Week 8:- 3D Finishing - Challenges 1

1) WHAT DO YOU UNDERSTAND BY THE 3D FINISH PROCESS?

• 3D finish is the process where design is being completely finish & to be ready for final simulation & 2D detailing.
• While finishing the design the nominality of holes is checked which ensures the easy assemble of all the units.
• The hole concentricity & holes size are checked which ensures the easy assembly of different parts.
• The gaps between the different units are used to ensure the easy assembly of all units.
• Fasteners are implemented as per the hole size & the standard color codes as per the customer requirements are applied to differentiate the type of hole whether it’s a simple hole, threaded hole or counterbore hole.
• Renaming the assembly & the part is done to give every part a different identity. So everyone can identify in which assembly the particular part is going to be fit.
• After doing all these things the model is sent for to simulation department to simulate the design with robots whether the gun is clashing or not & 2D detailing.

2) WHAT ARE THE POINTS NEED TO BE TAKEN CARE OF WHILE FINISHING THE DESIGN?

Following points are taken into consideration while finishing the design.

• Panel Data
• Welding & Rivet points
• PPSL- Purchase Part Source List
• PLP- Principle Locating Point
• Start From NC- Numerical Control
• Base Mounting Position Value
• Buyer OFF Sheet
• Colour Code Data

PANEL DATA

• Panel Knowledge
• Check Mis- assemble in panel
• Number of Panel

WELDING & RIVET DATA

• Get welding & Rivet data from costumer
• Welding & Rivet operation process

PROCESS FOR DESIGN

• Sketch should be fully constrained
• Gas out profile should be in thickness face with edge fillet
• 3mm radius for < 50mm thickness
• 5mm radius for > 50 mm thickness
• If use 5mm radius for 20mm plate it will remove material is large than 3mm
• Rough machining
• Fine machining
• Maintain 3mm machining step
• Clearance 3mm between shim and machining steps
• In some case 2mm and 2.5mm machining step can use
• Edge fillet 5mm, it depends upon tool diameter
• Avoid unnecessary fine machining
• Holes

NC- NUMERICAL CONTROL

• Start from NC
• NC champing surface should cover 16mm diameter of Principle Locating Pin Point.
• NC should be in absolute and have round off value in x, y, z direction.
• NC clamping should be in plain surface (no bend, curved surface).
• If two or three panels are there, having same Principle Locating Pin the clamping surface must be common for both panels.
• Maintaining minimum clearance 15mm between NC (make parts) to be panel and weld points.
• Maintain clearance 10mm in special case 5mm.
• Mention non- magnetic stainless steel (nmss) note if welding point is very close to NC.
• Length of NC small in size to avoid vibration.

MAKE PART

• Overall length should not be in 0.5 value both horizontal & vertical like 95.5
• Ribs can be added to avoid over hanging and to give strength to the part.
• Designing the weldment in part body or product-depend upon no. of parts.
• Welding clearance
• Weldment clearance minimum 5mm.

GENERAL CHECK LIST

• Unit should be in absolute in tool vise.
• All NC should be in absolute.
• NC face should ne round off except angle nc (found off in one side)
• Gas cut profile there should be there.
• Thickness face machining step depend on stock size.
• NC dowel should be in slip fit and mounting part should have press fit
• Riser base mounting in slip fit
• Hole should be inline
• Check clash analysis
• Colour code
• Check 3d properties.

3) WHAT ARE THE ROUGH LOCATORS & WHAT IS THEIR USE?

