P11213 LVE: Modular Student Attachment Assembly/Manufacturing Plan

Transcription

1 Table of contents P11213 LVE: Modular Student Attachment Assembly/Manufacturing Plan 1 MATERIALS AND PURCHASING REQUIRED DOCUMENTATION FACILITIES TRAINING STAFF SCHEDULE EQUIPMENT REQUIRED PERSONEL REQUIREMENTS I/O SHROUD MOUNTING PLATE LVE MOUNTING PINS SERVO, SUPPORT, GRIPPER, AND PIN MOUNTS SERVO MOUNTING GEAR SCREWS, NUTS, COTTER PINS, WASHERS, CLEVIS PINS GRIPPER CONTROL BOARD AND I/O BOARD PCB Assembly: Daughter Card Assembly: Software Downloading: Wiring Assembly... 12

2 16 STUDENT LINKS SYSTEM ASSEMBLY Chassis IO Interface Servo Assembly Bracket Mounting Link Assembly Gripper Attachment Pin Installment Servo Support MSA Attachment to LVE ASSEMBLY DRAWING... 23

3 P11213: LVE Modular Student Attachment Assembly/Manufacturing Plan 1 MATERIALS AND PURCHASING Materials for the system shall be purchased from the companies listed on the bill of materials using the product numbers indicated. This plan is designed to walk through the manufacturing of each component to most efficiently produce the components for the design. 2 REQUIRED DOCUMENTATION Mechanicals: - IO Shroud: Controls: - Control Board Schematic: %20MSA%20Mainboard%20-%20v1%20-%20Schematic.pdf - Control Board Layout file: %20MSA%20Mainboard%20-%20v1%20-%20Layout%20-%20Top.pdf - I/O Board Schematic: %20LVE%20MSA%20Chassis%20IO%20v1%20-%20Sch.pdf - I/O Board Layout: %20LVE%20MSA%20Chassis%20IO%20v1%20-%20Brd.pdf (Note: All files can be opened with the latest version of EagleCAD by Cadsoft ( or any PDF reader) 3 FACILITIES Mechanicals: - RIT Mechanical Engineering Machine Shop - RIT Mechanical Engineering Wood Shop Controls: - Surface Mount Technology (SMT) Laboratory Center for Integrated Manufacturing Studies (CIMS) Rochester Institute of Technology 4 TRAINING STAFF Mechanical: In case of issues with machining, be sure to consult with the lab supervisors, and ask for permission before using the machinery. Dave Hathaway Operations Manager

4 Phone: Office: 2361 Gleason Controls: Jeffrey G. Lonneville SMT Lab Manager Phone: Fax: Office: CIMS SCHEDULE Mechanicals: - I/O Shroud Printing 3 weeks - Machining Components 6 hours - Gripper Assembly 5 minutes Controls: - PCB Manufacture- Depends on FAB house (4-5 weeks worst case) - Hardware Assembly 2 hours - Software Downloading 5 minutes 6 EQUIPMENT REQUIRED Mechanical: - Hack Saw (Wood Shop, Brinkman Lab) - Digital Readout Mill (Building 9 Machine Shop) - Digital Readout Lathe (Building 9 Machine Shop) - Band Saw (Building 9, Machine Shop) - Belt Sander (Building 9, Machine Shop) Controls: - Bill of Materials Components - Printed Circuit Boards - Printed Circuit Board Layout and Schematic - Microscope - Solder Iron - Solder/Solder Paste - Solder Wick - Tweezers - Manual Thermal Reflow Station - Computer with USB Ports - USB Cable - Adjustable power supply (able to limit current and voltage)

