Challenge

Week 3:- BiW Fixture Design Methodologies Challenges

MMallikarjunarao Tirumalasetti22 Jun 2021

Q1 Ans

Design methodology

So in this methodology, we learn about three design processes, we're going to study how do we proceed while doing a design. And one of the things that we take care of structuring or design tree so we'll be learning how to structure the design tree, and how to name the particular component or particular assembly, or the part of an assembly, which is very easy to read and very easy to understand.
The design methodology is nothing but steps followed during the concept of designing stages of fixture design is basically, when we do a conceptualization of our design, there are a few millimeters that we have to consider, and then we start moving towards the design.

The design methodology is divided into four subcategories

Purchase Order
Inputs From Customer
Percentage Completion
Criteria Design Output

1.Purchase Order

It is basically a confirmation from the customer side, that we are ready to start the designing or, go ahead.

2.Inputs From Customer

Input From customers are the major inputs that we get from the customers, how do we study those inputs, what kind of information and get out of those inputs, These are the criteria that we mentioned in this particular input from the customer.

3. Percentage Completion Criteria

Percentage completion criteria are basically schedule. What time we can complete the entire process again this is more detailed. So when we are going to complete the entire design, then we're going to move on to simulation on all these subcategories would be considered in percentage completion criteria like a probability to when we can complete the entire fixture design.

4. Design Output

In BIW fixture design or any industry. We don't only just design a particular component and just give the CAD file to the customer, you have to give a lot of documents like 3d documents,2d documents, which is the detailing part, and as well as other factors as well like bom, bom bill of material and other documents as well about this particular component and their standards, all has to be submitted to the customer.

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Q2 Ans

Designing Inputs

To start designing a fixture below are the Inputs from the customer

Functional Requirements
Preferred Standard Components
car Products
Layout
Ergo Data
Weld Study
Standard Detailing Templates

1. Functional Requirements

In functional requirements, this is basically what kind of function that particular fixture design is going to have, for example, welding, Glueing, riveting fastening this kind of information will be given to us from the financial department.

2. Preferred standard component

The preferred standard component is basically what kind of standard components that the customer already has. And we have to design, according to the standard component itself. And this inputs actually saves a lot of time, as it saves a lot of efforts from our side as well as the company side as well. So if they have any components that we already have their standards, then we don't have to design those particular components. First of all, and then they don't have to purchase it from the outside as well.

3. car products

Car products like 3d files, read files, as well as to learn and to study what kind of geometrical tolerances and what kind of PLP points (Principle Locating Points) where we can fix those pinion edge and or the clamping edge and then putting a position.

4. layout

A layout is basically a layout of the entire assembly line to understand the process and the flow of work.

5. Ergo Data

Ergo data is basically involved well manual operators are involved, and every company has different types of standards for aggregate data, so we'll be getting that particular input from the customer so these are the standards that we follow So, this kind of Ergo data we get from the customer.

6. Weld Study

weld study means A study of the particular gun that we are going to use for welding and where we are going to weld. So if you're doing spot welding what kind of spot welding we are going to do a number of welding to the particular component.

7. Standard Detailing Templates

Standard detailing template means every company has different types of standards, so they will give us detailing templates about how to detail the particular component and dimensions.

Q3 Ans

Input get from "Car Products"

Car products like 3d files, read files, as well as to learn and to study what kind of geometrical tolerances and what kind of PLP points (Principle Locating Points) where we can fix those pinion edge and or the clamping edge and then putting a position.

Car Products includes

GD&T
Part list
The revision part thickness
Cad Files Of Car
Parts Clamp Plan
Product Assembly
Process Sheet

1. GD&T

The First Car products include GD and T the geometrical dimensioning and tolerances of the particular parts.

GD&T provides information on Locating pins, rest, Clamps, Dumps & Slide information of each station.
The sequence of opening of clamps, dumps, and Slide stroke information.
In GD & T we will be learning about locating pins so where we can actually locate our pin units and best clamp. How the entire component is gonna rest, or it's going to get clamped and dumb and slide information in each station sequencing and opening of the clamp and slide Strock information.

