Week 1:- Introduction to BiW and Fixtures Challenge
1. answer
BIW is body in white refers to the welding sheet metal components which forms the vehile structure to which other components will be married. it supports the components like engine ,chassis , interior trim and exterior.
the parts of the biw are
- body sides -body inner,body outer
- underbody -front end under frame,main floor, rear end under frame
- closures-front door,reardoor,hood, deck lid
- roof- roof inner, roof outer
- fender
2. answer
The biw nomenclature shows the differents parts located in biw at their positions like front under frame which supports the engine , main floor supports the seating arrangement and passengers weight .body sides consists of two types body side inner and body side outer, in the body side inner is used for structural strength and outer body side should be looks good for the coustmers requirement no scratches and dents on it
3.answer
-fixrture is a device which holds the workpiece to be processed either welding,gluing, riveting etc.
-fixture must support the workpiece in a proper location which is capable of preventing the distortations during the job like weling
-fixture consists locating elements its need to be placed carefully, clamping has to be light and frim
-the other elements like clamping units and pin units should be clear in the woking area
-fixture ha s to be stable and rigied to withstand the welding stress and other stress
types of fixtures
1.production fixtures
production fixtures are used in the mass production purpose
2.pre prodcution operation fixtures
preproduction operation operation fixtures used for inital batch production to study the feasibilty of the vechile
3. checking fixtures
these fixtures are used for inspection purpose to measure the relative dimensions and compare with nominal values ,measuring instruments like CMM, sensors are fixed in this fixtures
4. answer
The basic principle of fixture design is 3-2-1 principle, for the fixture design the major portion of the design time is to spent on deciding the how to locate the work piece in fixture.
For any body there are 12 degrees of freedom
6-translatinal and 6- rotational
fixture design must restrict the all degrees of feedom of the work piece by using clampings are pin units to achieve the zero degree of freedom for the work piece
5. answer
assembly lines ->zones->stations
In the assembly lines different types panels are joined together in each specified zones
each panel categories will have individual zones
The biw stations consists of
-Tools
-Grippers
-Stands
-Miscellaneous
Tool- a tool is a device or fixture which consists of number of units to hold a car panels in general
types of tools
-GEO TOOL
-RE-SPOT TOOL
-MARRIAGE TOOL
-FRAMER TOOL
-CHECKING FIXTURES
GEO TOOL- It is a fixture in which the geometry on of the panels welded together accuratly.the pin tolerance in the geo toool is 0.15
RE-SPOT TOOL- A respot tool is fixture in which the remaining welding sports are not acheived in the geo tool are welded in the respot tool and the pin tolerance in respot fixture is about -0.28
MARRIAGE TOOL OR HEMMING TOOL-A marriage tool is a fixture in which the inner panel and outer panel assembly are joined together eithrt done by welding or by hemming in case of clousure panels
checking stations - a checking station tool is fixture which is used to check the dimensions of the car parts or assemblies ,positions and co-ordinates of the parts
-the work piece is hold by the fixture by t5he clamps and various measuring guages are introduced like CMM machine ,sensors to check the dimensions and compare with the nominal diemensions
Gripper- gripper is a device to hold the car panel and it is fixed to the manipulator end of the robot arm or end effector
types of grippers
-material handeling grippers(which handels the car panels from one tool station to another tool station)
-process gripper(process grippers are designed for handeling the car panel from one to another tool station in addidition to that process like pedestal welding,riveting,gluing,sealing etc.
-combo gripper(gripping +welding)
-dual gripper(gripping+ gripping)
STANDS
types of stands
-gluing stand(gluing gun is fixed to the standared stand which is grouted to the ground)
-docking stand(robots are selected for multi tasks like material handeling& welding which cannot carry both due to some load capacity of the robot,so the the robot will drop and pick the gripper or gun after completing the operation with help of docking stand
-date stamp stand (date stamping device is mounted on this date stamp stand).
6. answer
BASIC TERMINOLOGIES IN BIW FIXTURES
-NC/MYLARS/FINGERS(which holds the panels like clamping mylayrs and resting maylayrs)
-PLP(principle locating point)
-RISERS
-ROUGH LOCATORS
-HARDWARES
-CMM
-BASE UNIT,PIN UNIT,CLAMP UNIT
-NUMBER PLATE
-NAME PLATE
-CO-ORDINATE PLATE
-CLAMP ARM
-PIVOT
-SKIN SURFACE
-REED SWITCHS
-SENSORS