• A rough locator is a part designed to guide the operator to locate the car panel on to the pins accordingly.
• A rough locator can be of standard part or make part.
• Rough locators are used to help locate work pieces in the automation process.
• Locating refers to the desired location where we want the work piece to be sitting when it is getting on either worked on either by a person, team or a robot.
• Body part rough locators are provided to assist manual part loading to the tool.
• The following are general guidelines for rough locators.
• It is not required to finish cold/hot rolled steel for rough locators mounting. Use NAAMS standard rough locators whenever possible.
• Rough locators should not be placed in such a way that the operator feels difficult to place or lift the part in the fixture assembly.
• Rough locators must be designed with slots for ease of adjustment.
• Rough locators should have minimal part contact so that the operator can load the part to work location with ease.
• Excessive part contact may cause difficult part loading and unloading.
• Rough locators must never touch the part when it is nested or controlled by the primary tool locators.
• If the rough locators require a unique design, use the design parameters for the standard NAAMS rough locator as a guide.
• A rough locator is a part designed to guide the operator, to locate the car panel on to the pins accordingly.
• It is used to identify the correct orientation of the panel.
• It can be called as fool proofing method also.
• Because due to the rough locator the part cannot be loaded in incorrect position.
• The rough locators are set according to the angle of the respective panel hence part can only be loaded in defined orientation.

4)WHAT ARE THE POINTS NEED TO CONSIDER WHILE DESIGNING A ROUGH LOCATOR?

The points need to consider while designing a rough locator are as follows.

• Rough locators should be placed at the edges of the car panel, which it has to guide.
• It has to be placed in the same angle of the car part edge with a minimum distance of 2- 5mm from the edge of the car panel.
• Rough locators should guide the panel in arresting direction.
• Rough locators should start guiding the panel 10- 15 mm to the start of the pin engagement.
• It should be designed with entry angle for the car panel. Generally the angle ranges between 30- 45 degree.
• It should be designed with two slots to mount the easy adjustments.
• The slots should be in the direction of car part guiding.
• It should be designed in such a way that the slots are feasible and can be adjusted easily.
• Rough locators should have minimal part contact so that the operator can load the part to work location with ease.
• Excessive part contact may cause difficult part loading and unloading.
• It must never touch the part when it is nested or controlled by the primary tool locators.

5) WHAT IS THE GUN STUDY PROCESS

• Welding is mostly used in automobile industries and their requirements for fixtures that ease the welding process is a continuous developments task in any industry.
• In weld study process, the major procedure is to insert the gun in the total assembly and place the gun on the weld spots by creating a point on the tip.
• Adjust the weld gun for not getting any clashes from the 3D concept.
• Once all the weld spots are cleared without any clashes and it will be moved on to next procedure of simulation.
• In simulation, first the reach with respect to the weld spots has to be checked. Because robots are also having some limitations if it exceeds the robot will not work proper with 100 percent.
• So First we have to move and adjust the weld gun to identify the reach and to check for any clashes and adjust it accordingly.
• Car Body in White (BIW) is a complicated steel structure including 300-400 sheets with complex shapes and assembled by means of welding in a high rhythm through 55-75 robotic work stations.
• The fore most step taken before starting the welding fixture design, we must declare weld spots location for each and every panel.
• The location and orientation of other critical units of the fixture including clamps, locators, etc. are decided based on the weld spot distribution.
• In weld study, which gun and welding process has to used for fixture is to identified and decided. Gun has two different types and they are as follows.

1. C-Type gun
2. X- Type gun

A) C- TYPE GUN

• In C- type gun, one arm side is fixed and another arm is movable in linear direction of perpendicular to other arm. (Horizontal direction with respect to other arm)
• It includes the study of the weld matrix & the weld point positions. There are two types in weld point one is Geo weld which ensures the geometry of the assembly & second is Re- Spot weld points which adds strength to the welded parts.
• The fixture is designed for the car panel to hold it on the position, so we ensures that all the weld spots and weld gun do not access or any clashes with fixture tool.
• If any clashes defined while designing fixture, then we will only have to move on to redesign the tool.
• We have no permission to change a weld spot or clamping position without considering clients.

