Challenge

Week 4:- Pin Unit Design Challenge

SSujith Singh5 May 2022

Challange Aim

To Design a 2 Different types of Fixed Pin Unit with Different Pins, Riser, Blade, and Block and Design 2 Different types of Retractable Pin Unit with Different Pins, Riser, Blade, Cylinder, and Block.

Introduction to Pin Unit

Pin

Pins are used to positioning the car panel in fixture. There are two different type of pin units are used in fixture.

1) Fixed Pin Unit

2) Retractable Pin Unit

Fixed Pin Unit

Here the pin will be fixed in permanent position with the help of Pin retainers, L-Block and risers.

Retractable Pin Unit

Here the pin unit will be fixed with linear cylinder to move pin away from car panel. These cylinders are standard part will be used as per customer specification and design requirement. Tuenkers, HIWIN these industires having wide range of linear cylinders.

General Specifications

1) There are two standards: one for the in-line mounting (pin mounted in the ram) and one for the offset mounting (pin is offset from the shaft).

2) Two mounting brackets are available for outside and two for inside mounting (used in conjunction with NAAMS riser angle brackets):

Inside Mount: AHB006 & AHB007

Outside Mount: AHB010 & AHB011

3) Mounting pattern in the retractable locating pin housing will be 60 mm x 60 mm (that accommodates 2-M10 dowels and 4-M10 threaded holes)

In-Line Pin Mounting

Figure 3.01 shows the inline Pin Mounting standrad.

Figure 3.01

Offset (L-Block) Pin Mounting

Pins can be secured to the offset retracting locating pin units by utilizing the pin retainers, L-blocks. Figure 3.02 shows the offset Pin Mounting standrad.

Figure 3.02

The following part will be used in Pin Unit.

1) Locating Pin

2) Pin Retainer

3) Shims

4) Blades

5) Risers

Material of Constraction

1) Pin - C45, EN31

2) Pin Retainer - Mild Steel (ASTM36)/Stainless Steel (S.S 304)

3) Shims - Low Carbon Steel Equivalent/ C28000 Brass/304 Stainless Steel

4) Blade - Low Carbon Steel /ASTM 36

5) Riser - Low Carbon Steel /ASTM 36

Pin Unit Desgin Standrads

Hardness - 50-60 HRC /58-62 HRC

Tolerance for geo Pin - 0.15mm & repost pin -0.28mm

Surface Finish

Pin - Chrome Plating/Zinc Coating

Pin Retainer/Shims/Blades - Black oxide

Riser - Black oxide Surface should have flatness and Perpendicular to within 0.015 TIR (Total indicator runout)

Locating Pin

There are two different type of Locating pins will be used in fixture.

Figure 3.03

1) Round Head Pin

2) Diamond Head Pin

Round pin will be used to arrest car panel in 4 ways, whereas Diamond pin used to arrest 2 way if the hole is round and 4 way if the hole is slot.

Different shapes of pin head show in figure 3.04

Figure 3.04

Fundamentals of Pin Unit

The pin should engage 3 to 5mm from the car panel entry.
All pin should be accommodated with 2-way adjustable shims perpendicular to axis of pin.
The round pin should be used in case of 4 way arresting of car panel if the hole is round.
The round pin can be used for 2 way arresting of car panel only if the hole is slot.
The diamond pin should be used in case of 2 way arresting of car panel if the hole is round.
The diamond pin should be used in case of 4 way arresting of car part if the hole is slot.
The axis of the car panel hole & the axis of the pin should be the same axis.

Design Requirement of Locating Pin

The pin should be grinding surface on a 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 with the pin retainer.
All machined planes should be perpendicular to the axis of the pin shaft.
Pin must have a provision like a tapped hole from the bottom or a v-groove from the side.
A pin must be hardened (Heat treatment) & black oxide finished in general.