Ensure the artwork in your design file extends all the way to the bleed lines as displayed on the product template (this is the blue outline). This will ensure you don't have any unprinted areas appearing as a thin line on the edge of your packaging once it has been cut.
To Extend Artwork to the Bleed Lines:
- Paste your imagery into the Artwork layer (Command + V) or place it in a file from your desktop by heading to the File tab and selecting Place…
- Drag it to the bottom of the Artwork layer to ensure that it’s below all other components of your design
- Click and drag to extend the imagery so that it is stretched past the blue template lines (the bleed lines)