Supply Kit Project: Pneumatic Launcher

Transcription

1 GEORGIA INSTITUTE OF TECHNOLOGY George W. Woodruff School of Mechanical Engineering ME 2110 Creative Decisions and Design Spring 2010 Supply Kit Project: Pneumatic Launcher In order to successfully design and build a product, you must understand the capabilities of the supplies at your disposal. For example, you must understand how motors and sensors work. Furthermore, you must have knowledge of manufacturing processes, such as machining with milling machines and water-jet cutting machines. This project will help you develop an understanding of the supplies and manufacturing processes available to you in ME2110. Your goal is to build a pneumatic-powered launcher that shoots a Q-tip as far as possible. The launcher will be controlled by the ME2110 controller box. Therefore, Part 1 of this project will teach you how to program the controller box, as well as use the sensors and actuators in your supply kit. There are two separate task lists. Some of the students on each team will be assigned to list A, the other students will complete list B. Please refer to the mechatronics kit manual on the course website, which provides detailed information about each component of the kit along with specific examples of the programming syntax needed to control them. You will have to demonstrate the assigned tasks to your Studio Instructor or TA. They will then sign your assignment sheet, indicating the tasks have been completed. In Part 2, you will construct a pneumatic launcher. To do this, you are provided a detailed process plan and mechanical drawings for the device, which you will machine from plastic stock (Delrin). You will need to write a simple code telling the pneumatic valve provided in your kit to open, sending a pulse of pressurized air to your device, causing the Q-tip to shoot out. This studio is pass/fail. You must complete the assigned tasks to pass the course. 1) Deliverables due at the beginning of studio next week Complete 3 of the tasks on the mechatronics task list assigned to you, or complete one of the machined parts. 2) Deliverables due at the beginning of studio in two weeks Complete all of the tasks on the mechatronics task list assigned to you, or complete two of the machined parts. Furthermore, you must have your nameplate drawing ready to load onto the water-jet cutter. All nameplates will be cut in this studio section. 3) Deliverables due at the beginning of studio in three weeks Your pneumatic-powered Q-tip launcher must be completed. You will compete against other students in your studio to determine who can shoot a Q-tip the farthest. You will get two attempts to achieve the maximum distance. You must secure your device in place without holding it. However, the top of your shooter cannot be more than 1 foot above the ground. Note that you must share the computer controller and the pneumatic supplies with the other members of your team.

2 Part 1 Mechatronics This lab will provide experience with integrating electrical, mechanical, and pneumatic systems. The lab is broken down into two weeks. During the first week, part of your team will complete part A of the lab; part B will be completed by the rest of your group during the second week. Although the programming style will not be graded, the code written during these two labs should be helpful in developing the code for the final project. Therefore, it is important to program using a standard structure and adequately comment the code so the program will be easy to follow when referred to later on. The suggested format is: Constants Table Program Variables Main Program Subroutines Before attempting to perform these programming tasks, it is helpful to read through the Controller and the Pneumatic reference material available on the website and run through the Controller Box Tutorial. These should provide a good background to the layout of the controller box and how to implement the electro-mechanical-pneumatic components in a design. Several programs are going to be assigned each week. A checklist is provided to document progress through the assignment. After each task is completed, have the professor, or TA, initial the checklist to verify that the program works. Turn in the completed checklist before you leave. Feel free to ask the professor, TA, or peers for help in completion of this assignment.

3 Mechatronics Lab: Part A, Week 1 Names: 1. Have the DC Motor run for 2 seconds, stop for 2 seconds, run for 2 seconds, etc. 2. Connect a microswitch to P0 (START) and have the DC motor run at full speed when the switch is held down and turn off when the lever is released. Hint: Connect the microswitch to P0, read in the value of P0 when the lever is pressed and the value of P0 when the lever is released. The variable name corresponding to P0 is IN0 (it does not have to be defined). Note: This is what will happen during the competition. The machines will begin when the circuit on P0 is shorted (lever is pressed) and will stop when the circuit is opened (lever is released). These couple lines of code will be very important in your final design project. 3. Connect two microswitches and the pneumatics. The program starts with the cylinder retracted. When one switch is pressed, the cylinder should extend and remain extended after the switch is released. When the other switch is pressed, the cylinder should retract and remain retracted. This process should run indefinitely. 4. Connect two solenoids and two microswitches. When one microswitch is pressed, one solenoid is activated for 2 seconds and then release. When the other microswitch is pressed, the other solenoid is activated for 500 ms and then release. When one actuator is active the other cannot be activated. 5. Same as #4, only now the other actuator can be activated when the other is active. Hint: Put a short pause in the program loop and assume that the time through the loop is equal to the length of the pause. You ll know when to turn off the actuator by counting the number of times through the loop. Checklist for Part A:

