By Bao Loc Doan (Project Manager)

Requirement L2 – 3: Makeblock XY Plotter motors shall be modified to 0.05 mm error tolerance.

Introduction

The Makeblock XY Plotter came with two (2) Makeblock 42BYG stepper motors. The stepper motors control our x-axis and y-axis movements. Geared stepper motors were given as a suggestion to replace our current x and y axis stepper motors for higher accuracy. After testing the current stepper motors and presenting our PDR demo, it was agreed that the movement of the x-axis and y-axis are too slow.

Discussion

Figure 1 – Determining geared stepper motors (reference link at the end)

Our current stepper motor are bipolar stepper motors. Normally, these give more torque at low RPMs, while unipolar stepper motors spins faster for the same motor and power supply. The Makeblock Robot Plotter kit came with bipolar stepper motors as well as compatible stepper drivers.

We understand that what we are looking for are top output speed and the acceleration. Purchasing a 5:1 gearbox for the same stepper motor would change the step angle going from 1.8 degrees to 0.35 degrees if using the same stepper motor specs. After research, there is a Makeblock 5:1 geared 47BYG stepper motor that costs 59.99 per unit. This would make our machine increase accuracy by a factor of 5 but is out of our budget and would make our machine slower if we still microstep 1/16th. After obtaining the geared stepper motor, experiments will be conducted to determine if it’s possible to microstep the motors to 1/8th step and maintain desirable error specs.

We know that our Makeblock 42BYG motor does 200 steps/rev and since the driver is microstepping 1/16th, that means it can go 3200 steps per revolution. We could full step the motors, but we would lose accuracy, which is not wanted. The reason why full stepping the motor would make the machine lose accuracy is due to the possibility of the motor skipping a step or losing a step since each step is more distant. 

We would like to use the same mechanical parts as we do right now due to compatibility. If introduced to a different motor that may need a different voltage or current, then a different stepper driver would need to be developed in order to step the unit faster and thus spending more resources. Our current stepper motor is rated at 1.7 amps/phase, so in order to properly utilize the current stepper driver, the new motor must be rated at 1.7 amps/phase as well. We would need a motor that can run at least 5 times the motor speed of our current 42BYG, be driven by 1.7 amps/phase, rated 12 volts, and be priced under 35 dollars each (to fit in the budget) to maintain the same speed but have more accuracy.

A stepper motor driver that can step the motor higher could be a fix but our budget is very limited.

Conclusion

A 5:1 geared Makeblock 42BYG stepper motor will work in increasing our accuracy so our device could meet requirement L2 -3 – Makeblock XY Plotter motors shall be modified to 0.05 mm error tolerance. It will satisfy all compatibility requirements  as well but budget remains an issue due to the 5:1 geared Makeblock 42BYG motor being $59.99 per unit. The issue in a geared stepper motor lies in that it will definitely make the Makeblock XY plotter move slower than it already is if we keep the microstep at 1/16th. We will conduct experiments where we can find a ratio between accuracy and speed (possibly 1/8th step) that will satisfy our error requirement as well as produce a satisfactory parts per hour speed. However, the speed requirement is not mandatory for this semester and this can be resolved by modifying the stepper driver in future semesters. We conclude that the stepper motor(s) linked above would be a sufficient fit for our needs.

References

Stepper Online: Motors & Electronics. Retrieved April 1, 2016, from http://www.omc-stepperonline.com/high-torque-gear-ratio-51-planetary-gearbox-nema-14-stepper-14hs201504spg5-p-294.html

By Henry Nguyen ( Electronics and Control)

To satisfy requirement L2-7B:

A solenoid valve for vacuum system shall keep a stable temperature under 160° F during operation.  

Introduction

In order for our machine to be able to pick and place components, we will use a solenoid to restrict the airflow from our vacuum pump when our machine is placing components. We are to test the limits of our solenoid valve in order to see if it is suited for our 3D pick and place machine. A factor to consider is that our plastic tubing can only withstand 160° F or 71° C.

—Equipment and Materials

1. 12V solenoid valve

Figure 1. 12V Solenoid Valve

1. Non-contact infrared thermometer

Figure 2. Thermometer

1. 12V DC power supply (obtained from ET-113)

Procedure

1. We will be connecting our 12V DC power supply to our solenoid valve in order for our solenoid valve to be kept in the open position.
2. We shall allow our solenoid valve to be on for 75 minutes and check the temperature of our solenoid valve consistently.
3. We will also be constantly turning on and off our power supply in order to switch our solenoid valve off an on.

Results

After 75 minutes of run time, we were able to measure the temperature of our solenoid valve. Based on the following data, we were able to conclude that our solenoid valve will heat up rapidly to approximately 82° Celsius but will not heat up more than this. The rated temperature for our solenoid valve is -5°  – 80° C. When running our tests, we found that our solenoid valve heated up more than 80° C.

Table 1. Temperature of 12V Solenoid valve over time.

Conclusion

We have decided to return this solenoid valve because it is not suited for our 3D pick and place SMD machine. Since the solenoid valve heats up more than our maximum temperature of 71° C of our plastic tubing, it will not be ideal to use this solenoid. It is possible that our plastic tubing may melt onto our solenoid valve if it heats up pass 71° C.

Reference

Solenoid Valve Image:

DC 12V 1/4 Inch Electric Solenoid Valve for Air Water. (n.d.). Retrieved March 02, 2016, from http://www.amazon.com/dp/B00KKIH1YK/ref=sr_ph_1?ie=UTF8

By: Bao Loc Doan (Project Manager)

Christine Vu (Systems Engineer)

Henry Nguyen (Electronics Engineer)

Nasser Alsharafi (Manufacturing)

Program Objectives/Mission Profile

by Bao Loc Doan (Project Manager)

Program Objective Statement

When humans manually pick up and place down surface mount components onto a printed circuit board (PCB), there are problems with human accuracy and time efficiency. A pick and place surface mount device (SMD) is an automated device that can populate a PCB with surface mount components (resistors, capacitors, and IC chips) by referencing an EAGLE PCB file through the use of software. The pick and place SMD machine will be able to pick up the surface mount technology (SMT) components from 8 mm reel feeders and an integrated circuit (IC) tray and place the components down at the correct location until the board is finished. The customer has expressed the desire to create a pick and place SMD machine that can populate surface mount components as small as 0402 on all EE400D boards of Spring 2016 with the same specifications as the Madell Corporation Model DP2006-2.  The customer has expressed the desire to keep the budget of the project below $650 and finished before the end of Spring 2016.

