Drill Motor Controller With Waveform Speed Variation by Bit and Material
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Solution Overview
Problem
Handheld drills lack the ability to automatically adjust drill bit speed according to material and bit diameter, leading to inefficient drilling due to either stalling at low speeds or inadequate engagement at high speeds, as users can only approximate optimal speeds using qualitative settings.
Innovation Solution
A controller that automatically varies the drill bit's rotation speed using a waveform with characteristics determined by the material and bit diameter, allowing for continuous speed adjustment independent of axial movement or force, using a processor to control the motor and deliver optimal power at different radial points on the cutting edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drill bit rotates at high speed, then the drilling efficiency is improved, but the cutting edge cannot adequately engage with the workpiece causing it to rotate above the workpiece
Solution Approach 1:
The controller varies the rotational speed of the drill bit periodically according to a waveform pattern, creating cycles of high speed (for efficiency) and lower speed (for proper engagement). This periodic variation allows the system to achieve both high productivity and reliable cutting edge engagement with the workpiece.
Solution Approach 2:
The system transitions from static fixed-speed operation to dynamic variable-speed operation. The controller continuously adjusts the rotational speed based on waveform characteristics, enabling the drill bit to adapt its speed dynamically between engagement phases and efficient cutting phases.
2Reliability
If the drill bit rotates at low speed, then the cutting edge can engage with the workpiece, but the drill bit may stall
Solution Approach 1:
The waveform-based speed control creates periodic cycles where the drill bit operates at lower speeds for proper engagement and then increases to higher speeds for efficient cutting. This prevents stalling by ensuring the cutting edge maintains adequate engagement during lower speed phases while achieving high productivity during higher speed phases.
Solution Approach 2:
The system changes the rotational speed parameter dynamically according to waveform characteristics, transitioning between different speed states. This parameter variation allows the drill bit to operate at optimal speeds for engagement without stalling, and then achieve high speeds for efficient material removal.
3Ease of operation
If the user manually controls the drill speed using qualitative settings, then the operation is simple, but the optimal drilling speed cannot be precisely achieved
Solution Approach 1:
The controller automatically varies the drill bit speed according to pre-programmed waveform characteristics without requiring manual intervention. The system serves itself by autonomously adjusting speed parameters based on material and bit diameter inputs, eliminating the need for users to manually select from imprecise qualitative settings while maintaining operational simplicity.
Solution Approach 2:
The controller receives input parameters (material type, bit diameter) and automatically determines the appropriate waveform characteristics to achieve optimal drilling speed. This feedback-based automatic control system translates user inputs into precise speed variations, achieving both ease of operation and speed precision.
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 solution enhances drilling efficiency by ensuring the drill bit operates at optimal speeds for various materials and bit diameters, reducing the need for user pressure and enabling efficient cutting across the radius of the cutting edge, proven effective for drilling through steel, wood, hard rock, and masonry.
Implementation Method 1
the controller provides an electric current output to a motor engageable with the bit for rotating the bit, wherein the electric current output controls the speed of rotation of the bit by varying an output speed of the motor
Data Source
AI summary
A controller for controlling a motor of a drill comprising an output of a signal for controlling a speed of rotation of the motor, a processor for producing the signal, wherein the signal is automatically varied according to a waveform, wherein one or more characteristics of the waveform is determined by a material to be drilled and a diameter of the bit.