Determining plastic or cellulose levels in composites

A method comprising:

• calibrating a displacement-type capacitive sensor probe to a known dielectric constant of a first material;
• positioning a composite article within a detection range of the sensor probe, the composite article comprising the first material and a second material;
• measuring, using the sensor probe, a capacitive response of the composite article;
• determining, based on the measured capacitive response, an equivalent thickness of the first material in the composite article, wherein determining the equivalent thickness comprises comparing the measured capacitive response to a known capacitive response of a sample of the first material of a known thickness;
• and
• determine a percentage of the first material in the composite article based on the equivalent thickness of the first material and a thickness of the composite article.

A method comprising:

• calibrating a displacement-type capacitive sensor probe to a known dielectric constant of a first plastic or cellulose material;
• measuring a thickness of a composite roofing cover board comprising the first plastic or cellulose material and a second material;
• positioning the composite roofing cover board between the sensor probe and a ground plate;
• measuring, using the sensor probe, a capacitive response of the composite roofing cover board;
• determining, based on the measured capacitive response, an equivalent thickness of the first plastic or cellulose material in the composite roofing cover board, determining the equivalent thickness of the first plastic or cellulose material comprises comparing the measured capacitive response of the composite roofing cover board to a known capacitive response of a known thickness of a sample of the first plastic or composite material;
• and
• determining a percentage of the first plastic or cellulose material in the composite roofing cover board based on the equivalent thickness of the first plastic or cellulose material and the thickness of the composite roofing cover board.

A system comprising:

• a displacement-type capacitive sensor probe;
• and
• at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the at least one processor to:
• calibrate the sensor probe to a known dielectric constant of a first material;
• send an instruction to the calibrated sensor probe to measure a capacitive response of a composite article comprising the first material and a second material;
• receive the measured capacitive response from the calibrated sensor probe;
• determine, based on the measured capacitive response, an equivalent thickness of the first material in the composite article, wherein the material properties of the second material are not used to determine the equivalent thickness of the first material or the percentage of the first material in the composite article;
• and
• determine a percentage of the first material in the composite article based on the equivalent thickness of the first material and a thickness of the composite article.

A method comprising:

• calibrating a displacement-type capacitive sensor probe to a known dielectric constant of a first plastic or cellulose material;
• measuring a thickness of a composite roofing cover board comprising the first plastic or cellulose material and a second material;
• positioning the composite roofing cover board between the sensor probe and a ground plate;
• measuring, using the sensor probe, a capacitive response of the composite roofing cover board;
• determining, based on the measured capacitive response, an equivalent thickness of the first plastic or cellulose material in the composite roofing cover board, wherein the material properties of the second material are not used to determine the equivalent thickness of the first plastic or cellulose material or the percentage of the first plastic or cellulose material in the composite roofing cover board;
• and
• determining a percentage of the first plastic or cellulose material in the composite roofing cover board based on the equivalent thickness of the first plastic or cellulose material and the thickness of the composite roofing cover board.