Plasma cleaning machineThe core of the cleaning effect detection is to verify the degree of surface pollutant removal and the effectiveness of surface activity enhancement. Common methods can be divided into physical detection and chemical detection, which are simple to operate and highly practical. The specific steps are as follows:

1、 Physical detection method (intuitive judgment, quick to get started)

1. Contact angle measurement method

This is the core method for detecting changes in surface hydrophilicity/hydrophobicity. Plasma cleaning removes surface oil stains, increases active groups, and significantly reduces the contact angle.

Preparation tools: contact angle measuring instrument, deionized water (or specified test solution).

Operation steps:

Before cleaning: Take the sample to be tested, drop 1-2 μ L of deionized water onto the surface, measure the contact angle with an instrument and record the value.

After cleaning: Use the same method to drip and measure in the same area (or adjacent areas of the same material) of the sample.

Judgment criteria: If the contact angle significantly decreases after cleaning (such as from above 80 ° to below 30 °), it indicates good cleaning effect; If the numerical change is small, it may be due to insufficient cleaning parameters or the presence of residue.

2. Visual appearance/microscopic observation method

Suitable for samples with obvious particles and stains to quickly determine surface cleanliness.

Preparation tools: naked eye, optical microscope (or stereomicroscope).

Operation steps:

Observe the surface of the sample under the same lighting conditions before and after cleaning.

For small stains, use a microscope to magnify 50-200 times to observe changes in particle count and stain area.

Judgment criteria: After cleaning, if there are no visible particles, oil stains, or water stains on the surface, and the amount of impurities under the microscope is significantly reduced, then the cleaning is qualified.

2、 Chemical testing method (precise verification, suitable for professional needs)

1. Surface energy testing method (based on ink marking method, simplified version)

Using test inks with different surface energies to determine the surface activity of the sample and indirectly reflect the cleaning effect.

Preparation tool: Complete set of surface energy testing ink (such as 30-70 mN/m series).

Operation steps:

After cleaning, dip a cotton swab in low surface energy ink and draw a straight line on the surface of the sample.

If the ink line does not shrink continuously, it indicates that the surface energy of the sample is greater than or equal to the surface energy of the ink; If it shrinks into water droplets or breaks, it indicates insufficient surface energy and incomplete cleaning.

Reference standard: After most industrial cleaning, the surface energy of the sample needs to reach 38 mN/m or more.

2. Residual weight analysis method (suitable for detecting trace pollutants)

Suitable for scenarios with extremely high cleanliness requirements, such as semiconductors and precision electronic components, to quantify the residual amount of pollutants.

Preparation tools: Analytical balance (accuracy 0.01mg), drying oven.

Operation steps:

Before cleaning, place the sample in a drying oven to dry to a constant weight, weigh it with an analytical balance, and record m1.

After plasma cleaning, dry to a constant weight and record the weight in m2.

Judgment criteria: Calculate the weight difference Δ m=m1- m2, the larger Δ m, the more pollutants removed; If Δ m approaches 0, parameters such as cleaning power and time need to be adjusted.

3、 Precautions

detectionPlasma cleaning machineIt should be carried out shortly after cleaning (recommended within 30 minutes) to avoid the adsorption of pollutants in the air on the sample surface, which may affect the results.

When conducting comparative testing, it is necessary to ensure that the testing environment, location, and method of the samples before and after cleaning are consistent to reduce errors.

Different material samples (such as metal, plastic, glass) need to choose suitable detection methods. For example, contact angle method is preferred for plastic samples, and microscope observation can be combined for metal parts.