Application examples of industrial robots in numerical control processing

This article describes the application of FANUC robots to motor housing production lines. By adopting automatic robot loading / unloading technology and iRVision vision system, the trajectory of the robot can be rationally planned, and the Machining technology of industrial robots and the Machining technology of numerical control can be organically combined. The workpieces are automatically loaded and unloaded, and the finished products are automatically stacked, enabling high-precision, high-efficiency, low-cost machining.

Keywords: industrial robot, Cnc Machining combination, industrial automation

1. FANUC Robot

The automatic Machining line is equipped with two FANUC robots, the M-20iA handling system robot. One of the robots is the walking robot R1. Controlled by FANUC servo motor αi F12 / 3000, it has precision reducer, gear, rack drive, high reproducibility and can be easily adapted to the mechanical layout on both sides of the rail.

It is mainly used for gripping rough workpieces, loading machine tools, and gripping workpieces during machining. In addition, the processed product is taken out and transported to the conveyor belt.

Another fixed robot, R2, uses FANUC’s unique intelligent robot technology (iRVision vision function) to punch and stack finished products into baskets. FANUC Robot M-20iA The joints of each part of the robot are joint points or coordinate systems. The shape and position of each joint is shown in Figure 1.

2. Layout of automatic production line equipment

The motor casing automatic Machining production line consists of a supply conveyor and a blanking conveyor belt (equipped with the iRVision vision system). Figure 2 shows the device layout of walking robot R1 (rail type), fixed robot R2, two VM850 vertical machining centers, one CLX360 CNC lathe, completed basket, and system control cabinet.

CNC machining process

The workpiece is a motor casing for mass production as shown in Figure 3. The material is ADC12 aluminum alloy. Machining includes face milling, tapping, and boring.
The contents of the part Machining operation are assigned as follows.

• (1) As shown in Figure 4, VM850 vertical machining center 1, M4 threaded bottom drilling, M4 threading and milling outer cylindrical bossing.
• (2) As shown in Fig. 5, two VM850 machining centers, φ5.5 mm for drilling, aperture chamfering process.
• (3) The CLX360 CNC lathe chamfers inner holes, stepped holes, and holes as shown in Fig. 6.

In addition, special jigs need to be designed. The fixture of the machining center adopts the internal clamp method, and the CNC lathe adopts the external clamp method. The combined application technology of robots and Cnc Machine tools processes workpieces by automatic loading and unloading to improve machining efficiency.

4. Robot automatic loading / loading operation design

Design pneumatically fixed parts for robots based on the shape characteristics of workpieces including pneumatics, sensors and mechanical parts.
The work Machining process is as follows.

• 1. Place the blank work on the in-feed conveyor.
• 2. The walking robot R1 compound jig grips the rough-machined workpiece, moves it to the position of the machining center 1, and places the workpiece on the dedicated jig of the machining center 1. As shown in Figure 7.
• 3. After the machining center 1 is completed, the compound claw of the walking robot R1 removes the workpiece and moves to the position of the machining center 2, and mounts the workpiece on the dedicated jig of the machining center 2.

4. After the Machining center 2 is completed, the walking robot R1 takes in the work to the position of the CNC lathe and mounts the work on a dedicated jig.

After the workpiece is machined, the workpiece is removed and the robot walks to the workpiece turntable to perform the workpiece flip and swap positions.

5. After the workpieces have been replaced on the turntable, the robot R1 places the final product on the unloading conveyor.

The workpiece is unloaded by Robot R2 and automatically placed in the finished basket.

This completes the complete process. Each Machining step has a corresponding beat. After adjusting the CNC machining program and the robot motion program, you can perfectly combine CNC machining with robot loading and unloading.

Special jig design

According to the machining work of each of the three CNC machine tools, three sets of composite pneumatic clamps were designed and introduced as follows.

(1) Vertical machining center 1 Special jig:

Vertical machining center for drilling, tapping and milling of external bosses 1. Fixtures with pins on both sides of the pin are designed to position the workpiece and clamp it with a pneumatic rotary clamp.

(2) Jig for vertical machining center 2:

It features a vertical machining center 2, a drill 6φ 5.5mm through hole, a drilling chamfering process, a pneumatic 3-jaw self-centering chuck for clamping workpieces, and two elastic V-shaped block orientation fixtures.

(3) Special fixtures for CNC lathes:

CNC lathes are used for machining inner holes, notches and hole chamfers, and are designed with a jig with double pin positioning workpieces and a pneumatic rotary clamp clamp method.

6. Robot, PLC and CNC machine interface

In order to ensure the safe coordination between the robot and the CNC machine, a safe and reliable communication connection between the robot, the PLC and the CNC machine must be established.

On the hardware side, the corresponding I / O points between the three are connected by a shielded cable.

On the software side, the dedicated software for the robot and PLC interface collects the current state of the machine and robot and programs the corresponding control program corresponding to the load / unload logic to make it efficient between the CNC machine and the robot. Realize communication.

Key points need to address emergency stop signals, CNC machine ready signals, robot equipment air signals, loose fixture signals and CNC machine tool safety gate signals. Figure 16 shows the status monitoring screen of the CNC machine.

7. Conclusion

With the development of industrial robots, the level of intelligent robots has increased and the range of applications of robots has expanded. As an auxiliary part of CNC machine tools, the automatic loading and unloading mechanism of industrial robots is increasingly being evaluated by machine tool manufacturers and users. The error-free rapid communication between the robot control system and the machine control system and the accuracy of the robot movement ensure the reliability of the machining process of the system. The automatic Machining production line introduced in this paper brings together cutting-edge technologies such as robot technology, PLC technology, sensor detection technology, communication technology, and numerical control technology. A combination of industrial robot and CNC machine tool technology will be realized, simplifying the operation mode of CNC machine tool, improving the operation safety of CNC machine tool, and reducing the labor intensity of workers. The close connection between workloads, unloads and automated Machining greatly improves work efficiency and increases application value.