B) X- TYPE GUN

• In X-type gun, one arm is fixed and another arm is movable in angle position. (It moves like an arc)
• It includes the study of the weld matrix and the weld point positions.
• There are two types in weld point one is Geo weld which ensures the geometry of the assembly & second is Re- Spot weld points which adds strength to the welded parts.
• The fixture is designed for the car panel to hold it on the position so we ensure that all the weld spots and weld gun do not access or any clashes with fixture tool.
• If any clashes defined while designing the fixture, then we will only move on to redesign the tool.
• We have no permission to change a weld spot or clamping position without considering clients.

6) WHAT ARE THE POINTS NEED TO CONSIDER DURING THE GUN STUDY?

• Weld gun study is very time consuming process, the entire welding cycle time study depend on the no. of spots & the weld gun study.

Following are the points need to consider during the guns study.

• The axis of weld spot along welding direction must be normal to the weld surface.
• The no. of weld spots for the panel, the time required to spot the each weld and the total time required to complete all the weld spots has to be considered.
• The weld gun has only access to rotate on Z axis. Because if we rotate the weld gun on X and Y axis, the weld spots quality will reduce and the precision will get lost.
• During gun study, we have to consider clients cycle time and we have to maintain the cycle time compared to clients requirements.
• There are two types of weld spots such as Geo spot and Re-spot.
• These two spots are having different timings.
• For Geo spot it the timing is for 3 sec
• For Re- spot, the timing is for 2.5 sec.
• If we have one or more device models and we want to program, the behavior of each model in the work cell can be simulated over time. Instructions for each device are coded by giving sequence.
• If we have no issue with weld gun and we have to move on to be next procedure to run the pats to analyse there is any clash while weld gun reach at weld spots and the n if we done with that and finally move to sequence of operation.
• After sequencing all the device and paths, Finally simulation is run with collision check on and make sure all the weld spots and paths are clear from collision which using safe robots.

7) WHAT IS PNEUMATIC ROUTING

• Pneumatic systems should be efficient and leak free. Sometimes, they are not because of improper tube line routing- the result of either lack of knowledge or corners cut on planning time or both.
• Planning tube line routing is time investment, but it can have a big ROI especially for complex systems.
• During system design, routing should be developed as the next step after sizing the tube lines and selecting the appropriate fittings.

Some guidelines for planning appropriate tube line routing are as follows.

• Leave fitting joints as accessible as possible whereas inaccessible joints are difficult and time consuming to assemble, tighten and service.
• Use software tools to make labor intensive calculations such as pressure drop.
• Employ U-bends to allow for line contraction and expansion.
• Include offset bends to allow for motion under load, regardless of how rigid the system seems.
• Favor bends rather than straight tube lines, because a straight line tube assembly with no bends. For example, the test stand mentioned above can cause joint stain, which may lead to leakage.
• Make sure routing design allows room for assembly of any connections required.
• Minimize pressure drop by getting around obstructions with as few 90 degree bends as possible.
• One 90 degree bend has more pressure loss than two 45 degree bends.
• Route lines around rather than over areas that require regular access or maintenance.
• Design routing with clamping unit. Appropriate design leads logically to proper clamping. Often it is possible to clamp several lines together.
• Keep trouble shooting and maintenance in mind focus on logical design and avoid crossed lines.
• Design the tube line routing to reduce likelihood of users standing or climbing on plumbing.

8) WHAT IS SOLENOID VALVE

• Solenoid valve is an electromechanically operated valve.
• Solenoid valves are electrically activated valves, typically used to control the flow or direction of air or liquid in fluid power systems.
• It can be used in both pneumatic and hydraulic fluid power functions and the spool or poppet design of most solenoid valves makes them perfect for various functions and applications.
• Solenoid valves are the most frequently used control elements in the fluid. Their tasks are to shut off, release, dose, distribute or mix fluids.
• They are found in many applications.
• Solenoid offers fast and safe switching, high reliability, long service, good medium compatibility of the materials used, low control power and sompact design.

The various parts of the solenoid valve and their working are as follows.

