Week 1:- Introduction to BiW and Fixtures Challenge

1.What is BIW & define its parts?

Ans : BIW - Body in White.

• In BIW sheetmetal components are joind or welded to form a vehicle body or structure.
• BIW is generally refer as conponents structure after welding & before painting process in automotive industries.
• BIW is not includes moving parts like Engine, Doors, etc. They are assembled with BIW unit.

Above figure shows the BIW Structure

BIW parts :

Body Side	Under Body	Closures	Roof	Fender
Inner side Outer side	Front end Frame Main floor Rear end floor	Front door Rear door Hood Deck lid	Inner side roof Outer side roof

2. What do you understand by BIW nomenclature?

Ans :

• BIW structure is made by assembled various components by welding process.

Figure shows BIW nomenclature details

3. What is fixture & its types?

Ans : Fixture :

• A fixture is a work-holding or support device during joining process (welding) by using 3-2-1 principle, generally used in the manufacturing industry.
• A fixture's primary purpose is to create a secure mounting point for a workpiece, allowing for support during operation and increased accuracy, precision, reliability, and interchangeability in the finished parts. It also serves to reduce working time by allowing quick set-up, and by smoothing the transition from part to part.

Figure : Fixture

Types of Fixture:

1. Production Fixture - Used in mass production.

2. Pre-Production Operation Fixrture - Used in Batch production for maintain feasibility.

3. Checking Fixture - For geometrically inspection purpose.

4. What is basic principle of fixture design?

Ans :

For a fixture designer, the major portion of design time is spent deciding how to locate the work piece in the fixture.

Any free body has a total of twelve degrees of freedom as below,

6 translational degrees of freedom: +X, -X, +Y, -Y, +Z, -Z

And 6 rotational degrees of freedom:

• Clockwise around X axis (CROT-X)

• Anticlockwise around X axis (ACROT-X)

• Clockwise around Y axis (CROT-Y)

• Anticlockwise around Y axis (ACROT-Y)

• Clockwise around Z axis (CROT-Z)

• Anticlockwise around Z axis (ACROT-Z)

Figure : 12 Degree of Freedom

Above fig shows 12 Degree of Freedom, all relate to the central axes of the workpiece. Notice the six axial degrees of freedom and six radial degrees of freedom. The axial degrees of freedom permit straight-line movement in both directions along the three principal axes, shown as x, y, and z. The radial degrees of freedom permit rotational movement, in both clockwise and counterclockwise radial directions, around the same three axes.

The devices that restrict a workpiece's movement are the locators. The locators, therefore, must be strong enough to maintain the position of the workpiece and to resist the cutting forces.

5. Elaborate types of BIW Stations?

Ans : There are different types of BIW stations.

BIW Stations	Types of Stations
Tools	Geo tool Re spot tool Marriage tool Framer tool, etc.
Gripper	Material handling gripper Process gripper Combo gripper Dual gripper
Stands	Padestal stand Gluing stand Docking stand Date stamp stand, etc.
Miscellaneous	Cutting Buffing stand Racks Pallets Take out trolleys Conveyors, etc.

1. Tools: A tool is a fixture which consits no. of units together to a car parts.

a) Geo tool:

• A geo tool is a fixture in which geometry of panel are welded together in such a way is should not deform & give precise finished product after clamping is open.
• The pin tolerance for geo pin will be clouser tolerance i.e. -0.15mm in general.

b) Respot tool:

• A respot is a fixture in which remaining weld spot which are not achieved in geo tool are weled for pre welded panels from geo tools.
• The pin tolerance for a respot pin will be tolerance with -0.28mm in general.
• It is less precise as compare to geo tool.

c) Marriage tool:

• A mirrage tool is a fixture in which the inner panel assembly & outer panel assembly are joined together.
• They are done by welding or hamming in case of clouser panel.

2. Gripper: Gripper is a device or a fixture which holds the car panel and is fixed to the manipulating end of a robot or at end effector. Also know as EOAS - End of Arm Tooling.

a) Material handling gripper:

• Material handling grippers are designed for handling or transferthe car panel from one station to the another station.

b) Process gripper:

• Process gripper are designed for handling the car panel from one station to another station in addition to that it undergoes process like pedestal welding, pedestal riveting, gluing, sealing, etc.

c) Combo gripper:

• Combo gripper are designed for handling car panel from one station to another station, also with combination of weld gun at another side of gripper for welding.
• Refer as Gripper + Weld gun.

d) Dual gripper:

• Dual gripper are designed for handling car panel from one station to another station, having both sided welding gripper.
• Refer as Gripper + Gripper.

3. Stand:

a) Pedestal gun stand:

• Weld gun is mounted to a fixed stand which is grounted to the floor permanantly, where the process gripper carries the car panel to weld the spot with this fix weld gun.

Figure: Pedestal Gun Stand

b) Gluing gun:

• Gluing gun is fixed to the welded or a standard stand which is grounted to the floor permenantly.

Figure: Gluing stand

c) Docking stand:

• When robots are selected for multiple tasking operations like material handling, welding, riveting, etc., which can not carry due to some limitation like pay load capacity of robot, space constraint. The robot will drop & pick the gripper or gun after completing the respective operation with the help of docking stand.

Figure: Docking stand

d) Date stamp stand:

• The panel will get the date embossed on to it, with date stamping device mounted on this date stamp stand.

4. Miscellaneous:

a) Buffer stand:

• Buffer stand are used for storage purpose, no. of assemblies can hold by using buffer stand.
• To eliminates the buffer time occures due to maintanance.

b) Take out trolleys:

• Take out trolleys are used to take care of panel out of the robotic working cell between the cycle for inspection purpose.

Figure: Take Out Trolley

c) Conveyor:

• Conveyors are used to moves of parts, assemblys from one station to another stations.

6. What are the basic terminologies used in the BIW fixture?

Ans:

1. NC / Mylars :

• It is used to hold the panel from top & bottom sides.
• To avoid deformation during welding process.
• It have clamping & resting arragements for holding a panel from both sides.

Figure: Mylar

2. PLP -

• Principle Locating Point are where pins are mounted to insure panel is mounting accuratly.

Figure: Principle Locating Point

3. Blade:

• Blades are mounted on raiser to hold the panel through NC/Mylars.

4. Raiser:

• Raiser is manufaturing part which provides required height to panel.

Figure: Raiser

5. Shims:

• Shims are plate between the mylars clamps to avoid deformation due to tolerances.
• Shims are in sizes 0.1,0.2,0.5,0.8,1 mm etc.

6. Rough locator:

• Rough locator acts as a guide.
• When operator start to fix the panel on fixture base, rough locator used a guide the panel.

7. Hardwares:

• Bolts, Nuts, fasteners, etc are used to joined mechanical parts together.

8. CMM:

• Coordianate measuring machine is used to check the coordinate of assembly as per cad data.

9. Units:

• Unit is a assembly of multiple parts which performs operations.

10. Number Plate:

• It is an aluminium embossing mounting on every assembly or unit for recognizing it data.

11. Coordinate plate:

• It is used for locating the exact mounting area of units on fixture base.

12. Name plate:

• It is gives basic information of fixture.

13. Clamp arm:

• Clamp arm on which mylars are mounted to hold the panel.
• Clamp arm are mounted on cylinders.

Figure: Clamp Arm

14. Pivot:

• Pivot is type of pin which is used to insure the attachment of clamp arm on the cylinder.

15. Sensors:

• Sensors are used to detect whether panel is mounted to nor.