Coiling Machine Thermal Expansion Compensation
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Solution Overview
Problem
Conventional mandrel-less coiling machines face challenges in maintaining the desired shape of coil springs during both cold and warm working processes, particularly due to temperature-induced shape shifts and misalignment of cutting tools.
Innovation Solution
A coiling machine equipped with a material guide, first and second pins, a pitch tool, a heating device, and a temperature sensor, controlled by a controller that adjusts the positions of the pins and cutting tool based on shape data and temperature feedback to maintain the desired curvature and cutting position accuracy across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a material of a coil spring is heated to a warm working range to perform a warm working process, then the yield strength is improved by dynamic strain aging, but the shape of the coil spring formed may be significantly shifted from a desired shape depending on the temperature of the material
Solution Approach 1:
The controller pre-adjusts the positions of the first pin and second pin based on the detected material temperature before the bending process occurs. This preliminary positioning compensates for thermal expansion and material softening effects, ensuring the coil spring achieves the desired shape despite being processed at elevated temperatures.
Solution Approach 2:
The temperature sensor continuously monitors the material temperature and feeds this information back to the controller. The controller then dynamically adjusts the pin positions based on the actual temperature, creating a closed-loop control system that maintains shape accuracy throughout the warm working process.
2Ease of manufacture
If a material of a coil spring is heated to a warm working range, then the manufacturing process can be simplified by using residual heat, but the position of a cutting tool is shifted from a proper position making it impossible to cut the coil spring desirably
Solution Approach 1:
The controller pre-adjusts the cutting tool position based on the detected material temperature before the cutting operation. This preliminary positioning compensates for thermal expansion and material softening effects, ensuring the coil spring is cut at the correct location despite being processed at elevated temperatures.
Solution Approach 2:
The temperature sensor continuously monitors the material temperature and feeds this information back to the controller. The controller then dynamically adjusts the cutting tool position based on the actual temperature, creating a closed-loop control system that maintains cutting accuracy throughout the warm working process.
3Device complexity
If a coil spring is manufactured through a cold working process, then the manufacturing equipment is simpler, but a heating process such as strain relief annealing and hot setting are performed after coiling requiring reheating
Solution Approach 1:
The system changes the processing temperature parameter from cold working (room temperature) to warm working (elevated but below recrystallization temperature). This parameter change allows the material to be processed at a temperature that maintains strength while reducing the need for subsequent heating operations, as the residual heat from warm working can be utilized for post-processing treatments.
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 machine effectively produces coil springs with minimal shape deviation from the desired form during both cold and warm working processes, ensuring accurate cutting and consistent quality.
Implementation Method 1
a heating device configured to heat the material
Implementation Method 2
a temperature sensor configured to detect a temperature of the material
Implementation Method 3
the controller is configured to change a position of the first pin and a position of the second pin such that a radius of curvature of the arc part increases when the sensor increases
Data Source
AI summary
A coiling machine includes a material guide, first pin, second pin, pitch tool, cutting tool, heating device, temperature sensor, and controller. A material is bent between the first pin and the second pin to form an arc part between the first pin and the second pin. The controller select control data corresponding to the temperature of the material from a plurality of control data corresponding to a processing temperature. Then, the positions of the first pin and the second pin are controlled such that a radius of curvature of the arc part increases when the temperature of the material increases, and the position of the cutting tool is controlled such that a gap between the center of curvature of the arc part and the cutting tool increases.