Invention Reference Number
In wire-arc additive manufacturing and hot-wire laser additive manufacturing, wire is fed into a melt pool and melted through the arc or laser process. A critical part of this wire feed is a copper contact tip that makes electrical contact with the wire, while simultaneously providing a consistent wire feed position. Contact tips are also used in conventional welding processes. In all welding processes, contact tips are a consumable that is replaced periodically. Over time the wire running through the tip wears the tip and creates an oblong exit hole. In conventional welding, tips are replaced when the wear makes electrical contact unreliable; this is usually a few hundred hours. However, in additive manufacturing, the tip wear makes the wire position unreliable, leading to unexpected melt pool location/shape. Consequently, tips are replaced frequently (usually every half hour) to avoid this issue. Because most prints are far longer than this, regular print interruption is necessary to replace tips. These interruptions can cause problems such as interlaminar defects, cold joints and increased residual stress. Longer lasting tips would avoid this regular replacement of tips, and the consequent print interruptions and defects.
Contact
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