Analysis on the Reduction in Lead Time by Lean Manufacturing Techniques for Handling CNC

Analysis on the Reduction in Lead time by Lean manufacturing techniques for handling CNC Machines

National Level Technical paper meet for management studies, Advaita 2012 Page 5

Balamurugan L,

Department of Mechanical Engineering,

Sri Chandrasekharendra Saraswathi Viswa Maha Vidyalaya, Kanchipuram – 631561, Tamilnadu, India, E-mail:

Abstract: To reduce the standard time of the Supervisor in controlling the CNC Machine by Agile manufacturing methods such as Server connection using Java servlet Code in a linux based web hosts and another technique using GSM Module with IMEI security detection (Text Messaging) and furthermore, the low cost and effective technique such as Wi-Fi Module through intranet connection in the entire industry using USART/USB which concurrently increases production rate by centralized detection of the complete industry/firm/company starting from customer enquiry, inventory, manufacturing, machining till logistics and delivery.

Keywords: ST-RX02-ASK Receiver with AT89S52 microcontroller (RF Transmission), RS 232 Convertor, Video Server

National Level Technical paper meet for management studies, Advaita 2012 Page 5

1. INTRODUCTION:

Competition in the market is getting more and more globalized and the fast technological changes force manufacturers to search for new ways to stimulate the productive system to the market requirements. Several proposals have been put forward in an attempt to solve the problem of the control of productive systems distributed whenever it is necessary to include a new process in the system. To reach this goal, it is necessary to develop a new model which includes agile manufacturing. The purpose of this presentation is to project the control of agile productive systems with Computerized Numerical Control (CNC) using it’s Open Architecture by either connecting the CNC with Server Module (using Java servlet code) or connecting the CNC with Radio Frequency Module (ST-RX02-ASK Receiver & AT89S52 microcontroller) or connecting CNC with the GSM Module (Global System for mobile communication) using RS-232 Convertor, thereby reducing the Standard time of the supervisor which effects on increase in production rate.

2. Overview of Computer Numerically Controlled Machine:

2.1 Manual Operation Mode:

In this mode, manual machine operations can be performed, which provides equivalent manual operation functions of conventional CNC machines. The following manual operations can be performed in this mode are rotating the handles to move manually the machine sliding table and controlling the spindle speed. Turn coolants, laser beam on/off. Make a simple marking/cutting. Other misalliance manual operations can be done with this manual overriding mode and the auto operation mode is generally followed during cycle time.

2.2 Auto Operation Mode:

In this mode, a CNC program can run automatically. The execution of a CNC program can be stopped or paused. Current status of the machine, tool position and executing commands are displayed on the screen. Dry run, simulation and 3D-profile scan functions can also be performed in this mode.

2.3 CNC Program Compiler

CNC program compiling is a basic and core function of a CNC controller. The data input to a CNC system is through CNC programs. A CNC program cannot be executed directly by a CNC controller. Before it can be executed, the CNC program must be translated into a sequence of machine commands, representing much detailed and simpler machine control instructions. We call the process of the translation compiling.

3. Optimized Methodologies:

Instead of encoding the Go- codes and Machine Codes on the CNC machine manually, the standard time of the supervisor can be minimized by remotely controlling the CNC through various techniques. They’re,

1. Controlling CNC with ST-RX02-ASK Receiver and AT89S52 microcontroller embedded in CNC with RF Module in pc/laptop.

2. Controlling CNC with GSM Module using RS-232 Convertor and A-bis Interface connected in CNC Microcontroller

3. Controlling CNC with Web Server using Java Servlet Codes.

3.1 Wi-Fi Module:

A stepper motor in the CNC Machine is an electromechanical device, which converts electrical pulses into discrete mechanical movements.

We can control the stepper motor wirelessly through RF link. In this paper we are controlling the stepper motor wirelessly through RF link. We are using RF module and AT89S52 microcontroller to achieve this motive. Following are the main components are…

1. RF Module

2. Microcontroller.

3. Output mechanical transducer (stepper motor).

ULN Darlington Pair is for providing ULTRA LOW NOISE in the Stepper Motor of the CNC Machine.

3.1.1 Features

Range in open space (NTP): 100m

RX Receiver Frequency: 433 MHz

Low Power Consumption

Easy For Application as we are using Wireless Fidelity service as the intranet connection to control the services and manufacturing sector, method of handling is user friendly by the individual working API’s and remote access throughout the factory environment. Multiple CNC can be controlled by the relay switches.

