Rotary Drive Control for Hot Forming Machine Cycle Timing
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Solution Overview
Problem
Hot forming machines face reduced production frequency due to fixed gear ratios that cannot accommodate varying glass tube diameters, leading to extended processing times and inefficient use of machine cycles.
Innovation Solution
Implementing a control unit that adjusts the angular velocity of the drive shaft during the movement and standstill phases of a step cycle, allowing for variable speed changes without overloading the gearbox, thereby optimizing the ratio between transfer and processing times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the speed of the drive shaft is reduced to extend standstill time for larger glass diameters, then the processing time at each station is extended, but the production frequency is reduced
Solution Approach 1:
The drive shaft speed is made variable rather than constant. The control unit adjusts the angular velocity dynamically: higher speed during movement phase for quick transfer, lower speed during standstill phase for adequate processing time. This dynamic speed adjustment resolves the contradiction by allowing both extended processing time and maintained production frequency.
Solution Approach 2:
The angular velocity parameter of the drive shaft is changed between different operational phases. By implementing variable speed control with distinct velocity values for movement phase versus standstill phase, the system optimizes both processing quality and production throughput, eliminating the need to reduce overall speed for larger glass diameters.
2Loss of time
If the transfer time is shortened to increase efficiency, then the product frequency increases, but the fixed gear ratio prevents independent adjustment of transfer and processing times
Solution Approach 1:
The system transitions from fixed gear ratio to dynamic speed control. The control unit independently regulates the drive shaft speed during movement phase versus standstill phase, enabling flexible adjustment of the transfer time to processing time ratio without mechanical gear changes, thus resolving the adaptability constraint.
Solution Approach 2:
The fixed mechanical gear ratio system is replaced with an electronically controlled variable speed drive. This substitution allows the transfer time to be independently optimized without being constrained by mechanical gear geometry, enabling the system to achieve both shortened transfer time and maintained processing time through electronic speed regulation.
3Ease of operation
If the drive shaft rotates at constant speed, then the control is simple, but the ratio between transfer time and processing time is fixed and cannot be optimized
Solution Approach 1:
The control system evolves from constant speed to variable speed with automated phase detection. The control unit automatically identifies movement and standstill phases and applies appropriate speed values, maintaining operational simplicity while enabling optimization of the transfer-to-processing time ratio for improved productivity.
Data Source
AI summary
A method for controlling a rotary drive of a hot forming machine having a plurality of processing stations arranged in a circular manner and a rotary table arranged thereabove, in which glass tubes to be processed are held and moved from one processing station to the next by a stepwise rotary movement, is provided. The rotary table is driven by a step gear by which a movement of a drive shaft is translated into a cyclic step movement, a step cycle of which comprises a movement phase and a subsequent standstill phase. A first value for the angular velocity of the drive shaft is assumed at a first time in the movement phase of the step cycle and a second value different from the first value is assumed at a second time in the standstill phase of the same step cycle.