Application Analysis of Adaptive Machining Control Technology on CNC Machine Tools

How to improve the machining efficiency of metal cutting CNC machine tools, make full use of the maximum speed of the machine spindle, the maximum load and the maximum feed rate of the shaft, and process the workpiece with variable material and cutting amount, and at the same time automatically protect the machine tool and spindle system, and protect the expensive Imported tools, which have become more and more concerned by end users and machine tool builders. Israel's OMAT's ACM adaptive control and monitoring system is designed to meet this requirement and to provide an ideal solution to this problem from a control perspective.

OMAT ACM is an important option for Siemens 840D CNC system. It can be supplied in various versions, such as external ACM device, pure software integrated ACM, PC card software and hardware hybrid ACM and unit software and hardware hybrid ACM. Among them, the first All kinds of hardware and software are used in ACM devices, and there are many external wirings, but they are not limited by CNC system and spindle drive. They are mainly used for old systems and machine tools that cannot install integrated ACM system. The second and third types are software-based ACM systems with little or no external wiring, but are limited by the non-export type CNC system, requiring a high version of the system software, which is currently difficult to implement in the 840D system exported to China. Therefore, we selected the fourth version of the ACM system in cooperation with OMAT.

Unit software and hardware hybrid ACM system working principle

The ACM system consists of three parts (Figure 1).

Figure 1 Unit hardware and software hybrid ACM system

. ACM control unit: Digital output to the NCU of the 840D system, analog input signal from the OMAT power sensor module. The spindle power signal collected by the ACM measurement communicates with the PC part of the CNC via the SINUMERIK RS232 serial port.

. ACM real-time control software: integrated in the microprocessor of the ACM control unit.

. ACM User Screen Interface: The Windows user graphical interface is used to configure and monitor the adaptive control process.

ACM is a real-time adaptive control system that samples the spindle load changes in real time and automatically adjusts the machine feedrate to the optimum value. And the real-time monitoring records the spindle cutting load, feed rate change, tool wear and other processing parameters, and outputs graphics and data to the Windows user graphical interface. This data can also be stored on the hard drive for later review.

Installation and commissioning

1. Hardware installation

The schematic diagram is shown in Figure 2. The spindle power is measured by the OMAT LA55-P type current transformer. After the power converter is amplified, the 9-pin plug is input to the ACM control unit; the feed trimming digital signal is input to the PLC input module; The ACM control unit and the PCU50 (user operation interface) are connected by RS232 serial communication. In addition, there are the following control signals: the input signal to the PLC after ACM is activated; the ACM has a fault feed hold signal; and the PLC alarm causes the ACM to generate a reset ACM RESET signal.

Figure 2 Schematic

2.PLC software programming

(1) Download the OMAT standard PLC control program FB30 and call it in OB1:

CALL FB30 "OMAT_CYCLIC FB"

ACMFEEDOUT := IB40 //Feed trim signal from ACM ACMFEEDOUT := I40.6 //Alarm feed hold signal from ACM ACMFEEDOUT := I40.7 //Activation signal from ACM

ACMFEEDOUT := T10 //Activation delay signal from ACM (2) Partial modification Siemens standard MCP (machine control panel) management subroutine FC19:

U DB50.DBX11.0 "OMAT_CYCLIC FB_IDB". ACMALARMOUT //PLC alarm signal R≠#MST_Inp23 [ 0 > "NC_STOP" //Stop NC

(3) Programming NC alarm text program (program omitted)

(4) Modify the machine parameters: MD12030 OVER_FACTOR_FEEDRATE[23>=1.3MD12030 OVER_FACTOR_FEEDRATE[24>=1.4

MD12030 OVER_FACTOR_FEEDRATE[25>=1.5 null3.ACM user graphical interface PC software installation

(1) Create a new OPMS directory under F:>\OEM

(2) Copy the following files on the OMAT floppy disk into the new directory F:>\OEM\OPMS.OPMS.MDI .OPMS.ZUS

(3) Copy the files 025_GR.DLL and 025_UK.DLL to F:>\OEM\LANGUAGE; open the file RE_GR.INI and RE_UK.INI insert statement: HSKT=“OMATIVE ACM”

(4) Open the file REGIE.INI insert statement under F:>\OEM:

TASK=NAME:=OPMS, TimeOut=6000

(5) Copy OPMS.INI to F:>\OEM; copy OPMS.EXE to F:>\HMI_ADV(6) Restart Siemens HMI after installation.

Run the OMAT ACM system

Figure 3 ACM main screen

After the ACM PC software is installed, add the soft key named OMAT ACM in the main menu of Siemens 840D system. Press this key to enter the main screen of ACM (see Figure 3). The main screen displays the following information. ACM operation mode, one of three ways to choose. Status monitoring, overload, run, spindle, online/offline, etc. The spindle power and feed rate are real-time curves and values. Current running value, reference number, part number, starting machining time, running time, cutting workpiece time, saving time (%), minimum feed rate (%), maximum feed rate (%), current trim value ( %).

ACM working mode:

ACM start/stop mode: Start or stop the operation automatically or manually by the NC program H function.

Cutting parameter input mode: cutting parameters such as tool type, number of teeth, workpiece material, cutting amount (depth) and speed can be manually (Preset) or automatically recorded in the Learn mode, and then learned (by learn) Monitor machine operation according to recorded parameters.

ACM operation mode:

Feed control mode: ACM continuously measures the spindle load and automatically adjusts the feed rate in real time. When an overload occurs, an alarm is issued to stop the machine.

Monitoring mode: ACM continuously measures the spindle load but does not adjust the feed rate. There are two monitoring modes to choose from - maximum load monitoring or load tolerance monitoring.

Event recording mode: In this mode, ACM only stores the dynamic cutting data in the system memory, and does not perform output processing.

OMAT ACM features and effects

The traditional metalworking tool fracture is undetectable and controllable, the tool wear is manually monitored, and the efficiency is low. The adaptive control technology of the OMAT ACM system challenges the traditional machining technology, optimizes the metal cutting CNC machining process, and improves the machining efficiency. Typical application statistics: contour milling saves about 38%; milling slots save about 34%; 3D milling saves about 37%; drilling saves about 28%. And has the following protection functions: milling cutter break protection (alarm and Stop to prevent damage to the workpiece and subsequent tools); deep hole drilling tool break protection (alarm and stop); tool wear monitoring (digital display wear); spindle overload protection (alarm or stop).

Thanks to OMAT ACM's unique adaptive control technology, the effect is significant, and many well-known foreign companies such as Siemens AG, Turbinenwerke, Chevron Aerospace, Boeing, General Electric, Mitsubishi Motors, Toshiba GE and Toyota Motors have used it extensively. , achieved significant results.

Jiaoda Kunji Technology Co., Ltd. cooperated with Israel OMAT Company to successfully integrate the unit software and hardware hybrid ACM system on the 840D system of the horizontal machine tool center THM4680, and also made a large surface workpiece cutting comparison experiment, cutting efficiency. Increase the machine load quantification control of ACM and the safety protection function of the tool and the spindle, so that the operator can safely use the machine tool at full load without causing damage to the machine tool. This is especially suitable for surface cutting, machining of hard materials such as cast steel, mold processing, deep hole drilling, and the use of high-priced imported tools. Well-known enterprises in the domestic aerospace, textile, home appliances and other industries are also taking the lead in the use of this product. It is believed that with the popularization and application of advanced metal processing concepts such as CNC machining technology and high-speed cutting in domestic enterprises, adaptive processing technology will be widely used.