Week 8:- 3D Finishing - Challenges 1

What do you understand by the 3D finish process?

3D finish is a process where the design is being completely finish and to be ready for final simulation & 2d detailing.

These is the process before sending the part for final simulation.

In these process the parts are checked for proper clearance and the nominality is also maintained.

The machining sides of parts are applied with colour codes for representation.

Parts are checked for hole concentricity & size, standard colour codes are applied for holes and the fastners are also implemented.

Renaming of parts is done for easy indentification in assembly.

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

Following points need to be taken care of while finishing the design:

• Hole concentricity & hole sizes
• Machining area
• Nominality
• Holes colouring standard
• Pneumatic lay-outing
• Gaps checking
• Fasteners implementation
• Avoiding clash between different parts
• Mylars splitting as per panel profile
• Proper renaming of parts/assemblies as per the standard

What are rough Locators & what is their use?

Rough locators are basically used where manual loading of panels are to implemented on the fixture.

These are used to guide the panels in correct position & orientation.

These also help for proper Poka -Yoke.

Materials used for rough locators are MS or similar metal.

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

Following points need to be considered while designing the rough locators:

• Height of rough locators should not be more than the permissible ergo height of the fixture.
• The entry point/ top point of the rough locator must be 10mm-15mm above the panel surface.
• Rough locators should have adjustment in the direction of guiding plane.
• 2 mm gap to be maintained between rough locator and panel at the time of design & we can provide adjustment of 5-10 mm in the positive or negative direction of guide plane.
• Rough locators can be rod type or flat type, depending upon the standards and other conditions.

What is the gun study process?

Gun is the device used to make spot welding on the panel. It may also be called as weld gun. The Gun may differ depending upon the application.

Fixtures will be designed by considering the weld spots on the panel.

After designing the fixture the CAD file of the gun is placed on the weld spots to check whether the gun is maintaining clearances with the fixture.

If one of a fixture is obstructing with the weld gun the position of the gun or fixture is slightly ajusted inorder to avoid crash.

After adjusting the Fixtures the coordinates of the welds be taken for further operations of Weld Gun.

This process of checking the clearances between the gun and fixture by placing the gun on weld spots is called as gun study process.

What are the points need to consider during the Gun study?

The points that need to be considered during the Gun study are:

• 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 each weld & the total time required to complete all the weld spots must be calculated initially.
• There should be adequate space between weld gun and fixture unit.
• Make changes in fixtures if there is any collision with spots or with fixtures unit.
• The welding operation must be collision free.

What is pneumatic routing?

In BIW welding fixture all toggle clamp, pin cylinder, slides are operated via pneumatic.

Generally cylinder are designed to operate at max pressure of 12-13 bar. As it expensive and difficult to maintain 10-12 bar in shop floor it is preferred to design pneumatic systems at 6 bar pressure. Also pneumatic delivers less force compared to hydraulic system.

Therefore, pneumatic system is mostly preferred over hydraulic system in BIW welding fixture.

The pneumatic devices used in fixtures like clamp cylinder,pin cylinder, slides, etc requires continuous supply of compressed air for its operation. This supply of compressed air is provided by single pneumatic cylinder and all the fixture units are connected to this through pipes & hoses.

The routing of this pipes must be proper without any obstacles.

These pipes are routed through square ducts.

Proper Pneumatic lay-outing or routing is very much important to be shown in design, as it helps in describing the best possible way to keep all pneumatic pipes neat & away from welding spatters which can cause wear or tear of pneumatic pipes.

In pneumatic lay-outing all pipes from cylinders are shown connected to valve banks and passes through a safety box like structure.

What is the solenoid valve?

A solenoid valve is an electrically activated valve, typically used to control the flow or direction of air in systems.

A solenoid valve is an efficient method of converting electrical signals into pneumatic functions. Applying electricity to the solenoid quickly directs air through the valve and into the circuit.

Solenoid valves are used to actuate the air flow in cylinders as per the sequence through manual or PLC operated system.

These devices are used to control the BIW equipments.

What is the valve bank?

Valve Banks are basically a system in which n numbers of solenoid valves are mounted, in order to maintain one common inlet & outlet of air to all the valves.

Valve banks are mostly mounted on the fixture sides or on the base plate depending upon the various conditions.

Example: If we have 4 operating sequences in one process of cylinder, this means we will be using 4 solenoid valves, corresponding to 4 different sequences, and for these 4 valves to be mounted together on one valve bank. This means a valve bank with 4+1 valve stations are to be used, 1 extra blank station is taken as a spare for future considerations.

Selection can be done as per the requirement & data sheets available on the catalogue or websites.

Various major suppliers for valves & valve banks are SMC, Festo, CKD, Janatics etc

What is sensor & brief about its application in automation?

A sensor is a device used to sense the car panel by using Electrical sensors. These signals form the sensors will be fed to the PLC and so the next process will be executed by this signal.

Sensors also helps in avoiding the human errors, such as wrong orientation of panel, missing of a panel/part in an assembly etc.

Sensors are basically used in automated systems.

Sensors can help us achieve better quality and less chances of errors.

There are wide range of sensors available that can be implemented over various conditions.

Selection of the sensors can be easily done by referring the catalogues or data sheets available on web sites.

What are the types of the sensor?

The types of sensors used are:

• Proximity sensors
• LASER sensors
• Photo electric sensors

Some major sensor manufactures are IFM, Pepperl-fuchs, SICK, Omron etc

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

Fundamental points that need to be considered while designing the Sensor Unit are:

• Every single loose panel which are being welded in a tool should be sensed.
• Each panel should be sensed by 1 to 2 sensors depend on the size of panel, preferred to be in diagonal opposite ends of panel.
• Every sensor should be mounted in a 3 direction adjustable way in general.