Melt Cutter

Like die cutters, melt cutters are used to prevent gravitational extension and therefore thinning of the extrudate during die swell measurement. The melt cutter operates by cutting the extrudate below the die swell measurement unit using a scissor action. Either one or both extrudate strands can be cut.

The cutting action is automatic and is controlled by a sensor placed just below the melt cutters themselves. The sensor is activated when either strand reaches the level of the sensor. A special die swell device 'single axis, twin extrudate' is available for use in conjunction with the melt cutters when both strands are being cut. This arrangement enables simultaneous use of both of the rheometer bores for die swell measurements.

Typically, with a 1mm die, a shear rate range of less than 1 1/s to more than 1000 1/s can be covered by the cutters depending on the material and temperature.