DEVELOPMENT OF AN OPEN TYPE CNC SYSTEM FOR A 3-AXIS MICRO CNC MACHINE

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 6, June 2017, pp , Article ID: IJMET_08_06_048 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed DEVELOPMENT OF AN OPEN TYPE CNC SYSTEM FOR A 3-AXIS MICRO CNC MACHINE Lakshmipathi Yerra, K. Chinnamaddaiah and Subramanyam B Department of Mechanical Engineering, MLR Institute of Technology, Hyderabad, Telangana, India P. Ravikanth Raju Department of Mechanical Engineering, Anurag Group of Institutions, Ghatkesar (M), R.R. Dist., Telangana, India ABSTRACT The technologies on microminiaturization have a worldwide practical application prospect. Current researches require fabrication techniques which can effectively and economically produce micro-scale components with complex 3D features over a wide range of material types. Comparing to macro mechanical machining processes, micro mechanical machining such as micro milling can create complicated micro structures on various materials using miniature tools with high material removal rates. In order to improve the machining performance to provide high accuracy, it is necessary to develop a proper CNC system for this machine tool. For the requirements of actual micro machining, some special features designed by the users should be added into the control system which usually has been integrated in commercial software provided by suppliers as a grbl. So it is difficult to develop the efficient and economic CNC system. Open CNC system is also called as Open-architecture CNC system, it could be complimentary technology to achieve high reliability control and multiple machining tasks. In this system most integrated functions could run as real-time parallel processes. The main objective of this project is to develop an open type CNC system for a 3 axis micro CNC machine and evaluate the performance of the whole system for the following machining experiments. Key words: CNC, Micro system, 3-Axis. Cite this Article: Lakshmipathi Yerra, K. Chinnamaddaiah, Subramanyam B and P. Ravikanth Raju. Development of an Open Type CNC System for a 3-Axis Micro CNC Machine. International Journal of Mechanical Engineering and Technology, 8(6), 2017, pp editor@iaeme.com

2 Development of an Open Type CNC System for a 3-Axis Micro CNC Machine 1. INTRODUCTION Increase in the rapid growth of Technology significantly increased the usage and utilization of CNC systems in industries but at considerable expensive. The idea on fabrication of low cost CNC came forward to reduce the cost and complexity in CNC systems. This paper discusses the development of a low cost CNC which is capable of 3-axis simultaneous interpolated operation. The lower cost is achieved by incorporating the features of a standard PC interface with micro-controller based CNC system in an Arduino based embedded system. The system also features an offline G-Code parser and then interpreted on the micro-controller from a USB. Improved procedures are employed in the system to reduce the computational Overheads in controlling a 3-axis CNC machine, while avoiding any loss in overall system performance. 2. WORKING PRINCIPLE Computer numerical control machine tools are such type of machine tools that have revolutionized machining processes. It is nothing but using a computer as a mean to control a machine that produces useful objects from solid blocks of material. CNC machine works under a close loop system that means when an operation is performed by executing a program, a feedback is coming back to the CNC system. This is not a descriptive answer of what is CNC machine. The working principle of Micro CNC system block diagram as shown in figure COMPONENTS OF CNC The usual CNC milling machine requires different tools in order to serve different functions. This feature enables the CNC milling machine to execute several functions in one operation. The machine operator is not required to change the tool for the machine to perform another function. Automatic tool changer, CAD/CAM system software, display unit, is shown in figure.2, 3, 4. G-codes and M-codes will be use in the CNC system Axis Micro CNC Machine Machine structure is the backbone of the machine tool. It integrates all machine components into a complete system. The machine structure is crucial to the performance of the machine tools since it is directly affecting the static and dynamic stiffness, as well as the damping response of the machine tool. A carefully designed structure can provide high stiffness, result in higher operation bandwidth and more precise operation. The X-axis guiding system will usually be smaller than the Z-axis rails, because they only have to carry the weight of a small carriage and cutting tool, not the entire gantry. Gantry machines may have one tool carriage or many tool carriages. Sometimes the tool carriages will each have their own drive motor that moves them in the X-axis, and sometimes there will be only one motor that drives the X-axis, and all of the tool carriages will be connected together by a steel band, tie rod, wire rope, or similar mechanical device. The 3-Axis Micro CNC Machine is shown in fig Specifications of Open Type 3-axis Micro CNC Machine X-Axis reach : 40 mm Y-Axis reach : 40 mm Z-Axis reach : 40 mm Total work space : 40, Power supply : 12 V 1 A Number of stepper motors : editor@iaeme.com

