Insert molding for PVC fittings

Insert Molding for PVC Fittings

Our insert molding molds for PVC fittings are built to handle the tricky combination of soft PVC and rigid brass inserts, and they are designed to do it reliably, run after run.

Mold Material

We use premium mold steels depending on your production volume. For general runs, we go with P20 or 718H. For higher volumes or more abrasive PVC compounds, we step up to S136 or H13 with nitriding treatment. Brass inserts sit in hardened cores and locating pins, so they stay accurate over millions of cycles.

Mold Type

These are typically horizontal injection molds with a two-plate or three-plate structure. Because the brass insert has to be held precisely during injection, we often use a slider, lifter, or specially designed insert-holding mechanism. For high-volume jobs, we recommend a hot runner system to cut waste and keep cycle times short.

Equipment Parameters

• Clamping force: 80–250 tons
• Injection pressure: 80–150 MPa
• Melt temperature: 170–190°C for PVC
• Mold temperature: around 40°C
• Brass insert preheat: 110–130°C
• Injection speed: slow, screw surface velocity 0.15–0.2 m/s
• Packing pressure: applied for 3–4 seconds

Application Scenarios

These molds are mainly used for PVC fittings with brass inserts—think water pipe connectors, elbow joints, tees, couplings, faucet adapters, irrigation fittings, and industrial fluid line connectors. Anywhere you need a strong, leak-free threaded connection molded right into the plastic part.

Process Advantages

Insert molding gives you a real chemical and mechanical bond between the PVC and the brass insert. That means the joint is strong—no spinning, no pull-out. It is also sealed tight, so no leaks under pressure. And since the brass is fully encapsulated, it resists corrosion far better than an exposed metal thread. The result is a fitting that is durable, reliable, and built to last.

Our Advantages

• Mold Design: We engineer insert-holding features, cooling layout, and gating specifically for PVC + brass, so you get consistent filling and no insert shift.
• CNC Machining: Our in-house CNC shop holds tight tolerances on cavity, core, and insert seats—critical for a leak-free fit.
• Quality Control: We inspect every mold with CMM, check insert fit and alignment, and run sample shots to verify bonding, sealing, and dimensional accuracy before shipping.
• If you are interested, contact us by Email: contact@yxplasticmolding.com