Week 1:- Introduction to BiW and Fixtures Challenge

1. What is BIW & define its parts?

To industry body manufacturer in segment like does, engine, roof, closures etc. All the parts are used to join and make Complete body structure. At the end of framing line body receive door bonnet, tailgate and front wings which have been built separately.

OR
Body in White (B.I.W.) refers to the welded sheet metal components which form the vehicles structure to which the other components will be married, i.e., engine, chassis, exterior and interior trim.
Body in white of BIW refers to the stages, in automotive design or automotive Manufacturing in which car body parts ( doors, hoods, and deck lids) has been assembled to designed but before the components (chassis, motor) and trim [windstand, seats etc) have been added.

BTW is called before the welding or painting this body is submerged into the liquid called primers which is in greay in color so.

• Consist of 600 to 700 ports of different car body.
• It also have 5000 spots all over the body.
• In it for joining MAG and Seam welding used to get the robust and strong welded body.

The BIW body is sub divide into the differnt pats such as follow:-

• Body sides:- This also divide into the Body side outdoor and Body side inner.
• Under body:-  This will make a platform for the entire BIW and each component is assembled. The Undercarriage is the section of a vehicle that is underneath the main cabin of the vehicle. For trucks and automobiles, the Undercarriage contains the chassis. On the underbody this also divide into the Front end under frame ,Main floor, Rear end under frame.
• Closure :- Automotive closures are a non-structural part of the vehicle that are hinged to the body frames, such as doors, to allow entry and exit from the vehicle. Automotive closures are a critical part of the vehicle, as they contribute to vehicle safety and add functional value.
  This also divide into the Fornt frame , Rear frame, Hood , Deck lid.
• Roof :- This also divide into the Roof inner and Outer.
• Fender :-  Fenders are an intricate sheet of metal covering the wheel well of your car. Fenders are designed in a manner to provide resistance against wind and other roadside debris.

2.What do you understand by BIW nomenclature?

Body-in-white (BiW) is the name given to a car body's sheet when all its components—barring moving parts (e.g., hoods, fenders, etc.), trims (e.g., glass, seats, etc.), or chassis subassemblies—have been welded together. Usually, BiW constitutes about 27% of a car's curb weight.

Nomenclature is basically choosing names for things we have no. of parts in it. All parts have different names.As automotive industry is spread worldwide. Every nation has its own language. So the same part in BIW have different name in its region.

For example, One component of BIW is called suspension tower in UK & same component called shock tower in U.S. Below fig show BIW nomenclature.

Below fig. shows UK Vs U.S. Nomenclature.

3. What is fixture & its types?
It is fixture which consist of number of units together to hold a car part in general. 
Fixtures are work-holding devices and locating elements that locate, hold, and support the workpiece in a fixed, proper position during the machining process with respect to the machining tools. The most common type of fixture is the vise jaw found in nearly all workshops. 

Their main advantages are:

• Increased productivity
• Increased machining accuracy
• High-speed manufacturing process
• Maintained interchangeability
• High clamping rigidity for CNC and turning operations on large parts
• The increased quality level of the finished product 
  OR

A device which used to hold locate and support the Component in the manufachreing industry. It ensure to provide stability to the pand when process being done on that part.

Ex. In General welding fixture consist of number of units together to hold the Car panel and is mounted on a base unit.

→This fixture design to hold and support various component.

→ It necessary to support them in proper location which is capable of preventing distorations in work pieces during welding

→ For this locating elements need to be placed carefully, clamping-light but firm placement of clamping elements has be clear to welding area and fixture has quite stable and riged to withstood to welding stresses.

→ This are need to be assesable for maintance purpose in certain duration or time . 

Types:-

• Production Fixture:- As name suggest this fixture is used for mass production. It is fixture on which car body get assemble & go to end customer. These types of fixture require high constancy through its operation to maintain geometry of parts.
  These kinds of fixtures are used in the main production line or mass production departments in a company. for example, the assembly line is where all the sheet metal BIW parts are joined or welded together so a production fixture is used to check the geometries and fast production in less time.

• Pre-production Fixture:- It is generally defined as prototype fixture. It is designed to study feasibility of initial batch production to check which things are need to be improving before starting production. This fixture is base of production fixture in benchmark and criteria & helps us to rectify error. In preproduction operation fixture there will be more involvement of manual operations, engineer, and quality person. It has larger cycle time than production fixture. But won’t practice by designing preproduction fixture because it takes lots of time & cost. 

• Checking Fixture:- As name suggest this fixture is used for checking assembly which came out from geo fixture.A checking fixture is a quality assurance tool used in industries to check for the quality of components with complex shapes. They aren't used in making components but to accept or reject already made components according to the dimensional accuracy.

4.What is the basic principle of fixture design?

It is device which holds the work piece to be processed (welded). by using 3-2-1 principle.
6 translation 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)

3-2-1 locating principle

3-21 principle where these pins are located on the 1st principle plane ie. xy, yz, zx and two plane To Caled on the 2nd plane which is perpandicular to the 1st plane and at last one pin on the plane which is mutually perpandicular to 1st and 2nd planes.