5 7 PERSONEL REQUIREMENTS Mechanicals: - 2 Team Members to machine all machinable parts - Lab Management Available for Training/Assistance during normal business hours Controls: - 1 Team Member o 1 Member to Place Solder Paste, Place Components on PCB, and operate the Reflow Station - Lab Manager Available for Training/Assistance during normal business hours. 8 I/O SHROUD The I/O shroud (part 21) is meant as an interface to the connectors for the control board to the external components to be connected. The shroud should sit flush with the outside surface of the LVE paneling and will be made of white opaque plastic. The part can be 3D printed in the Brickman lab here on campus. Lead time for on campus projects is typically 2-3 weeks. The order can be placed online at: Details for the documents for placing the order are available online MOUNTING PLATE The mounting plate is to be made from an opaque white Plexiglas material. The material comes in a plastic sheet of the desired thickness, typically with a paper on each surface to protect it from scratches. The plate must be machined as follow. 1. Obtain a drawing of the mounting plate, part number 1 ( 2. Mark an 8 by 8 section on the plate to become the actual size of the mounting plate. 3. Use the hack saw in the wood shop section of the Brinkman lab in the engineering building to cut the plate down to size. Be sure to draw the saw in slowly as to avoid cracking. Leave the protective paper on throughout this process. Be careful not to pull the saw in an out, but rather make single traverses through the material from front to back. 4. Place the material in a standard digital readout mill in the main section of the mechanical engineering lab. The plate shall be placed on a piece of scrap plywood slightly smaller than the plate, to support the plastic while being cut. 5. Put in the correct size drill bit (1/4 hole). The use of 1/4 standard fractional drill bit is sufficient for the material and as a clearance for 1/4-20 bolts. 6. Zero the bit on the corner of the plate, being sure to move the origin on the x-y plane inwards by the radius of the bit. Make sure the machine is running while touching off on the corners. A hole center finder may be used for this procedure. 7. Proceed to drill out all the holes as specified by the hole table on the drawing. 8. Using a 1/4 end mill, remove the material required for the I/O mounting point as in the drawing. 9. After all procedures, remove the plate from the mill.

6 10. Peel the paper off the plate. Use of water or low amounts of heating may be used. 11. Cut off all burrs and leftover material with a knife, sand paper, or the belt sander as desired. 12. Part complete. I/O Port Notching Mounting Holes 8 x8 Platform 10 LVE MOUNTING PINS The LVE mounting pins are used to attach the mounting plate to the LVE by press fitting into the studs of the chassis section. Holes are drilled in the pins to allow cotter pins for quick and easy attachment to the chassis. Since standard press pins are a case hardened steel, softer steel pins will be custom made to allow this additional machining. The part shall follow the following machining process. 1. Obtain a drawing of the mounting pins, part number 16 ( 2. Mark a length of steel on the steel rod of the minimum length of 5 pins per LVE, adding on the necessary amount of slack for free play. 3. Place the steel rod in the lathe using a standard center mount chuck or more preferably, a collet made to fit the material obtained. 4. Turn down the rod to the desired diameter as called out in the print for the first pin. 5. Remove the rod from the lathe. 6. Cut the desired section off the rod above the desired lengths leaving a small amount of room to be ground off. Do this using the band saw in the machine shop of building Sand off the ends if they are rough from the band saw, using the belt sander in the machine shop. 8. Measure the length of the pin. Now place back into the lath, and resurface the end down to length until the desired length is found. Remove from the lathe. 9. Place the pins now into the vice on a digital readout mill. Zero the machine on all sides as required to mark the hole properly. 10. Drill a pilot hole using a center drill, smaller than that of the final hole diameter. 11. Using the correct diameter drill bit (1/8 ) drill the hole desired at the proper depth.

7 12. Remove the pin from the vice. 13. Repeat for the desired number of press fit pins. 14. De-burr and remove any excess material not necessary. 15. Part complete. 11 SERVO, SUPPORT, GRIPPER, AND PIN MOUNTS There are 5 mounting locations on the MSA which utilize the angle aluminum purchased. Each requires bolting on each surface, so holding tolerances in both planes is highly important. Each process begins with a similar manner, but is completed with a different hole pattern. The parts should be made as follows. 1. Obtain drawings for the brackets and mounting surfaces, part numbers 2, 3, 13, and 17 ( 2. Mark the length of the angle iron desired. 3. Cut the length desired on the band saw in the machine shop. It s best to cut with the flange edges sitting flat on the table, and the right angle pointing directly upwards. Leave some extra room to be ground down flat. 4. Repeat for each component. 5. Place each component in a mill device such that the edge is overhanging the device. Face the side of the part to make a square edge. 6. Repeat with the part flipped, cutting the final pass to the desired length. 7. Place each angle in the vice of a digital readout mill. This is best done using a horizontal standoff to support the angle. Zero the component on the desired right angle corner to maintain dimensioning. Be sure the machine is running while touching off on the part to not damage the blade, and account for the radius of the bit. 8. Cut or drill the desired holes or openings in each component. 9. Once complete, flip the part by 90 degrees such that the opposite back surface is exposed. 10. Zero the machine off the same corner to maintain dimensioning with respect to each side. 11. Cut or drill the required openings in the part. 12. Remove the part from the mill. 13. Remove and de-burr any excess material from drilling. 14. Repeat for each component. 15. Parts complete.

