Narrow-Hole EDM Flow Control for Long Pipe Electrode Accuracy
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Solution Overview
Problem
In narrow-hole electric discharge machines, using long pipe electrodes for improved productivity and reduced exchange frequency is challenging due to fluctuations in inner diameter and machining fluid ejection amounts, especially with constant pressure control, which affects machining accuracy and speed.
Innovation Solution
A narrow-hole electric discharge machine equipped with a variable flow rate pump, flow sensors, and a storage unit for set flow rates tailored to each pipe electrode size, allowing precise control of machining fluid supply to maintain consistent ejection, even with wear and length changes of the pipe electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If constant pressure control is used to supply machining fluid, then the system is simple to operate, but the ejection amount fluctuates due to inner diameter variations in long pipe electrodes
Solution Approach 1:
The patent transitions from constant pressure control to constant flow rate control by changing the control parameter from pressure to flow rate. The pump control unit adjusts the pump output based on flow sensor feedback to maintain a set flow rate, which compensates for inner diameter fluctuations in long pipe electrodes and ensures stable ejection amount.
2Productivity
If long pipe electrodes are used to improve productivity, then pipe electrode exchange frequency is reduced, but ejection amount fluctuates due to inner diameter variations and wear
Solution Approach 1:
The patent introduces a feedback control system where a flow sensor detects the actual flow rate of machining fluid and feeds this information back to the pump control unit. The control unit adjusts the pump output to maintain the set flow rate, compensating for inner diameter variations and wear in long pipe electrodes, thereby ensuring stable ejection amount throughout the pipe electrode's service life.
3Device complexity
If feed screw structure is used to supply machining fluid, then the device is simple in structure, but supply amount is influenced by feed screw pitch accuracy which fluctuates in long feed screws
Solution Approach 1:
The patent replaces the mechanical feed screw system with a pump-based fluid delivery system controlled by flow sensing and feedback. This substitution eliminates the accumulation of pitch accuracy errors in long feed screws and provides more reliable supply amount control through electronic feedback, while maintaining reasonable device complexity.
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
This configuration enables stable high-speed and high-precision machining with reduced pipe electrode exchange frequency, improving productivity by maintaining consistent machining fluid flow despite variations in pipe electrode length and diameter.
Implementation Method 1
a variable flow rate pump for supplying the machining fluid to the pipe electrode
Implementation Method 2
a flow sensor, provided in piping between the pump and the pipe electrode, for detecting a flow rate of the machining fluid flowing in the piping
Implementation Method 3
a pump control unit configured to drive the pump so as to maintain a detection value of the flow sensor at the set flow rate stored in the storage unit
Data Source
AI summary
A narrow-hole electric discharge machine (100) is provided with: a pump (52) with a variable flow rate that supplies machining fluid to a pipe electrode (28); a flow rate sensor (56) provided in a pipe between the pump (52) and the pipe electrode (28), the flow rate sensor (56) being configured to detect the flow rate of the machining fluid flowing through the pipe; a storage unit (58b) that stores a set flow rate of a jet flow suitable for each cross-sectional size of a plurality of pipe electrodes (28) having different cross-sectional sizes; and a pump control unit (58a) that drives the pump (52) such that the value detected by the flow rate sensor (56) is kept at the set flow rate stored in the storage unit (58b) suitable for the cross-sectional size of the pipe electrode (28) currently attached to a main shaft (114).