Project 2

Aim : 

1) Initiate a concept of fixture design with reference to all inputs provided for the car panel.

2) Complete 3D finish work.

3) Complete 2D finish with output documentation.

4) Write a detailed report describing the process and attach relevant images.

Report : 

1) Fixture concept design : 

A fixture is a work holding or support device used in the manufacturing industry. Fixtures are used to securely locate (position in a specific location or orientation) and support the work, ensuring that all parts produced using the fixture will maintain conformity and interchangeability. Using a fixture improves the economy of production by allowing smooth operation and quick transition from part to part.

Following part is given for the fixture design. Which include 5 parts shown by different colors as well.

Following 5 data is required to design the BIW fixture.

First to understand scope of the work. Means what is expected by customer. Every customer has its specific requirement and it may have own raw material, electric, pneumatic, cad, design standards. Every customer also gives different inputs and expects output e.g. 2d drawing, process sheet in xls, pdf, CAD format of design, layout format, OLP.

Functional requirement is the basic requirement which defines the function of the fixture whether it is being used for welding, hemming, checking fixture or storage racks. Depending on this the design considerations are going to change while designing the fixture.

• Bill of material (BOM) of the componenets to be welded - spot welding.
• CAD panel data or at least 2D drawing of assembly and individual panel data.
• Sheet metal panel thickness plays a major role to decide 2 metal or 3 metal weld.
• Spot detail information like total no. of spots and spacing between the spots.
• Weld information clarity from drawing like 2 metal or 3 metal welding.
• PLP (Principle locating points) of the individual panel and total assembly.
• Cycle time - if calculated or can be found out as per manual or robotic welding process.
• Process sheet if process engineering is done - where loading sequence, no. of clamp data and gun data is mentioned. 
• All clamping cylinder and fixtures standards.
• CAD - software guidlines
• Raw material standards
• Design guidelines
• Bought out item (Purchased parts) standards like pneumatic items, toggle clamp, bearing, screw, dowel etc. company information.

The fixture will be the spot welding fixture where robotic gun will be used for spot welding hence the fixture should have ample of the space that the spot gun should come in and do its work should go out without striking to any of the part of the fixture. The green spots shown in the image are spot weld where the spot welding will be done by the welding gun. So we have to place the fixture parts by considering the spot weld & also by doing the gun study we have to check the fouling of parts with the gun.

For designing any fixture 3-2-1 principle is the most important thing to be considered. Hence also 3-2-1 principle is taken into consideration while designing. Different units are used to fulfill the requirement of constraining the DOF of different prt like Fix pin units, Retractable pin units, Power clamp units, Rest units etc.

 Designing of various units

Base Unit 

Pin units

  Fix Pin unit

Retractable pin unit

Clamp units

Power clamp units

Swivel clamp units:

Rest Unit

Total Assembly : 

3D Finishing

3D finishing is the process where design is being completely finish & to be ready for final simulation & 2D detailing.

Following points are taken into consideration while finishing the design.

• Hole concentricity & hole sizes : All parts hole concentricity is checked & confirmed while finishing the parts.
• Machining area : The machining area in every part is defined & the machining area is highlighted by using orande colour.
• Nominality : All units dimensions are maintained nominal to facilitate easy assembly of the unit.
• Holes colouring standard : Color code standard used in the 3D finishing.

         1. Cyan - Simple hole 

         2. Yellow - Threaded hole 

         3. Orange - Machined area

         4. Blue - Dowel pin hole

• Fasteners implementation : Fasteners are implemented in all unit as per the requirement & load on the part.
• Avoiding clash between different part : Proper gap is maintained between parts to avoid the clash.
• Mylar splitting as per panel profile : Mylar spliiting are confirmed while finishing the design.
• Proper renaming of parts/assemblies as per standard : Proper renaming of parts & assemblies are done while finishing the design hence we can identify each & every part easily with unique identification.

Colour coding :

Design tree  :

2D Detailing

A 2D drawing view consists of two dimensional elements. A 2D drawing view allows you to quickly create or modify a drawing view without making changes to a part or assembly document.

In fixture detailing key sheet of every unit is done which gives the idea of placing unit in assembly.