Film Thickness

Smithers Pira determines film thickness using two methods; Spot thickness and Gravimetric thickness. Both are performed in accordance to relevant international standards.

Spot Thickness

The thickness of a sample of plastics film or sheeting can be measured by mechanical scanning using a digital deadweight micrometer. This method is used to look at the thickness uniformity across a film sample.

Smithers Pira is UKAS accredited to BS 2782:6 method 630A.

Smithers Pira also tests in accordance with International standard ISO 4593 and ASTM F 2251.

Gravimetric Thickness and Yield

The gravimetric thickness is calculated from measurements of mass, area and density of a sample. It can provide a more accurate determination of the average thickness of a plastic film and is used in particular for measuring the thickness of embossed sheeting.

Plastic film yield is the area per unit mass of a film roll. The film yield determines the number of packs that can be produced from a roll weight.

Smithers Pira can test for gravimetric film thickness and yield in accordance with British standard BS 2782: 631A, International standard ISO 4591 and ASTM D4321.