Mission Profile

Once an EAGLE PCB file provided by any project from EE400D up until Spring 2016 is uploaded, the pick and place SMD machine shall begin populating SMT components from four 8 mm reel feeders and one IC tray onto the PCB. The smallest SMT component that will be placed is component size 0402. The pick and place SMD machine will be modified from a Makeblock XY plotter and replicate the error specification of the Madell Corporation Model DP2006-2.

Requirements

Level 1 Program/Project Requirements

by Bao Loc Doan (Project Manager)

To satisfy our customer, a list of requirements that our end product needs to meet were created. These requirements will move the design forward and provide traceability to our program objectives and mission profile.

1. The SMD pick and place machine shall pick up and place down all SMT components provided by any EE400D PCB up until the end of Spring 2016.
2. The SMD pick and place machine shall be modified from an XY Plotter to have the same error specification of Madell Corporation Model DP2006-2  (n.d).
3. Software for the SMD pick and place machine shall accept all EAGLE PCB files of EE400D projects up until Spring 2016.
4. The SMD pick and place machine shall have four 8mm reel feeders and one IC tray.
5. SMT component size 0402 shall be the smallest component that the pick and place SMD machine can pick up.
6. Total cost of finished project must be under $650.
7. Deadline to complete the pick and place SMD machine shall be before the end of Spring 2016.

Level 2 System/Subsystem Requirements

by Christine Vu (Systems Engineer)

Level 2 System and Level 2 Subsystem Requirements are listed below. The process of forming requirements is not only crucial to the overall design of the project but also difficult to form due to the customer’s needs and the nonlinearity of designing. Through many revisions, the level 2 requirements were officially determined. Because this project is new to the Arxterra blog, references were obtained through scholarly journal research and outside resources other than the Arxterra blog.

Source Material:

Arra, M. , Geiger, D. , Shangguan, D. , & Sjöberg, J. (2004). A study of smt assembly processes

for fine pitch csp packages. Soldering & Surface Mount Technology, 16(3), 16-21.

CadSoft Computer GmbH and CadSoft Inc. (2011). EAGLE Freeware. Retrieved from:

http://www.cadsoftusa.com/download-eagle/freeware/

Changzhou Douwei Electric Co. Ltd. (n.d.). 42BYG Stepping Motor. Datasheet.

Makeblock. (2014, June 9). XY Plotter 2.0 How it works? Retrieved from:

https://www.youtube.com/watch?v=gY0xMYrWBDg

Panasonic. (2014, Feb. 4). Precision Thick Film Chip Resistors. Datasheet.

Shenzhen Maker Works Technology Co., Ltd. (2013). X-Y Plotter Robot Kit. Retrieved from:

http://www.makeblock.cc/xy-plotter-robot-kit/

TCI Precision. (2005). Blanchard Grinding. Retrieved from: http://tciprecision.com/machine-ready-blanks/capabilities/Blanchard%20Grinding

Telecommunications Industry Association. (2001). TIA/EIA-568-B.1: Commercial Building

Telecommunications Cabling Standard.

VBsProjects. (2014, July 12). Homemade SMD Pick and Place Machine – complete cycle.

Retrieved from: https://www.youtube.com/watch?v=CRSLbo_8nTQ#t=7m34s

Notes on Requirements:

L2 – # – Level 2 System Requirements (i.e. L2 – 1)

L2 – #x – Level 2 Subsystem Requirements (i.e. L2 – 1a)

Design Innovation

Creativity Presentation

System/Subsystem Design

Product Breakdown Structure

By Christine Vu (Systems Engineer) and Henry Nguyen (Electronics Engineer)

Figure 1. Product Breakdown Structure

The Product Breakdown Structure (PBS) shows all the functional blocks of our pick and place 3D SMD machine. The hardware is split into three different categories: Component Feeders, Vacuum Head, and X-Y Table. We will need a minimum of 4x micro servos to control our 4x 8mm reel feeders and an IC chip tray. The Vacuum head will consist of a vacuum to suction the components, a syringe or vacuum pen to pick up our components, a solenoid valve to block airflow and allow our components to be placed, and finally a stepper motor for rotation of the A axis. The X-Y Table is purchased from MakeBlock; however, we will need an aluminum surface table, slider rods, stepper motors, and calibration sensors to orientate our components. For software, we plan on using Arduino to program the Arduino Uno and Me Orion microcontrollers. Software must be able to convert Gerber files into G-code which can be read by our Me Orion microcontroller. We will need to be able to control all axis of our machine, the calibration sensor, component feeders, and solenoid valve through software.

Software Design

by Christine Vu (Systems Engineer)

The Makeblock X-Y Plotter Robot Kit software begins with the submission of a gcode file. An EAGLE file is submitted and converted to gcode for the Arduino sketch to translate. There are three main subroutines to process the gcode coordinates–process_string, stepper_control, and vacuum_control. In process_string, the code searches for x-coordinates, y-coordinates, and z-coordinates. In the stepper_control, x-,y-, and z-coordinates, are processed to move the motors. The vacuum_control is used to detect when the vacuum tubing should open and close according to the change in the z-coordinates.

