Plastic bottles are commonly used packaging materials in modern packaging. They are beautiful in appearance, easy to process, easy to print, and low in cost. They are widely used in food and beverage, medicine, cosmetics and other industries.
The processing of plastic bottles generally adopts processes such as injection molding of the preform, and then blow molding. In the blow molding process, the thickness of the bottle body, bottle bottom and other parts will be uneven due to the influence of temperature and equipment. The thinner part of the bottle body is generally the weak part of the plastic bottle's mechanical properties (such as pressure capacity and pressure resistance) and barrier properties (such as the transmission rate of water vapor and oxygen), which reduces the performance of the entire plastic bottle.
Magnetic induction method thickness test
The principle of this method is based on the Hall effect theory. When measuring thickness, a small steel ball is placed on one side of the test material and the probe is placed on the other side. Rotate the bottle, the steel ball receives the magnetic force of the probe and moves at the same time. The magnetic induction sensor can measure the distance from the probe to the steel ball to obtain the wall thickness of the plastic bottle.The characteristic of this kind of instrument is that it does not damage the sample and is convenient to measure, but it is not easy to measure the concave and convex part of the plastic bottle, and the instrument is expensive.
Contact measurement
This kind of wall thickness measurement method is now a more widely used wall thickness measurement method. The principle is: put the measuring support rod into the bottle, use its dart head to touch the measuring part, and place the measuring meter head of the capacity grid sensor on the corresponding part of the plastic bottle body to contact the bottle body and correspond to the dart head. Read the thickness value reading on the measuring table.
You can refer to the plastic bottle thickness gauge. This instrument has fast testing, comprehensive measurement parts, easy replacement of accessories, and low cost. However, the stability of the mechanical structure of the instrument is relatively high required.
Test thickness of Slice
This is the original method of wall thickness measurement. Due to the limitations of the technology at the time, in the early testing of plastic bottles, many laboratory technicians cut the bottles into pieces, and then tested their thickness with a screw micrometer and calipers. The cost of this method is very low, but it is considered that the accuracy is large and the test efficiency is low, and it is a way that is gradually eliminated.
There are also online thickness detection methods such as infrared method and ultrasonic method for the wall thickness detection of plastic bottles.