Free switching method for actuators of four-axis additive and subtractive composite numerical control machine tool

Abstract

The invention discloses a free switching method for actuators of a four-axis additive and subtractive composite numerical control machine tool, and aims to solve the problems that most laser additive-milling and subtractive composite machining numerical control machine tools at present are respectively provided with a milling tool magazine and a cladding head storage chamber, and free switching of a milling tool and a cladding head can be realized in the additive and subtractive process; however, according to the machine tool structure capable of switching the milling cutter and the laser head simultaneously, the manufacturing difficulty of the machine tool is improved, and the cutter switching auxiliary time for part machining of the machine tool is prolonged. Free switching of the milling cutter and the laser head in the increasing and decreasing process is achieved through the method that the milling cutter library calls the milling cutter and the adjustable hydraulic device to control stretching and retracting of the laser head and the control logic, the structural design and manufacturing difficulty of the additive and subtractive machine tool is lowered, and the switching auxiliary time of the laser additive-milling and subtractive combined machining cutter is shortened.

Description

Technical Field

[0001] The invention belongs to the field of additive manufacturing and remanufacturing, and relates to a method for freely switching actuators of a four-axis additive and subtractive composite CNC machine tool. Background Art

[0002] Industrial green development has become the general trend and trend of the international community. It is the only way for my country to build an ecological civilization and the inherent requirement for building a manufacturing power. It is an effective means to repair parts with high manufacturing costs and high remanufacturing value through laser cladding technology to achieve or exceed the original performance. This manufacturing process can greatly extend the service life of the product and reduce the cost of product use. It has been widely used in aviation, aerospace, petrochemical, mining machinery and other fields, and has produced good economic and social benefits. However, the forming method of laser cladding materials determines the inevitability of the existence of the "ladder effect". Because there is a principle error between the layers of the laser cladding structure, the manufacturing accuracy of the workpiece is seriously reduced. Therefore, taking necessary measures to eliminate the step effect is an effective means to improve the accuracy of additive manufacturing parts and promote the wider application of additive manufacturing parts. Summary of the invention

[0003] Purpose of the invention: After the additive manufacturing parts are processed, they need to be separated from the substrate. Except for laser selective melting and electron beam selective melting, the processed parts generally cannot be put into use directly, and they need to be processed by subtractive milling to remove excess materials. When the additive parts are transferred to the subtractive machine for finishing, the parts need to be clamped and positioned again. Therefore, the clamping allowance, positioning reference and milling allowance for subtractive materials must be reserved during the additive process. Increasing the allowance on the basis of complex structures will inevitably increase the difficulty of processing, and even make the efficiency and economy of additive processing not as good as subtractive processing. In addition, it is not easy to reserve positioning references for complex structures. These processes make the practical application of additive manufacturing more complicated, and the efficiency is reduced accordingly. It is also difficult to accurately control the shape and dimensional accuracy of the formed parts. In order to make full use of the advantages of additive manufacturing, expand the application scope of additive processing, improve its processing efficiency and accuracy, the advantages of both additive and subtractive processes are combined to realize the rapid additive manufacturing of parts, and greatly improve the manufacturing accuracy of parts through subtractive finishing. At present, most CNC machine tools for laser additive-milling and material reduction composite processing are respectively equipped with a milling tool library and a cladding head storage room, so that the milling tool and the cladding head can be freely switched during the additive-reducing process. However, the machine tool structure that simultaneously switches the milling tool and the laser cladding head not only increases the manufacturing difficulty of the machine tool, but also prolongs the tool switching auxiliary time of machine tool parts processing. Therefore, it is extremely important to design a method for controlling the cladding head by calling the milling tool and an adjustable hydraulic device through the milling tool library, reducing the difficulty of machine tool structure design and manufacturing, and shortening the tool switching auxiliary time of laser additive-milling and material reduction composite processing.

[0004] Schematic diagram of additive and subtractive machine tools and auxiliary devices such as Figure 1 As shown in the figure, the schematic diagram of the additive and subtractive material machine tool and its auxiliary devices mainly include 1 laser head, 2 connection block 1, 3 connection block 2, 4 shock-absorbing pad, 5 hydraulic device, 6 column, 7 tool magazine, 8 tool, 9 cooling pipe, 10 rotary table, 11 base, 12 feeding device, 13 protective gas storage device, 14 laser generator, and 15 cooling device. Above the machine bed are the slide, saddle, column, etc., which respectively drive the X-axis, Y-axis, and Z-axis of the machine tool. The left side of the machine tool is 7 subtractive material magazine, and the right side of the spindle is 5 hydraulic device, which mainly realizes the telescopic adjustment of the laser head. During the subtractive process, the vibration excited by the cutting force is transmitted to the laser head, which will seriously affect the service life of the lens in the laser head. Installing a shock-absorbing pad between the laser head telescopic adjustment device and the machine tool spindle can effectively improve the service life of the laser head. The connection block 2 realizes the bolt connection between the hydraulic device and the machine tool spindle housing. The connection block 1 realizes the connection between the piston rod end of the hydraulic device and the laser head. The connection block 1 is bolted to the piston rod end of the pressure device and the laser head.

