Week 3:- BiW Fixture Design Methodologies Challenges

1.DESIGN METHODOLOGY:-

Design methodology is nothing but step followed by during a concept of designing staged of biw fixture design.

see the follwing chart of design methodology,

2.INPUTS FROM CUSTOMER:-

Inputs of custmer for design is

• Functional requirement
• Preferred standard components
• Car product
• Layput
• Ergo Data
• Weld study
• Standard detailing templates

3.Input we get in CAR PRODUCT:-

• GD&T
• CAD DATA
• PART LIST
• CLAMP PLAN
• PRODUCT ASSY DETAIL SHEET

4.ClAMPING PLAN:-

Clamping pin given for design for where pin unit ,clamp unit, resting unit is placed exact location provided.

see image

5.PURPOSE OF LAYOUT:-

In which station what process happen and which robot what work would be done is seen in layout also spacing on each robot and other area detail seen.

6.ERGO DATA:-

Ergo data is provided the human behavior and moment activity of human on working place.

Also provided the working heigth of job and working safety zone of human.

7.WELDING PLAN:-

Welding study includes

1.welding gun detail

2.Weld Matrix & Weld Ponits

A)Geo Welding Points

B)Re-spot Weld Points

8.Percentage Complation of designing stage:-

Please check the following chart

9.OUT PUT OF DESIGN

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

Unitized tools:(multiple units on a common base) require two types of drawing sheets

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

Non-unitized tools: Tools that can stand alone and can be detailed completely on a layout sheet.

• The output should compile following point.

1. Approved standard components are to be used wherever possible
2. Design must be as simple and economical as possible
3. Design must comply with all current safety and ergonomic requirements
4. Design must provide for controlled and damage free handling of product Adequate error proofing provision must be incorporated into each design by providing Proximity switches, Rough locators etc.
5. The weight of the moving parts must be kept to a minimum while maintaining maximum strength.
6. Frames and structures are to be simple and sturdy.
7. Design clearance and accessibility for routine maintenance and service. Motion control must be considered on any moving equipments.
8. Designer is responsible to validate clamps and all weld guns.

Strcuture of Design Tree:-

The Structure of design tree is shown in following chart,

The output should compile following point.

1. Approved standard components are to be used wherever possible
2. Design must be as simple and economical as possible
3. Design must comply with all current safety and ergonomic requirements
4. Design must provide for controlled and damage free handling of product Adequate error proofing provision must be incorporated into each design by providing Proximity switches, Rough locators etc.
5. The weight of the moving parts must be kept to a minimum while maintaining maximum strength.
6. Frames and structures are to be simple and sturdy.
7. Design clearance and accessibility for routine maintenance and service. Motion control must be considered on any moving equipments.
8. Designer is responsible to validate clamps and all weld guns.

UNIT:- unit are holding a multiple type of unitied device like blade,riser,sensor,pin,pin retainer etc,

The follwing chart show diffterent units

FIXED PIN UNIT:-

The unit which located the car panel using pin.

Different parts of pin unit:-

The pin unit main contain pin,pin retainer,block,shim,blade,Riser,hardware.

REST UNIT:-

Resting Unit is unit which rest the part or car panel for z direction or any resting direction.

Resting unit included by rest mylar or rest NC or Resting block,shim,blade,Riser.

BASIC FUNDAMENTAL OF DESIGN SENSOR UNIT:-

Sensors help to capture what is going on in the real world. This deck explains how real-world information, such as car pane or part is fitted on biw or not these information useful electronics format that can be analyzed, manipulated, stored or sent to another device.

ROUGH LOCATOR

Following are the points need to be considered while designing the rough locator Rough locator should be placed at the edges of the car panel, which it has to guide.

• Rough locator has to be placed in the same angle of the car part edge with a minimum distance of 2-5 mm from the edge of the car part.
• Rough locator should guide the panel in pin arresting direction.
• Rough locator should start guiding the panel before 10 to 15mm to the start of he pin engagement.
• Rough locator should be designed with an entry angle for the car panel.
• Generally, it ranges between 30-45 degree.
• Rough locator should be designed with two slots to mount the easy adjustments.
• The slots should be in the direction of car part guiding.

BASE UNIT:-

Introduction:

1.Base Unit:

A base unit is the unit designed to mount all the other units(Clamp unit, Pin unit, rest unit etc.) of the tool, also other parts necessary for a tool like pneumatic valve box, trunking cable path will also be mounted on to a base unit. Base unit also mounts the components like Valve Bank, Junction Box, Eye Bolts, trunking cable path etc.

