Week 1:- Introduction to BiW and Fixtures Challenge

1. Body in white refers to the stage in automobile manufacturing where all sheet metal components such as roof, body side, under body, back door, cross members and other components are welded together.The resulting body is dipped into a primer solution that is grey in colour. Thus gets the name Body in White.

Body in white are classified into Body sides, Underbody, Closures, Roof, Fender.

2.BIW nomenclature consists of all the Different parts of BIW Structure.

3.Fixture is a device which holds the work piece to be processed(welded) in position by using 3-2-1 principle.

There are three types of fixtures. They are

i. Production fixtures - Used for mass production

ii. Preproduction fixtures-For initial batch production

iii. Checking fixtures- For car panel geometric inspection purpose.

4. Fixture design is based on 3-2-1 priciple wherein we arrest all 12 Degrees of freedom of the workpiece to locate it in the fixture which are 6 Translational - X,-X,Y,-Y,Z,-Z and 6 Rotational DOF - clockwise X,Y,Z and Anticlockwise X,Y,Z directions.

5. BIW Stations Loading station -This is the station where car parts are being loaded.

Geo station-It is the station designed to provide the geometrical accuracy of the car part

Respot station- Normally car part is moved from Geo to Respot station, where the indivisual panels where the remaining weld spots are covered which are not welded in Geo station.

Glue Station -It is the station where a layer of glue or sealer is applied on the car part to avoid leaks between two joining parts.

Hemming station- Inner and outer automative parts are hemmed together in this station.

Marriage station- Astation where inner and outer panels are married to form an assembly. Normally situated between glueing and hemming stations.

Lock and Dock stations-A station where car part is held by the gripper and the complete gripper is located and clamped.

6. Basic terminologies used in BIW Fixtures are

NC-Numerical control

PLP-Principle locating point

GD AND T-Geometric Dimensioning and tolerancing.

NC Patch-25mmX25mm patch on the car panel where rest is placed.

Body line- Position of the car part with respect to the absolute position. Where absolute is the position of the car. The point is OEM specific.

Mylar chopping - Method of chooping surface of mylar matching the surface of the car panel.

Backup - Backup is the part which supports or backs up a car part against a clamp.

Finger - It is moveable part which is used to clamp the car part and is usually mounted on the arm of the clamp.

Blade, Pin unit, Clamp unit, Dump unit, Gripper, Cylindicators, Spacers, Shims.