Week 4:- Pin Unit Design Challenge

AIM :

To design Pin Units for the given sample component in both fixed and retractable types and to understand the designing procedures, fundamentals, and standards for a pin unit of the BIW fixture design.

INTRODUCTION :

• Pin unit is a unit designed to locate car panels using pins.
• Components that consist of the unit are :

1. PIN
2. PIN RETAINER
3. SHIMS
4. BLOCKS
5. BLADE
6. RISER
7. CYLINDERS

• Pin unit is a part of the 3-2-1 locating principle of fixture design.
• It restricts 6 degrees of freedom of the part.

PIN:

• Pin is the part which locates the car panel. It can be a make part or standard part.
• It should be grinding surface on shaft with fits onto which the the pin retainer will be fitted.
• The mounting surface of the pin should be fine machined surface.
• The pin should have a step  machined surface to lock the rotation, which matches with the pin retainer.
• All machined planes should be perpendicular to the axis of the pin shaft.
• pin must have a provision like tapped hole from the bottom or a v-groove from the side.
• A pin must be hardened (Heat treatment) & black oxide finished in general.

PIN RETAINER

A pin retainer 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 is used to hold the locating pins firmly.

CONSIDERATION :

• A pin retainer is a part which holds the pin in position, the pin retainer can either be a make part or a stand 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 the step to lock the rotation of the pin.
• The pin 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 & at least with one screw hole to maintain the tolerance and part also pin retainer is used to hold the locating pins firmly.

SHIMS/SPACERS:

• Shims/Spacers are standard parts which are used for adjustments of locators (NC Blocks & Pin retainers) to get precise location of a pin with respect to car part.
• It helps to compensate for deviation in manufacturing processes.

BLOCKS:

• Block is used to provide a 2 directional adjustment of pins with the help of shims.L-Blocks are most commonly used in general.

BLADE:

• Blade is a part like a plate, which connects the parts of a unit to a riser. In general, the blade can either be making part or a standard part.
• Blade is the plates which are attached to raiser.
• Blade is also attached or mounted with cylinders, arms etc.

RISER:

• Riser is a manufacturing part used to raise/height the assemblies of fixtures.
• One end of the raiser will be attached to the base unit while the other end will be attached to the Blade.
• It is a part on which all the parts of a unit are mounted on the base plate of a tool. In general, the riser can either be making a part or standard part.
• Raiser can be of two types. They are,
  • 'L' type risers.
  • Square tube risers.

 FIXED PIN:

RETRACTABLE PINS:

                                                            Retractable pins at down position

CONCLSUION:         

  The pin units for the given panel is designed and retractable pins also designed.