cutting so that the burrs appear in the intended direction. By changing the cutting path so that burrs appear outside the work, it is easier to take burrs in the later process. In addition to flat milling and side processing with flat milling, the direction of the blade tip also greatly affects the occurrence of burrs. Generally, downcuts (downward cutting) facing down (downward shaving) can reduce the outbreak of burrs than the upcut (upward cutting) in which the edge is turned up (upward cutting).
In order to make burrs easier in the post process, the primary processing will be as small as possible with the primary processing. In order to keep the burrs small, it is important to divide into multiple paths without shaving at once. By changing the direction of sending the tool, you can reduce the burr.
We will review the cutting conditions such as the cut amount and the number of revolutions and take measures to prevent it. Adjustment of cutting conditions also affects processing efficiency and finishing quality, so balance is important.
By reducing the cut amount, it suppresses the plastic deformation of the work and reduces the burr. It is also effective to increase the number of blades of the tools and reduce the cut amount per blade. It is important to note that if the cut amount is too shallow, the tool will cause a "slip phenomenon" that will slip on the top of the work.
Coolant prevents work deformation and weld by frictional heat, eliminating the remaining shaving that causes burr. By using a high -voltage coolant, you can also wash off the cut powder that is entangled with the tools that cause burrs and the fine burrs remaining in the work.
By reducing the number of revolutions and sending speeds, the plastic deformation of the work is suppressed, and the burrs are reduced. Lowering the cutting conditions eliminates large plastic deformation, but the processing efficiency is greatly reduced. Therefore, it is necessary to devise a processing process, such as dropping cutting conditions only when finishing.
In this article, I explained the causes of Bali, which cannot be avoided by cutting processing, and the countermeasures. The cause of burr varies depending on the material and shape of the work, but it is important to use the processing process that does not easily occur. Let's aim for machine processing with less burrs to improve cutting technologies.