2. Part list

Part list Means what kind of assembly, those parts are going to be.

For example, the first assembly is going to be between put in a panel and that which is going to get attached. And then the next one will be the hinge. So every assembly will have a different section in it. So, we have to design different assembly parts.
In the part list, they are part numbers, part names are mentioned. Every part having a different name.

3. The revision part thickness

In the revision, the first component has 21 divisions. So the cost and patent are revised 21 times. Division of the tooling means the tool as device 30 times, and the pre-production fixture is revised 30 times.

4. Part thickness

Part thickness is very important in a particular assembly to let's say if you're assembling a part of thickness 1mm,2mm,.75mm, so this will give you what kind of value that you can do, or what kind of gun that you have to use. So it's also a very important parameter to consider.

5. Cad Files Of Car Parts

CAD files of cad products mean the 3d component that we required from all the Cad parts.

6. Clamp Plan

Clamp Plam is a very important input that we get in the car products is where exactly we can place those clamping units are the particular pin Units.
we should never change the position of the particular clamp or the pin, which is given in these data.
we can change our design a little bit here or there, but we should not change the input design data about the clamp position or the pin position.

7. Product Assembly Process Sheet

In the Product Assembly Process Sheet what kind of products we are going to assemble in that particular component or the particular Unit.

Q4 Ans

Clamp Plan

Clamp Plan is a very important input that we get in the car products is where exactly we can place those clamping units are the particular pin Units.

we should never change the position of the particular clamp or the pin, which is given in these data.
we can change our design a little bit here or there, but we should not change the input design data about the clamp position or the pin position.
In the Clamp plan, there is a clamp unit, pin unit and it is more detailed. It also gives the exact location of y and Z coordinates designing as well you can just input these coordinates and you can start designing from there.
If the three coordinates, whole diameter, and everything are already given to design the entire future design phase, and it sometimes ministry as well. It happens that another thought position, also given very close to the clamp, or the clamp location. So always ask whether you have changed the clamp position.
You should never change the vent position or the clamp position without asking it So always be vary about these situations So the tool might get damaged or the department gets damaged so for that itself need to clarify once again before doing any changes in the clamp.

Q5 Ans

layout

A Layout is basically a layout of the entire assembly line to understand the process and the flow of work.

The layout sheet will give you information about all the fixtures are placed the robots are going to work on it.
In the layout sheet, the circle around the robot is called the Trapped area of that particular robot.
So this is basically the reachability of that robot and which is confined to the particular circle.
For example, Robot is going to work on the fixture, Details also mentioned the geo 250 and then the number is given 250, and as you can see, 250 02 so this is dueling to one or two it's going to use there. So, this robot is going to work on the site first. Then after finishing the site. This fixture is going to rotate. And then it will come to T 01, and these two robots are going to work on the other side of the fixture. Similarly, this robot is also going to work on the particular component as well.
The entire sheet will give you that plan of the layout of what are the constraints that are there from the customer side itself.
if you want to do any changes, for example, you're changing the geo fixture design and it's gonna exceed a little bit bigger or smaller inside you have to inform the customer and you have to get the customers permission to do that so that he will also be able to change the design. If we present him with anything.

The layout provides information about

Flow Of Parts

In the flow of parts how the particular component is going to move from one unit to another or one station to another station.

Station Pitch

In Station pitch a distance between two stations. What is the space concept that they have between two stations?

Robot Stations

Robot stations and positions where the robot placed stations.

Accessories Like Tool Changer and Tip Dresser

Accessories like tool changes and tipless. So where are those also placed? So that is it the robot wants to change the particular tool, which it has to go to the particular location and change it or the tip dresses if you have a welding gun which is you're going to use a trip this is useful. Again, as I said before, I used to shop on the tip of the particular gun.
Subassembly links are basically how particular fixtures how the assembly fixtures that are linked to the main assembly line,

Loading/Unloading Sequence/Heights

Platform height and loading and unloading sequence of height.

