What are U-bottom, K-bottom, and Straight-bottom?
Stand-up pouches come with multiple sealing styles for the bottom.The most common is U-bottom (available in "trimmed" and "untrimmed" versions during pouch making).Overseas customers often request K-bottom solutions (also available in trimmed and untrimmed versions).The straight-bottom solution is generally only used for hand-made sample pouches (no need for a bottom sealing die).
Option 1: U-bottom
Note: For this type of bottom sealing die, you can choose whether to add "air vents".
The bottoms of the above three pouches are untrimmed.Its disadvantage is that a ~3mm colored edge from the front/back panel transition will appear inside the pouch bottom.Its advantage is that it saves labor and material costs.
The bottoms of these pouches above are made with a "bleed" and undergo a 5mm trimming process during production.This results in a uniform, aesthetically pleasing bottom color with no extra colored edges,but it incurs higher process and material costs.
Option 2: K-bottom
The bottoms of the above pouches are heat-sealed with a 10mm edge.This K-bottom design delivers better standing performance and a flatter, more attractive appearance...
The bottom edges of these K-bottom pouches clearly have no heat sealing or trimming.This design offers better expandability for the pouch bottom, allowing it to hold more contents.
Option 3: Straight-bottom (saves the bottom sealing die, ideal for sample making)
This "straight-bottom" is also called a flat bottom.It is only used as an alternative for U-bottom sample prototyping.For mass production, the standard U-bottom sealing die will be adopted,which provides better pouch sealing performance.
