Week 4:- Pin Unit Design Challenge

AIM-Pin Unit Design

Pin unit is designed to locate the car panel using pins. It consists of different part such as pin, pin
retainer, shims/spacers, block, blade or adaptor plate and riser.

Before we go to these parts we should know about shimming and should know how it works.

Shim is a set of thin plates (2 mm, 1mm, 0.5 mm, 0.25mm) that are used to adjust the gap or used for a better fit.

3-2-1 principle

The 3-2-1 principle of location (six point location principle) is used to constrain the movement of workpiece
along the three axes XX, YY, and ZZ. This is achieved by providing six locating points, 3 pins in base plate, 2
pins in vertical plane and 1 pin in a plane which is perpendicular to first two planes.

A workpiece will be completely confined when blanked against:
3 points in one plane: The “3” in 3-2-1 refers to 3 locators (passive fixture elements) on the primary
locating/datum surface.
2 points in another plane: The “2” in 3-2-1 refers to 2 locators on the secondary locating/datum surface.
1 point in a third plane: The “1” in 3-2-1 refers to 1 locator on the tertiary locating/datum surface

Two types of PIN UNITS

⦁ Fixed pin unit

Under this pin have two shapes iround & diamonds depend upon the 2 ways and 4ways location

ROUND FIX PIN UNIT

DIAMONDS FIX PIN UNIT

PIN-

Pins are used to locking the rotational movement of the panel. Generally there two types of Pins, one is Round Pin and another one is a Diamond pin. We use two and three-directional shimming for pins as per the angle of the pin w.r.t. the carline. In some cases, we use a collared pin, when the pin is supposed to support the panel as well. For this kind of pin, we provide 3 way shimming irrespective of pin angle to the carline. 

PIN RETAINER 

 Pin Retainer is also called Pin Block . This block holds the pin and restricts the rotational motion of the pin. Pin Block can be either manufactured one or Standard.

L BLO0CK

A plate shaped as L is called an L block. This part is used as a connection between mylar and Blade. Generally, L blocks are used to provide shimming. It is not necessary that L blocks are only used for shimming, its uses changes as per the requirements, At some places, it is used just to connect one part to another. Similar to the L block one more block is used which is in the shape of T. So this block is called a T Block.

SHIM

Shim is a set of thin plates (2 mm, 1mm, 0.5 mm, 0.25mm) that are used to adjust the gap or used for a better fit. in case no proper fitting between mylar and Panel due to manufacturing errors then this error can be removed using shims. Shims are placed in the carline position so that gap can be adjusted in the required direction like X, Y, or Z.

RISER

The part which is mounted on the base plate and holds a clamp or pin cylinder on it, is called Riser. Riser can be Standard Part or manufactured part, it varies from project to project. A riser can be a Single part or welded part. Standard risers also have various shapes and sizes.

                                                                

⦁ Retractable pin unit

A retractable pin unit is a unit designed to locate the car panel using pins, but the entire pin package parts will be mounted on the retractable pneumatic cylinder. Pin, shims, L Block, pneumatic retractable cylinder, riser are the parts of retractable pin unit

                                                 

DIAMOND PIN UINT

SPECIFICATION TREE

Feature tree

Retractable pin unit

⦁ Retractable pin unit

PIN UNIT WITH BASE PLATE