Week 6:- Clamp Unit & Pin-Clamp Unit Design Challenge

*Designing Clamp Units with Swivel Cylinders for a BIW Fixture.

Given Panel:

Two types of Clamp units used to clamp the car panel. They are:

• Power Clamp Unit.
• Swivel Clamp Unit.

To weld these parts ,they must be fixed using 3-2-1 principle:

3-2-1 PRINCIPLE:

  Fixture must correctly locate a workpiece in a given orientation with respect to a cutting tool or measuring device, or with respect to another component. Locating and clamping of a component are the most critical functions of any work holding fixture.

  A workpiece free in space can move in an infinite number of directions. For analysis, this motion can be broken down into twelve directional movements  or "degres of freedom". All twelve degrees of freedom must be restricted to ensure proper referencing of workpiece.

                                                    

  The best and most effective method of part location is reffered to as the 3-2-1 method.

  6 Translational degeers of freedom : +x,-x,+y,-y,+z,-z.

  6 Rotational degrees of freedom.

If we fix the clamps as per the 12 degrees of freedom listed above, then we can arrest the panel in a fixed position.

6- degrees of fredom are restricted by 2- pin units.

6- degrees of freedom are restricted by 3-clamp units and rest units.

SWIVEL CLAMP UNIT:

Clamp unit is a unit designed to hold /clamp the car panel with NC blocks/mylars / rest by using a Swivel Clamp cylinders .

PARTS OF SWIVEL CLAMP UNIT:

1. Mylar/NC block/Finger: Finger is a movable part which is used to hold the car part from top against backup and they are usualy mounted on the clamp arm.
2. L-block: L - shaped blocks are used to mount the finger to clamp arm, besides allowing adjustments for locator pin in two directions.
3. Shim/Spacer: They allow the finger to be moved to the correct xy locating and allow the customer to make adjustments to improve the quality of their product.
4. Blade: Part onto which the af oreside element are attached to.
5. Riser: L- shaped or T shaped tall block which regularly patterened holes to attach the above mentioned parts in modular way blade, spacer & mylers. Riser is either a make part or standard part.
6. Stopper: The function of stopper is to restrict clamp going beyond the limit. Stopper is mounted between clamp arm and rest/blade. Stopper has two parts male and female, when this two parts meet they restrict motion.

                 

Designing 4 Swivel type Clamp Units:

   1.    

    

   2.

    

   3.

    

  4.

   

*It is easy to remove the component from the fixture. And can be seen from the following image.

  

General Tree Structure:

Simple Tree of a Single Clamp Unit Product:

Final Fixture including Pin Units:

*Hence the panel is arrested in all 12 Degrees of Freedom by following '3-2-1 Prinicple'.