Week 8:- 3D Finishing - Challenges 1

What do you understand by the 3D finish process?

3D finish process means to finish the design is being completely and make it ready for final simulation & 2D detailing. The following are the basic rules to be followed in 3d finishing: 

1. The nominality of holes is to be checked which ensures the easy assembly of all the units.
2. The hole concentricity & holes sizes should be checked which ensures the easy assembly of different parts.
3. The gaps between the different units are checked to ensure the proper individual working of different units.
4. Fasteners are implemented as per the hole size & the standard color codes as per the customer requirement are applied to differentiate the type of hole wheather its a simple hole, threaded hole or counterbore hole. 
5. The standard colours used for holes are  Violet  for open Hole, Yellow for Threaded Hole, Orange for Machined area, Skyblue for Dowel pin Hole.
6. Renaming of the assembly and the parts is to be done to give every part a different identity so everyone can identify in which assembly this part is going to be fit.
7. After all the above steps the model is sent for simulation & 2D detailing.

What are the points need to be taken care of while finishing the design?

1. Hole concentricity & hole sizes: All parts are to be checked for hole concentricity and to be confirmed for easy assembly while finishing the parts.
2. Machining Area: The machining area in every part should be  defined and the machining area should be highlighted by using standard color code.
3. Nominality: All units dimensions shoild be maintained nominal to facilitate easy assembly of the unit.
4. Holes colouring standard: Color Code standard as per the customer requirement should be applied in the 3D finishing. Violet  for Simple Hole, Yellow for Threaded Hole, Orange for Machined area, Skyblue for Dowel pin Hole.
5. Pneumatic Layouting: pneumatic layouting is collection of different pneumatic pipes which works as a inlet to the pneumatic cylinder. It should be done properly for proper functioning of the units.
6. Gaps checking: Proper gap should be maintained between units to avoid the clash between the diffrent units.
7. Fasteners implementation: Fasteners should be implimented in all unit as per the requirement & load on the part.
8. Mylar splitting as per panel profile: Mylar splitting should be  confirmed while finishing the design. This should be done as per the thickness and shape of the panel you have in the fixtures.
9. Proper renaming of parts/assemblies as per standard: Proper renaming of parts & assemblies should be done while finishing the design hence we can identify each & every part easily with unique identification.

What are 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.

Uses of rough locators:

• Rough locators are used to help locate workpieces in the automation process. Locating refers to the desired location where you want the workpiece to be when it is getting worked on either by a person, team, or robot.
• The accuracy of the locating components directly affects the consistency and how the final product will come out. This is why these components are essential to your setup
• 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 direction & orientation.

What are the points you need to consider while designing a rough locator?

      Following are the points need to be considered while designing the rough locator

1)Rough locator should be placed at the edges of the car panel, which it has to guide.

2)Rough locator has to be placed in the same angle of the car part edge with a minimum distance of 2-5 mm from the edge of the car part.

3)Rough locator should guide the panel in pin arresting direction.

4)Rough locator should start guiding the panel before 10 to 15mm to the start of the pin engagement.

5)Rough locator should be designed with entry anglle for the car panel. Generally it ranges between 30-45 degree.

6)Rough locator should be designed with two slots to mount the easy adjustments.

7)The slots should be in the direction of car part guiding.

What is the gun study process?

Welding is predominantely used process in automobile industries and requirements for the welding process is a continuous development task in any industry. In BIW the complicated steel-structure including 300mm to 500mm sheets with complex shape and are assembled by means of welding. The first step taken before starting the design of welding fixture is to arrive at the spot weld locations. The location and orientation of other critical units of the fixture including clamps, locators etc., are decided based on the weld spot distribution.

      The above image shows the weld gun used for spot welding and the weld matrix and weld locations where the welding is to be done. There will be two different types of weld points one is geo weld points and respot weld points. Geo weld points are welded in frst stretch and the respot welded points are done in second go. 

      Gun study basically includes the study of the weld gun (A portable device for semiautomatic welding of parts of various articles) which is going to be used for the operation depending on the size of the part, Thickness of the part etc.

typical weld gun

In the weld gun study the gun which is going to be used while spot welding is checked over the panel by using the 3D software. The fixture is designed for the car panel to hold it on the position, the weld gun position is checked over the predefined spot weld points, wheather the gun fall to the fixture unit or not. If the weld gun fall to the fixture unit then redesigning of that unit or the repositioning of that unit is done & again confirmed wheather the gun is falling or not. Fixtures are redesigned if the gun falls to the fixture unit, the weld spot positions remain same.

