Week 1:- Introduction to BiW and Fixtures Challenge
1. Biw
BIW is a stage in automotive design and manufacturing. BIW refers to the body shell design of an automotive product such as cars. It is just a sheet metal welded structure. BIW will not have doors, engines, chassis or any other moving parts.
Biw - Body in white
It is the assembly of which parts are joined like
Automotive manufacturers such as General Motors, Ford, and Honda, use the term BIW to refer to a fully assembled automotive frame/ structure.
1.Body side
2.Under body
3.Closures-a.front door
b.rear door
c.hood
4.Roof -Inner and outer roof
5.Fender
Body side
It is a side section of an automobile body that usually wraps around the wheel well between the door and trunk lid .
2.Under body
- The underbody of a car is the area beneath the car’s body that is not visible from the outside. It includes the car’s frame, suspension, exhaust system, fuel tank, and other components.
- The underbody is exposed to various elements such as water, mud, salt, and debris from the road, which can cause rust and corrosion over time
- To protect the under body from the rusting the under body coating is done.
3.Closures
Closures are the different parts designed for to provide access to the passenger compartment the different closures are front door, rear door, Hood, Deck lid etc..
4.Roof
A car roof is responsible for protecting the passenger from rain, wind, sunlight, accidents.Roof rails are provided to give strength to the outer panel and also provide support to other commodities present in a car.
5.Fender
It is the front side member of the car which cover the wheel side of the car. The fender is the car body part that frames the wheel. The purpose of using fender is to avoid chiping.Fender will be helpful to prevent sand and other mub particles which is going to chip inside the engine.
2.Biw nomenclature
Nomenclature is basically consists of parts in the biw.it showa what are the parts present in the biw.Helps identify the parts where it should be fitted while in assembly of biw.
In different countries they use different name for different parts for example they use name for centre tunnel as just tunnel in the other country.
Nomenclature helps to identify the parts of the biw.
Biw components
- Dashboard mounting panel
- Windscreen & Rear Window rail
- Cant rail
- Roof structure
- Side Sill
- Quarter panel or window
- cross member
- Heel Board
- Front & rear Valance
- Scuttle
- Firewall
- Floor, seat & Boot pan
- Front & rear Spring tower
- Central Console
- Front & Rear Wheel arch
3.What is fixture and types of fixture?
Fixture: Fixture is a work holding device used hold the work without guiding the tool.A fixture is an engineering device equipped to locate, hold, and support a product during a manufacturing operation. It is developed by amalgamating fixture bodies, locators, supports, and clamps. The components of a fixture design are available in wider range that allows engineers to select the right one befitting their workpiece and operation.
Parts of fixture
- Locator
- Clamps
- Pins
This are common elements of the fixture based on the design requirement the elements of the fixtures will manufactured or standard parts are bought and they are used.
The principle used to design fixture is 3-2-1 principle .
Design consideration while designing fixture
- The design should be rigid
- The material used it should have high strength.
- The clamping elements should not obstruct the while welding .
- Clamping should be light in weight.
Types of fixtures
1.Production Fixture
Production fixtures are devices that are used to hold and support workpieces during manufacturing operations 1. They are essential elements of production processes as they are required in most of the automated manufacturing, inspection, and assembly operations.
2.Pre-production fixture
It is generally designed as a prototype fixture for the initial batch production to study the feasibility and make any changes and improvements for the production fixtures. Thus this is a base fixture which helps us rectify any short comings which we might face at the pre production level.
3.Checking Fixture
It is used for inspecting the assembly where the element is placed in correct position .Checking fixtures are mainly used for certifying the final product whether it satisfies all the needs to meet the standards. Checking fixtures are specially designed for repeatability, accuracy, and reliability along with a strong focus on operator ergonomics. They are used in mass production of parts detection for auto parts such as trim edge, surface profile, hole size, flatness.
4.Basic principles of fixture
6 degrees in - x+,x-,y+,y-,z+,z-
6 degrees - clock wise and counter clock wise-x,y,z
12 degree of freedom can be achieved.
If the work piece is arrested in all directions than only there will be no vibration and other parts movement to make work piece fitted in one place without moving the 12 degree of freedom comes into picture.
Principle of fixture design
- Satisfy the stability and reliability of workpiece positioning during use.
- There is sufficient load bearing or clamping force to ensure the construction process of the workpiece on the fixture.
- Satisfy the simple and fast operation in the clamping process.
- Vulnerable parts must be of a structure that can be quickly replaced.
- Keep the design simple in order to minimize cost and to avoid breakdown caused by over-complication.
- Utilize standard and ‘bought out’ parts as much as possible.
- Ensure that the workpiece can be loaded into and removed from the equipment.
- The 3-2-1 method is the fundamental principle for all types of fixture design.
5.Types of biw stations
1.Tools-Geo tool, Re spot tool, Marriage tool, Framer tool
2.Grippers-Material handling gripper, Process gripper etc
3.Stands-Glueing stand, Pedestal stand
4.Miscelloenous-Buffer,take out trolley, conveyors
1.Tools Station
Geo tool
In this station geometry of two parts are fixed. it can be either using welding or riveting . In this station precision and geomatry of the finished product is defined Locating pins have closer tolerance of 0/-0.15.
Re-spot tool
Once product comes out of the Geo Station and there are left out spots where spot welding or riveting is to be done. then it is moved to another station , that station is called Re-spot station.
Marriage tool
In this Station inner and outer panels are joined. In this station to avoid the impression on the outer panel Opper strips are used in between the weld tip and A-class surface.
2.Grippers station
Grippers are devices that allow robots to lift and move objects. They includes magnetic grippers, vacuum grippers and so on. When combined with a robot arm, grippers enable manufacturers to automate critical processes, such as assembly, pick and place.
Types of gripper
1.Material handling gripper-Holding of car panel from one station to other station by the help of grippers.
2.Process gripper-Process grippers are designed to hold the panel and move from one unit to other unit. Different processes are performed under process gripper pedestal welding, pedestal welding, gluing, sealing etc.
3.Combination gripper-Both material holding and processing is done at one .
3.Stands
Pedestal stand-It is used for mounting the robots.
Guling stand-Used for mounting the glue gun
Docking stand-Support for the gripper
4.Miscellous
Some of other elements like buffer, take out trolley conveyors are in this station.
6.Basic terminology used in fixtures
1.Mylars
Holding the panel to and bottom from top clamping and bottom rest clamping.
2.Riser
The part which is mounted on the base plate and holds a clamp or pin cylinder on it, is called Riser. Riser can be Standard Part or manufactured part, it varies from project to proj
A plate shaped as L is called an L block. This part is used as a connection between mylar and Blade. L blocks are used to provide shimming. It is not necessary that L blocks are only used for shimming, its uses changes as per the requirements, At some places, it is used just to connect one part to another. Similar to the L block one more block is used which is in the shape of T. So this block is called a T Block.
4.Pin block
Pin Block is also called Pin Retainer. This block holds the pin and restricts the rotational motion of the pin. Pin Block can be either manufactured one or Standard.
5.Blade
The plate which connects Riser to the Clamp cylinder is named Blade. This plate plays an important role in building the unit. The plate can be of any shape. But we need to keep in mind that the plate should be as compact as possible.
6.Pin
Pins are used to locking the rotational movement of the panel.
7.Shims
If tolerance of the part is not achieved then shims are used to achieve tolerance the shims comes in dimensions of 1mm,0.5mm
8.Number plate - It is for recognizing the unit .
9.Location Round Pin- Pin used to location BIW sheet metal parts.