3 Lakshmipathi Yerra, K. Chinnamaddaiah, Subramanyam B and P. Ravikanth Raju 3.3. Working Principle of Open Type 3-axis Micro CNC Machine Computer numerical control machine tools are such type of machine tools that have revolutionized machining processes. It is nothing but using a computer as a mean to control a machine that produces useful objects from solid blocks of material. CNC machine works under a close loop system that means when an operation is performed by executing a program, a feedback is coming back to the CNC system. This is not a descriptive answer of what is CNC machine. If we starts with a material block in a CNC machine after a certain time machine gives us a finished product like a spur gear, rifle barrel etc. Thus we can see that CNC machine performs various jobs in a single machine tool Parts of Open Type 3-Axis Micro CNC Machine The following are the parts which are to be use in the development of 3-axis Micro CNC Machine. Linear actuators : 3 12v 1A Adapter : 1 Stepper Motor Drivers : 3 Arduino : 1 Extra Wire Motherboard mounts Various screws/nuts/bolts Soldering Iron Drill 4. EXPERIMENTAL SET UP In the process of experimental set up the required mechanical components should be mounting Assembling of Mechanical Components of Open Type 3-Axis Micro CNC Machine In assembling of mechanical components some type of casing to mount the motor trays onto. Let s start with the Y-Axis. The Y-Axis will go back and forth, so take one of the motor trays and mount it parallel to the length of the casing close to one end. Make sure it s aligned as straight as possible and use some motherboard mounting screws to mount it. For the X-axis mount it perpendicular to the length of another optical drive case, again making it close to one end and aligning it as straight as possible. Then mount it using motherboard mounting screws as well. As for the Z drive, we will need to mount it to the laser housing sled of the X-drive. In order to do this, we need to find some way to extend and create a platform to mount it to. In this system motherboard mounts and an electrical plate covers are used. Then fastened the final motor tray to the electrical plate cover on the X-Axis and also mounted another electrical plate cover to the laser housing sled on the Y-axis to provide it a flat platform as well. Once all of the drives mounted, the final step is to attach the X & Z axis to the Y- axis. If the system wants to mount the X- axis perpendicular to the Y- axis (looks like an L shape) and adjust them so that the Z- axis is aligned over the Y- axis. Scrub through each axis to make sure none of them are overshooting or running into each other. After the alignment set, screw everything together. The system ended up using an L Bracket, but you may be fine just screwing one case directly into the other case editor@iaeme.com

4 Development of an Open Type CNC System for a 3-Axis Micro CNC Machine 4.2. Connecting the Electronics for Open Type 3-Axis Micro CNC Machine To get everything wired up so that it works, we need 5 components: Arduino Uno : 1 Easy Stepper Motor Driver : 3 PC Power Supply : 1 The Arduino Uno is the device that will be controlling everything. It is essentially the brains of the device. But by itself, it has issues controlling the stepper motors directly. To resolve all Arduino/Stepper motor issues, it will need a Stepper Motor Driver for each motor (in this case, will need 3). The Arduino Uno is shown in fig SOFTWARE INSTALLATION At this point, all the hardware should be completed. The only thing that s left to do now is to install the software that will make it run. The CNC machine runs off of a programming language called G-Code. It essentially tells the X, Y, and Z axis which specific coordinates it needs to go to. By itself, Arduino has a difficult time interpreting G-Code, so we will need to install a G-Code interpreter program called Grbl. Here are the steps you need to take to install Grbl on your Arudion (Uno) Grbl Grbl is a free, open source, high performance software for controlling the motion of machines that move, that make things, or that make things move, and will run on a straight Arduino. If the maker movement was an industry, Grbl would be the industry standard. Most open source 3D printers have Grbl in their hearts. It has been adapted for use in hundreds of projects including laser cutters, automatic hand writers, hole drillers, graffiti painters and oddball drawing machines. Due to its performance, simplicity and frugal hardware requirements Grbl has grown into a little open source phenomenon. Grbl is a no-compromise, high performance, low cost alternative to parallel-port-based motion control for CNC milling. It will run on a vanilla Arduino (Duemillanove/Uno) as long as it sports an AT Mega 328. The controller is written in highly optimized C utilizing every clever feature of the AVR-chips to achieve precise timing and asynchronous operation. It is able to maintain up to 30 KHz of stable, jitter free control pulses. It accepts standardscompliant g-code and has been tested with the output of several CAM tools with no problems. Arcs, circles and helical motion are fully supported, as well as, all other primary G-code commands. Macro functions, variables, and most canned cycles are not supported, but we think GUIs can do a much better job at translating them into straight g-code anyhow. List of Supported G-Codes in Grbl v0.8c Master: Non-Modal Commands: G4, G10L2, G10L20, G28, G30, G28.1, G30.1, G53, G92, G92.1 Motion Modes: G0, G1, G2, G3, G38.2, G38.3, G38.4, G38.5, G80 Feed Rate Modes: G93, G94 Unit Modes: G20, G21 Distance Modes: G90, G91 Arc IJK Distance Modes: G91.1 Plane Select Modes: G17, G18, G19 Tool Length Offset Modes: G43.1, G49 Cutter Compensation Modes: G40 Coordinate System Modes: G54, G55, G56, G57, G58, G59 Control Modes: G61 Program Flow: M0, M1, M2, M30* Coolant Control: M7*, M8, M editor@iaeme.com

