Week 1:- Introduction to BiW and Fixtures Challenge

1. The meaning of BIW is Body In White is in automotive industry in which car body frame been joined together to form a new part, which is by welding method or other joining process. Its consists of 5 parts, which is body side, under body, closure, roof and the last one is fender.

2. BIW (Body In White) nomenclature is the term used in the system either by using UK or US description.

3. Fixture is a device to hold or support the work piece to be welded used in the industry. There 3 types of fixtures which is production fixture, Pre production operation fixtures (PPO) and Checking Fixtures.

4. Basic principle of fixture design

• 6 translations degree of freedom : +x, -x, +y, -y, +z, -z
• 6 rotational degree 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)

5. Types of BIW stations:

A. Tools

• Geo Tool : A fixture that the geometry of panels which welded together is accurate.
• Re-spot tool : Fixture that remaining weld spots which geo tool cannot achieve in welded. The weld spot for this tool is for rigid or stifness only. Pin tolerance for respot pin is -0.28 in general.
• Marriage/Hemming tool : Fixture that inner pannel & outer pannel assembly are joined as a new part.
• Framer tool : After marriage tool process will be framer tool. Tool roof is attached to the output of marriage tool. A car form a frame after roof is attached by using framer tool.
• Checking tool : To check the parts or assemblies to make sure all the coordinates, dimension & position are following to the specific tolerances. Its also a tool where workpiece is hold onto & several measuring gauges used to make sure the dimension is correct. Can be gauge, fixed & automated checking fixture types.

B. Grippers

• Material Handling Gripper : designed for handling the car panel from one tool (station) to other tool (station).
• Process Gripper : To carryout some process like gluing, welding, riveting etc in addition with material handling.
• Combo gripper : multitasking (both process like gluing & material handling held at same time)

C. Stands

• Pedestal stands : Weld gun is grounted to the floor permanently, where the process gripper carries car panel to wled the spot with fixed weld gun.
• Gluing & sealer stand : Also grounded to the floor permanently.
• Docking stand : Robot will drop & pick the gripper or gun after completing the respective operation with the help of docking stand.

6. Basic terminologies used in BIW fixture:

• NC/Mylars/Fingers : Which hold the panel from top & bottom. Doesnt allow the deformation of the part cause by welding stress.
• PLP (Principle locating points) : Points used for the accurate location of panels to maintain the geometry of the assembly.
• Blade : plates that are attached to raiser.
• Raiser : manufacturing part used to raise or height the assemblies of fixtures.
• Shims : thin material used to fit in small gaps or spaces between objects. Often used to support, better fit. Type of shims are wood shim, stone shim, plastic shim, metal shim, and paper shim.
• Rough locators : manual fixtures that provided at the end of panel. Acts as a guide for operator and to place panel in the fixture in right position.
• Hardwares : A fasteners used to connect/lock the parts of fixture together in fixed posiiton.
• CMM (Coordinate Measuring Machine) : Device that measures the geometry of physical object by using probe to sensing discrete points on the surface of the object.
• Units : Units which is Base unit, Pin unit, Clamping unit & Rest unit.
• Number plates : Every unit has number which embossed on aluminium plate for identification.
• Coordinate plates
• Name plate : Panel name, model name, panel number, fixture type, fixture weight, company name, Asset ID etc will engraved in the name plate.
• Clamp arm : clamping unit that moves ove rthe axis.
• Pivot : Axis that clamp arm rotates.
• Class "A" surface / Skin surface :
• Reed switches : Electrical parts used in automated fixtures that run by PLC programming. Operated by applied magnetic field.
• Sensors : Attached at the main part of panel & sub-assemblies of panels.