What are the design points of blow molding products in Dalian?

Dalian blow molding products have become an indispensable part of modern industrial production and daily life due to their high efficiency, flexibility, and low cost. With the continuous advancement of technology and changes in market demand, blow molding technology and products will continue to innovate and develop, providing higher quality and environmentally friendly solutions for various industries. In the future, the blow molding industry will make greater breakthroughs in environmental protection, intelligence, and high performance, making important contributions to the global economy and sustainable development.

Extrusion blow molding is a common blow molding process, suitable for producing hollow products such as bottles, cans, and barrels. Extrusion blow molding uses an extruder to melt plastic and extrude a tubular billet, which is then placed into a mold for blow molding. The injection molding blow molding process first melts the plastic through an injection molding machine and injects it into a mold to form a preform, which is then placed into a blow molding mold for blow molding. This process is suitable for producing high-precision, complex shaped products such as pharmaceutical bottles, cosmetic bottles, etc.

What are the design points of blow molding products in Dalian?

1、 Material selection: matching usage scenarios and process characteristics

1. Basic performance adaptation

Mechanical strength:

Choose high-density polyethylene (HDPE) or polypropylene (PP) for high load scenarios (such as industrial pallets) to enhance impact resistance;

Transparent packaging (such as beverage bottles) should be made of polyethylene terephthalate (PET) to balance transparency and puncture resistance.

Environmental resistance:

Outdoor products (such as trash cans) need to be added with anti ultraviolet (UV) additives to prevent aging and cracking;

Food contact scenarios (such as edible oil tanks) must use food grade raw materials (such as FDA certified PE) that meet safety standards.

Processing fluidity:

Choose materials with high melt index (MI) for complex shapes or thin-walled products, such as low-density polyethylene (LDPE), to enhance the filling ability.

2. Environmental protection and cost balance

Biodegradable materials such as PLA (polylactic acid) and PBAT (polybutylene terephthalate) are preferred;

Prioritize the use of recycled materials in low-cost scenarios (ensuring performance standards are met) to reduce raw material costs.

2、 Structural Design: Balancing Forming Feasibility and Functional Use

1. Wall thickness design: uniformity and stress optimization

Principle of uniform wall thickness:

To avoid insufficient inflation or rupture caused by local thinning (such as at bottlenecks), it is recommended to achieve a minimum wall thickness of 0.5mm;

The stress concentration areas (such as the bottom and shoulders of the container) should be appropriately thickened (by 10% to 20%) to improve the anti drop performance.

Gradient transition:

Arc transition (radius ≥ 2mm) is used in different wall thickness areas to avoid melt retention or uneven cooling caused by right angle turning.

2. Geometric shape and ease of demolding

Avoid complex concave structures:

Blow molding molds are split type, and concave structures can make demolding difficult. Therefore, simple cylindrical, spherical, or conical designs should be prioritized;

If special structures are required (such as threaded bottle caps), they can be achieved through secondary processing in the later stage (such as rotary melting, hot pressing).

Demoulding slope:

The demolding slope of the outer surface is ≥ 1.5 °, and the inner surface is ≥ 2 °, which facilitates the quick detachment of the finished product from the mold and reduces wear.

3. Strengthen the reinforcement and support structure

Design circular or axial reinforcement ribs on the inner wall of large containers (such as chemical storage tanks) to enhance their compressive performance;

Tray products adopt a honeycomb or grid shaped bottom structure, which not only reduces weight but also enhances load-bearing capacity (such as blow molded trays with a load-bearing capacity of 1-2 tons).

3、 Mold adaptation: ensure molding quality and production efficiency

1. Classification line design

Concealed location: Priority should be given to non visual surfaces (such as the side of the bottle or the bottom edge of the container) to avoid affecting the appearance;

Width control: The width of the parting line is ≤ 0.3mm. If it is too wide, it can easily produce burrs and increase post-processing costs.

2. Exhaust system optimization

Open exhaust holes (with a diameter of 0.5-1mm) at the high points of the mold cavity to prevent air retention, which can cause bubbles and material shortages;

Complex shaped molds can use gap exhaust (with a reserved gap of 0.02~0.05mm on the parting surface) to assist in air discharge.

3. Cooling system design

The mold needs to be evenly distributed with cooling water channels to avoid local overheating and prolonged molding cycle (such as controlling the temperature of the cooling roller for film blowing at 30-50 ℃);

Thick walled products can be cooled in sections, first rapidly cooling the outer layer and then slowly cooling the interior to reduce internal stress.

4、 Functional optimization: enhancing user experience and practicality

1. Human Machine Engineering Design

Handheld products (such as cosmetic bottles):

The bottle body is designed with anti slip patterns or concave convex surfaces to enhance grip comfort;

The bottle cap adopts an easy to open structure (such as flip cover, rotating buckle) to reduce the difficulty of use.

Industrial containers:

Set up a diversion port or pouring angle (such as a 45 ° inclined port) at the top to facilitate liquid pouring;

Large storage tanks are equipped with flange interfaces or liquid level observation windows to meet functional requirements.

2. Surface treatment and printing

Matte and frosted surfaces can be achieved through mold textures to enhance texture (such as high-end cosmetic bottles);

Reserved printing area for packaging products (with a flat surface and no dents) for easy screen printing or hot stamping of logos in the later stage.

Blow molded bottles and containers are the main forms of food packaging, such as beverage bottles, edible oil bottles, seasoning bottles, etc. PET bottles have become the main choice for beverage packaging due to their transparency and hygiene. Blow molded products are used in the pharmaceutical industry to produce medicine bottles, eye drops bottles, infusion bottles, etc. Its high precision and hygiene ensure the safety and stability of the drug.

Choose suitable thermoplastic materials such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), etc. Heating plastic particles or powders through an extruder or injection molding machine to a molten state, forming tubular or sheet-like plastic blanks. Place the melted plastic blank into the mold and inflate it with air pressure to make it tightly adhere to the inner wall of the mold, forming the desired shape.