Q6 Ans

Ergo Data

Ergo data is basically involved well manual operators are involved, and every company has different types of standards for aggregate data, so we'll be getting that particular input from the customer so these are the standards that we follow So, this kind of Ergo data we get from the customer.

Ergonomics refers to the study of human behavior and movements.
Ergo data provides information of loading height, working safety zone of the operator, etc.

Ergo data is basically where is given when a manual operation is required. So this import will be given in regards to how their standards of Ergo data so this is one of the standards of the country that they follow for an ERGO data so height and a minimum height of the session we mentioned here, and also the distance, which is required for the operator from the fixture design except.
So this is very important as images to the study of human behavior and moments, and your data provides information of loading height working safety zone and operation. So it also gives you the safety zone of a particular man operator. So, how much distance is supposed to be from the weld gun?
The heights are mentioned because of the operator itself, he should not bend, while doing the operation. It was going to be a strain on his back, the height should not be way too much so that he can't even see what are the other particles because it's gonna be uncomfortable for him and his shoulders are gonna get frayed.
So this is basically to make the operator as comfortable as possible so that he will be more efficient in doing work and he will not take a lot of time while doing the particular assembly.
The distance from the operator and the component be 1070 is the particular component and this is the reachability 300 if it is there, and the max reachability of the particular operators is 380, so he doesn't have to stretch his arm to get that particular company if it is 380 it's totally fine. If it is 300 that is also acceptable and 1070 particular components or particular parts location.
The height of that particular component that is acceptable will be around is the operator's waist size, which is easily accessible for him. Again, the maximum height should be 1500, which is also easily accessible to him, and which is done.
So this is the schematic example of how the algorithm looks like. Effective economic data or effective ergonomic friendly mixture designers, the better the efficiency of the particular operator to work on it, and the less the time consuming, so it's going to be a very important factor, wherever the manual operator doesn't work.

Q7 Ans

Weld Study

weld study means A study of the particular gun that we are going to use for welding and where we are going to weld. So if we doing spot welding what kind of spot welding we are going to do a number of welding to the particular component.

Weld Study includes

Weld Gun Details
Weld matrix and weld points
Geo weld points and Respot Weld Points

1. Weld Gun Details

This involves the study of the gun. So this is one of the examples of a welding gun, which is used in assembly. So weld study includes weld Gun detail weld matrix and weld points.

2. Weld matrix and weld points

Weld points are basically where the welding is going to happen at which point at which coordinates are going to happen.

3. Geo weld points and Respot Weld Points

The data of weld Metrix and weld points will be given to you in the form of spears i.e Green and red Spears.
At that point, welding is going to happen.
Geo spots are Red in Color and Re spots are Green in color. All the red spheres are going to happen in geostationary.
In the respot station where the green welding is going to happen. So this is happening where one component is going to attach to this particular component, and in the other station, the other component gets to attach.

Q8 Ans

Percentage of completion criteria

Percentage completion criteria are basically schedule. What time we can complete the entire process again this is more detailed. So when we are going to complete the entire design, then we're going to move on to simulation on all these subcategories would be considered in percentage completion cafeteria like a probability to when we can complete the entire fixture design.

Percentage Completion Criteria is followed in the designing stages and dispatch stages of welding fixtures.

0-25% Input and concept design
25-40% Concept approval and simulation
40-85% Design freezing and detailing
85-100% Check and Final dispatch

Percentage completion criteria are followed in the design stages and dispatch stages of the welding fixtures.
For example, where the how much of the task and how much of the project that you have already finished and is it actually lining up with the schedule that you have planned before. And these are the information that we get from particularly a percentage completion criteria.

1. Input and concept designing - 0-25%

In this, they were given four days to design the fixtures that mean we have to complete 25% of the task within four days.