VAVLE BODY

• This is the body of the valve to which the solenoid valve is connected. The valve is usually connected in the process flow pipeline to control the flow of certain fluid like liquid or air.
• The flow from the valve is controlled by the handle, but in case of the automatic valve the solenoid valve is connected to the valve.

INLET PORT OF THE VALVE

This is the port through which the fluid enters inside the automatic valve and from here it can enter into the final process.

OUTLET PORT

• The fluid that is allowed to pass through the automatic valve leaves the valve through the outlet port.
• The solenoid valve controls the flow of the fluid from inlet port to the outlet port.
• The outlet port is eventually connected to the process where the fluid is required.

COIL/SOLENOID

• This is the body of the solenoid coil.
• The body of the solenoid coil is cylindrical in shape and it is hollow from inside.
• The body is covered with steel covering and it has metallic finish.
• Inside the solenoid valve, there is solenoid coil.

COIL WINDINGS

• The solenoid consists of several turns of the enameled wire wound around the ferromagnetic material like steel or iron.
• The coil forms the shape of the hollow cylinder.
• Externally this coil is covered with the steel covering and inside the hollow part there is a plunger or the piston, whose motion inside the hollow space is controlled by the spring.

LEAD WIRES

• These are external connections of the solenoid valve that are connected to the electrical supply.
• The current is supplied to the solenoid valve from these wires.
• When the solenoid valve is energized, the current flows through these wires to the solenoid valve and when the solenoid valve is de-energized the flow of current stops.

PULGNER OR PISTON

• This is the solid round metallic part cylindrical in shape and placed in the hollow portion the solenoid valve.
• When the electrical current is passed through the solenoid valve, the magnetic field is generated inside the hollow space.
• Due to this the plunger tends to move vertically in the hollow space.
• When the electrical current is stopped to the solenoid valve, the magnetic field is stopped and the plunger remains the existing place due to force of the spring.

SPRING

• The plunger moves inside the hollow space due to the action of the magnetic filed against the action of the spring.
• The magnetic field generated inside the solenoid valve tends to stop the motion of the plunger in which ever the position it is.
• This action of spring against the magnetic field helps keeping the plunger in the position where the flow of current to the solenoid valve is stopped.
• The spring performs very crucial action inside the hollow space.
• For one, the plunger is in the vertical position, so the spring helps keeping it at the desired position instead of allowing the plunger to fall to the bottom due to gravity when the current to the solenoid valve is stopped.
• Secondly, the spring also prevents the movement of the plunger due to force of the fluid flowing through the valve body.
• If the spring was not there the plunger would have moved up when the fluid is present and moved down when the fluid is not there.
• Thus the spring actually forces the plunger to carry out the control of the fluid.
• It allows the movement of the plunger only to the extent when the electric current is flowing through the solenoid valve.

ORIFICE

• The orifice is an important part of the valve through which the fluid is flowing. It is the connection between the inlet and the outlet port.
• The flow of fluid from inlet port to the outlet port takes place from this port.
• In the ordinary valves, this port is covered with the valve disc at the bottom of the stem of valves, the opening of the orifice are controlled by the handle but in case of the solenoid valves, the opening of the orifice is controlled by the plunger.
• The movement of the plunger is in turn controlled by the spring and the current flowing through the solenoid valve.

WORKING OF SOLENOID VALVE

• Initially the sensor senses the process towards the outlet side of the solenoid valve.
• When it senses that certain quantity of the flow of the fluid is required, it allows the current to pass through the solenoid valve.
• Due to this the valve gets energized and the magnetic field is generated which triggers the movement of the plunger against the action of the spring.
• Due to this plunger moves in upwards direction, which allows the opening of the orifice.
• At this instant the flow of the fluid is allowed from the inlet port to the outlet port.
• If the current passing through the solenoid valve is constant, the position of the plunger and hence opening of the orifice remains constant,
• If the sensor senses that more flow of the fluid is required, it allows the increase in current passing through the solenoid valve which creates more magnetic field and more upwards motion of the plunger.
• This leads to further opening of the orifice and more flow of the fluid from the inlet port to the outlet.
• If the required flow of fluid is less, the sensor allows passage of the lesser current to the solenoid valve.
• When the sensor senses that the fluid is no more required in the process, it stops the flow of the current to the solenoid valve completely.
• Due to this, solenoid valve gets de-energized and the plunger reaches the bottom most position and closes the orifice completely thus stopping the flow of fluid from the inlet port to the outlet port.
• In this way the solenoid coil operates the valve as if it is being operated by the human being.
• When the flow of the certain quantity of fluid is required it opens the valve to required extent and when the flow is not required it shuts the valve entirely.

