Week 4:- Pin Unit Design Challenge

PIN UNIT DESIGN (FIXED PIN & RETRACTABLE PIN)

OBJECTIVE: To design the pin unit for given component in both fixed and retractable types

INTRODUCTION:

• Pin unit is used to locate car panels using pin
• It consist of riser,blade, pin retainer, shims and cylinders
• Pin unit is a part of the 3-2-1 location principle of fixture design.
• It restricts 6 degees of freedom of the part

Fundamental of pin unit design:

• Pin should engage 3-5mm from car panel entry surface
• all pins should be accomodated with 2 way adjustable shims
• Round pins should be used incase of 4 way arresting of car part if the hole is round
• Diamond pins should be used for 2 way arresting of part if the hole is round.

There are two types of pin unit :-

i - Fixed pin unit

ii- Retractable pin unit

Number of parts are:-

Pin retainer - It is used to support or carry pin.

Blocks - Block can be machined in any desired shape according to fixture. It is normal shape of rectange or square clock or L type shaped block.

Shims or spacer - shims or spacer are used to compensate tolerance stack up. In pin unit we need to control two direction that are C and Y using shims or space. Shims are generally thin sized plates used in group called shimpack and spacer are used as single plate and can be mcahined accordingly.

Blade- blades are bolted on riser

Riser - Riser are used to increase the height of the fixture and it is a standard parts.

FIXED PIN UNITS:-

RISER:-

PINS:-

SHIMS:-

BLOCKS:-

BLADES:-

PIN UNITS:-

RETRACTABLE PIN UNITS:-

ROUND PIN

DIAMOND PIN

CONCLUSION:- Pin unit design has been successfully completed.