Die Bonder Load Shaft Rotary Coupling for Bonding Force
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Solution Overview
Problem
Conventional die bonders face challenges in generating a large bonding force while maintaining accuracy and correcting rotary offsets during the die bonding process, leading to potential placement errors due to structural deformation and lack of theta motion.
Innovation Solution
A die bonder with a bond head featuring a load shaft, a bond force motor, a rotary motor, and a magnetic coupler that allows the load shaft to rotate relative to the bond force motor, enabling decoupling of rotary motion and providing a large bonding force with precision alignment and theta compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a pneumatic cylinder is used to provide bonding force, then a large bonding force can be applied, but the bond head cannot produce theta motion for rotary compensation
Solution Approach 1:
The system is divided into separate functional modules: the pneumatic cylinder provides bonding force while the rotary motor provides theta motion. The load shaft acts as a common interface that receives both the axial force from the pneumatic cylinder and the rotary motion from the rotary motor, allowing independent operation of each function without interference
Solution Approach 2:
The load shaft serves multiple functions simultaneously: it transmits the axial bonding force from the pneumatic cylinder while also rotating to provide theta motion compensation. This single component handles both linear force transmission and rotary motion, eliminating the need for separate mechanisms
2Stability of the object's composition
If the load shaft is fixedly coupled to the pneumatic cylinder, then axial motion is maintained, but rotary motion decoupling is prevented
Solution Approach 1:
The coupling between the load shaft and pneumatic cylinder is designed with differentiated properties: axially, the connection is rigid and fixed to maintain stable force transmission, while radially/rotarily, the connection allows independent rotation. This anisotropic coupling behavior enables both axial stability and rotary independence simultaneously
3Manufacturing precision
If the bond head rotates for alignment, then theta compensation is achieved, but structural deformation and placement errors occur
Solution Approach 1:
The vision system captures images and calculates the required theta compensation angle before the bonding operation. The bond head then rotates to the predetermined alignment angle, and only after alignment is complete does the bonding force is applied. This sequential approach ensures alignment is achieved without introducing deformation errors
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves accurate die bonding with a large bonding force, reducing placement errors and structural deformation by decoupling rotary motion from the bond force motor, allowing for precise alignment and correction of rotary offsets.
Implementation Method 1
a bearing which is configured to allow the load shaft to rotate about the rotational axis relative to the bond force motor
Data Source
AI summary
A die bonder comprises a bond head having a load shaft which passes through the bond head and a collet located at one end of the load shaft for holding a die to be bonded. A bond force motor is operative to drive the load shaft along a travel axis in directions towards and away from a die bonding position. A rotary motor is operative to rotate the load shaft about a rotational axis parallel to the travel axis. A coupler which comprises a bearing couples the load shaft to the bond force motor to allow the load shaft to rotate about the rotational axis relative to the bond force motor.