Week 4:- Pin Unit Design Challenge

FIXED PIN UNIT:

A fixed Pin Unit is designed to locate the car panel using pins. And below are the different parts of a fixed pin unit in general.

• Fixed Pin Unit is designed to locate the car panel using pins.
• And below are the different parts of a fixed pin uint in general.

Fundamentals of Pin Unit Design:

It is necessary to have two pins to locate a car panel. And here one pin must arrest 4-way (4 translational) and the other must arrest 2-way (i.e. 2 rotational) of a car panel.

1. The pin should engage 3 to 5 mm from the car part entry surface.
2. All pins should be accommodated with 2-way adjustable shims irrespective of the direction of arresting.
3. Round pins should be used in case of 4-way arresting of the car part if the hole is round.
4. Round pins can be used for 2 way arresting car parts only if the hole is slot.
5. Diamond pins should be used in case of 2-way arresting of the car part if the hole is round.
6. Diamond pins should be used in case of 4-way arresting of the car part if the hole is slotted.

The axis of the car panel hole and the axis of the pins should be the same. (In general)

The pin tolerance for a geo pin will be of closer tolerance i.e. -0.15 mm and for respot pin is -0.28 mm.

Typical Parts of a Pin Unit:

Pin:

The pin is a part that locates the car panel. A pin can either be a make part or a standard part also.

• The pin should have a grinding surface on the shaft with fits on to which the pin retainer will be fitted.
• The mounting surface of the pin should be a finely machined surface.
• The pin should have a step machine surface to lock the rotation, which matches the pin retainer.
• The 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.
• The pin must have a fastening provision like a tapped hole from the bottom or a V grove from the side.
• A pin must be hardened ( Heat treatment) and black oxide finished in general.

Pin Retainer:

A Pin Retainer is a part that holds the pin in position, the pin retainer can either be a make part or a standard part also.

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

Block / L Block:

These parts are mainly used to accommodate the shimming directions as per fundamentals 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 adjustments of locators ( NC Blocks and Pin retainers) for obtaining the desired values for the precise working of a unit with respect to the car parts. In general, adjust the Design to manufacturing deviation.

We need to design the shim pack, which consists of 5 Shims for a thickness of 2mm-1 no., 1mm - 2 nos., and 0.5mm - 2 nos.

Blade:

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

Riser:

The riser is a part on which all the parts of a unit are mounted and mounted on the base plate of a tool. In general, the riser can either be made part of a standard part.

Dowel holes and machined surfaces:

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

RETRACTABLE PIN UNIT:

A Retractable pin unit is designed to locate the car panel using pins, but the entire pin package parts will be mounted on the retractable pneumatic cylinder.

And below are the different parts of a retractable pin unit in general.

PIN UNIT DESIGN USING CATIA V5:

1. Design 2 Different types of Fixed Pin Units with Different Pins, Risers, Blades, and Block.

TYPE 1:

TYPE 2:

2. Design 2 Different types of Retractable Pin Units with Different Pins, Risers, Blades, Cylinders, and Blocks.

TYPE 1:

TYPE 2:

CONCLUSION:

I completed the task by considering all the design rules and the relevant files of the design are attached.