What re the points need to consider during the gun study?

Weld gun study is very time consuming process, the entire welding cycle time study depends on the number of weld spots.

   Following are the points need to consider during gun study

• The axis of weld spot along welding direction must be normal to the weld surface.
• The no. of weld spots for the panel and the time required to spot the each weld determine the total time required to complete all the weld spots.
• 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 Sequences. The sequence defines the motion, manipulation and action of the devices. Based on the distance of each tag point from home position, motion type, speed and acceleration – one can obtain cycle time for each device assigned with sequences. This way robot cycle time is precisely calculated.
• After sequencing all the devices, a simulation is run with "collision check" ON and made sure that the welding operation is collision free.

What is pneumatic routing?

Pneumatic systems should be efficient and leak free. Sometimes, they are not, because of improper tube line routing which resulted due to either lack of knowledge, or corners cut on planning time, or both.

      Planning tube line routing is a 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.

There are some guidelines provided for routing as shown below

• Leave fitting joints as accessible as possible. 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, like the example of the test stand mentioned above, can cause joint stain, which may lead to leaking.
• Make sure routing design allows room for assembly of any connections required.
• Minimize pressure drop by getting around obstructions with as few 90° bends as possible. One 90° bend has more pressure loss than two 45° bends.
• Route lines around rather than over areas that require regular access or maintenance.
• Design routing with clamping in mind. Appropriate design leads logically to proper clamping. Often, it’s possible to clamp several lines together.
• Keep troubleshooting 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

What is the solenoid valve?

Solenoid valve is an electromechanical valve. Solenoid valves differ in the characteristics of the electric current they use, the strength of the magnetic field they generate, the mechanism they use to regulate the fluid, and the type and characteristics of fluid they control. The mechanism varies from linear action, plunger-type actuators to pivoted-armature actuators and rocker actuators. The valve can use a two-port design to regulate a flow or use a three or more port design to switch flows between ports. Multiple solenoid valves can be placed together on a manifold. Solenoid valves are the most frequently used control elements in fluidics Their tasks are to shut off, release, dose, distribute or mix fluids. They are found in many application areas. Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design.

Basic 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 the 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 the 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 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.

What is the valve bank?

v

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 ambient.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 ambient.

What is sensor & brief about its application in automation?What is sensor & brief about its application in automation?

Sensor is a device which detects or measures a physical property and records, indicates, or otherwise responds to it. A unit designed to sense car panel using electrical sensors is called sensor unit. The from the sensors is send to the PLC so the next process is executed by this signal. The sensor is very sensitive & easily damagable part so sensor cover is provided to the sensor for safety purpose.

Sensors in 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 following are the various types of sensors used in industrial automation: Proximity sensors, Vision sensors, Ultrasonic sensors, Position sensors, Photoelectric sensors, Temperature sensors, Inclination sensors, etc. The applications 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 in semiconductor process equipment.

       For example displacement sensor is 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.

What are the types of the sensor?

• Temperature Sensor
• Proximity Sensor
• Accelerometer
• IR Sensor (Infrared Sensor)
• Pressure Sensor
• Light Sensor
• Ultrasonic Sensor
• Smoke, Gas and Alcohol Sensor
• Touch Sensor
• Color Sensor
• Humidity Sensor
• Tilt Sensor
• Flow and Level Sensor

All these sensors are used for measuring one of the physical properties like Temperature, Resistance, Capacitance, Conduction, Heat Transfer etc.

What are the fundamental points that need to consider while designing or selection of sensor?

The fundamental points to be considered while designing or selection of sesnsor are:

• Sensor unit is unit designed to sense the the car panel by using Electrical sensors.
• The signal from sensors will be fed to the PLC and sothe next process will be executed will be this signal.
• Sensos are used for the confirming their is panel/component present or not.
• it should help to avoid human error.
• Basially sensors should be equal numers as camare to numbers of panels in a assembly. for ex. if 9 panels are in assembly, so their should be atleast 9 sensors used.
• sensors should be Slot is designed in such a way that it can be adjusted in 3 direction.
•  Sensors should provide safety to the operator.
• Typically Proximity, LASER, Photo electric Sensors are used in fixtures.
• Some Major sensor manufactures are IFM,Pepperi-funchs, SICK, OMERON, etc