Week 4:- Pin Unit Design Challenge
DESIGN OF FIX PIN AND RETRACTABLE PIN UNIT
INTRODUCTION
The fix pin and the retractable pin units are hole constraining fixtures for car panels.
FIXED PIN UNIT:
Fixed pin unit is a unit designed to locate the car panel using pins.
The parts of fixed pin are:
- Pin
- Pin retainer
- Shim / spacer
- Block
- Blade or Adapter plate
- Riser.

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.
Types of retractable pin:
- Single rod
- Double rod
FUNDAMENTAL OF PIN UNIT:
It is necessary to have two pins to locate a car panel. One pin must arrest 4 ways (4 translational) and the other must arrest 2 ways (2 rotational) of a car panel.
- pin should engage 3 - 5 mm from car part entry surface.
- All pins should be accommodated with 2 ways adjustable shims irrespective of direction of arresting.
- Round pin should be used in case of 4 way arresting of car part if the hole is round.
- Round pin should be used in case of 2 way arresting of car part if the hole is slot.
- Diamond pins can be used for 4 way arresting of car part only if the hole is round.
- Diamond pins can be used for 2 way arresting of car part only if the hole is slot.
OBJECTIVE
The objective of the current project is to design and model two types of fix pin and retractable pin units along with retainers, blocks, shims, blade and riser in CATIA software.
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.








CONCLUSION
The fix pin and retractable pin units are modeled in the CATIA V5 software. In fixture design, it is advised to use the standard parts where ever it is necessary. If any new part is to be installed then the part can be modeled as per the customer requirements.