Wire-Fed Additive Manufacturing Control for Clean Wire Retraction
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Solution Overview
Problem
In additive manufacturing using metal wires, the formation of lumps at the leading end due to incomplete solidification and adhesion issues affects machining quality, increasing process complexity and reducing accuracy.
Innovation Solution
An additive manufacturing apparatus with a driving unit that switches from feeding to retracting the wire based on a machining program, ensuring precise control over the wire's position relative to the beam, thereby preventing lump formation and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the focus is moved away from the end portion before stopping the beam while lowering the wire supply rate, then adhesion of the wire to the bead is reduced, but a lump is formed at the leading end of the wire due to melting and solidification
Solution Approach 1:
The wire supply rate is lowered in advance before moving the focus away, preparing the wire for clean separation. This preliminary action ensures the wire is ready for retraction without forming lumps, while still preventing adhesion to the bead by maintaining reduced supply rate during the focus transition.
Solution Approach 2:
Instead of moving the focus away first and then lowering the wire supply rate (which causes lumps), the invention inverts the sequence by lowering the wire supply rate first and then moving the focus away. This reversed sequence eliminates lump formation while achieving adhesion reduction.
2Reliability
If the wire supply rate is lowered and focus moved away before stopping the beam, then wire adhesion to bead is reduced, but the process complexity increases due to additional cutting and cleaning operations
Solution Approach 1:
The harmful lump formation is extracted and eliminated by reversing the sequence of operations. By lowering the wire supply rate before moving the focus away, the problematic melting-solidification cycle at the wire leading end is prevented, removing the need for subsequent cutting and cleaning operations.
Solution Approach 2:
The wire supply rate control system automatically prepares the wire for clean separation by lowering the supply rate in advance. This self-service mechanism prevents adhesion and lump formation simultaneously, eliminating the need for additional manual intervention or complex post-processing steps.
3Reliability
If the wire supply rate is lowered before stopping the beam, then adhesion is reduced, but machining quality deteriorates due to lump formation at the leading end
Solution Approach 1:
The invention inverts the conventional sequence by lowering the wire supply rate before moving the focus away, rather than moving the focus away first. This reversal prevents the wire leading end from being molten during focus transition, eliminating lump formation and maintaining high machining quality while still reducing adhesion.
Solution Approach 2:
The wire supply rate is lowered in advance as a preliminary action before the focus moves away. This preparation ensures the wire is in the optimal state for clean separation, preventing both adhesion to the bead and lump formation at the leading end, thereby maintaining machining quality.
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
Improves machining quality by reducing lump formation and adhesion, enhancing the accuracy and efficiency of the additive manufacturing process.
Implementation Method 1
manufactures modeled objects by applying a material molten by irradiation with a beam to an object to be machined
Implementation Method 2
Some additive manufacturing apparatuses manufacture modeled objects by locally melting a material using a beam emitted from a machining head
Data Source
AI summary
An additive manufacturing apparatus includes a laser oscillator that is a beam source that outputs a beam, and a rotary motor that is a driving unit that changes the relative positions of a material fed from a wire spool that is a supply source of a wire that is the material and an object to be machined. The driving unit is capable of performing first driving for feeding the material from the supply source toward the object to be machined and second driving for pulling back the fed material to the supply source, and switches from the first driving to the second driving on the basis of a machining program.