8 Intermediate Step Brackets 12 SERVO MOUNTING GEAR The servo mounting gear is made of plastic, and must be slightly altered to allow for more bulky machine screws to be used. This should hopefully improve the durability and life of the part, as well as make machining easier. This should be performed as shown. 1. Obtain a drawing for the servo output gear part number 5 ( 2. Place the servo gear in the vice of a digital readout mill, such that the flat side is facing upwards exposed to the mill. 3. Zero the machine on the output gear, finding the exact center of the output gear. Make sure a small enough bit is used (approximately the same size as being used to cut) and that the machine is running while this is being performed. Make sure the pre-drilled holes in the gear are either being removed by the new hole or out of range so as to keep integrity of the hole. 4. Offset the drill placement as desired by the drawing, and drill the desired holes in the output gear. 5. Remove the part from the mill. 6. Remove and de-burr the part, removing the extra material. 7. Part complete. 13 SCREWS, NUTS, COTTER PINS, WASHERS, CLEVIS PINS These materials are all obtained and will be assembled as purchased. 14 GRIPPER The gripper is to be ordered and will be received with assembly instructions. The final assembly will look as follows.

9 MSA Gripper Assembly 15 CONTROL BOARD AND I/O BOARD The control board for the MSA interfaces with the main control board for the entire MSA. This part has the longest lead time of all parts in the MSA, and should be ordered allowing more than 6 weeks to allow for the boards to be printed and shipped. Note: the Gerber files were generated by using the CAM script provided by Sparkfun Electronics for BatchPCB.com (The CAM script is also available on EDGE) 15.1 PCB Assembly: 1. Use microscope and solder station to place solder paste on Top PCB pads. 2. Place Surface Mount Components on top of PCB with tweezers. Check orientation of parts with PCB layout and schematic. 3. Use Manual Thermal Reflow Station to solidify the connection between components and pads. 4. Allow PCB to cool. Wait at least 30 seconds before handling PCB. 5. If the PCB is still hot, use a pair of pliers to move the board. 6. Use microscope and multi-meter to check for short circuits on PCB. 7. Use microscope and solder station to place solder paste on bottom pads. 8. Place Surface Mount Components on bottom of PCB with tweezers. Check orientation of parts with PCB layout and schematic. 9. Allow PCB to cool. Wait at least 30 seconds before handling PCB. 10. Use microscope and multi-meter to check for short circuits on PCB. 11. Use solder and solder iron to solder all thru-hole parts and connectors to the PCB Daughter Card Assembly: 1. Use solder and solder iron to solder the thru-hole header pins on each long edge of the daughter card

10 2. Insert the daughter card into the control board. Note the orientation. a. The reset button should be closest to the 6 pin ISP programming header (See the illustration below) Power supply: The power supply connection is located at the blue screw terminal port on the lower left hand side of the MSA control board. This connector only accepts gauge wire. Connect as follows:

11 1. Insert positive lead (with copper exposed) into the port marked positive 2. Tighten wire down with screw driver 3. Insert positive lead (with copper exposed) into the port marked negative 4. Tighten wire down with screw driver 5. Power the control board with a desktop power supply. Provide 7V with a 100 ma current limit. 6. The green LED and the red LEDs should light up when power is applied Software Downloading: 1. Download Arduino IDE and code from EDGE. 2. Connect a unpopulated Arduino board to a PC using USB A cable. a. Note: a USB-to-RS232 board from Sparkfun.com or Pololu.com can suffice as well

12 3. Connect a ground wire from the unpopulated Arduino board to the control board. 4. Connect the TX and RX pins of the unpopulated Arduino board to the TX and RX pins of the control board respectively 5. Open Arduino IDE. 6. Go to File open and navigate to the Arduino Code, click open. 7. Select the correct board type(arduino with Atmega328). 8. Select the correct com port for the Arduino. 9. Click the program button. 10. Wait for all but TX LED to stop blinking. 11. Remove all wire connections after programming Wiring Assembly The wiring necessary for connection between the I/O ports, main control board, MSA control board, and power supply shall be assembled as follows. Battery Connection: The battery connection is located at the blue screw terminal port on the lower left hand side of the MSA control board. This connector only accepts gauge wire. Connect as follows:

13 1. Insert positive lead (with copper exposed) into the port marked positive 2. Tighten wire down with screw driver 3. Insert positive lead (with copper exposed) into the port marked negative 4. Tighten wire down with screw driver 5. When connected the green LED and the red LED should light up. Serial connection: 1. Connect provided two-pin serial jumper wire (Sparkfun Part PRT-10367) to the UART header on the MSA control board. (Located top left hand corner) a. Note: ensure the Red wire is connected to the pin labeled TX 2. Connect the other end to the UART pins on the LVE Control board. a. Note: ensure the Red wire is connected to the pin labeled RX