5 Lakshmipathi Yerra, K. Chinnamaddaiah, Subramanyam B and P. Ravikanth Raju Spindle Control: M3, M4, M5 Valid Non-Command Words: F, I, J, K, L, N, P, R, S, T, X, Y, Z The software GRBL is shown in fig Flashing Grbl to Arduino UNO Flashing a hex file to your Arduino is simple with windows. First, plug in your Arduino into any USB port of your Windows machine and then determine the assigned COM port of your Arduino. To Determine your Arduino's COM port: Windows XP: Right click on "My Computer", select "Properties", select "Device Manager". Windows 7: Click "Start" -> Right click "Computer" -> Select "Manage" -> Select "Device Manager" from left pane In the tree, expand "Ports (COM & LPT)" Your Arduino will be the USB Serial Port (COMX), where the X represents the COM number, for example COM6. If there are multiple USB serial ports, right click each one and check the manufacturer, the Arduino will be "FTDI". To flash a grbl hex to an Arduino: Download and extract XLoader. Open XLoader and select your Arduino's COM port from the drop down menu on the lower left. Select the appropriate device from the dropdown list titled "Device". Check that Xloader set the correct baud rate for the device: for Duemilanove/Nano (ATmega 328) or for Uno (ATmega 328). Now use the browse button on the top right of the form to browse to your grbl hex file. Once the grbl hex file is selected, click "Upload" After clicking upload, you'll see the RX/TX lights going wild on your Arduino. The upload process generally takes about 10 seconds to finish. Once completed, a message will appear in the bottom left corner of X Loader telling you how many bytes were uploaded. If there was an error, it would show instead of the total bytes uploaded. Steps should be similar and may be done through the command prompt. 6. CONTROLS OF MICRO CNC Using the Arrow tool (from top left toolbar), select your entire image. Move it to the bottom left corner of the grid. You can pan around the grid by selecting the Hand tool from the toolbar. Use it to drag the image back to the center of the screen. From the upper right corner of the page, change the measurements to cm. Using the scale option from Edit > Scaled Selected, scale the object down and move it so that it fits within the single square that is in the corner of the grid (use the picture to the left as reference). With the image still selected, go to Cam > Follow Path Operations. Change the target depth to -1, the safety height to 1 and the step down to 0.1 and then click OK editor@iaeme.com

6 Development of an Open Type CNC System for a 3-Axis Micro CNC Machine Then go to Cam > Calculate Selected to calculate the path. Lastly, go to Cam > Export G-code to save the G-Code of your image. 7. RESULT AND DISCUSSION The open type micro CNC system is completed by integrating stepper motors to arduino through the stepper motor drivers.now the software GRBL is uploaded to arduino chip which is controlled by GRBL controller by the help of which we can send G-codes. The G-codes are the cause of the motion of the stepper motors which cause motions in X, Y, Z -axes respectively. The Micro CNC is shown in fig FIGURES Figure 1 Micro CNC system block diagram Figure 2 Automatic Tool Changer Figure 3 CAD/CAM Software editor@iaeme.com

7 Lakshmipathi Yerra, K. Chinnamaddaiah, Subramanyam B and P. Ravikanth Raju Figure 4 Display unit Figure 5 Mounting of 3- axis Micro CNC Figure 6 Arduino Uno Figure 7 GRBL editor@iaeme.com

8 Development of an Open Type CNC System for a 3-Axis Micro CNC Machine Figure 8 Micro CNC 9. CONCLUSIONS The high spindle speed reduces the chip load which reduces the forces between the tool and the material. A high-speed / low-force machining yield less heat, reduces tool deflection, and allows machining of thinner walled work pieces. This results in cooler machining, superior surface quality and better accuracy. It is used to drill small and highly accurate holes which are becoming a common requirement across a range of industries and applications. REFERENCES [1] Yung C. Shin, Henry Chin, Michael J. Brink, Studied the Characterization of CNC machining centers, Journal of Manufacturing Systems,1991. [2] I. Pahole, L. Rataj, M. Ficko, S. Klancnik, S.Brezovnik, M. Brezocnik, and J. Balic, "Construction and evaluation of low-cost table CNC milling machine",2009. International Journal of Modern Engineering Research (IJMER) (Vol.2, Issue.1, Jan-Feb 2012) ISSN: 2249 [3] V.K. Pabolu and K.N.H. Srinivas, "Design and implementation of a three dimensional CNC machine",2010. [4] T. Andrei and I. Nae, did the workout on "Practical applications performed by a stepper motor CNC router", [5] P.A. Sherring da Rocha Jr., R.D.S. Souza, and M.Emilia de Lima Tostes, "Prototype CNC machine design", [6] M. Karthick, M. Sundarraj and T. Raja, Design and Control of ATC for Shorter Time Interval in CNC Machines. International Journal of Mechanical Engineering and Technology, 8(3), 2017, pp [7] Mufaddal A. Saifee, Dr. Usha S. Mehta, Design and Implementation of 3-Axis Linear Interpol Ation Controller in FPGA for CNC Machines and Robotics. International Journal of Advanced Research in Engineering and Technology (IJARET), Volume 5, Issue 9, September (2014), pp editor@iaeme.com