Sizing Cage Installation Guidelines

Overview: Installing the sizing cage properly is essential to overall flexibility of the blown film line. More specifically, layflat control and production rate are directly affected when the cage is not installed properly.

To get the most performance from the sizing cage, you want to make the best use of the available vertical travel of the cage. Most cages come with about one meter (~40 inches) of vertical travel. Optionally, up to two meters (~80 inches) of vertical travel can be provided.

Vertical Position: To help decide the proper mounting position for the vertical support of the cage, consideration of the lowest typical frost line position is required. For optimum IBC performance, cage should be able to be lowered so the IBC sensors are about 75mm (3 inches) below the lowest typical frost line. At the same time, the cage position should raise to the highest typical frost line position. Click here or on the picture to see an enlarged view. Make sure the X-Y alignment bolts are in the center of the adjustment position before welding or bolting the cage to the tower.

Proper Sensor Position

Cage Alignment: Before aligning the cage, the die and primary nips need to be leveled and centered. Then align the cage to a plumb bob that hangs from the primary nips. Start by aligning the main frame using the X-Y adjustment bolts. Afterward, open the cage diameter to the maximum size and make sure all cage arms are equidistant from the outer frame. Most cages have individual arm adjustments. The final step is to run the line and verify the cage is centered around the bubble. Verify the film thickness profile is within specifications and there is no bulge in the bubble before moving the cage.

Cage Alignment


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