Week 1:- Introduction to BiW and Fixtures Challenge

Q1.WHAT IS BIW AND DEFINE ITS PARTS?

ANSWER:-

BODY IN WHITE(BIW):-

Body InWhite(BIW) refers to welded sheet metal components which form the vehicle structure to which the other components will be joined i.e.engine,chasis,interior and exterior trims.Body in white refers to the stage in automotive design or automotive manufacturing in which the car body sheet metal(including doors,hoods,and decj lids) has been assembled or desingned but before the components (chasis,motor)and trim (windshields,sests,upholstery,electronic,etc.) have been added.

BIW is the stage in automotive design or automobile manufacturing in which the car sheel metal components are been assembled by welding or by other joining method.Biw also need to be light weight structure so that there can be a possibility of reduced fuel consumption and increased performance.

MAJOR INFLUENCING FACTORS OF BIW DESIGN:-

1)Number of parts

2)Materials

3)Inernal structural reinforcement

There are two types of body structure in use:-

1.Monocoque Body

In this type of body structure,chasis inbuilt in the biw itself and there is no seperate chasis.Wheel are directly mounted to the biw with the help of a suspension system.

2.Frame mounted body Structure:-

In this type body structure,the body is mounted on the seperate chassis or frame and wheels are mounted on the chasis,not to the body.

BIW PARTS:-

1)BODY SIDES:-

The side word parts of the BIW structure falls into this category.

1.Body side Outer:-This refers to the sidewards outer parts of body/frame.

2.Body side inner:-This refers to the sideward inner parts of the body/Frame.

2)UNDER BODY:-

The bootom/dowmward parts of the BIW structure falls into this category.

1.Front end under frame:-This refers to the frame under the front end i.e under the engine bonnet.

2.Main floor:-This refers to the frame under the middle i.e,. under the seats.

3.Rear end under frame:-This refers to the frame under the rear end i.e.under the boot cabin.

Closueres:-

The closing parts of the BIW structures such as doors/lids parts fall into this category.

1.Front Door:-This refers to the parts of front door panels of the automobile.

2.Rear Door:-This refers to the parts of rear door panels of the automobile.

3.Hood:-This refers to the closure door the hood of the automobile.

4.Deck lid:-This refers to the closure lid of the deck of the automobile.

5.Roof:-The top covering parts of the biw structure falls into this category.

5.Fender:-

A fender is the curved portion of the car's body that sits over and houses the wheels.Its primary purpose is to prevent sand,mud,rocks and other road spray from being thrown into air by the rotating tire.

Q2)What do you understood by BIW nomenclature?

ANSWER:-

The accurate naming of objects in the natural worlds has resulted in a variety of international namenclature.The terms are standard bit they differ in some countries.As automotive industries spread worldwide,the terms and standerds willbe different for similar componenets.For example,One components of BIW is known as inner wing pannein UK description another side the same component of BIW is konown as the motor compartment side panel in US description.

Q3)What is fixtures and its types:-

ANSWER:-

A fixture is device which holds the workpice to be processed by using 3-2-1 principle.In general,a welding fixture (Tool) consist of no of units together to hold the car panel,and is mounted on the base unit.

Welding fixtures are normally designed to hold and support the various components to be welded.Its necessary to support them in proper location which is capable of preventing distortion in workpiece during welding.

Types of Fixtures:-

• Production Fixtures:- Its used in mass production purpose.
• Pre-production opertaion fixtures(PPO):-For intial batch production to study the feasibility.
• Checking Fixture:-For car panel geometric inspection purpose.

1)Production fixtures:-

This fixtures is used for mass production it requires high consistency through its operation to maintain the geometry of the parts so that material used is well tested foe hardness and aesthetics.The quality for maintaning the dimensions and tolerances are also checked.The production fixtures need to easy maintenance purpose.The fixture needs some maintenance after completuf no.of operations.

2)Pre-Prodcution Fixtures:-

Thses fixtures are designed as a prototype fixture to check the feasibility of initial batch production and to check which things need to be improved before starting.

These fixtures can be taken as the base fixtures which sets the benchmark and criteria which help us to rectify the errors that we could get from preproduction opertaion fixtures.In this many engineers and qulity-related persons are required.

3)Checking Fixtures:-

As the name suggested these fixtures are used for checking no operations like welding gluing or hemming are carried out in these fixtures.The gauges are used in these Fixtures to get the dimensions and the tolerances part having and the data is compared with the designed dimensions to check wether thepart is ok or not.The geometry of the welded part is also checked in these fixtures to ensure the part maintain the required dimensions and geometry.

Q4)What is the basic principle of Fixture Design?

ANSWER:-

3-2-1 Principle is uesd for the design of the fixtures.

For a fixture designer,the major portion of design time is spent deciding how to locate the workpiece in the fixture.We know that any free body has a total of twelve degree of freedom as below:

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

And 6 rotational degree of freedom:

1.Clockwise around X-axis(CROT-X)

2.Anti-clockwise around X-axis (ACROT-X)

3.Clockwise around Y-axis(CROT-Y)

4.Anti-Clockwise around Y-axis (ACROT-Y)

5.Clockwise around Z-axis (CROT-Z)

6.Anti-clockwise around Z-axis(ACROT-Z)

To make sure the proper fixing of the part we need to restrict all the 12 degree of freedom of the workpiece.The major portion of the time of BIW fixture designer is spent deciding how to fix these all degree of freedom.

Primary Locator:-

First,the three locator or supports are placed under the workpiece.It will be positioned on the primary locating surface also known as a datum.It will restrict 5 degree of freedom.

1.Axial Movement downward along z-axis

2.Rotational movement around X and Y axis.