Figure 2. Software Design

Electronic System Design

Source Material

Me Orion:

• Schematic:
  • Makeblock. (2014, June 25). Makeblock_Orion_Schematic_V1.0.PDF. Retreived Februrary 18, 2016, from http://learn.makeblock.cc/learn/resources/Makeblock_Orion_Schematic_V1.0.PDF
• Specifications:
  • Me Orion(Base on Arduino UNO). (n.d.). Retrieved February 26, 2016, from http://www.makeblock.cc/me-orion-base-on-arduino-uno/

Me Stepper Driver:

• Schematic:
  • Makeblock. (2014, June 25). Me_Stepper_Motor_Schematic.png. Retreived Februrary 18, 2016, from
  • http://wiki.makeblock.cc/images/4/40/Me_Stepper_Motor_Schematic.png
• Specifications:
  • Me Stepper Motor Driver. (n.d.). Retrieved February 26, 2016, from http://www.makeblock.cc/me-stepper-motor-driver/

System Block Diagram

By Christine Vu (Systems Engineer) and Henry Nguyen (Electronics Engineer)

Figure 3. System Block Diagram

The images above is the system block diagram for our pick and place 3D SMD Machine. We are currently using a Me Orion microcontroller provided by Makeblock. This microcontroller has an Atmega3280-AU microprocessor, 8 Me RJ25 ports, two Me Stepper drivers, and 3 Me RJ25 adaptors. The pin outs for each Me RJ25 port is shown above which is connected to our microprocessor. Every port on our Me RJ25 has a SDA and SCL which is our I2C. This will be all connected to our PC4 and PC5 respectively. We will be using ports J1, J2, J3, J6 and J7. The first two ports is to control our X and Y axis stepper motors. J6 and J3 is to control our X and Y axis limit switches respectively. Finally J7 is to control our Z-axis micro servo. We plan on having another micro servo to serve as our A-axis component orientation which may connect to any other available ports. Next we are considering a Adafruit 16-Channel I2C interface in order to connect all of our micro servos for our reel feeders. We currently will need 4 servos for this purpose; however, for future semesters, they may need to implement more reel feeders. Our vacuum will be constantly running on a separate power source. The solenoid valve will close off the vacuum to prevent suction. This will allow our components to be placed onto our PCB after our machine picks it up.

Interface Definition

Figure 4. Interface Matrix

The image above is the interface matrix for our pick and place 3D SMD machine. We will be utilizing an Arduino Uno, Me Orion, and Me Stepper Driver. Me Orion and the Me Stepper Driver came with our X-Y Plotter. This Me Orion is based off of an Arduino Uno, which will allow us to code using Arduino, Scratch. and AduBlock. We will be using this microcontroller because it has 8 RJ25 ports which will be useful for all of our actuators. The Me Stepper Driver will be used to precisely control our stepper motors by operating our motors in full, half, quarter, eighth, and sixteenth step modes. This modes can be easily changed using the built-in DIP Switch. We will need 4 Me Stepper Drivers in order to control all of our stepper motors on each axis (x,y,z,A).

Figure 5. Me Orion Schematic

Figure 6. Me Stepper Driver Schematic

Specification for  Me Orion:

Operating Voltage: 6-12V DC power;

Microcontroller: ATmega238;

Detecting Angle: prefer at 30 degree angle;

Dimension: 80 x 60 x 18 mm (Length x Width x Height);

Specification for Me Stepper Driver:

• Max current: ±1.35A
• Max motor drive voltage: 25V    
• Note: Me BaseBoard max supply  voltage 12V

• Logic voltage: 5V
• Dimensions: 48mm*24mm(Length × Width)

Mechanical Design

By Nasser Alsharafi (Manufacturing)

In this part of the project for the XY plotter I am coming up with the design of a Reel Feeder. The main purpose of a reel feeder is to feed the machine with the surface mounted parts. The reel feeder is made of aluminum. The main function of the Reel Feeder wheel is to roll and pass on the parts to the Reel Feeder base, which then the parts will be picked up by the vacuum.

Figure 7. Complete reel feeder assembly 3D model

Figure 8. Reel feeder base

The base sheet of the reel feeder has four channels called the grooves in which the tape passes through. The base sheet of the reel feeder has a length of 270 mm and a width of 82 mm. Each of the grooves on the base sheet of the reel feeder has a width of 8 mm. The main function of the reel feeder is to guide the tape to the part of the feeder where the chip is first pulled and then picked by a vacuum pen. This action helps in preparation of the next chip. After, the chip is taken by the vacuum pen and is placed on the PBC board.

Figure 9. Reel feeder wheel

Figure 10. Drawing of initial reel feeder base

Currently, our reel feeder is manual, so there can be further improvements by making the reel feeder automatic. In order to make the reel feeder automatic, I have to design a mounting bracket for 4 micro-servos. Each channel has single micro-servo to pull back the tape while pushing the reel forward. This will be implemented by working with Henry Nguyen to control the micro-servos.   

Design and Unique Tasks

Design

by Nasser Alsharafi (Manufacturing)

The pick and place vacuum nozzle system was sketched out. We had to take into consideration the weight of the entire system and make sure our actuator can support that weight.

Figure 11. Actuator Design

Unique Tasks

By Bao Loc Doan (Project Manager), Henry Nguyen (Electronics Engineer), Christine Vu (Systems Engineer)

The stepper motor movement for the X and Y axis were mirrored. If we wanted the XY plotter to move left, it would move right. If we wanted the XY plotter to move up, it would move down. The solution was to change the connection of the wires to the opposite orientation. There are 4 wires that are output from the stepper motor. The wire colors are green, blue, red, and black. Rather than inputting it as green,blue,red,black into the connector, we switched the orientation to black, red, blue, and green. This changed the stepper motor orientation.

The limit switches also were not working correctly. When the XY plotter was supposed to stop due to it reaching the limits of its working area, the XY plotter kept going and ramming into the edges of the XY plotter. The manual for the XY plotter had the limit switches going from an RJ25 into port 5 of the Arduino. This was wrong. After hours of debugging and testing software, we realized this error. The limit switches ended up working after plugging it into port 7 of the Arduino.

Project Status

by Bao Loc Doan (Project Manager), Christine Vu (Systems Engineer), and Henry Nguyen (Electronics Engineer)

Currently, we were able to successfully translate an EAGLE PCB file to G-CODE. There are two layers, TORIGINS and TPLACE, specifically from EAGLE PCB that were used. TORIGINS displays the centerpoint of each component and TPLACE displays the outline of the component so the system could possibly recognize which orientation the component should be placed. The issue that we are currently facing is interpreting all the G-CODE location sets and translating it in a way for our XY plotter to properly read them.

Figure 12. Torigins and Tplace layers

In order to successfully translate EAGLE to GCODE, the EAGLE file needs to be exported into a .DXF file. Then we can use ACEconverter to translate the .DXF file to GCODE. Using Notepad++, then the Z-axis can be modified to our needs.

