Screw Plugs for Plastic Mold

Name: Screw Plugs for Plastic Mold — JIS Standard Hex Socket | Long & Seat Type
Brand: Axiom Molds
Availability: InStock
Rating: 4.9 (128 reviews)

JIS standard hex socket screw plugs for sealing cooling channels, fluid passages, and access ports in injection molds. Available in long type (deep-seated) and seat type (flush-mounted) configurations.

Screw Plugs

Long Type Hex Socket Screw Plugs — JIS Standard

Deep-seated hex socket screw plugs for cooling channel sealing. Longer thread engagement for higher pressure rating.

JIS Standard Screw Plugs — Hex Socket Seat Type MSWZ

Seat Type Screw Plugs — MSWZ Series

Flush-mounted hex socket screw plugs with seat sealing structure. MSWZ series for controlled sealing in compact spaces.

Long Type vs Seat Type Screw Plugs

Feature	Long Type	Seat Type (MSWZ)
Thread Length	Extended (2-3x nominal diameter)	Standard (1-1.5x nominal diameter)
Sealing Method	Thread interference + sealant	Seat face contact + thread
Pressure Rating	Higher (more thread engagement)	Standard (seat provides additional seal)
Installation Depth	Deep (plug sits below surface)	Flush (plug face aligns with mold surface)
Best For	High-pressure cooling circuits, deep ports	Surface-accessible ports, frequent maintenance

Selection rule: Use long type for cooling channels operating above 1.0 MPa water pressure. Use seat type when the plug must be flush with the mold surface or when frequent removal for maintenance is expected.

📖 In-Depth Technical Guide: Read our full analysis onHow to Seal Cooling Channels with Screw Plugs →

Application Scenarios

Cooling Channel End Sealing

Pain point: Gun-drilled cooling channels require reliable end sealing that withstands coolant pressure and thermal cycling.

Why it fits: Long type screw plugs with PTFE sealant provide leak-proof sealing even under 1.5 MPa coolant pressure and temperature cycling between 10-120°C.

Maintenance Access Ports

Pain point: Flush access ports for cleaning or inspection require easy removal without damaging the port threads.

Why it fits: Seat type MSWZ plugs provide reliable sealing with lower torque requirements and are designed for repeated installation/removal without thread degradation.

Engineering Resources

Application Guide

How to Seal Cooling Channels — Screw Plug Guide

Thread selection, sealant application, and pressure testing procedures.

Frequently Asked Questions

What thread sealant should I use with mold screw plugs?+

PTFE tape (3-4 wraps clockwise) is the standard for water cooling circuits up to 120°C. For oil-based temperature control units (>120°C), use anaerobic thread sealant rated for the operating temperature. Never use silicone sealant — it can contaminate the cooling circuit and clog small passages.

How do I determine the correct screw plug thread size?+

Measure the tapped port diameter and pitch with a thread gauge. JIS screw plugs follow standard metric thread sizes (M8 to M30). The most common sizes for mold cooling channels are M10x1.0, M12x1.5, and M16x1.5.

Can screw plugs be reused after removal?+

Yes, if the threads are undamaged. Clean old sealant from both the plug and port threads before reinstallation. Apply fresh sealant and torque to specification. If threads show galling or cross-threading damage, replace the plug.

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