Week 5:- Rest Unit & Clamp Unit Design Challenge
Aim:
1. Design 3 different types of power clamp unit with different pin, riser, blade and block.
2. Design 2 different types of rest unit.
Make a detailed report describing the process and attach relevant image.
Introduction
A clamp is a fastening device used to hold parts firmly together, i.e. to prevent parts or subassemblies from moving relative to one another. According to the above definition, clamps are most commonly used in carpentry cutting or gluing operations, welding or cutting in metalworking, and the like. Clamps are found in almost every workshop because they are simply irreplaceable; when it comes to performing various specific tasks, their main purpose is to replace a dependable extra pair of hands that every handyman requires. It consists of clamp arm, finger,
back up/rest, shims, and pneumatic clamp cylinder riser.
Basic terminologies used in the BIW fixture
The following terminologies are used in BIW
1. A) NC/Mylars/Fingers
Mylars are the component that holds the panel while These are placed from topside & from the bottom side also. The top side Mylars called Clamping Mylars & the bottom side Mylars called Resting Mylars. Every clamping Mylars have resting Mylars. It doesn't allow deformation of the part due to welding stresses.
B) Principle locating point (PLP)
These are the points that are used for the accurate location of the part to maintain the geometry of the part. There is lots of holes on the panel which are not accurate due to stamping operation. The PLP are defined in the drawing. The positional dimensions or relative dimensions are very precise in stamping & in fixtures also.
C)A Risers
Risers are of different types like L-typer rises, Square tube riser Riser is the manufacturing part which gives height to the assemblies.
D)A Blade
Blades are plates mounted on the Other parts like cylinder, arms, etc are mounted on the blade.
E)A Shims
Shims are the small part that comes with the thickness of 0.1mm, 0.2mm, 0.5mm, etc. These will compensate for the stackup tolerance which reflects at the panel holding part called We give tolerance to all the parts of the fixture. Du to this tolerance, the Mylars will either lift up or goes down from their defined position.If the Mylars go down from the defined height it will make an impression or dent on the panel.If the Mylars lift up then there will be a distorsion due to welding stress. To adjust the Mylars At its defined position we use shims so the panel won't be deformed & also don't get any impression on it.
L) Clamp Arm
The clamp arm is the part of the clamp unit which moves an Over clamp arm the Mylars are mounted.
3-2-1 principle
The 3-2-1 principle of location (six point location principle) is used to constrain the movement of workpiece along the three axes XX, YY, and ZZ. This is achieved by providing six locating points, 3 pins in base plate, 2 pins in vertical plane and 1 pin in a plane which is perpendicular to first two planes.
A workpiece will be completely confined when blanked against:
3 points in one plane: The “3” in 3-2-1 refers to 3 locators (passive fixture elements) on the primary
locating/datum surface.
2 points in another plane: The “2” in 3-2-1 refers to 2 locators on the secondary locating/datum surface.
1 point in a third plane: The “1” in 3-2-1 refers to 1 locator on the tertiary locating/datum surface
Rest Unit
It is used to rest the components/part on it during the operation. The shim and spacer are used to adjust rest block as
per requirement. The riser is used to get the part at the required heights and generally it is used as standard part.
CLAMP UNIT 1
CLAMP UNIT 2
CLAMP UNIT 3
CLAMP UNIT 4
CLAMP UNIT AND REST UNIT