2. Concept approval and simulation - 25-40%

The concept of design is approved here, and the simulation check is done here, which is 25 to 40% of your design is complete in Comcept approval and simulation.

3. Design freezing and detailing - 40-85%

In this process, the design is getting Freeze. That means the design is getting finalized. And the detailing is going to start again. Once the detailing is finished, and the design is also feezed that means you have completed at least 40 to 85% of the task.

4. Check and Final dispatch - 85-100%

This stage is the final stage, Here checking the quality check usage and the final dispatch, which is the output that we are going to give to the customer, which is from 85 to 100%.

Q9 Ans

Design Output

In BIW fixture design or any industry. We don't only just design a particular component and just give the CAD file to the customer, you have to give a lot of documents like 3d documents,2d documents, which is the detailing part, and as well as other factors as well like bom, bom bill of material and other documents as well about this particular component and their standards, all has to be submitted to the customer.

The output is 3D models and the 2D drawing of the tools

Unitized Tools
Non-unitized Tools

1. Unitized Tools

In the unitized tools testing requires two types of a drawing sheet, which is one key sheet and a layout sheet.
So an example of unitized tools are fixtures, tools So where exactly multiple units are a placed.
For example, in the entire assembly welding fixtures, where a pin unit, clamp unit, rest unit, and the panel, everything is included so that for those things.
Key sheet - An index of units and their placements on the tool base.
Layout sheet - A detailed drawing of individual units to include all of their components.

So, it is basically an index of units and placements on the tool base, so the key sheet going to show you the placement and the location of that particular tool on the tool base where exactly the tool is placed. And what is his exact position in a particular place?
Layout sheet is a detailed drawing of that particular tool, where it's gonna show you, detailed components and how you're designed the particular component.

2. Non-Unitized Tools

Tools that can stand alone and can be detailed completely on a layout sheet.
Non-unitized tools are basically tools like Stands and tool changers is also an example of non-unitized tools where you don't need a key sheet, you can actually use to layout sheet and complete the entire documentation of the particular component. So these areas are known as non-unitized tools.

Q10 Ans

Structuring a design tree
Structuring a design tree implies a process where all the assemblies and parts are named in a specific standard. Every customer will have their own set of standards to structure the design tree.
It is an important process that helps us to identify the specific part or assembly as to which project, tool/unit it belongs to. This helps us to avoid errors during design study, manufacturing, assembly, inspection.
If the parts are the assemblies are not named properly or the design tree is not structured properly, it will create confusion to understand the design and may create major possibilities of making an error.
The naming of a fixture or a unit or a part gives the information as to which project, tool or unit, it belongs to
It can help us identify the number of items of the same type or different type that are being used in an assembly. Two or more components which have similar design are given the same name such that one component is taken as a reference during manufacturing.
In a design tree, the parts which are designed by us should be placed at the top.
The standard parts which are used by the customer must be placed below the list of the designed part, by not placing the standard parts in the design tree would be led to manufacturing these parts again and would take up both money and time spent on the project.
The other standard parts or parts that are procured from outside must be placed in the bottom of the design tree like the fasteners, cylinders, etc.

Q11 Ans

Units

The fixture is the assembly of different units. Some of the units used in fixture assembly are the Base unit, Pin unit, Clamp unit, etc.
Unit is used to perform a specific function in the fixture. Units are part of the unitized tool.

Units are of two types as follows.

Simple unit
Complex unit

a. Simple unit

The simple unit as the name suggests has a simple design, the design process and manufacturing is also simple.

The simple units are further classified as below:

Rest unit
Fixed pin unit
Retract pin unit
Rough locator unit
Sensor unit
Base unit

b. Complex Unit

As opposed to the simple unit, the complex unit has a complex design process and manufacturing process. They are classified as follows

Slide
Dump

1. Rest Unit

The Rest unit is the unit on which the components are rested. There is no upper clamping and no force is applied.
Rest units generally have a riser, blade, and rest Mylar.

