CNC milling tool Offset refers to the phenomenon that the milling tool deviates from the originally set processing path or position during the CNC milling process. This article will tell you how to prevent milling tool Offset.
To prevent CNC milling tool offset, measures can be taken from multiple aspects such as tools, workpieces, cutting parameters, and machine tools, as follows:
Tools
Choose the right tool: Choose the right tool material, type, and specification according to the processing material and process requirements. For example, when processing materials with higher hardness, carbide tools should be used; when milling complex contours, choose the right tool radius and number of blades to ensure that the cutting force is evenly distributed and reduce the possibility of tool offset.
Ensure tool quality: Use reliable and high-precision tools to avoid offset caused by manufacturing errors or defects in the tool itself. When purchasing tools, choose products produced by regular manufacturers and check the tool’s appearance, dimensional accuracy and other indicators.
Replace tools regularly: Replace tools regularly according to the wear and service life of the tool. Develop a reasonable tool replacement plan to avoid continued use of the tool after excessive wear. For example, after processing a certain number of workpieces, even if the tool does not seem to be severely worn, it should be replaced.
Correctly install the tool: Strictly follow the tool installation requirements to ensure that the tool is firmly installed and has good coaxiality with the spindle. Using appropriate toolholders and clamping devices, such as hydraulic toolholders and heat shrink toolholders, can provide better clamping force and precision. After installation, tool runout detection is required to ensure that the tool runout is within the allowable range.
Workpiece aspect
Ensure material uniformity: Before processing, inspect the workpiece material to ensure that the hardness, density, etc. of the material are uniform. For uneven materials, appropriate pretreatment measures can be taken, such as heat treatment such as normalizing and tempering of forgings to improve the uniformity of the material structure.
Reasonable clamping of workpieces: Select appropriate clamping methods and fixtures to ensure that the workpiece is accurately positioned and firmly clamped during processing to avoid displacement of the workpiece due to cutting force, which in turn causes tool offset. When clamping, pay attention to the distribution of clamping points and the size of clamping force to prevent deformation of the workpiece.
Cutting parameters aspect
Optimize cutting parameters: According to the workpiece material, tool performance and processing requirements, reasonably select cutting speed, feed rate and cutting depth. Generally speaking, appropriately reducing cutting speed and feed rate and increasing the number of cuts can reduce cutting force and reduce the risk of tool offset.
Use appropriate cutting strategies: Select appropriate cutting strategies, such as down milling or reverse milling, according to the shape, structure and processing technology of the workpiece. When down milling, the cutting force direction of the tool is the same as the feed direction of the workpiece, which is conducive to reducing tool offset; reverse milling is suitable for some processing with high surface quality requirements.
Machine tool equipment
Regularly maintain the machine tool: formulate a strict machine tool maintenance plan, and regularly clean, lubricate, accurately test and adjust the machine tool. Check the wear of the guide rails and replace the severely worn guide rails in time; adjust the gap of the lead screw to ensure transmission accuracy.
Check the accuracy of the machine tool: Regularly check the accuracy of the machine tool, such as the rotation accuracy of the spindle, the flatness of the worktable, the verticality and parallelism of the coordinate axis, etc. When the accuracy is found to be out of tolerance, repair or adjust it in time.
Ensure the stability of the machine tool: The machine tool should be installed on a stable foundation to avoid vibration and impact. The surrounding environment should be kept stable to avoid drastic changes in factors such as temperature and humidity that affect the accuracy and stability of the machine tool.
Programming and operation
Precise programming: When writing CNC programs, the tool path and cutting parameters must be accurately calculated, and factors such as tool radius compensation and length compensation must be considered to ensure the accuracy of the program. For complex parts processing, tool paths can be generated through computer-aided programming (CAM) software to improve programming accuracy.
Standardized operation: Operators should strictly follow the operating procedures for processing, and carefully check the installation of tools and workpieces and the setting of cutting parameters before processing. During the processing, closely observe the processing status and promptly detect and handle abnormal situations.
CNC milling tool offset will have a negative impact on machining accuracy and quality, and may even cause the workpiece to be scrapped in severe cases. Therefore, effective preventive and compensatory measures need to be taken in CNC machining to control milling tool offset.
