Now, the appearance inspection of medical plastic bottles mainly includes the overall shape, surface tone, glossiness, appearance quality and other quality characteristics perceived by human vision. The basis of appearance quality inspection is that different parts of the plastic bottle have different defects, and different appearance defect standards are formulated. The appearance quality of the plastic bottle body is usually marked with a lower allowable limit or a standard sample is made. The standard sample is better, and one for each defect is sealed for verification.


Several external dimensions of medical plastic bottles are mainly measured as follows:

① Measurement of the overall height of the plastic bottle: the so-called overall height of the plastic bottle refers to the vertical distance from the plastic bottle mouth to the bottom of the bottle. The test method is to place the plastic bottle on a horizontal plane, contact one end of the vernier caliper with the higher point of the bottle mouth, then rotate the bottle 360 degrees, read out the larger and smaller size values, and check whether they are consistent with the size of the design drawing.


② Measurement of the external diameter of the plastic bottle mouth: the specific measurement method is to cross the measuring tool scale across the center of the bottle mouth, avoid the position of the bottle body mold closing line, rotate the circular bottle mouth 360 degrees at the thread of the main shaft tight mouth, measure the larger and smaller values, and compare with the bottle body design drawing. The external diameter error should be controlled within the range of plus or minus 0.10 mm.


③ Measurement of the external diameter of the plastic bottle: the measurement method is to use the measuring surface of the vernier caliper to contact the measuring position of the larger external diameter of the bottle body, tighten the vernier caliper, rotate the plastic bottle body 360 degrees, and record the size of the larger value and the smaller value. The error should be controlled within the range of 0.10mm.


④ Measurement of the wall thickness of each part of the plastic bottle: For the pharmaceutical plastic bottle with a circular revolving body, cut the measuring area of the symmetrical part with a knife so that the measuring tool can enter the detection point where each part of the bottle can be measured. At this time, the thickness of the plastic bottle mouth, the thickness of the shoulder, the thickness of the body, and the thickness of the symmetrical part of the bottle bottom can be strictly measured, and record the larger value and the smaller value, Check whether the dimensional tolerance is within the standard requirements according to the design drawings of the bottle products.


At present, due to the different precision of the equipment used to produce the plastic bottle, the different raw materials and process parameters selected, the changes in the external dimension accuracy of the medical plastic bottle are different. Generally, the plastic bottles produced with the same equipment, same raw materials and molding method should be stored at 23+/- 2 ℃ in the constant temperature room for the specified time and then measured. Under stable process molding conditions, the appearance measurement should be carried out according to the reference dimensions of different parts of the product's appearance design drawing.