2. Base Unit

The base unit is the unit that is used to mount all the other units like clamping unit, rest unit, pin unit, etc, other parts like automation box are also mounted on a base unit.

3. Fixed Pin Unit

Fixed pins are the nonmovable fixed pins that are used to locate the part in the fixture.

4.Retractable pin unit

Retractable pin unit is opposite to fixed unit which can be moved up and down up to a certain distance. It is used for unloading complex panels after welding.

5. Slide unit

Sliding units are used in a fixture when there are a lot of space constraints, where usage of different units is very difficult in order to design the assembly.

Q12 Ans

Fixed Pin unit

Fixed pin units are used in a fixture to locate the car panel during any operation.
Pin, Pin retainer, Shims, blade, riser are the parts of the fixed pin unit.
Pin retainer is used to mount the pin.
The pin retainer block has two-way shims. Shims are very important in designing a pin unit as it helps to avoid the stack up tolerances during the assembly process.

The purpose of the Fixed pin unit.

The fixed pin unit is used to arrest the 6 degrees of freedom of the assembly of a fixture. The other six degrees of freedom are arrested by the three rest units.
Pins help to locate the part of an assembly very accurately for the welding operation.

Q13 Ans

Parts of a fixed unit

The different parts of a fixed pin unit are as follows

Pin
Pin Retainer
Shims
Blade
Riser

1. Pin

Pins are used for accurately locating the part to welded in an assembly. The holes in the part of the assembly are inserted on these pins.
The pins constrain the degrees of freedom of the part of the fixture.
The diameter of the pins has tighter tolerances as compared to the diameter of the hole in the part.

2. Pin Retainer

Pin retainer is used to hold the locating pins. The pin retainer block has two-way shims.

3. Shims

Shims are small parts of the thickness of 0.1,0.2,0.3 mm. The shims are used to compensate for the difference due to the stack-up tolerance of the assembly, which eventually results in the improper holding of the panel if the Mylar holds it loosely. On the other hand, if the Mylar holds the panel very tightly then it will form an impression in the panel. Shims play a major role by adjusting the Mylar to the defined position.

4. Blade

Blades are plates that are attached to the raiser.
The cylinders and other additional arms are mounted on a Blade.

5. Raiser

A raiser is a part that is used to raise the height of the fixture.
The raiser is fixed to the base of the fixture and the blade is mounted on the raiser There are two types of raisers 1.L type raiser 2.Square Tube raisers.

Q14 Ans

Rest unit

The rest units are designed to support the car panels using Mylar.
The primary purpose of the Rest unit is to rest the car panel.

The parts of the rest units are as follows.

Mylar
Blade
Riser

1. Mylar

Mylar is the part that holds the panel from above and below during the operation.
The top side of Mylar is called the clamping Mylar. Whereas, the bottom side Mylar is known as resting Mylar. Every Clamping Mylar will have a resting Mylar.
It holds the panel in such a way that it does not deform during the welding process. The below image shows basic Clamping and Resting Mylar.
Mylar is the part that holds the panel from above and below during the operation.
The top side of Mylar is called the clamping Mylar. Whereas, the bottom side Mylar is known as resting Mylar. Every Clamping Mylar will have a resting Mylar.
It holds the panel in such a way that it does not deform during the welding process. The below image shows basic Clamping and Resting Mylar.

2. Blade

Blades are plates that are attached to the raiser.
The cylinders and other additional arms are mounted on a Blade.

3. Raiser

A raiser is a part that is used to raise the height of the fixture.
The raiser is fixed to the base of the fixture and the blade is mounted on the raiser
There are two types of raisers 1.L type raiser 2.Square Tube raisers.