5. Elaborate types of BIW Stations?

Tool :- It is fixture which Consist of number of units. Together to hold a car part in general.

Geo. Tool/fixture :- It is a fixture in which the geometry of the panels which are welded together is defined accuretly 
Pin tolerance fire a Geo pin will be closer tolerance.

Ex. Hole 20mm Pin 19.85 mm dia.

Re-spot Tool :- It is tool fixture in which remaining weld spot. which are not achieved in geo tool are welded for the Pre welded panel from the geotrol.
The pin tolerance for respot pin will be of toterance with -0.28 in general. 

Ex. Hole 20mm. Pin 19.72 

Massage/hemming tool :- A marriage or hemming tool is a fixture in which the inner panel assembly and outdoor panel assembly ase joined together. This is done by welding or by hemming in case of clouser panels.

Checking station:- A checking station tool is a fixture which is use to check the automobile / automotive parts of assemblies. ensuring all the Coordinates, relative dimensions and position as per the tolerance. A checking station can be gauge type, fixed type & automated checking fixtures. It checking gauge is tool where part is hold & Various measuring gouges are introduced to ensuse dia. & repeatability.
Fixed type of checking tool used where work piece is fixed with Clamps & pins & CMM machine used which meanese Co-ordinates of  different points of the panel on assembly.

• Gripper - It is a device / fixture which holds the cars panel and fixed to the manipulating end of robot or an end effecotur. Also known as EOAT End of Arm Tooling. 
  Material handling
  Gripper (MH):-  This are designed for handling the cars panel. from one tool (station) to other tool (station).
• Process Gripper - This are designed fore handling cas pand  from one tool (station) to other. And in addition to that it under goes process like pedestal welding pedestal riveting, sealing, Gluing etc.
• Combo Gripper - This are designed for handling Car -panel from one tool (station) to other. And in addition to that in Consist of Gun on other side for welding. Gripper + Gun
• Dual Gripper - This is designed for handling the car panel from one tool (station) to other tool (station) with two sided gripper. Gripper + Gripper

Gluing and selare stand :- This is fixed to welded or std. Stand which is grounded to the floors permenantly due to its Contineus used it may change in position after a year on etc.

Docking stand:- When robots are selected for multi-tasking like material handling & welding which cannot carry both due to some limitations (pay load capacity of rboot of space constraint) the robot will drop and pick up gripper or Gun after completing respective operation with help of Docking stand. 

Date and stamp Stand :- The panel will get a date stamp embossed on to it with the date stamping device mounted on date stamp stand.

Pedestal Gun stand :- Weld Gun is mounted to fixed stand. which is  grounded to the floor permently where the process gripper Carries the Car panel to weld the spot with fixed weld gun.

Take out Trolley :- Take out Trolley is used to take the Car panel Cut of the robotic working cell between the cycle for inspection purpose.

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

NC/MYLARS/FINGERS:- These are parts are used to hold panel. They are globally called as mylar. Top side mylar is called as clamping mylar & bottom side is called resting mylar. Every clamping mylar should have resting mylar. It is jaw type. It prevent panel from deforming while welding.

Principle locating point (PLP) :-  These are point which are used for the accurate location of part to maintain the geometry of assembly. means principle locating points are those where we use pin for locating panel. These are defined in drawing. The positional dimensions or relative dimensions are very precise in stamping & in fixture also.

Risers:-  Risers can be of L-type, welded or square tube or frame type. These are basically manufactured parts are used to give height to assembly.

Blades:- Blades are plates attached to riser. Other part likes cylinder, arms etc are mounted on the blade.

Shims- In fixture we are providing tolerance to each part mostly manufactured. Those tolerance tend to stack up & reflect together. In order to avoid that we use shims so we can easily adjust after assembly so whatever stack up there we will rectify it through shims. Shims come in thickness of 0.1, 0.2, 0.5 etc.

Rough locators:- Rough locators are those used majorly for manual fixture. There is chance that operator can place part in wrong orientation mistakenly. The rough locator will work as a guide while placing the part in the fixture & part will be loaded in desired orientation.

Hardwares:- Hardwares are like the hex head bolts, allen bolt, hex nuts, spring washers, self locking nuts etc.

CMM:- CMM stands for coordinate measuring machine. It is a device that measures the geometry of physical objects by sensing discrete points on the surface of object with probe. It generates report by comparing the data with the CAD file data.

Units:-  The fixture is assembly of different types of units to form a fixture. There are different unit like pin unit, base unit, clamping unit etc

Name plate:-  The plate on which basic information described like company name, fixture name, fixture weight, panel name are embossed & joined to fixture.

Clamp arm:- Clamp arm is part of clamp unit which moves about axis. Over clamp are mylars are mounted

Pivot:- It is axis about which clamp arm will rotates.

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

Switches & sensor:-  These are the electric components used in automated fixtures. The sensor & reed switches are used only in that situation where fixture is fully automatic or semiautomatic that run through PLC, control panel etc. Sensor are used to detect part present or not, clamp is close or open whereas reed switches confirms position of piston i.e. it is at top or down. Below fig shows unit used in BIW.