Typical Parts of Base Unit:

• Base Plate:A flat supporting plate or frame at the base of a column, designed to distribute the column's weight over a greater area and provide increased stability. The base plate has no of holes drilled on it which will act as mounting points for clamp unit, pin unit and so on. Base Plate is a machined plate made of steel or Aluminium of thickness 25mm to 40mm on which the holes are drilled to mount diffrent units like rest units, clamp units, pin units etc.

• Pedestal:Pedestal is a part or an assembly (welded structure) that joins the base plate to the oor plate. Pedestal can be a standard part or a make part, depending on size and height of fixture. Standard pedestals are available in different heights. Pedestals are also available in different inclinations. Depending on the size of base plate, the number of pedestal for a fixture can vary for load distribution. Trucking Channel:Trunking Channel is a duct that carries all the electrical and pneumatic connections (wires and pipes) for units of the tool. It has a thickness of few millimetres.

• Valve Box:Valve Box is a standard part which contains all the valves for the pneumatic units. The valve box is the box which includes different solenoid valves. The pneumatic fixtures work on air pressure provided to it. So the arrangement of air pressure inlet & outlet is done within this valve box. The trunking channel includes all the pressure inlet cables going to the pneumatic parts of the fixture & protects them from damaging while operation is in process. Eye Bolt:Eye Bolts are the bolts that are used to lift the fixture for transportation by inserting hooks into them.

• Floor Plate:Floor Plates is grouted to the floor with xed bolt on the ground. Floor plates are also called foundation plates. There is a clearance of 10mm between pedestal base plate and oor plate. This gap is used to level the entire tool using leveling bolts. Weld bars are used to position the positions permanently. Weldbars are steel plates along the sides of base plate of pedestal.

DUMP UNIT:-

Following points are need to while designing Dump unit.

1) Dump units are used when we can not use normal units like clamp unit, pin unit etc. Due to some space constraints. The designed parts should be small in size but can do their functions effectively.

2) It contains the dump cylinder which will be the heavier part in all the unit. The riser & blade should have enough strength to bear the load of the cylinder & all the unit as well. The riser & blade thickness should be more in this type of unts.

3) The parts should be designed by considering the open condition of the unit. In the open condition of the unit the parts should not fall to another unit.

4) We can use any cylinder in this case which suits our requirements. In the below image of the dump unit Both clamp cylinder & hinge cylinders are used.

SLIDE UNIT:-

A slide unit can have a clamp or a pin or a rest unit attached to it which slides forward and performs the required operation. On completion of the operation, slide moves back.

. It has a cylinder which pushes the assembly forward.

Assembly is mounted on a plate, which is attached to guide rails.

. There are sensors on the extreme ends of the slide to sense the position of the slide.

• It has stop docks on either side of the slide to stop the cylinder at the required position.

• It has a locking mechanism which ensures that the slide does not move in a particular position as it may affect the welding quality and may damage the panel.

• Slide units are commonly used at places where there are space constraints.

• The opening and closing of the slide should not fowl

Slide units are used at places where there are space constraints and places where there is less accessibility. Sometimes, there are too many small panels near each other and there is not enough space as each panel requires resting, location using 2 pins, clamping and sensing. This becomes even more difficult when the panel is at angles. To solve this problem, a slide unit mounts rest, clamp or pin unit or all of them on a slide using guide rails, guide blocks, a cylinder, locking mechanism, stop blocks and sensors. When a particular panel is to be welded, this slide moves forward, fixes the panel and on completion of the operation, slide moves back and gets locked at its position. Similarly, the same is done for other panels.

Guide rails should be lubricated well.

The lubricant has the following roles:

(1) Minimizes friction in the travelling unit to prevent seizure and reduce wear. (2) Forms oil on the raceway to decrease stress acting on the surface and extend rolling life.

What are the points you need to consider while designing a Slide unit?

A sliding unit comes under the category of complex units. Few points that need to be considered while designing a slide unit are:

1 Weight carrying Capacity

There are different kinds of guide rails available in the market, each having a different load capacity. Hence, we calculate the weight of our assembly and calculate the weight capacity of the rail. Hence, we choose rail based on its load-carrying capacity.

2 Push and Pull Forces

We need to check the push and pull forces and check if it is enough to push and pull the slide especially when the slide is at an inclination.

3 Locking Mechanism

The locking mechanism ensures that the slide does not move while it is at open or retract position. If the slide moves while welding, it can damage the panel as the positional accuracy will be hampered.

4 Stopper Blocks

Stopper blocks are used to stop the slide at the required position. It is important as if the slide unit has rest mylars and pins, they need to be stopped at their respective position for proper resting and location. Without a stopper, it may dent the panel.