Q15 Ans

Basic fundamentals to design a Sensor unit

A sensor unit is used to sense whether the car panel is placed in the fixture or not.
The sensors will send the signals to PLC systems and so the next process will be executed by this signal. The number of sensors used in a fixture will depend upon the number of parts used for the assembly.
Every panel should by one or two panels depending on the size of the part and in such case they are placed in the opposite direction.
The mounting of the sensors should be in such a way that they are adjustable in three directions. Some of the major sensor manufacturers are IFM, SICK, OMRON, etc

The types of sensors used are as follows

1. Proximity Sensor.

The proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact.
A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal.

2. LASER sensor

A laser sensor is a kind of sensor that uses laser technology to measure. It is generally composed of laser, optical parts, and photoelectric devices.
It can convert the measured physical parameters (such as length, flow, speed, etc.) into optical signals, and then use a photoelectric converter to convert the optical signals into electrical signals.

3. Photoelectric Sensors

Photoelectric sensors are made up of a light source (LED), a receiver (phototransistor), a signal converter, and an amplifier.
The phototransistor analyzes incoming light, verifies that it is from the LED, and appropriately triggers an output.

Q16 Ans

Rough locators unit

Rough locators are majorly used in manual fixtures.
The rough locators will guide the operators to place the part in the correct position and orientation.
The rough locator can be a standard part or take part.

The fundamentals of rough locators are as follows

Rough locators have to be placed at the edge of the car panel in order to guide them.
There must a gap of 2-5 mm between the rough locator and the car panel in order to avoid damage during loading and unloading.
Rough locators have to be placed at the same angle as the car panel. Rough locators should guide the panel in pin arresting direction.
Rough locators should start guiding the panels 10-15mm before the pin engagement
Rough locators should be designed with an entry angle for the car panel which is around 35-40 degrees. Rough locators should be designed with two slots to mount for easy adjustments.
The slots should be in direction of the car part guiding.

Q17 Ans

Base unit

The base unit is designed to mount all the other units like clamp unit, pin unit, rest unit, etc of the tool, also other parts like pneumatic valve box, trunking cable path will also be mounted on the base unit.

The parts of the base unit are as follows:

Valve box
Trunking Channel
Measuring hole cover
Eyebolt
Pedestal
Floorplates

1. Valve box

A valve box is used to supply pneumatic cylinders assembled in the fixture.
The valve box consists of solenoid valves with an inlet and outlet which controls the supply of air to the cylinder.

2. Truncking channel

Trunking channel is a hollow passage that guides and covers the pneumatic and electrical linings.

3. Measuring hole cover

The measuring hole cover the coordinates of the measuring holes are mentioned.
These coordinates are used as references for placing the other units and also for the CMM inspection purposes.

4. Eyebolts

Eyebolts are placed in the base unit in order to lift the base unit and move it from one place to another.

5. Pedestal

The pedestal is a stand-like structure where the entire unit of the base will be mounted.

6. Floorplates

Floorplates are used to mount the entire base on the floor.

Q18 Ans

Dump unit

Dump unit is found in complex fixture
A dump unit is used when there are geometrical constraints while placing a panel.
It consists of a dump cylinder to perform clamping and unclamping operation.

Functions Of Dump Unit

If you have a particular constraint and you cannot assemble in a normal way to use this use it in different ways again it has the same dumb cylinder and and it has open position and a closed position.and it has Clamp Cylinder Unit too.
That is why this are very complex and design.
if you have any geometrical constraints, you can use this dampener to constrain your components.

Q19 Ans

Sliding units

Sliding units are basically used in places where you have a lot of constraints or space constraints when you cannot use different types of units to design the entire assembly. So, here you will use this sliding Only.

Sliding cylinder

The sliding cylinder has One open position and One closed position, which has to guide the rails' direction to the entire panel is going to move.

Position locking unit

Position locking unit which will lock the position at that particular point doesn't allow the entire plate to move.

Sensor Unit

Sensors need to sense whether this entire component has reached here or not.

Stopper blocks

Stopper blocks as I said initially to control the entire panel moving and it's a moving part.

Week 3:- BiW Fixture Design Methodologies Challenges

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Ship work like this
in your own course.