Ablation
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Ablative plate
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Ablation technology uses heat to blast the surface of the plate and reveal the printing surface below.
These plates consist of a non-grained aluminum layer covered with an ink-receptive layer followed by an infrared-absorbent layer. The infrared layer acts as a primer for the top coating – PVA or the silicon, depending on whether the plate is intended for dry or wet printing. The IR laser images the plate by ablating the infrared-absorbent layer to reveal the ink-receptive layer beneath.
The first plates based on this technology needed a washout process to remove the ablation debris. Those plates had a run length of up to 50,000 impressions. Later ablation plates used a curing step that extended the run length of the plates to 100,000 impressions. Contemporary ablation plates need no washout or curing; however, they do require water on the press to work. The ablation debris washout using the fountain solution on the press machine. The run length for these latest ablation plates is up to 50,000 impressions.
These plates cannot be baked. They also do not have grained aluminum for efficient water handling of the press. To provide the necessary hydrophilic and oleophilic ink and water handling properties of the plate, they rely entirely upon the ink-receptive layer and the PVA or silicon top layer. This severely limits their run length.