Challenge

Week 4:- Pin Unit Design Challenge

IImtiyaj Mathakiya12 Mar 2023

Pin Unit Design

AIM:- To design 2 different types of fixed pin units with different pins, riser, blade & block, and 2 different types of retractable pin units with different pins, riser, blade, cylinder & block. Fixed pin unit- In this type of unit, the pin is fixed by means of a pin retainer & rise.

TYPES OF PIN UNITS:

Fixed pin unit- In this type of unit, the pin is fixed by means of a pin retainer & riser.
Retractable pin unit- In this type of unit, there is the provision of moving of pin in the up-down direction.

Fixed Pin Unit.

Fixed pin unit is a unit designed to locate the car panel using pins.

below are the different parts of a fixed pin unit.

Pin Retainer

Shims/Spacers

Block

Blade or Adaptor Plate

Riser

Retractable Pin.

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.

below are the different parts of a retractable pin unit.

Shims/Spacers

L Block

Pneumatic

Single rod

retractable cylinder

Riser

Fundamentals Of Pin Unit Design.

it is necessary to have two pin to locate a car panel. and here one pin must arrest 4 way (4translation) and other must arrest 2 way (i.e 2 rotational) of car panel.

Pin should engage 3 to 5 mm from car part entry surface.
All pins should be accomodated with 2 way adjustable shims irrespective of direction of arresting.
Round pins should be used in case of 4 way arresting of car paart if the hole is round.
Round pin can be used for 2 way arresting of car part only if the hole is slot.
Diamond pins should be used in case of 2 way arresting of car part if the hole is round.
Diamond pins should be used in case of 4 way arresting of carpart ift he hole is slotted.

The axis of the car panel hole and the axis of the pin should be same.(in general)

the pin tolerance for a geo pin will be of closer tolerancei.e.-0.5mm and forre-spot pin is -0.28mm.

Typical parts of a pin unit.

Pin:- Pin a part which locates the car panel. A pin can either be a make part or a standard part also.

Pin should have grinding surface on shaft with fits on to which the pin retainer will be fitted.

the mounting surface of the pin should be a fine machined surface.

the pin should have a step machine surface to lock the rotation, which matches with the pin retainer

the pin mounting surface of the pin retainer to the blocks should be a machined surface

all machined planes should be perpendicular to the axis of the pin shaft

pin must have a fastening provision like tapped hole from the bottom or a V groove from the side

A pin must be hardened ( Heat tratment) and black oxide finfished in general.

Pin Retainer:-

Apin ratainer is a part which holds the pin in position, the pin retainer can either be a make part or a standard part also.

Pin retainer should have a hole with a fit, on to which the pin will be fixed.
The pin mounting surface of the pin retainer should be a fine machined surface.
The pin mounting surface of the pin retainer should have a step to lock the rotattion of the pin.
The mounting surface of the pin retainer to the blocks should be a machined surface.
The pin retainer will be fixed to a block or a L block to the riser with 2 dowel holes (pins) and at least with one screw hole to maintain the tolerance.

Block / L Block:-

These parts are mainly used to accommodate the shimming directions as per fundamental in general. also in some cases used for other design feasibility.

Shims / Spacers:-

Shims and spacers are some standard parts in general. which are used for adjustmentsa of locators (NC block and pin retainer) for obtaining the desired values for the precise working of a unit with respect to car part. in general to adjust the design to manufacturing deviation.

Blade:-

Blade is part like a plate, which connects the part of a unit to a riser. in general the blade can be either a make part or a standard part.

Riser:-

Riser is a part on which all the parts of a unit are mounted. and is mounted on the base plate of a tool. in general the riser can either be make be part or a standerd part.

Dowel holes and machined surfaces:-

All make parts which are to be asssembled with tolerance should be designed with 2 dowel holes and at least of 1 to 6 threaded / free hole (depends on size). and to be fine machined for the mounting surface with 3 to 5 mm step machining.

Typically, locating pins are used for controlled, fine tolerance positioning of a, For example, a pallet that is moved along one axis, where the drive mechanism is not accurate and stable enough to place it in a position sufficiently accurate to execute a particular process, the use of locating pins may be the best solution.

The Diamond Shape is a critical feature that helps with machining inaccuracies and smoother locating When two round headpins are installed onto one plate, the distance between two mounting holes must be extremely precise and even then, the workpiece will not be placed on the base as easily as it would with the use of a diamond shape pin.

There are several styles of Pin Head They serve different purposes and can be utilized in a variety of applications.

DESIGN METHODOLOGY

The project is titled with the “P001_Z01_ST010_00_00”. All the parts in the feature tree of the CATIA must follow the same process for easy identification of parts in the assembly.

NOTE :- All the part Should be in Isolate part. Go to Right Click on the part in the feature tree then COMPONENTs then Click on ISOLATE PART.

Fixed Pin:-