Principle and manufacturing process of medicinal plastic bottle blow molding

1. Production process

(1) "Squeeze blowing", also known as hollow extrusion blow molding.

The extruder continuously extrudes the hollow tube, cuts it into small pieces with scissors (manual) or a cutting device (automatically), and then moves it into an extrusion blow mold to blow mold.

Advantages: simple equipment, low investment, low cost.

Disadvantages: the bottle mouth is not flat, the seal is very poor. The raw material is usually LDPE, the barrier property is much lower than HDPE/PP, and the shelf life of the charge is short.

(2) Two-step method "Note-Blow".

"Injection, blow molding" is carried out separately by two separate machines, commonly known as the "two-step method."

The first step: injection molding of the tube blank by a common injection molding machine, the bottle head portion (bottle opening, thread) of the tube blank has been formed;

Step 2: Manually place the tube blank on a honeycomb heater or an automatic circulation heating belt to heat and adjust the temperature, and then move it to the blow molding machine to blow it with compressed air.

Advantages: The equipment is simpler and the investment is less. The bottle mouth is flat and well sealed. The variety development is fast, the mold cost is low, and the cost price is medium and low.

Disadvantages: Injection tube blank and blow molding are carried out step by step, easy to transfer pollution, difficult to ensure bacterial inspection, poor product identity, not suitable for mass production.

(3) One-step "Note-Blow".

"Injection, blow molding" is done on the same machine.

Different models are divided into three stations and two stations "Note-Blow".

The three stations of the station "Note-Blow" bottle making machine are equilateral triangles distributed at an angle of 120°. The first station is the injection molding station, the second station is the blow molding station, and the third station is The bottle removal station.

The three stations can be operated at the same time, with high production efficiency, short cycle, and can be automatically counted and packaged with the conveyor belt. It can truly achieve “no contact” with the human hand during the whole process of medicinal plastic bottle production to ensure the product is clean and hygienic.

The second station of the two-station "blow-blow" plastic machine can be arranged up, down or front and rear.

The first station is an injection molding station and the second station is a blow molding station. Due to the lack of a dedicated de-bottle and cooling station, it is more difficult to achieve fully automatic counting and packaging (generally for bulk manual counting). In addition, the production cycle is longer and the production efficiency is lower than the three stations.

advantage:

High degree of automation and high production capacity. The bottle mouth is flat and the seal is excellent. HDPE/PP raw material is selected, the bottle wall is uniform, the barrier property is excellent, and the storage and shelf life is long. At present, domestic standardized drug package enterprises basically adopt one-step "injection" process equipment, of which the "three-station" structure is the main.

Disadvantages:

The equipment investment is large, the mold is complex, and the system configuration requirements are high. Not suitable for small varieties, small batch production. However, high-volume production can achieve high quality and low cost with good economic returns.

2. Common plastic materials

Solid pharmaceutical packaging should use HDPE/PP, one-step "injection-blowing" process to produce polyolefin plastic containers; liquid drug filling should be used.

Plastic containers produced by the PET/PP "Note-Pu-Blow" process.

Second, medicinal plastic containers "note-blowing" molding equipment and mold

The structure includes: injection mold (initial mold), blow mold (forming mold), mold core rod (three groups), hot runner, sub-nozzle, de-cucking card, and core rod assembly.

Mold material, thermal expansion coefficient, surface finish, processing technology and precision, design level, debugging experience, especially the control of injection mold temperature have an impact on the quality of the final vial.