Figure 13. ACEconverter and Notepad++

A trade-off study on the vacuum system was conducted as well. We are currently deciding which aquarium pump to use, whether it is 20 gal, 40 gal, or 100 gal. There are still experiments that need to be conducted and we will provide updates when those experiments are done. The trade-off study blog was created and can be seen here.

A separate blog has already been made for the XY plotter that was purchased and that blog will explain all design ideas as well as provide updates on how the XY plotter functions. The blog can be seen here.

Work Breakdown Structure

By Bao Loc Doan (Project Manager) and Christine Vu (Systems Engineer)

Our Work Breakdown Structure (WBS) was modeled after the Robot Project WBS. Each division will have tasks delegated to them and will be their primary responsibility to complete. As mentioned in 05 Preliminary Project Plan PDF, the WBS will be a “…  hierarchical tree structure where each node (group) is the responsibility of only one engineer.”  A completion of the WBS will indicate a successful project. The chart below will be the pick and place SMD machine WBS.

Figure 14. Work Breakdown Structure

Source Material

[1] G.Hill (2016, Feb). 05 Preliminary Project Plan [Online]. Available: 05 Preliminary Project Plan PDF

Project Schedule

A project schedule will lay out the deadlines that each engineer needs to conform to when assigned to their tasks. The schedule will allow the engineer to understand how much time they have left as well as the progression needed to complete the project. When deadlines are not met, there will be a chart illustrating the remaining cumulative work as well as baseline cumulative work.

Top Level Schedule

By Bao Loc Doan (Project Manager) and Christine Vu (Systems Engineer)

The top level schedule tasks were derived from our WBS. Each module in the WBS were taken into account. While working with the systems engineer, we developed a schedule that will divide all tasks in a progression that we believe will lead to project completion. Each required task will have a time estimate, and failure to meet the time estimated will result in the delay of every task assigned after. The chart below is the pick and place SMD top level schedule.

Figure 15. Top Level Schedule

System/Subsystem Level Tasks

By Henry Nguyen (Electronics Engineer), Christine Vu (Systems Engineer), and Nasser Alsharafi (Manufacturing)

Reference top level schedule for system/subsystem level tasks.

Burn Down and Project Percent Completion

by Bao Loc Doan (Project Manager)

A burn down graph is a visual representation of the expected progression and remaining progression. The top level schedule was created in ProjectLibre, so we had to use Excel to create a burn down graph. The task burn down and the percent burn down will be shown below.

Figure 16. Burn Down Graphs

System Resource Reports

Mass Report

By Christine Vu (Systems Engineer)

Table 1. Mass Report

Summary

The pick and place SMD machine will not need a power resource report because we are not limited in power. A waiver request will be submitted for approval.

The mass resource report is on the vacuum system to determine the mass. The stepper motor expected weight have been obtained from the Makeblock specifications on their X-Y Plotter Robot Kit (Shenzhen Maker Works Technology Co., Ltd., 2013).

The Makeblock Stepper Motor Driver is a component used to control the stepper motor with  the ArduinoUno. It contains a stepper driver chip, 4 wire bi-polar stepper motors, a potentiometer, DIP switch, and a heat sink.

Because the components have not been purchased, project allocation, actual mass, and contingency will be obtained after trade-off studies have been conducted.

Source Material:

Shenzhen Maker Works Technology Co., Ltd. (2013). Me Stepper Motor Driver. Retrieved from:http://www.makeblock.cc/me-stepper-motor-driver/

Project Cost Estimate

By Bao Loc Doan (Project Manager) and Christine Vu (Systems Engineer)

Table 2. Cost Report

Summary

The cost report supports all parts needed so far to construct the pick and place SMD machine for Spring 2016.

The Makeblock XY Plotter is an XY plotter that can be easily modified to our needs. This specific XY plotter has a working area of 12” x 15” so it can easily fit our PCB fabrication requirements (4” x 3.2” as per free Eagle CAD board working area) and additional reel feeders. The Makeblock XY plotter ships all the parts as a kit and would be much more efficient to build since we would no longer need to design the entire XY plotter. The accuracy of this XY plotter needs to be increased by a factor of 2 (as requested by the customer) and a simple solution is to implement a geared stepper motor.

The Makeblock Gearbox Stepper Motor will be implemented into our pick and place SMD machine so our precision error meets customer standards of 0.002”.

The aquarium pump, solenoid valve, tubing, syringe, and connectors shall be used for the vacuum system in the pick and place SMD machine. The aquarium pump is easily modified to become a vacuum and the solenoid valve with brass fittings will control when the vacuum suctions in order to pick and up and place down the components as intended. The tubing, syringe, and connectors will connect each individual component to make the vacuum system.

All of our surface mount resistors and capacitors shall be placed in the 4x 8 mm reel feeders so they can be populated onto the PCB. After Spring 2016, 16x 8 mm reel feeders will be implemented into the pick and place SMD machine.

The aluminum surface will be the working area of the entire pick and place SMD machine. The machinist labor is included into the price. The Makeblock XY plotter will need to securely fit into the aluminum surface and there will also be an aluminum clamping system that needs to be drilled into the aluminum surface.

The Makeblock stepper motor driver will be used in conjunction with the Makeblock stepper motor to control our vacuum nozzle. In order for the vacuum to be able to pick up components, the ability to move in the Z-axis is required. We have plans to implement one Makeblock stepper motor on the z-axis and will need the circuitry required.

by Bao Loc Doan (Project Manager)

Christine Vu (Systems Engineer)

Henry Nguyen (Electronics Engineer)

Nasser Alsharafi (Manufacturing)

Work Breakdown Structure

By Bao Loc Doan (Project Manager) and Christine Vu (Systems Engineer)

Our Work Breakdown Structure (WBS) was modeled after the Robot Project WBS. Each division will have tasks delegated to them and will be their primary responsibility to complete. As mentioned in 05 Preliminary Project Plan PDF, the WBS will be a “…  hierarchical tree structure where each node (group) is the responsibility of only one engineer.”  A completion of the WBS will indicate a successful project. The chart below will be the pick and place SMD machine WBS.

