Week 3:- BiW Fixture Design Methodologies Challenges

1)

Design methodology is steps followed in concept designing stages of fixture design.

it has four stages.

1)purchase order.

2)Inputs from customer.

3)completion criteria.

4)Design output.

2)Inputs from customer.

1)functional requirements.

a)welding fixture.

b)hemming.

c)forming.

d)checking fixture.

2)Standards used in design of fixtures

a)ABB standards.

b)Tunkers.

c)NAAM.

3)Car Products.

4)Layout.

5)ergo data.

6)Weld study.

7)Standard detailing templates.

3)Car products.

1.)G.D and T.

2)CAD files.

3)PLP points.

4)Clamp plan.

5)Product assembly Process sheet.

4) clamp plan.

It gives information of Pins,Locators,Rest ,Dumps.It gives detailed information for where the necessary clamping is to be provided for fixing the componenets.

5)Layout purpose.

the layout gives us detailed guidelines of how the flow of operations will be performed and how much operations and what operations will be performed at each stage.

if five components are to be then firstly two will be joined at one station and nextly the other ones will be joined subsequently at other stations.

it has be step by step approach to move further in assembly.It gives information of where the fixtures and robots will be placed.

it provides following information.

1) flow of parts.

2)station pich.

3)Robot stations.

4)tool changer and tip dressors.

5)subassembly links.

6)platform height.

7)loading and unloading points.

6) Ergo data.

Every design should be ergonomically sturdy .It is info about the man ,machine and environment so that the operator working on it does not feel fatiqued and safety is properly provided.It provides info of loading heights .

7)Weld study.

Weld study includes.

1.Weld gun details.

2.weld matrix and weld points.

a)geo weld points.

it are points provided where welding will be done at first instance.

b)Re-spot weld points.

these are the points where later on welding will be done.

3)product assembly sheet.

8) Percentage design criteria.

The percenatge crieteria denotes the design and dispatch stages.

1)0-25 percent. -Input and Concept design.

2)25-50 percent-concept approval and simulation check.

3)50-75 =Design freezing and detailing.

4)75-100 =Check and final dispatch.

9)Design output.

The output is 3D drawing and 2D drawings of the tools.

unitized tools:

It requires two types of drawing sheets.

a) Key sheets.

the index of units and their placements on tool base.

detailed drawing of individual units to include all of their components.

Non utitized tools.

tools that can stand alone and no requirement of detailing them.

basics to be followed.

approved standard components are to be used.

design must be simple and economical.

design mustconform to all all safety and ergonomic standards.

design must provide for controlled and damage free handling.

weight of moving parts should be kept minimum.

10)structuring a design tree. and its importance.

structuring a design tree is of outmost importance because from these only the main assembly ,subparts and other standards parts can be easily distinguished properly.

1.it is useful in identification of parts to which project,tool it belongs to.

2.it hellps us in avoiding errors instudy, manufacturing and assembly.

3.naming the fixture or units it gives gives info to which zone or location it belongs to.

4.it helps us in quantity of items used and to which subgroup it belongs to.

11)What is unit, and its different types.

The unit is generally a part of tool or a fixture and its types are generally given below.

Types of units.

1.Rest unit.

2.fixed pin unit.

3.Retract pin unit.

4.Rough locator unit.

5.Sensor unit.

6.Base unit.

Complex units.

Slide unit s and Dump units.

12)FIxed pin unit.

It is used to arrest certain degree of freedom of the the component so that it does not move.

fixed pin unit has apin to properly locate the part.IT has shims for 2 D motion in order to compensate stack up tolerance.

13).parts of fixed pin unit are.

1.pin

2.shim.

3.pin retainer.

4.Block.

5.Blade and adaptor.

14)Purpose of rest unit.

It is unit simply to rest components at proper location so that they are properly aligned.

its components are .

1.NC block.

2.Spacer.

3.Blade.

4.Riser.

15)Sensor unit is designed to locate the part .so that it accurately senses the position of the part.

the signals from the sensor will be fed to the PLC and accordingly the plc takes the decision.

1.Every singal unit in the car panel should be sensed.

2.Every car panel should be sensed by 1 or 2 sensors.

3.every sensor should have 3 directional adjustment for sensing purpose.

16)Rough locator is generally used for locating the part properly.

It can be standard part or make part.

1.Rough locators should be placed at the edges of car panel.which it has a guide.

2.rough locators should be placed at same angle with minimum distance of 2 mm from part.

3.rough locators should have entry angle of 10-15 degrees.

4.the slot should be in direction of car part guiding.

5.Guide units can be standard or can be manufactured in house according to drawing.

17)What is base unit,describe its part.

the base unit is generally used to house the other parts on it.the parts are generally eyebolts,they are generally used to house various units like clamp unit,locating unit,rough locators on it.

its parts are.

1.Trunking channel.

2.Base plate.

3.Valve box.

4.Eye bolt.

5.Pedestal.

6.weld bar.

7.floor plate

18).what is dump unit. and what are its functions.

the dump units are generally used for purpose the purpose of clamping the part.and its function is to clamp the job .it typically has dump cylinder.

19)slide unit.and its part.

slide unit is generally used for areas whwre space constraints are very low .it generally has slide unit attached to it.