4 Mechatronics Lab: Part B, Week 2 Names: 1. Connect the stepper motor and the DC motor. Make them run clockwise for five seconds, stop for 2.5 seconds, run counter-clockwise for five seconds, and then stop for 2.5 seconds. Repeat this sequence five times. 2. Perform the same act as #1, but always have the stepper motor and the DC motor rotating in opposite directions. 3. Connect the IR distance sensor and one stepper motor. Have the motor run if the reading > 128 and have the motor stop if the reading <127. Put a two-second pause between distance sensor readings. 4. Connect the encoder and have the DC motor run at full speed when the encoder is being rotated and stopped when it is not being rotated. 5. Connect the encoder and the pneumatics. When the encoder is rotated 5 complete revolutions, the actuator should extend and remain extended until the encoder is rotated 3 complete revolutions. The cylinder should only extend 4 times, then remain retracted regardless of how many times the encoder is rotated. Checklist for Part B:

5 MACHINE SHOP SAFETY ALWAYS WEAR SAFETY GLASSES Even when you are not working on a machine, you must wear safety glasses. A chip from a machine someone else is working on could fly into your eye. MACHINING Follow directions. If you don t know how to do something, ask. Before you start the machine: Study the machine. Know which parts move, which are stationary, and which are sharp. Double check that your workpiece is securely held. Remove chuck keys and wrenches. Do not leave machines running unattended. Clean up machines after you use them. A dirty machine is unsafe and uncomfortable to work on. Do not use compressed air to blow machines clean. This endangers people's eyes and can force dirt into machine bearings. Report all broken or non-working machines. CLOTHING, JEWELRY, AND HAIR Wear long pants (to your shoes). Wear short sleeves or roll up sleeves. Wear closed toe shoes and socks. Remove all jewelry - watches, bracelets, rings, necklaces, dangling earrings. Long hair or beards must be tied back. If your hair is caught in spinning machinery, it will be pulled out if you're lucky. If you're unlucky, you will be pulled into the machine. No ties, scarves, and dangling clothes. SAFE CONDUCT IN THE MACHINE SHOP Be aware of what's going on around you. For example, be careful not to bump into someone while they're cutting with the bandsaw (they could lose a finger!). Concentrate on what you're doing. If you get tired, leave. Don't hurry. If you catch yourself rushing, slow down. Don't rush speeds and feeds. You'll end up damaging your part, the tools, and maybe the machine itself. Listen to the machine. If something doesn't sound right, turn the machine off. Don't let someone else talk you into doing something dangerous. Don't attempt to measure a part that's moving. No fooling around. VIOLATIONS OF THESE RULES WILL RESULT IN IMMEDIATE REMOVAL FROM THE MACHINE SHOP.

6 Part 2 - ME 2110 Machining Assignment Pneumatic Cotton Swab (Q-Tip ) Launcher Process Plan for Pneumatic Launcher 1. Obtain nominal 1.5 and 3.5 lengths of round delrin stock 2. Face one end on lathe, flip over and face other end to final lengths 3. Drill 1/4 thru hole along the axis of the 3.5 segment using the tailstock of the lathe (see ME2110-1). 4. Mark 5/16 drill bit with a line 3-3/8 from the tip. 5. Drill 5/16 X 3-3/8 hole axially using the tailstock of the lathe using the mark as a guide for the drill depth. 6. Drill #36 radial thru hole for set screw using a milling machine 7. Tap #36 hole with #6-32 UNC threads 8. Chuck the 1.5 segment in the headstock of the lathe and turn 3/4 length to 5/16 diameter. (see ME2110-2) 9. Cut off 1/2 of the 5/16 diameter shaft using the band saw and set aside; this will serve as your piston 10. Continuing with the now 1 segment, flip over and drill 1/8 thru hole axially 11. Drill 9.0mm x ½ hole axially using the tailstock of the lathe 12. Tap 9.0mm hole with M10x1.0mm tap Process Plan for Stand: 1. Obtain nominal 2 length of square 1 x1 delrin stock 2. Mill ½ deep T-shaped pocket in stand for holding 3-way fitting and tube quick disconnect fitting (shown in ME2110-3) 3. Cut a ½ x 1 aluminum plate with your initials on the water jet cutter and glue onto your stand (see ME2110-4)

7 Nameplate Design and Production Each person will be required to produce one nameplate. The plate itself will be produced utilizing the OMAX waterjet cutter and will be attached to the base of your pneumatic launcher. The plate dimensions are restricted to 0.5 x1 with 1/16 radius corners and will be cut into 1/16 thick aluminum. These features are shown schematically in the attached figure labeled ME The plate can be of any appropriate design as long as it fits within the specified 0.5 x1 space (In the example shown initials are cut into the plate). In order to cut the object on the water jet, however, certain guidelines must be followed: The design should be created in AutoCAD or OMAX Layout (provided in the 2110 lab). If created in AutoCAD the design must be saved as a dxf file and imported into OMAX Layout. Connected cutouts can be made but floating features are not allowed (i.e. no bulls-eyes). No features smaller than 0.05 are permitted. The part must cut within 1 minute in the simulated OMAX Make.

8

9

10

11