Figure 1. Work Breakdown Structure

Source Material

[1] G.Hill (2016, Feb). 05 Preliminary Project Plan [Online]. Available: 05 Preliminary Project Plan PDF

Project Schedule

A project schedule will lay out the deadlines that each engineer needs to conform to when assigned to their tasks. The schedule will allow the engineer to understand how much time they have left as well as the progression needed to complete the project. When deadlines are not met, there will be a chart illustrating the remaining cumulative work as well as baseline cumulative work.

Top Level Schedule

By Bao Loc Doan (Project Manager) and Christine Vu (Systems Engineer)

The top level schedule tasks were derived from our WBS. Each module in the WBS were taken into account. While working with the systems engineer, we developed a schedule that will divide all tasks in a progression that we believe will lead to project completion. Each required task will have a time estimate, and failure to meet the time estimated will result in the delay of every task assigned after. The chart below is the pick and place SMD top level schedule.

Figure 2. Top Level Schedule

System/Subsystem Level Tasks

By Bao Loc Doan (Project Manager), Henry Nguyen (Electronics Engineer), Christine Vu (Systems Engineer), and Nasser Alsharafi (Manufacturing)

Reference top level schedule for system/subsystem level tasks.

Burn Down and Project Percent Completion

by Bao Loc Doan (Project Manager)

A burn down graph is a visual representation of the expected progression and remaining progression. The top level schedule was created in ProjectLibre, so we had to use Excel to create a burn down graph. The task burn down and the percent burn down will be shown below.

Figure 3. Burn Down Graphs

System Resource Reports

By Christine Vu (Systems Engineer)

Table 1. Mass Report

Summary

The pick and place SMD machine will not need a power resource report because we are not limited in power. A waiver request will be submitted for approval.

The mass resource report is on the vacuum system to determine the mass. The stepper motor expected weight have been obtained from the Makeblock specifications on their X-Y Plotter Robot Kit (Shenzhen Maker Works Technology Co., Ltd., 2013).

The Makeblock Stepper Motor Driver is a component used to control the stepper motor with  the ArduinoUno. It contains a stepper driver chip, 4 wire bi-polar stepper motors, a potentiometer, DIP switch, and a heat sink.

Because the components have not been purchased, project allocation, actual mass, and contingency will be obtained after trade-off studies have been conducted.

Source Material:

Shenzhen Maker Works Technology Co., Ltd. (2013). Me Stepper Motor Driver. Retrieved from:http://www.makeblock.cc/me-stepper-motor-driver/

Project Cost Estimate

By Bao Loc Doan (Project Manager) and Christine Vu (Systems Engineer)

Table 2. Cost Report

Summary

The cost report supports all parts needed so far to construct the pick and place SMD machine for Spring 2016.

The Makeblock XY Plotter is an XY plotter that can be easily modified to our needs. This specific XY plotter has a working area of 12” x 15” so it can easily fit our PCB fabrication requirements (4” x 3.2” as per free Eagle CAD board working area) and additional reel feeders. The Makeblock XY plotter ships all the parts as a kit and would be much more efficient to build since we would no longer need to design the entire XY plotter. The accuracy of this XY plotter needs to be increased by a factor of 2 (as requested by the customer) and a simple solution is to implement a geared stepper motor.

The Makeblock Gearbox Stepper Motor will be implemented into our pick and place SMD machine so our precision error meets customer standards of 0.002”.

The aquarium pump, solenoid valve, tubing, syringe, and connectors shall be used for the vacuum system in the pick and place SMD machine. The aquarium pump is easily modified to become a vacuum and the solenoid valve with brass fittings will control when the vacuum suctions in order to pick and up and place down the components as intended. The tubing, syringe, and connectors will connect each individual component to make the vacuum system.

All of our surface mount resistors and capacitors shall be placed in the 4x 8 mm reel feeders so they can be populated onto the PCB. After Spring 2016, 16x 8 mm reel feeders will be implemented into the pick and place SMD machine.

The aluminum surface will be the working area of the entire pick and place SMD machine. The machinist labor is included into the price. The Makeblock XY plotter will need to securely fit into the aluminum surface and there will also be an aluminum clamping system that needs to be drilled into the aluminum surface.

The Makeblock stepper motor driver will be used in conjunction with the Makeblock stepper motor to control our vacuum nozzle. In order for the vacuum to be able to pick up components, the ability to move in the Z-axis is required. We have plans to implement one Makeblock stepper motor on the z-axis and will need the circuitry required.

By: Bao Loc Doan (Project Manager)

Christine Vu (Systems Engineer)

Henry Nguyen (Electronics Engineer)

Nasser Alsharafi (Manufacturing)

Program Objectives/Mission Profile

by Bao Loc Doan (Project Manager)

Program Objective Statement

When humans manually pick and place surface mount components onto a printed circuit board (PCB), there are problems with human accuracy and time efficiency. A pick and place surface mount device (SMD) is an automated device that can populate a PCB with surface mount components (resistors, capacitors, and IC chips) by referencing a Gerber file through the use of software. The pick and place SMD machine will be able to pick up the surface mount technology (SMT) components from 8 mm reel feeders and an integrated circuit (IC) tray and place the components down at the correct location until the board is finished. The customer has expressed the desire to create a pick and place SMD machine that can populate surface mount components as small as 0402 on all EE400D boards of Spring 2016 with the same specifications as the Madell Corporation Model DP2006-2.  The customer has expressed the desire to keep the budget of the project below $650 and finished before the end of Spring 2016.

Mission Profile

Once a gerber file provided by any project from EE400D up until Spring 2016 is uploaded, the pick and place SMD machine shall begin populating SMT components from four 8 mm reel feeders and one IC tray onto the PCB. The smallest SMT component that will be placed is component size 0402. The pick and place SMD machine will be modified from a Makeblock XY plotter and replicate the error specification of the Madell Corporation Model DP2006-2.

Requirements

Level 1 Program/Project Requirements

by Bao Loc Doan (Project Manager)

To satisfy our customer, a list of requirements that our end product needs to meet were created. These requirements will move the design forward and provide traceability to our program objectives and mission profile.