3.1.2 RF Transmitter for Sending G Codes & M Codes from Laptop/Workstation:

3.1.3 RF Receiver

3.2 GSM Module:

The method involves encoding Go codes/ M- Codes to the CNC’s GSM Module through Global System for mobile communication service. The network providers can be of users’ choice in accordance with the availability of the network provider in the circumferential area of the CNC Machine.

3.2.1 Role of RS-232 Convertor in GSM Module:

It acts as a interfacing Modem between the Data Terminating Equipment (mobile) and the Data Communicating Equipment (GSM Modem in the CNC Machine). It’s used for the conversion of voltage between TTL Level & RS-232 Level through 9-pin/25-pin connector.

3.2.2 Role of Micro Controller-AT89S52 in GSM Module:

The AT-89S52 is a widely available in market, cost effective, low-power, high permanence CMOS microcontroller with 4k bytes of in-system programmable flash memory. It can be used as full duplex UART serial channel.

3.2.3 Supervisor’s Mobile Transmitter:

The Mobile System consists of the smart card named as SIM card (Subscriber’s Identity Module), in which the network provider depends upon the supervisor’s selection. Each mobile system consists of unique IMEI (International Mobile Equipment Identity) and SIM card consists of IMSI (International Mobile Subscriber Identity). The IMEI is provided for security, whereas, the IMSI is to segregate the Supervisor’s commands to CNC Machine.

3.2.4 Usage of A-bis Interface:

The A-bis interface connects the commands (received as signals) from the mobile with the Base Station Controller. The commands from the BSC are received to CNC, and then it’s executed through Microcontroller with help of RS-232 connector.

3.3 Cyber Machining: The system is composed of three activities that are described in this model: graphic user interface (GUI) for Tele-Operation; Webcam for image/video capture; and Web CNC for tele-operation of the CNC machine. It is based on a client–server architecture, Servers, represented by the programs located at a workstation, responsible for the capture of images and supervisory control of the CNC turning center; and the client, represented by a Java Applet. The Web CNC tele-operation server is composed of the video server and tele-operation servers of the machine that provides command services, execution of programs, download and upload of programs, mistake proofing . The video server is responsible for video and image capture using four cameras, and for their distribution through the TCP/IP protocol. The other servers, associated with the tele-operation services, work in a bi-directional way, receiving commands through the Internet and sending status data regarding the machine. The developed system is quite versatile and robust, allowing the production of parts remotely through the Internet, applying e-manufacturing and tele manufacturing concepts.

3.3.1Multi-level security system:

The multi-level security system accessed from the User Display controls access to the CNC. To view information on CNC, the user must log in. CNC uses this information to decide what pages the user can display, and whether or not they have access to particular displays such as the web browser, what adjustments they can perform, and whether or not they can configure CNC. This security is enforced on the server, and the clients, ensuring that only authorized users can view and change information. Each user is a member of a workgroup, which determines their access rights. This allows easy editing of user access rights. The User display shows all the user workgroups, and the users within the selected workgroup. It enables users to log in. Logging in enables CNC to display the options that apply to the particular user’s authority, and access rights. It is also possible to restrict access to particular IP addresses, thus preventing access from unauthorized computers.

3.3.2 Database:

CNC use SQL Server Express Edition, which supports databases up to 4 GB. Other versions of SQL Server that support larger databases are available from Microsoft. CNC provides automatic database backup

3.3.3 Database password protection:

The CNC’s database can be protected by a password; this prevents the information being manipulated from outside the CNC without the password. This password protects the database.

3.3.4 Our Web based server prototype snapshots:

4. Conclusion:

Thus, by implementing the GSM Module (RS 232 Convertor), RF Module (ST-RX02-ASK Receiver & AT89S52 microcontroller ) and Server Side Modeling in CNC Machines (Trend Open Protocol Server) , the reduction in standard time is achieved and need of High Level End User is minimized with High Level of Security.

5. References:

5.1 Bibliography:

1. CNC Programming Handbook, Peter Smid.

2. CNC Handling Methodologies, Phillis A.

5.2 Webliography:

http://www.asme.org/

http://www.howstuffworks.com/

http://www.balaconsultancy.in/

National Level Technical paper meet for management studies, Advaita 2012 Page 5