[0005] Control logic: On the left side of the machine tool are the tool magazine and the spindle cladding head telescopic adjustment device. The cladding head is stored separately and is separated from the processing environment. Figure 2 As shown, when the laser cooling device and the laser generating device are in the waiting state, the CNC system controls the milling cutter on the spindle to be switched to the tool magazine on the left side of the machine tool to avoid interference between the tool and the rotary table and the workpiece. After the system receives the feedback signal of successful tool change, it moves the spindle to a safe position, and controls the extension of the piston rod by the laser head hydraulic telescopic device through the M auxiliary instruction defined by the CNC machine tool PLC, so that the laser head is in the waiting state, and puts the laser head in the waiting position according to the G code compiled by CAM. After the CNC system receives the position feedback of the laser head, the PLC turns on the protective gas device, the powder feeding device and the laser generating device respectively through the M auxiliary instruction, and the CNC system controls the laser head according to the planned path through the G code. Figure 3 After the additive program is executed, the PLC controls the laser generator, powder feeding device, and protective gas device to turn off the light, powder, and gas through the M auxiliary instructions. The CNC system controls the Z axis to move the laser head to a safe height. The PLC controls the M auxiliary instructions to control the laser head hydraulic telescopic device to control the contraction of the piston rod, in preparation for the main axis to safely switch to the subtractive tool. Figure 4 As a schematic diagram of milling subtractive machining, the PLC switches the subtractive tool to the spindle by controlling the tool switching M code to prepare for subtractive machining, and the CNC system completes the subtractive work according to the planned path through the G code. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 :Schematic diagram of additive and subtractive machine tools and auxiliary devices

[0007] Figure 2 :Increase or decrease material control logic

[0008] Figure 3 :Schematic diagram of laser additive manufacturing

[0009] Figure 4 : Schematic diagram of laser subtraction.

Claims

1. A method for freely switching actuators of a four-axis additive and subtractive composite CNC machine tool, characterized in that: The present invention is mainly applicable to the switching and calling of the laser head and the milling tool during the machining process of the additive and subtractive composite CNC machine tool. The present invention mainly includes the four-axis CNC machine tool body, the laser head, the connecting block 1, the connecting block 2, the vibration damping pad, the hydraulic device, the milling tool and other parts and the free switching method and control logic of the milling tool and the laser head.

2. According to claim 1, a method for freely switching actuators of a four-axis additive and subtractive composite CNC machine tool is characterized in that Installing a vibration damping pad between the laser head telescopic adjustment device and the machine tool spindle can effectively improve the service life of the laser head. The connecting block 2 realizes the bolt connection between the hydraulic device and the machine tool spindle housing. The connecting block 1 realizes the connection between the piston rod end of the hydraulic device and the laser head. The connecting block 1 is bolted to the piston rod end of the pressure device and the laser head.

3. According to claim 1, a method for freely switching actuators of a four-axis additive and subtractive composite CNC machine tool is characterized in that The laser head is installed on the side wall of the spindle, and the extension and retraction of the laser head is controlled by a hydraulic device.

4. According to claim 1, a method for freely switching actuators of a four-axis additive and subtractive composite CNC machine tool is characterized in that The control logic for free switching of the milling tool and the laser head is as follows: When the laser cooling device and the laser generating device are in the waiting state, the CNC system controls the milling cutter on the spindle to switch to the tool magazine on the left side of the machine tool to avoid interference between the tool and the rotary table and the workpiece. After the system receives the feedback signal of successful tool change, it moves the spindle to a safe position, and controls the extension of the piston rod of the laser head hydraulic telescopic device through the M auxiliary instruction defined by the CNC machine tool PLC, so that the laser head is in the waiting state, and puts the laser head in the waiting position according to the G code compiled by CAM. After the CNC system receives the position feedback of the laser head, the PLC turns on the protective gas device, the powder feeding device and the laser generating device respectively through the M auxiliary instruction, and the CNC system controls the laser head to complete the additive according to the planned path through the G code. After the additive program is executed, the PLC controls the laser generator, powder feeding device, and protective gas device to turn off the light, powder, and gas through M auxiliary instructions. The CNC system controls the Z axis to move the laser head to a safe height. The PLC controls the M auxiliary instruction to control the laser head hydraulic telescopic device to control the contraction of the piston rod to prepare for the spindle to safely switch the subtractive tool. The PLC switches the subtractive tool to the spindle by controlling the tool switching M code to prepare for subtractive processing. The CNC system completes the subtractive work according to the planned path through G code.

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