Week 3:- BiW Fixture Design Methodologies Challenges
1)Design Methodology:-
Design Methodology is nothing but the steps followed during the concept desigining stages of fixtures design.
a)Purchase order
b)Input customer
c)Percentage completion criteria
d)Design output
2)Inputs from customer:-
a)Functional requirements
b)Preferred standard components
c)Car product
d)Layout
e)Ergo data
f)Weld study
h)Standard detalling templates
3)Car Product:-
a)GD & T
b)Part list
c)Cad files of car part
d)Clamp plan
e)Product assembly processes sheet.
4)clamp plan:-It provides the location of pins,rest,clamp,dumps etc.
5)The purpose of layout is provides information of :-
a)flow of parts
b)station pitch
c)robot station
d)accessories like tool change & tip dresser
f)sub assembly
g)platform height
h)loading/unloading sequence/heights
6)Ergo data:-
Ergonomic refers to the study of human behaviour &movements.Ergo data provides information of loading height,working saftey zone of operator etc.
7)weld study inculdes:-
A)Weld gun details
B)Weld matrix & weld points:-a)geo weld points
b)re-spot weld points
8)The criteria for percentage completion in the designing stages % dispatch stages of the weldeing fixtures.
0-25%=Input & concept stages
25-40%=concept approval & simulation check.
40-85%=design freezing & detalling
85-100%=check & final dispatch
9)Output design :-
The output design is 3D models & the 2D drawings of the tools.
A)Utilized tools(multiple units on a comman base)requrie two types of drawing sheets:-
a)Key sheet:-an index of units of there placements on the tool base.
b)layout sheet:-a detailed drawing of individual units to include all of there components.
B)Non-utlized tools:- tools that can stand alone & can be detailed completely on a layout sheet.
10)Struturng a design tree:-
Struturing a design tree implies to a processe where all the assemblies & parts are named in a specification standard.different customer have different set of standard to struture a design tree.It is an important processes which helps to identify a specific part or assembly as to which project,tool ot unit.This helps us to avoid the errors during design study,manufaturing,assembly,inspection etc.If the parts or assemblies are not named properly or the design tree is not struture properly.It will create confusion to understand to design and may create major possibilites of making an error.Naming of a fixture or unit or a part gives the information as to which project or zone or assembly do they belong.It can help us to identify the quantity of items of same tyoe or different types thet are being used in an asmbely.
11)Unit:-Contents of a tool:-
A)Utilized tool:-a)Simple unit:-1)Rest Unit.
2)Fixed pin unit.
3)Retract pin unit.
4)Rough locator unit.
5)Sensor unit.
6)Base unit.
b)Complex unit:-1)Slide unit.
2)Dump unit.
B)Non-utilized tool:-a)Stands
b)Take out trolleys
c)conveyor
d)Turn tables
e)Some grippers
12)Fixed pin unit:-
Is an unit designed locate car panel using pins,and below are the different parts of a fixed pin unit in general. pin,pin retainer,shims/spacers,blocks,blade or adaptor plate,riser.
13)Rest unit:-
A unit designed to rest/support the car panel using NC blocks/may largest and below are the different part of rest unit in general,NC blocks,spacer,blade,riser.
14)The basic Fundamental of sensor unit design;-
1)Every single loose panel which are being welded in a tool should be sensed.
2)Each panel should be sensed by 1 to 2 sensors depened on the size of panel,prefered to be in diagonal opposite ends of panel.
3)Every sensor should be mountesd in a three direction adjustable way in general.
15)A rough locator is part a designed to guide the oprator,to locate the car panel on the pins accordingly.A rough locator can be of standard part or make part.
Basic fundamental of rough locator design:-
1)The slot should be in the direction of car part guiding.
2)Rough locator should be placed at the edges of the car panel,which it has to guide.
3)Rough locators has to be placed in the same angle of the car part edge with a minimum distance of 2-5mm from the edge of the car part.
4)Rrough locators should guide the panel in pin arresting direction.(In general)
5)Rough locators should stat guiding the panel before 10 to 15mm to the start of the pin engagement.
6)Rough locators should be designed with entry angle for car part entry.
7)Rough locators should be designed with two slots to mount for easy adjustment.(In general)
8)The slots should be in the direction of car part guiding.
16)Base unit:-A base unitis designed to mount all the other parts necessary for a tool like pneumatic valve box,fruncking cable path will also be mounted on to a base unit.
Base unit parts:-1)trucking channel.
2)base plate.
3)Valve box.
4)Measuring hole cover.
5)Eye bolt.
6)Pedastal.
7)Weld bar.
8)Floor plate.
17)Dump unit:-A complex unit which has a lot unit of parts.
Dump unit function:-1) Clamp cyclinder unit.
2)Open position.
3)Dump cyclinder.
18)Slide unit:-Combine the function of the hydraulic cyclinder with the function of mechanical linear guidance.
slide unit are,commonly used:-1)Close position.
2)Guide rail.
3)Sensor unit.
4)Stopper block.
5)Open position.
6)Slide cyclinder.
7)Guide block.
8)Position locking unit.
9)Open position.