9) WHAT IS THE VALVE BANK?

• Valve bank is the arrangement of no. of solenoid valves.
• Valve bank will have common inlet port, a single servo line to each of the pneumatic valves and independent vent passages for each solenoid.
• On the solenoid bank, each of the solenoid valves separately controls the feed of high pressure servo air to a single pneumatic valve.
• The valve is actuated by selectively energizing the corresponding solenoid to allow servo air to the servo port of the valve.
• To return the valve to its fail- safe position, the solenoid is de-energized to vent the servo port of the valve to the ambient.
• The solenoids are two-stage pilot valves and are normally open with the solenoid de-energized allowing high pressure supply air to the servo ports of the downstream pneumatic valves.
• Energizing the solenoid blocks high pressure air supply and simultaneously vents the pneumatic valve servo chamber to atmosphere, closing the respective pneumatic valve.
• The two- stage solenoid are designed to provide fast response times.
• The electrical configuration is a dual- coil redundant design providing an isolated circuit topology housed in a single package.
• Each coil is independent and identical in function.
• Common features of valve bank are as follows.

1. These are designed for high vibration levels.
2. It uses aluminum alloy manifolds for light weight
3. These are designed for high-temperature environments.
4. Design architecture allows easy selection of two to six solenoid valves.

10) WHAT IS SENSOR AND BRIEF ABOUT ITS APPLICATION IN AUTOMATION?

• Sensor is a device which detects or measure a physical property and record, indicates or otherwise responds to it.
• A unit designed to sense car panel using electrical sensors is called sensor unit.
• The sensor is very sensitive & easily damageable part so sensor cover is provided to the sensor for safety purpose.

SENSORS IN INDUSTRIAL AUTOMATION

• In the industrial automation section, sensors play a very important role to make the products intelligent and highly automatic.
• These allow one to detect, analyze, measure and process various changes like change in position, length, height, appearance and displacement that occurs in the production sites.
• These sensors also play an important role in predicting and preventing many future events, thus, catering to the needs of many sensing applications.
• The various types of sensors used in industrial automation are Proximity sensors, vision sensors, ultrasonic sensors, position sensors, photoelectric sensors, temperature sensors, inclination sensors, etc.
• The application for position sensors as a whole are broad. They can be used in anything from motion control of a robot, tank level sensing or even is semiconductor process equipment.
• Displacement sensors are used in the precision positioning of objects at the nanometer level and in the measurement of precision thickness of disk drives, assembly line testing and machine tool metrology.
• It is widely used in machining.

AUTOPILOT SYSTEM IN AIRCRAFTS

• Almost all civilian and military aircrafts have the feature of automatic flight control system or sometimes called as Autopilot.
• An automatic flight control system consists of several sensors for various tasks like speed control, height, position, doors, obstacle, fuel maneuvering and many more.
• A computer then provides control signal to different parts like engines, flags, rudders, etc. that help in a smooth flight.
• The combination of sensors, computers and mechanics makes it possible to run the plane in autopilot mode.
• All the parameters i.e. the sensors (which give inputs to the computers), the computers (the brains of the system) and the mechanics (the outputs of the system like engines and motors) are equally important in building a successful automated systems.

11) WHAT ARE THE TYPES OF SENSORS?