14 Ribbon cable assembly: The ribbon cable assembly provides a straight through connection from the MSA Control board to the chassis I/O board. 1. Insert the ribbon cable connector with the ribbon leading away from the control board 2. Insert the ribbon cable into the chassis I/O board. a. Note: The middle notch in the connector on the PCB should not be covered by the ribbon cable 16 STUDENT LINKS The student links are the part that will be continuously be remade each time an MSA project is created. These links will vary greatly in their lengths, hole patterns, and sometimes shape. Each

15 student will be responsible for creating their own link as part of the lab section of their class. The links should follow the standard protocol and be made as follows. 1. Obtain student made drawings for the materials and parts listed as part numbers 6, 11, and Obtain the link material in the shop, and mark the required length desired for the link. 3. Cut the required length for each link on the band saw in the machine shop. 4. Use the belt sander to smooth out any rough edges and remove burrs or excess material. 5. Place the link material in the vice of a digital reading mill. Be sure to properly support the link and allow room behind the link for all holes to be made. 6. Zero the part on the mill using the required bit, making sure the machine is operating while zeroing. 7. Drill the necessary openings and holes in the links as called out by the student made link drawings. 8. Add required machining as necessary. 9. Remove all burrs or excess material. 10. Repeat for each link. 11. Parts complete. 17 SYSTEM ASSEMBLY 17.1 Chassis IO Interface The servo connections are made to the chassis IO interface board via the cutout in the cab of the LVE. The servo connections can be made as indicated below:

16 Note: The control signals for the servo headers should be to the left. (White or Orange Wires) 17.2 Servo Assembly The servo connects to the servo mount by sliding the servo through the opening. Note it s a tight fit and some filing may be required to get the appropriate clearance for the wiring. Once the servo has been fit within the bracket, it may be mounted with 4-40 x 1/2" bolts and nuts at the retaining locations. Servo Servo Mount Retaining Bolts and Nuts Servo Assembly 17.3 Bracket Mounting All the brackets mounted to the mounting plate may be attached using the required bolts and nuts as required. The mounting bolts are 1/4-20 pan head machine screws, with corresponding nuts. The nuts are fastened to the underside of the mounting plate.note to

17 check here for alignment of the holes for brackets and servos with the designed link geometry. Pinned Brackets Mounting Bolts and Nuts Servo Brackets 17.4 Link Assembly The link and servo output gear must be assembled before attaching the output gear to the servo. This is achieved by bolting the servo bracket to the link with the required 4-40 bolts and nuts as required.

18 Driving Link Servo Output Gear Servo Output Gear Driving Link Mounting Bolts and Nuts Once this is included, the output gear can be attached to the servo.

19 Attached Pinned Link Arm Attached Drive Link Arm After the brackets are all in place and the servo and link have been connected, the remainder of the links may be attached using the necessary amount of spacers, clevis pins, and cotter pins as desired. Attached Pinned Link Arm

20 17.5 Gripper Attachment The gripper is attached using the gripper mount using 4-40 hex screws included. The mount should first be connected to the gripper and second connected to the top link on the arm as desired by the design. Note the nuts and bolts used to connect the servo to the servo bracket are same as that for the gripper to the gripper bracket. Also, the bolts for connecting the link to the gripper bracket are the same as the mounting bolts and nuts. Gripper Nuts and Bolts Gripper 17.6 Pin Installment The dowel pins are to be permanently pressed into the studs of the chassis subsystem. This can be achieved by hand if possible, or by using an arbor press. If the pins can t be pressed in, remove a small amount of material on the lathe (about increments until it fits with a press). If the bottom of the pin hole should be exactly 0.25 above the top of the stud. If it s too high, press further in or remove and cut down material. If it s too low pull up until at the proper height.

21 Attached Pin 17.7 Servo Support Due to the nature of potential impacts to the system, the servo should be properly supported using a balance pin. Here, the use of spacers, clevis pins, and cotter pins whould be incorporated to press the servo mount onto the servo and help remove some axial load from the servo output shaft. Servo Support 17.8 MSA Attachment to LVE The MSA can be attached to the platform LVE by sliding the mounting plate over the dowel pins in the correct orientation, and sliding cotter pins through the exposed holes. The servos can be connected to the LVE controls through the I/O port exposed on the LVE. Note the correct orientation of the servo wiring as denoted in the I/O and controls assembly. The assembly of the MSA system is the complete and operational.

22 Attached MSA LVE

23 18 ASSEMBLY DRAWING Attached below is the assembly drawing of the MSA.