1. The pick and place SMD machine shall be able to assemble all EE400D PCB’s by the end of Spring 2016.
2. The pick and place SMD machine shall pick up a component and place down a component with a maximum of 0.05 mm error (specification of Madell Corporation Model DP2006-2).
3. Software for the pick and place SMD machine shall accept all Gerber files of EE400D projects up until Spring 2016.
4. The pick and place SMD machine shall have four 8mm reel feeders and one IC tray.
5. SMT component size 0402 shall be the smallest component that the pick and place SMD machine can pick up. 
6. Total cost of finished project must be under $650.
7. Deadline to complete the pick and place SMD machine shall be before the end of Spring 2016.

Level 2 System/Subsystem Requirements

by Christine Vu (Systems Engineer)

Level 2 System and Level 2 Subsystem Requirements are listed below. The process of forming requirements is not only crucial to the overall design of the project but also difficult to form due to the customer’s needs and the nonlinearity of designing. Through many revisions, the level 2 requirements were officially determined. Because this project is new to the Arxterra blog, references were obtained through scholarly journal research and outside resources other than the Arxterra blog.

Source Material:

Arra, M. , Geiger, D. , Shangguan, D. , & Sjöberg, J. (2004). A study of smt assembly processes

for fine pitch csp packages. Soldering & Surface Mount Technology, 16(3), 16-21.

CadSoft Computer GmbH and CadSoft Inc. (2011). EAGLE Freeware. Retrieved from:

http://www.cadsoftusa.com/download-eagle/freeware/

Changzhou Douwei Electric Co. Ltd. (n.d.). 42BYG Stepping Motor. Datasheet.

Makeblock. (2014, June 9). XY Plotter 2.0 How it works? Retrieved from:

https://www.youtube.com/watch?v=gY0xMYrWBDg

Panasonic. (2014, Feb. 4). Precision Thick Film Chip Resistors. Datasheet.

Shenzhen Maker Works Technology Co., Ltd. (2013). X-Y Plotter Robot Kit. Retrieved from:

http://www.makeblock.cc/xy-plotter-robot-kit/

TCI Precision. (2005). Blanchard Grinding. Retrieved from: http://tciprecision.com/machine-ready-blanks/capabilities/Blanchard%20Grinding

Telecommunications Industry Association. (2001). TIA/EIA-568-B.1: Commercial Building

Telecommunications Cabling Standard.

VBsProjects. (2014, July 12). Homemade SMD Pick and Place Machine – complete cycle.

Retrieved from: https://www.youtube.com/watch?v=CRSLbo_8nTQ#t=7m34s

Notes on Requirements:

L2 – # – Level 2 System Requirements (i.e. L2 – 1)

L2 – #x – Level 2 Subsystem Requirements (i.e. L2 – 1a)

L2 – 1 Working area must be within 12.2”x15.35” (310mmx390mm) based on the Makeblock X-Y Plotter.

Explanation: The MakeBlock X-Y Plotter Robot Kit design specifications indicated the working area size as shown above (Shenzhen Maker Works Technology Co., Ltd., 2013). The working area is the area that the motors can move. This requirement will be verified through the use of a measuring tape tool. Tolerances will be taken account depending on the measuring tape that will be used.

L2-1a   Working Area shall fit a 4″ x 3.2″ PCB for EE400D students.

Explanation: EE400D Students will be using EagleCAD software to design their PCB.

The free version limits the PCB design size as 4” x 3.2” (CadSoft Computer GmbH and CadSoft Inc., 2011). This can be verified by the use of a measurement tape tool.

L2-1b  Surface to hold PCB shall be smooth with dimension tolerances to ±.001″, parallelism to .001″, and flatness to .001″.

Explanation: The process to place SMT components will begin with the application of solder paste by hand. This requires a very smooth surface that may require Blanchard grinding. These tolerances were taken from industrial Blanchard grinding standards (TCI Precision, 2005). This will be verified from the company that we plan on using.

L2-1c   PCBs laid out for assembly shall be on a surface at 0° with respect to the floor. A test shall be used to determine a safe tolerance.

Explanation: To improve precision, it is important to ensure that the machine will run in a straight line and parallel to the floor. This will keep the SMT components from falling off the PCB. A digital leveler will be used. Tolerances will depend on the leveler used.

L2-1d  All wires shall refrain from contact with the working surface.

Explanation: The Makeblock X-Y Plotter lacks the placement of wires. During plotting, wires are touching the surface (Makeblock, 2014). This should be avoided due to the addition of more wires, reel feeders, and IC trays in the working area. Wires dragging against the surface may also cause problems with wire protection.

L2-1e   All wires using RJ25 connectors shall have a minimum bend radius of 4x its diameter.

Explanation: The pick and place SMD machine has repetitive movement, where a vacuum system will pick up a SMT component and place it down a PCB one at a time. Since wires will be moving along the vacuum system, repetitive movement may affect the lifespan of the wires. Therefore, a general rule-of-thumb to prevent wire fatigue is to set a minimum bend radius of 4 times its diameter (Telecommunications Industry Association, 2001). The bend radius shall be measured from the start of the curve to the end of the curve using measuring tape. Tolerances will depend on the tool being used.

L2-1f   A clamping system shall hold all PCBs for EE400D students with maximum size 4″ x 3.2″.

Explanation: A clamping system will provide stability when the vacuum system is placing down the SMT components and indicate the maximum PCB size 4” x 3.2”, which is the limited PCB size for the free version of EagleCAD (CadSoft Computer GmbH and CadSoft Inc., 2011). This will be verified by clamping a 4” x 3.2” PCB. The clamped PCB should not be able to move once the machine is operating.

L2 – 2 The pick and place SMD machine shall pick up and place down all required integrated circuit chips according to EE400D PCB’s provided up until Spring 2016.

Explanation: The purpose of a pick and place SMD machine is to assemble a PCB design given by EE400D Students. It is important to note that integrated chips will also be placed down. This will be verified by the provided Gerber file.

L2-2a   A vacuum system shall pick up all required IC chips according to EE400D PCB’s provided.

Explanation: A vacuum system is the subsystem that will be used to pick up SMT components such as the integrated circuit (IC) chip. It also indicates that a vacuum system must be strong enough to hold the IC chip. This will be verified by testing the worst-case scenario, where the heaviest IC chip will be picked up by the vacuum system.  Explanation of the duration will be indicated in the next requirement, L2-2b.

