PVC Pipe Fittings Types and Injection Mold Design

In modern fluid delivery systems, PVC pipe fittings have become core components in building drainage, industrial pipelines, agricultural irrigation, etc. due to their light weight, high strength, corrosion resistance, and low cost. As a key node in the pipeline network, the types of joints for PVC pipe fittings are constantly enriched. From equal-diameter tees to reducing elbows, from flange interfaces to flexible sockets, each type of joint carries a specific functional mission and together weaves into the "nerve network" of the pipeline system.

This article will start from the classification and function of PVC pipe fittings, analyze the key requirements of its structural characteristics on mold design, and discuss the technical difficulties and solutions in the injection molding process based on typical cases.

PVC pipe fittings are also called pipe connectors. It is a removable fitting that connects two pipes or tubes. Different types of PVC fittings have unique applications and uses.

A pipe coupling is a short pipe or tube with a socket or thread at one or both ends. It is used to repair, modify or connect pipes of different materials or sizes between two sections of pipes.

In the pipeline system, a "tee" is a fitting that connects three pipes, while a "cross" is a fitting that connects four pipes, forming an intersection or intersection

Elbows are mainly used to change the flow direction of the pipeline and connect pipes of different or same diameters. The angles are usually 90 degrees, 45 degrees, and 180 degrees. Pipe turning is achieved through specific angles to adapt to the requirements of building structure or space layout.

Reducer is a key component in the pipeline system used to connect two sections of pipes or pipe fittings of different diameters. Through tapering (concentric reducer) or eccentric structure (eccentric reducer), the flow rate and pressure distribution are adjusted to reduce the risk of cavitation or liquid accumulation.

End Cap is a fitting used to seal the end of a pipe in a pipe system to prevent fluid leakage, foreign matter from entering, or contaminants from escaping. The pipe cap is removable, which is convenient for later maintenance or access to equipment.

Flange connects two sections of pipes tightly by fastening the flange and bolts to form a stable and sealed pipe system. The removability of the flange facilitates later maintenance. It is often used to connect water pumps, valves and other equipment.

The design of the pipe fitting port is a socket or a spigot. During installation, evenly apply solvent-based glue on the joint surface of the socket and the spigot to make the pipe fitting and the pipe firmly connected. This connection method is relatively simple and suitable for quick installation on site.

The pipe and the joint are tightly connected through the bite of the thread to form a stable pipeline system. The pipe and the joint are tightly connected through the bite of the thread to form a stable pipeline system. Its main features: easy connection, easy disassembly, and good sealing.

The union is a common component used to connect two sections of pipelines in the pipeline system. Its core feature is to provide flexible installation and disassembly solutions, making pipeline maintenance, replacement or system modification more convenient, thereby reducing maintenance costs and time costs.

The push-fit is a device that can quickly connect or disconnect pipelines without tools. It is widely used in hydraulic, pneumatic, cooling systems and other fields. Its core advantage lies in efficient and convenient disassembly and assembly capabilities.

Avoid damage to key structures: The parting surface should avoid functional areas such as the thread and sealing surface of the joint to prevent precision reduction or appearance defects when opening and closing the mold.

Simplify the core pulling structure: For complex joints, the parting surface design should be combined with the core pulling mechanism to reduce the side core pulling stroke and improve the stability of the mold.

Female thread forming: The internal thread is demoulded by rotating the core pulling rod to avoid thread deformation.

Side hole structure processing: An inclined guide column or a hydraulically driven slider is used to complete the lateral core pulling of the side hole or branch pipe to ensure that there is no residual burr after forming.

Cold runner: low cost, suitable for small joints or low precision requirements, but the runner condensate waste needs to be considered.

Hot runner: reduces material waste, suitable for multi-cavity molds or high-precision joint production, but the initial investment is large.

Avoid weld marks: The gate should be set at a place where the joint wall thickness is uniform to avoid weld marks when the plastic flows.

Multi-gate balance: For large joints, use multiple gates for symmetrical feeding to reduce shrinkage deformation.

Conformal water channel: The cooling water channel is designed along the joint contour to ensure uniform cooling of uneven thickness parts (such as elbow corners) and reduce internal stress.

Parameter control: Water channel diameter 6-12mm, 1.5-2 times the water channel diameter from the mold surface, and the water flow speed is controlled at 2-5m/s.

Wear-resistant steel: such as H13 (heat-treated hardness HRC48-52), to resist PVC corrosive gas and injection impact.

Surface strengthening: nitriding or hard chrome plating is used to improve the wear resistance of the cavity surface and extend the life of the mold.

Low-cost solution: non-critical parts (such as mold frames) can use pre-hardened steel (such as P20) to reduce overall costs.

High-precision parts: alloy steel (such as NAK80) is used for cores and cavities, taking into account both polishing performance and durability.

Pipe fittings are the "joints" of the pipeline system, and their functions are multi-dimensional: from basic connection and sealing to advanced flow control, layout optimization, and system maintainability and standardization improvement. With the development of industrial technology, pipe fittings are constantly innovating (such as quick connectors and intelligent monitoring connectors), further expanding their application value in the fields of automation and high precision.