## Blow-Up Ratio (BUR) Calculator

## What is Blow Up Ratio?

The **blow-up ratio** is a term commonly used in the plastics and polymer industries, particularly in the context of film extrusion. It refers to the ratio of the diameter of the inflated bubble (the tube of molten plastic) to the diameter of the die from which the plastic is extruded.

## What is a Blow-Up Ratio Calculator?

The **Blow-Up Ratio Calculator** is a tool used to compute the BUR based on the diameters of the extruded bubble and the die. This ratio is critical because it helps manufacturers control the properties of the final plastic film, such as thickness, strength, and transparency. Maintaining the correct BUR ensures that the product meets specific quality standards and performs as expected in its intended application.

## Blow-Up Ratio (BUR) Formula

The blow-up ratio (BUR) is a key parameter in the film extrusion process. It is defined as the ratio of the diameter of the inflated bubble to the diameter of the die.

### Formula:

The blow-up ratio (\(BUR\)) is calculated using the following formula:

\[ BUR = \frac{D_b}{D_d} \]

Where:

- \(D_b\) = Diameter of the bubble
- \(D_d\) = Diameter of the die

#### Example:

Consider a scenario where the diameter of the bubble (\(D_b\)) is 120 cm and the diameter of the die (\(D_d\)) is 60 cm.

### Step 1: Calculate the Blow-Up Ratio

Using the formula:

\[ BUR = \frac{120 \, \text{cm}}{60 \, \text{cm}} = 2.0 \]

### Step 2: Interpretation

The calculated blow-up ratio (BUR) is 2.0. This indicates that the diameter of the bubble is twice the diameter of the die, which could influence the film's thickness and mechanical properties.