L2-2b  Duration of suction to pick up IC chips shall begin from picking at IC tray to the placement on the PCB.

Explanation: Although picking up the SMT components are lightweight, it may be important to verify the duration of how long the vacuum system takes to pick up a component and place it on the PCB. A stopwatch will be used to time the process.

L2-2c   A solenoid valve shall close airway of the vacuum tubing each time IC chips are placed down.

Explanation: The vacuum system will be controlled through the opening and closing of a solenoid valve. This can be verified by testing the software to control the solenoid valve picking and placing the IC chip. This requirement is also noted for the rest of the SMT components in L2-8b.

L2 – 3 Pick and place SMD machine shall self-correct all orientation of IC chips before placement.      

Explanation: This requirement is to ensure that the pick and place machine is able to auto-orientate IC chips in case the chip is placed incorrectly on the IC tray. This can be verified through testing of the worse-case IC chip.

L2-3a   A sensor area shall detect the number of pins on IC chips.

Explanation: A feature that may be included to support our pick and place SMD machine is to create an area to correct the configuration of the IC chip when it is removed from the IC tray. This idea was based on one of a homemade pick and place SMD machine (VBsProjects, 2014).

L2-3b  In order to keep suction of the IC chip after pick-up, all IC chips shall be rotated about the A-axis.

Explanation: As stated in L2-3a, it is important to note how the IC chip will be corrected. That is, a motor may be used to move about the A-axis. VBsProjects (2014) demonstrates how the IC chip will be corrected. This will be verified by test – an IC chip will be picked up by the vacuum system and taken to the sensor area, where it will be corrected.

L2 – 4  Makeblock X-Y Plotter motors shall be modified to a maximum of 0.05 mm error.        

Explanation: The Makeblock X-Y Plotter online specifications indicate that the precision error is 0.1 mm (Shenzhen Maker Works Technology Co., Ltd., 2013). Calculations may be verified based on the distance between the SMT mounting holes (Arra etc., 2004).  

L2-4a   Resolution of all axes motors shall be less than 1.8°/step.

Explanation: The Makeblock X-Y plotter uses 42BYG Stepper motors to control the x-axis and y-axis, which indicate a resolution of 1.8°/step (Changzhou Douwei Electric Co. Ltd., n.d.). To improve the precision, a possible solution is to switch the stepper motors into better ones. This may be verified through the use of datasheets.

L2-4b  Z-axis motor shall move the vacuum system at 90° with a tolerance of 1° with respect to the floor.

Explanation: The Z-axis control on the Makeblock X-Y plotter uses a servo motor that moves up and down at an angle (Makeblock, 2014). If the z-axis is not modified, then the vacuum tubing may be bent and the vacuum system will not function properly if it is picking up the SMT components at an angle.

L2 – 5 Software shall translate all Gerber files from EE400D PCB’s to G-Code files.     

Explanation: The Makeblock X-Y Plotter plots using G-code files. Arduino sketches have already been made to control the motors.

L2-5a   Software shall include all x-y coordinates for pick and place SMD machine to read.

Explanation: G-Code will be viewed on CNCViewer, a program that can present the locations of the SMT components on a PCB.

L2 – 6: All SMT resistors and capacitors shall remain in cut-tape of the reel feeders until the vacuum nozzle is ready to pick up the component.     

Explanation: This requirement is to acknowledge that the reel feeders are secure and in place. This will be verified using a checklist – determine whether the vacuum nozzle moves other SMT components when the nozzle picks up one SMT component, determine whether the motors cause vibrations of the working area, and determine whether the SMT components will be isolated while the system is placing the components.

L2-6a   Reel feeders shall be placed within working area, 12.2”x15.35”(310mmx390mm).

Explanation: Because our working area is confined to the Makeblock X-Y Plotter Robot Kit (Shenzhen Maker Works Technology Co., Ltd., 2013), the vacuum system must be able to reach the SMT components. Therefore, the reel feeders must be placed in an area where it is reachable.

L2-6b  Bracket to hold cut-tape of the reel feeders shall be higher than 1.10 mm.

Explanation: The reel feeder tape specifies the tape thickness to be 1.00 ± 0.10 mm (Panasonic, 2014). In order to hold the reel feeders in place, the bracket should be higher than this. This can be verified by placing the reel feeders in the bracket.

L2-6c   Micro servos shall automate all reel feeders.

Explanation: The pick and place SMD machine shall be automatic; therefore, a motor would be used to control each of the reel feeders. A trade-off study will be conducted on micro-servos.

L2-6d  All micro servos shall remove plastic covering from the reel feeder.

Explanation: A solution to control the feeder is to have a pulley attached to the micro servos. A specification on a pulley shall be determined.

L2 – 7: IC tray shall store all IC chips required for one PCB assembly.    

Explanation: The worst-case scenario will be used to determine the size of the IC tray.  

L2-7a   IC tray shall be placed within working area, 12.2”x15.35”(310mmx390mm).

Explanation: Similar to the L2-6a, the vacuum system must be able to reach the working area of the Makeblock X-Y Plotter Robot Kit (Shenzhen Maker Works Technology Co., Ltd., 2013).

L2 – 8: Vacuum system shall be able to pick up all SMT components as small as size 0402.

Explanation: This requirement was based on the customer requirement to pick up small components. This will be verified by picking up the SMT component size 0402.

L2-8a   Vacuum nozzle shall be smaller than 0.50 ± 0.05 mm.

Explanation: The nozzle size is based on the smallest component to pick up, which is 0402. According to the datasheet, SMT size 0402, 0.05 0.50 ± 0.05 mm (Panasonic, 2014)

L2-8b  A solenoid valve shall close airway of the vacuum tubing each time SMT resistor and capacitor components are placed down.

Explanation: Similar to L2-2c, a solenoid valve will be used to control the passageways of the vacuum tubing. A test shall be conducted to control the solenoid valve with ArduinoUno.

