Table of Contents
Sample categories are listed below, but feel free to change or add nodes to better correspond to your project and your Guide’s expectations. To save time and effort, add links to documents within your EDGE file repository whenever possible.
Feasibility / Engineering Analysis
Laser Characterization (OPTONCDT ILR1181 Laser Distance Sensor)
Time of Flight Sensor Fundamentals
Time of flight sensors (TOFs) operate by sending out a laser pulse. This laser pulse will then reflect off of a given surface and a portion of the laser pulse is returned to the sensor's aperture. The sensor then calculates the difference in time from when the signal was sent and went it was recieved to determine the distance of the surface from the sensor.
In any given environment, noise will be visible to the sensor. Fortunately, the infrared pulse from the sensor will have more power than the noise floor, clearly making it easily distinguishable.
Since we are using laser equipment, we must follow the standards and safety regulations defined by OSHA for Class II lasers
The sensor comes pre-packaged with a program interface that allows the following capabilities:
- Preset an offset value from user or using current distance from observed object
- Customize triggering value and trigger delay
- Configure Range and Switching Output Configuration for Alarms
- Configure Data Transmission rates and Data format
- Observe environmental temperatures and Distance
- Create, Assign, and Load configuration files for the program
- Real time distance observation plot / Statistics
- Save Data from readings into various formats
- Exportable to Excel
When the alarm line is low, the circuitry in the respective arrow is triggered, turning on the red LEDs; indicating the direction the billet is to be moved. When all alarms are high, the green LED circuitry for the circle indicator will turn on giving the go ahead to the operators. This setup requires 2 different types of circuit boards.
- Ground is the signal line
- When high circuit essential an open(no current flow)
- When low, voltage differential of 8V creates current flow of 8.546mA
- LEDs have maximum rating of 10mA
- LEDs will not be supplied to much current and will turn on
- All inputs high, no current to diodes, Power BJT is on which allows current to flow through the BJT and the LED's to draw power
- 9 Green Diodes, max rating of 20 mA
- Resistors set to 330 ohms to limit current.
- All inputs are low. Current drawn for LEDs is minimal at 30pA.
- Worst case only one input is low.
- Circuit still draws small current of 56.6pA
- LEDs should not glow with this current.
Display Circuit PCB Layout
Wire harness DiagramHere is a layout of the wiring that will be implemented to collect data onto the laptop as well as send the alarm voltage to the display.
Below is a link to additional drawings addressing the display, and the needed harness lengths for the given laser setup Additional Electrical Notes
To enable us to utilize the sensors from Sigma-Epsilon, protective housing is required. THe environment consists of high temperatures from preheated top and bottom dies (700 - 900 F), water, and lubricants. Therefore, the primary and secondary functions of the enclosure is for thermal insulation and foreign body protection, respectively.
The enclosure consists of an aluminum housing made of 1/8" sheet metal, and 1/4" milled block for the bottom. In order to guarantee the sensor is level and secured, the bottom portion of the enclosure must be thicker. The overall weight is 9.5 lbs.
The rear face of the enclosure supports an external port for the electrical signals and power to the sensor. The front face has a viewing hole, allowing the sensor to send and recieve infrared signals. The view hole is approximately 2" in diameter.
To enhance the performance of our sensor in the given environment, an air purge system is implmented. This air purge system will expel air through the viewhole in order to clear debris within its line of sight.
To calculate the necessary insulation for our box we made the following assumptions:
- Thickness of the enclosure wall is 1" (0.125" of Aluminum and 0.875" of insulation)
- The heat flow rate from the radiation off of the billet is equivalent to the heat flow rate due to convection
- bulk temperature of air for convection heating is 900 F
- convection coeff. is equal to 15 W/m^2-K (for free convection of air)
- Excluding the convection from the purge air system
The resulting thermal conductivity necessary for our applications must be less than 0.116 W/m-K
The support offers the vertical and horizontal freedom for placing the laser's line-of-sight onto particular billet geometries. The overall build is made of aluminum block and tubing as well as a steel base that will interact with T-slot guide rails. The overall weight is 24 lbs. (Exploded View)
The horizontal travel is achieved using a double rail system. The steel base supports the vertical adjustment apparatus as well as the enclosure. The horizontal motion can be limited with the use of a set screw locking onto the track.
The vertical motion is achieved using telescoping tubing. There is a 5" adjustable height range that is maintained with the use of a 3/8" setscrew.
An alternative configuration for the sensors observing the die location only requires the steel rail support to fasten to the bottom of the enclosure.
Set Screw Analysis
To determine how much pressure is required from the set screws to hold up the enclosure a quick static analysis with friction was done. Using a weight of 14.24 lbs. for the weight, a friction coefficient of 1.05 ( Aluminum on Aluminum dry), and a minimum area of contact of 2.625 sq in. (representing the sensor at its maximum height), the necessary pressure is about 5.2 psi from a 3/8" set screw.
Rail Support System
The overall supporting structure of the system will rest on the shoe of the Die Press. The overall length is 4 ft and supports the horizontal travel of the sensors. The build is made of aluminum tubing and steel tracks. The weight is 43 lbs. without sensors and 88 lbs with the 1 billet sensor and 1 die sensor.
The system is secured to the shoe using a magnetic system attachment. This prevents the system from shifting before,during, and after the pressing process
A basic static analysis was done to determine the stability and strength of the setup. The results show a maximum stress of 123 psi on the guide rail and a maximum strain of 9.1565 micro-in/in , well within the safety of the system.
the display will be communicating with the operators on floor to adjust the billet accordingly Via an LED directional display. Three displays are to be used and located in view of the fork-lift operators, the press operator, and the personnel adjusting the billets. The displays will be exposed to water and lubrication from the forging processes.
A wash-down rated PVC enclosure is to be used. Its lightweight and easily customizable features make it a suitable choice for our applications. It will be vertically mounted to either a free-stand or magnetically adhered to the press structure.
Air Purge System
The air purge system to be implemented is a 1/8 HP pump with pressures equal to 10 psi and a mass flow rate of 0.65ft^3/min. This will be split six ways to each sensor housing. The hosing will be steel braided hosing and will feature quick disconnects to the enclosures.
Bill of Material (BOM)
One of our initial tests will verify the functional capabilities of the laser on glowing red metal. The selected laser has been tested to operate when view glowing red metal at lower temperatures, but unsure of higher temperatures. The following test procedure will address this uncertainty:
Due to the high temperatures, thermal expansion will be taken into account for the difference in cold and hot readings off of the test materials
Risk AssessmentExcel File
Detailed Design Review
- Need to ensure any fasteners to aluminum have helical-inserts for the steel fasteners (update drawings)
- Incorporate a knob set screw for easy setup ( no need for tools)
- Simulate additional weight onto tracks (i.e. person standing on tracks)