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

AIM

Design 3 Different types of Swivel Clamp Unit with Different Riser, Blade, and Clamp Arm for the given Car Panel. 

Design a Pin-Clamp Unit for the given Car Panel.

INTRODUCTION

In Fixture design, we have to arrest all degree of freedom by locating the panel at required position, after that we will design the fixture unit.

3-2-1 principle

Our ultimate intention for using pin unit is to fix the work piece so that it does not deviate from the position while the operation is being performed on it. For this reason we use 3-2-1 principle.

Every component we know has 6 degrees of freedom. They are listed below:

1. Translational motion along x-axis.
2. Translational motion along y-axis.
3. Translational motion along z-axis.
4. Rotational motion along x-axis.
5. Rotational motion along y-axis.
6. Rotational motion along y-axis.

Degrees of freedom can be simply understood as the direction in which any component can move. These 6 degrees becomes 12 if we consider translation along negative and rotation in anti-clockwise direction too. That means, every component can move in all the direction when it is free. But processes like welding, stamping or others and in fact every other cannot be carried out on such free to move body for obvious reasons. Thus the body must be constrained in all the major direction in order for the workman to work upon it. This constrain on motion is achieved by 3-2-1 principle.

In 3-2-1 principle we make use of locating pins in the given order to fix it on a fixture:

1. 3 pins are located on the bottom side of the component. These pins constrain the translational motion of the body in z direction and rotational motion along x-axis and y-axis. Thus 3 degrees are restricted. But the body still can rotate along z-axis and translate in x-axis and y-axis.
2. 2 pins are located on the back side of the component. These pins constrain the translational motion along x-axis and rotational motion along z-axis. Thus we have constrained 5 degrees in total. But translation along y-axis is still possible.
3. 1 pin located on the adjacent side of the 2 pins we can constrain the last degree that is translation along y-axis.

Thus we can constrain all the degrees of freedom of a body using 3-2-1 principle which used 6 pins for the same.

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.

Factors should be considered while designing a clamp unit:

• There should be adequate space between the cylinder & another part like riser, car panel because cylinder moves or swing while opening & closing
• Pin clamp unit used where two panel or component are located for welding.
• Clamping make in such way that it clamps two car panels at once
• All parts should snap & butt properly to each other.
• Make sure that parts of the clamping unit are 10 to 12 mm away from car panel so they do not damage car panel
• Minimum 30mm distance must be maintain between mounting holes

SWIVEL CLAMP UNIT: DESIGN -1

This Design have, Single finger type  clamp & rest mylar, L type Riser.

SWIVEL CLAMP UNIT: DESIGN -2

This Design have, Double finger type clamp & rest mylar, T type Riser.

SWIVEL CLAMP UNIT: DESIGN -3

This Design have, Single flat finger type clamp & rest mylar, T type Riser with Ribs.

SWIVEL CLAMP UNIT WITH PIN UNIT

4 way locating pin unit has combined  with swivel clamp unit design-3

FULL ASSEMBLY WITH CAR PANEL & BASE

Top view

There is no difficult to load & unload the car panel If clamp is open condition.

TREE STRUCTURE

Design-1

Design-2

Design-3

CONCLUSION

Thus we have designed 3 Different types of Swivel Clamp Unit with Different Riser, Blade, and Clamp Arm for the given Car Panel and a Pin-Clamp Unit for the given Car Panel.