Week 5:- Rest Unit & Clamp Unit Design Challenge

Rest Unit:

• Rest unit is unit designed to support car panel using Mylar/ NC block/ rest component is rested only, no upper clamp or force applied there. It is the simplest unit to design because it has fewer parts to design & the purpose is only resting of the car panel.
• Because of the simplicity the rest unit is combined with other unit to reduce the cost of the overall project.
• It can be combined with clamp unit to clamp as well as to rest the car panel. It can be combined with locating unit to locate as well as to rest the car panel. Also locating, clamping & Test unit can be combined together in one unit to reduce cost.
• There is no cylinder attached to it. It has rest Mylar, blade and riser & below is different parts of rest unit. Rest unit is also divided into simple support unit, multiple support units & retractable support unit.

Clamp Unit:

• A clamp unit is a unit designed to clamp/hold the car panel with NC blocks/Mylars/rest by using a pneumatic cylinder. Clamp arm, finger, Rest/backup, L-block, shims, riser, pneumatic cylinders are the typical parts of clamp unit.
• Clamping force should be considered while designing clamp unit. Usually clamp open position is 90 .Fingers are attached to clamp Mylar.
• In Clamp unit shim to one side is more enough because it will restrict translation motion in upward direction and downward direction only.
• There is another type of clamp unit known as swivel type. There is pivot pin around which clamp arm rotate.

Purpose of Rest Unit &Clamp Unit:

• The purpose of clamping tools is to securely hold the workpiece in position without obstructing the production process.
• It prevents the distortion during welding process and other processes.
• High clamping forces combined with compact dimensions are therfore the most important requirements for a clamping
  tool. For this reason, clamps are also equipped with mechanical transmission gear units.

Design Methodology:

• 3-2-1 Principle achieved by clamping and resting: The 3-2-1 principle is the fundamental principle of all fixture design. While designing a fixture a major part of time is spent in locating the workpiece in the fixture.
• The best & the most effective method of part location is referred to as the 3-2-1 method. Fixtures work on the 3-2-1 principle.
• 3 locators or supports are placed under the workpiece which establishes the part plane. Three locators are generally positioned at the primary locating surface.
• This restricts 2 axial movements downward & upward and 4 radial movements. As a result the 3 locators arrest six degrees
  of freedom.

THREE DIFFERENT TYPES OF CLAMPING UNITS

CLAMPING UNIT-1

CLAMPING UNIT-2

CLAMPING UNIT-3

CLAMPINUNIT WITH THEIR POSITION

REST UNITS

REST UNIT-2

ALL REST UNTS AND CLAMPING UNITS POSITION

TREE STRUCTURE