Design Innovation

Creativity Presentation

System/Subsystem Design

Product Breakdown Structure

By Christine Vu (Systems Engineer) and Henry Nguyen (Electronics Engineer)

Figure 1. Product Breakdown Structure

The Product Breakdown Structure (PBS) shows all the functional blocks of our pick and place 3D SMD machine. The hardware is split into three different categories: Component Feeders, Vacuum Head, and X-Y Table. We will need a minimum of 4x micro servos to control our 4x 8mm reel feeders and an IC chip tray. The Vacuum head will consist of a vacuum to suction the components, a syringe or vacuum pen to pick up our components, a solenoid valve to block airflow and allow our components to be placed, and finally a stepper motor for rotation of the A axis. The X-Y Table is purchased from MakeBlock; however, we will need an aluminum surface table, slider rods, stepper motors, and calibration sensors to orientate our components. For software, we plan on using Arduino to program the Arduino Uno and Me Orion microcontrollers. Software must be able to convert Gerber files into G-code which can be read by our Me Orion microcontroller. We will need to be able to control all axis of our machine, the calibration sensor, component feeders, and solenoid valve through software.

Electronic System Design

by Henry Nguyen (Electronics Engineer)

Source Material

Me Orion:

• Schematic:
  • Makeblock. (2014, June 25). Makeblock_Orion_Schematic_V1.0.PDF. Retreived Februrary 18, 2016, from http://learn.makeblock.cc/learn/resources/Makeblock_Orion_Schematic_V1.0.PDF
• Specifications:
  • Me Orion(Base on Arduino UNO). (n.d.). Retrieved February 26, 2016, from http://www.makeblock.cc/me-orion-base-on-arduino-uno/

Me Stepper Driver:

• Schematic:
  • Makeblock. (2014, June 25). Me_Stepper_Motor_Schematic.png. Retreived Februrary 18, 2016, from
  • http://wiki.makeblock.cc/images/4/40/Me_Stepper_Motor_Schematic.png
• Specifications:
  • Me Stepper Motor Driver. (n.d.). Retrieved February 26, 2016, from http://www.makeblock.cc/me-stepper-motor-driver/

System Block Diagram

Fig. 2. System Block Diagram

The image above is the system block diagram for our pick and place 3D SMD Machine. We will have 4 stepper motors, 4 micro servos, a vacuum, and a solenoid valve as our actuators. The 4 stepper motors are used to control our axis on our machine. We will have a X,Y,Z, and A axis. The A axis is for the rotating our vacuum nozzle in order to orientate our integrated circuits in the right position to place onto our PCB. We will also have 4 micro servos to control our reel feeders. We are planning on using these servos to move our components forward after our machine picks up the component from the reel feeders. The solenoid valve is to control our vacuum. Our vacuum will be constantly running on a separate power source. The solenoid valve will close off the vacuum to prevent suction. This will allow our components to be placed onto our PCB after our machine picks it up.

Interface Definition

Fig. 3. Interface Matrix

The image above is the interface matrix for our pick and place 3D SMD machine. We will be utilizing an Arduino Uno, Me Orion, and Me Stepper Driver. Me Orion and the Me Stepper Driver came with our X-Y Plotter. This Me Orion is based off of an Arduino Uno, which will allow us to code using Arduino, Scratch. and AduBlock. We will be using this microcontroller because it has 8 RJ25 ports which will be useful for all of our actuators. The Me Stepper Driver will be used to precisely control our stepper motors by operating our motors in full, half, quarter, eighth, and sixteenth step modes. This modes can be easily changed using the built-in DIP Switch. We will need 4 Me Stepper Drivers in order to control all of our stepper motors on each axis (x,y,z,A).

Fig. 4. Me Orion Schematic

Fig. 5. Me Stepper Driver Schematic

Specification for  Me Orion:

Operating Voltage: 6-12V DC power;

Microcontroller: ATmega238;

Detecting Angle: prefer at 30 degree angle;

Dimension: 80 x 60 x 18 mm (Length x Width x Height);

Specification for Me Stepper Driver:

• Max current: ±1.35A
• Max motor drive voltage: 25V    
• Note: Me BaseBoard max supply  voltage 12V

• Logic voltage: 5V
• Dimensions: 48mm*24mm(Length × Width)

Mechanical Design

By Nasser Alsharafi (Manufacturing)

In this part of the project for the XY plotter I am coming up with the design of a Reel Feeder. The main purpose of a reel feeder is to feed the machine with the surface mounted parts. The reel feeder is made of aluminum. The main function of the Reel Feeder wheel is to roll and pass on the parts to the Reel Feeder base, which then the parts will be picked up by the vacuum.

Fig. 6. Complete reel feeder assembly 3D model

Fig. 7. Reel feeder base

The base sheet of the reel feeder has four channels called the grooves in which the tape passes through. The base sheet of the reel feeder has a length of 270 mm and a width of 82 mm. Each of the grooves on the base sheet of the reel feeder has a width of 8 mm. The main function of the reel feeder is to guide the tape to the part of the feeder where the chip is first pulled and then picked by a vacuum pen. This action helps in preparation of the next chip. After, the chip is taken by the vacuum pen and is placed on the PBC board.

Fig. 8. Reel feeder wheel

Fig. 9. Drawing of initial reel feeder base

Currently, our reel feeder is manual, so there can be further improvements by making the reel feeder automatic. In order to make the reel feeder automatic, I have to design a mounting bracket for 4 micro-servos. Each channel has single micro-servo to pull back the tape while pushing the reel forward. This will be implemented by working with Henry Nguyen to control the micro-servos.   

Design and Unique Tasks

By Henry Nguyen (Electronics Engineer)

• Work with our X-Y Plotter and given programs in order to see how to control our actuators through software (02/19/16 – 02/28/16).
• Research Flatcam which can take Gerber files and generate G-Code for isolation routing.
  • This is for our precision software that will tell our machine exactly where to pick and place components (02/19/16 – 02/28/16)
• Look for local connections and prices for our aluminum surface table by 02/28/16.
• Review DIY tutorials on how to configure an aquarium pump into a vacuum system (02/22/16).
• Understand how to define actuators and power subsystems.
  • President Watts said he will review this in our division meeting (02/20/16).
• Research how to incorporate gyro, accelerometer, and/or magnetometer into inertial measurement unit in order to measure the angular rotation of our A-axis stepper motor (03/18/16).