Project 2

Purpose-

1)Initiate a concept of Fixture design.

2) Perform 3D finish on the Assembly design

3) Perform 2D finish with output documentation

4) Write a Detailed Report describing the process (what changes are made on the design) and attach relevant images.

Answer -

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 includes 5 parts shown by different colors as well.

Following5 data is required to desig5n the BIW fixture.

'- First to understand scope of the work. Means what is expected by customer. Every customer has its specific requirements 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 wheather 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 components to be welded- spot welding
• CAD panel data or at least 2D drawing of assembly and individual panel data
• Sheet metal panel thickness.Plays 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 location scheme) 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 guidelines
• 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 do its work should go out without striking to the any of the part of the fixture. The green spots shown in the image are the spot weld wh6ere 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.

By considering5 all above mentioned requirements following fixture design concept is prepared.

'- For designing any fixture 3-2-1 principle is the most important thing to be considered. Here also 3-2-1 principle is taken into consideration while designing. Different units are used to fullfill the requiremnt of constraining the DOF of different part like Fix pin units,retractable pin units, Power clamp units, Rest units etc.

Fig shows the entire fixture with the panel & without panel

As per the 3-2-1 principle of fixture we have to constaint degrees of freedom of the part so at the time operation there will be less chances of distortion. For this purpose fix pin units & Retractable pin units designed.

Fix pin unit have 2 way shimming adjustment & Retractable pin unit have 3 way shimming adjustment.

Power clamp unit is the unit designed to hold the car panel on the position to do some process over the part. It includes NC block/ Rest/ Mylar by using pneumatic clamp cylinder. The power clamping devices are utilized for positioning and holding product securely. It applies pressure on the product to hold it on the specified position. The holding should be firm enough to hold part on its position & also it should not damage the part as well.

A clamp cylinder is a pneumatic device works with pressurised air. The clamp cylider is used to open & close the parts fixed to the clamp arm fixed to the clamp body.

• Clamp cyliders are bought part.
• They are in general 40, 50, 63 & 80 bore capacity.
• Opens up to 135 degree for horizontal clamp mounting.
• Opens up to 105 degree for vertical clamp mounting.

2) 3D Finish -

- 3D finish 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.

1. Hole concentricity & hole sizes- All parts Hole concentricity is checked & confirmed while finishing the parts.
2. Machining Area- The machining area in every part is defined & the machining area is highlighted by using orange color.
3. Nominality- All units dimensions are maintained nominal to facilitate easy assembly of the unit.
4. 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
5. Fasteners implementation- Fasteners are implimented in all unit as per the requirement & load on the part.
6. Avoiding clash between different part- Proper gap is maintained between parts to avoid the clash.
7. Mylar splitting as per panel profile- Mylar splitting are confirmed while finishing the design.
8. 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.

3) 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 datailing Key sheet detailing of every unit is done which gives the idea placing of unit in assembly.