Week 4:- Pin Unit Design Challenge

Note:-Units are designed in Catia V5 2020

DESIGN PROCEDURE:

FORMULA & CALCULATION:

Length of the screw = [1.5 X (std. hole size)] + {distance between the surface of the part to the first surface of the other part}.

To fix the pin retainer & shim block using a standard screw we need to find the length of the screw using the above mentioned formula.

MATERIAL USED:

In general, the materials used for pins, pin retainers, shims, shim block, blades & risers are:

1. Pin: C45, EN31, SAE 8620 Steel, etc.
2. Pin retainer: steel/ ASTM A-36, SS type 303 or 304, etc.
3. Shims / spacer: S.A.E. 1010 CRS FULL HARD, COLD ROLLED STRIP STEEL S.A.E. 1010 FULL HARD, S.A.E. 1020 HRS etc.
4. shim block: STEEL ASTM A- 36, NM stainless, STEEL ASTM A-36, SS type 3030 or 304, etc.
5. Blade: STEEL ASTM A-36, etc.

PURPOSE OF PIN UNIT:

As by 3-2-1 locating principle, the introduction of two pins helps to arrest the 6 degrees of freedom (4 axial & 2 radial movements) whereas other 6 degrees of

freedom are arrested by introducing minimum three supports.

Typically, the locating pins are used to locate a body part in a position sufficiently accurate to execute a welding process.

The body part is constrained by a set of appropriately locating pin so total constraint by locating pin should be fully constrained at all times to prevent any

movement.

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 (i.e 4 translation) & other must have arrest 2 way (i,e 2 rotational) of a

car panel.

1. Pin should engage 3 to 5mm from car part entry surface.