• The following is a list of different types of sensors that are commonly used in various applications.
• All these sensors are used for measuring one of the physical properties like Temperature, Resistance, Capacitance, Conduction, Heat Transfer, etc.

1. Temperature Sensor
2. Proximity Sensor
3. Accelerometer
4. IR Sensor (Infrared Sensor)
5. Pressure Sensor
6. Light Sensor
7. Ultrasonic Sensor
8. Smoke, Gas and Alcohol Sensor
9. Touch Sensor
10. Color Sensor
11. Humidity Sensor
12. Tilt Sensor
13. Flow and Level Sensor

1) TEMPERATURE SENSOR

• One of the most common and most popular sensors is the Temperature sensor.
• A temperature Sensor, as the name suggests the temperature i.e. it measures the changes in the temperature.

2) PROXIMITY SENSOR

• Proximity sensor is a non-contact type sensor that detects the presence of an object.
• It can be implemented using different techniques like Optical (like infrared or laser), Ultrasonic, Hall effect, Capacitive, etc.

3) INFRARED SENSOR (IR SENSOR)

• IR sensors are light based sensor that are used in various applications like Proximity and Object detection.
• IR sensors are used as proximity sensors in almost all mobile phones.
• There are two types of infrared sensor or IR sensors such as Transmissive type and Reflective type.
• In Transmissive type IR sensor, the IR transmitter (usually an IR LED) and the IR Detector (usually a Photo diode) are positioned facing each other so that when an object passes between them, the sensor detects the object.
• The other type of IR sensor is a Reflective Type IR sensor.
• In this, the transmiiter and the detector are positioned adjacent to each other facing the object.
• When an object comes in front of the sensor, the sensor detects the object.
• Different applications where IR sensor is implemented are mobile phones, robots, industrial assembly, automobiles, etc.
• A small project where IR Sensors are used to turn on street lights and that is called as STREET LIGHT USING IR SENSORS.

4) ULSTRASONIC SENSORS

• An ultrasonic sensor is a non- contact type device that can be used to measure distance as well as velocity of an object.
• An ultrasonic sensor works based on the properties of the sound waves with frequency greater than that of the human audible range.
• Using the time of flight of the sound wave, an ultrasonic sensor can measure the distance of the object (similar to SONAR).
• The Doppler shift property of the sound wave is used to measure the velocity of an object.
• Arduino based range finder is a simple project using Ultrasonic sensor: Portable ultrasonic range meter.
• The small list of projects based on few of the above mentioned sensors are as follows.

A) Light sensor- Light detector using IDR

B) Smoke sensor- Smoke detector alarm circuit

C) Alcohol Sensor- how to make alcohol breathalyzer circuit?

D)Touch sensor- Touch dimmer switch circuit using arduin

E) Color sensor- arduino based color detector

F) Humidity sensor- dht11 humidity sensor on arduino

G) Tilt sensor- how to make a tilt sensor with arduino?

12) WHAT ARE THE FUNDAMENTAL POINTS THAT NEED TO CONSIDER WHILE DESIGNING OR SELECTION OF SENSOR?

• The most common type of sensors used in manufacturing, factory automation and machine control are proximity sensors, position sensors, inductive sensors, flow sensors, optical sensors and vision sensors.
• A signal converter is a critical related technology.
• Here is the list of the top operation condition requirements.

1. Accuracy and precision
2. Environment
3. Signal conditioning
4. Response speed
5. Sensing range
6. Repetition accuracy
7. Electrical connection
8. Mounting type
9. Temperature range
10. Voltage range

• Basically sensors should be equal numbers as compared to numbers of panels in assembly. For ex. If 9 panels are in assembly, so there should be atleast 9 sensors used.
• Sensors slot should be designed in such a way that it can be adjusted in 3 direction.
• Sensors are also used for safety purpose of the operator.
• Typically Proximity, Laser, Photo electric sensors are used in fixtures.
• Some major sensor manufacturers are IFM, Pepperifunchs, SICK, OMERON, etc.