Secondary Locator:-

The next two locators are normally placed on the secondary surface,restricting an additional 3 degrees of freedom.

1.Axial movement along the Y +axis

2.Rotation about the Z-axis

Tertiary Locator:-

This locator is positioned at the end of the part.it restict 1 degree of freedom.

Axial movement along the x-axis.

all these 6 locators will restrict a total of 9 degree of freedom.the remaining 3 degree of freedom (1,4 and 5)will be resticted by the clamps.To minimize the time consumption in assembly and dessembly,Have to use minimum number of pins to arrest a maximum number of degree of freedom.

Q5)Elaborate types of BIW stations:-

ANSWER:-

TOOL:-A toola fixture which consist of no of units together to hold the car part in general.

Tyoes of tools:-

1.Geo Tool:-A geo tool is fixture in which the geometry of the panels which are welded together is defined accuretly.The pin tolerance for the geo pin will be of closure tolerance i.e 0.15 in general.

2.Re-spot tool:-A re-spot tool is a fixture in which the remaining weld spot which are not achived in geo tool are welded for the pre-welded panel from the geo tool.

The pin tolerance for the re-spot pin will be of tolerance of - 0.28 in general.

3.Marriage or hemming tool:-A marriage or a hemming tool is fixture in which the inner panel assembly and outer panel assembly are joined together.

4.Checking Fixture:-A checking stastion tool is a fixture which is used to check the automotive parts or assemblies,ensuring all the coordinates,relative dimensions and postions as per tolerances.A checking station can be a gauge type,Fixed type and automated checking fixture.

A checking gauge is a tool where work piece is hold and various measuring gauges are introduced to ensure the dimensions and repeatability.

GRIPPERS:-

A gripper is a device or a fixture which holda the car panel and is fixed to the manipulating end of a robot or an end effector.also known as EOAT-End Of Arm Tooling.

1.Material handling gripper(MH)

2.Process gripper

3.Combo Gripper

4.Duel Gripper

STANDS AND TYPES OF STANDS:-

1.Gluing and sealer stand:-gluing gun or sealer gun is fixed to a welded or a standard stand which is grouted to the floor permanantly.

2.Docking stand:-When robots are selected for multitasking like material handling and welding,which cannot carry both due to some limitations.The robot will drop and pick the grippers or gun after compeleting the respective operation with the help of docking stands.

3.Date stamp stand:-The panel will get the date embossed om to it,with the date stamping device mounted on this stamp stand.

4.Pedestal Gun Stand:-Weld gun is mounted to a fixed stand which is grouted to the floor permanently,Where the process grippers carries the car panel to weld the spot with this fixed weld gun.

Q6)What are the basic terminologies used in the BIW fixtures?

ANSWER:-

1.NC/MYLARS/FINGERS:-

Mylars are the component that holds the panel while these are placed from topside and from the bottom side also.The top side mylars called clamping mylars and the bottom side mylars are called resting mylars.Every clamping mylars have resting mylars.It doesn't allow deformation of the part due to welding stresses.

2.Principle locating point (PLP):-

These are the points that are used for the accurate location of the part to maintain the geometry of the there is lots of holes on the panel which are not accurate due to stamping operation.The PLP are defined in the drawing.The positional or relative dimensions are very precise in stamping and in fixture also.

3.Risers:-

Risers are different types like l-typer risers,square tube riser is the manufacturing part which gives height to the assemblies.

4.Blade:-

Blades are plates mounted on the outer parts like cylinder,arms,etc are mounted on the blade.

5.Shims:-

Shims are the small part that comes with the thickness of 0.1mm,0.2mm,0.5mm,etc.These will compensate for the stackup tolerance which reflects at the panel holding part called we give tolerance to all the parts of the fixture.Due to this tolerance,the mylars will either lift up or goes down from defined position.If the mylars go down from the defined height it will make impression or dent on the panel.If the Mylars lift up then there will be distortion due to welding stress.To adjust the Mylars at its defined position we use Shims so that the panel Won't be deformed and also don't get eny impression on it.

6.Rough Locators:-

The operator can place the part in the wrong orientation the rough locator will work as a guide while placing the part in the fixture and the part will be loaded in the desired orientation.Its a part of Foolproofing.

7.Hardware:-

Hardware is like Hex head bolts,allen bolts,Hex nuts,Spring washers,Self-locking nuts.

8.CMM:-

CMM stands for co-ordinate measuring it's a device that measure the geometry of physical objects by sensing discrete points on the surface of the object with a probe.It Generates a report by comparing the data with the CAD file data.

9.Units:-

The fixture is assembly of different types of units to form a there are different types of units to form a there are different units like pin unit,Base unit,clamping unit etc.

10.Number plates:-

The number plate is a alluminium embossed plate placed on each unit for easily recognizing when needed.

11.Nameplate:-

The data like manufacturing comapny name,fixture type,fixture weight is embossed on the plate and jioned to the fixture.

12.Clamp arm:-

The clamp arm is the part of the clamp unit which moves on over clamp are the mylars are mounted.

13.Pivot:-

Its an axis about which the clamp arm will rotate to fix and unfix the part.

14.Class a surface/Skin surface:-

The outer panels of the car like a hood,door,backdoor,fender,roof are visible to the customer.The outer panels should be asethetically very good.No scratches or dent is acceptable over it.While designing the fixture to the skin surface the clamping material should be soft,so that it could not able to left any impression or dent over the skin.Generally,nylon or PU material is used for clamping purpose.

15.Reed Switches and sensors:-

Reed switches are electromagnetic sensors which are located on piston which tells us the pistion current position means piston is extended or retracted.sensors are used to determine that all the part which is to be processed are there are not it ensures that all the part are there.