Week 7:- Base Unit Design Challenges 1
1. BASE UNIT:
A Base unit refers to component or structure that serves as a foundation for the entire fixture assembly. It is a key element used to support and locate the vehicle body or body components during the manufacturing or assembly process.
PARTS OF BASE UNITS:
- Base Plate: Machined plate of 25 to 40mm thickness made of steel and aluminium on to which the holes are drifted to mount the individual units like clamp unit, pin unit, etc., of a tool.
- Trunking channel: A duct which accomodates all the pneumatic and electrical hoses and wires for the units of the tools.
- Valve Box: Standard part which will accomodates the pneumatic valves for the units.
- Measuring hole cover
- Eye bolt : These are used for transporting of the tool, using lift hooks. Forks lift holes will also be provided in some cases for transporting purpose.
- Pedestal: Part which connects the base plate to the floor plate. it is standard part in general, and in some cases it can be welded frame integrated with the base plate.
- Weld Bars: It is plate along the sides of the base plate of the pedestal.
- Floor plate: Floor plate is grouted to the floor with the fixed bolt on the ground. Floor plates are also called as foundation plates.
2. DESIGN CONSIDERATION FOR A BASE UNIT:
- Base Plate:
- should cover all units with its outer periphery including opening.
- BCS coordinates use while designing
- Datum holes/measuring holes should be drilled in line with a pitch of 1000mm in general.
- Number of datum holes depends on size of plate.
- Datum holes should be drilled at nominal value of coordinates, and in terms of 50 and 100. (in general) ex: X=100, Y=600, Z=250.
- Datum holes should be drilled with Diameter 100mm away from other units.
- Datum holes should be covered with Cover plates.
- Clearance of 10mm maintained between pedestal base plate and floor plate. This Clearance will be used by levelling screws, for levelling the entire tool.
- Weld bars are to be used to weld the positions permanently, after the levelling is done
The dump unit is typically a hydraulically or mechanically controlled device that allows for controlled tilting or dumping of the BIW assembly to specific angles or positions. It assists in providing better access to specific areas of the assembly, such as welding or inspection points, that may be difficult to reach in the standard orientation.
4. When designing a dump unit for BIW fixtures, several factors need to be considered:
- Weight capacity: The dump unit should be designed to support the weight of the BIW assembly safely.
- Stability and rigidity: The dump unit must maintain stability and rigidity during the tilting or dumping process to ensure precise positioning of the BIW assembly.
- Control mechanisms: The dump unit should incorporate hydraulic or mechanical control systems to enable smooth and controlled tilting or dumping actions.
- Safety features: The dump unit should include safety features such as interlocks, sensors, or emergency stop mechanisms to prevent accidents or injuries during operation.
- Integration with other fixtures: The dump unit should be designed to integrate seamlessly with other fixtures or tooling components used in the BIW manufacturing process.
5. SLIDE UNIT:
A slide unit typically refers to a movable mechanism or component within the fixture. BIW fixtures are used in automotive manufacturing to hold and position vehicle body components during assembly.
A slide unit within a BIW fixture allows for the adjustment or movement of certain parts of the fixture, such as clamps, locators, or supports. It enables precise positioning of the vehicle body components to ensure accurate assembly and welding processes.
The slide unit can be designed with various types of motion, such as linear sliding, rotational movement, or a combination of both. It is often equipped with locking mechanisms to secure the desired position once adjustments are made.
6. SLIDE UNIT DESIGN points to considered:
- Load Capacity: Consider the weight of the components being handled and any additional forces or stresses that may be exerted during the assembly process.
- Range of Motion: Define the required range of motion for the slide unit.
- Precision and Accuracy: Ensure that the slide unit provides the necessary precision and accuracy for the intended assembly process. Components such as clamps, locators, or supports should be securely positioned and held in place without any significant deviation.
- Stability and Rigidity: The slide unit should be designed to provide stability and rigidity to support the body components during assembly.
- Locking Mechanisms: Incorporate appropriate locking mechanisms to secure the slide unit in the desired position once adjustments are made. These mechanisms should be robust and reliable to prevent any unintentional movement during the assembly process.
- Maintenance and Accessibility:Ensure that components can be easily inspected, lubricated, and replaced if necessary.
- Compatibility: Ensure that it can be seamlessly integrated and synchronized with other components for efficient and effective operation.
- Safety Considerations:Ensure that it includes features such as safety interlocks, guards, or sensors to prevent accidents or injuries during operation.