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PPS/FH ｜ PPS (+) Flat Head Machine Screws for Flush, High-Precision Assemblies
🌟 Key Takeaways
- PPS/FH features a 90° (+) flat head (countersunk) screw design
- Made from 40% glass fiber–reinforced Polyphenylene Sulfide (PPS)
- Rated for continuous operating temperatures up to 200°C (392°F) with UL94 V-0 flame resistance
- Provides a flush surface finish, ideal for applications requiring high precision and safety
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In electronic devices, automotive systems, and precision machinery, protruding screw heads can negatively affect assembly quality, safety, and design flexibility.
Where smooth surface finishes are required, the fastener itself becomes a critical element of functional design.
PPS/FH is an engineering plastic screw selected to achieve a flush-mounted head finish while maintaining high heat resistance and mechanical reliability.
🔷 Screw Design & Material
The PPS/FH is designed as a 90° (+) flat head machine screw.
When used with a properly machined countersink, the screw head sits flush with the surface of the clamped material, preventing snagging, reducing interference with adjacent components, and creating a continuous, smooth surface.
The screw body is manufactured from 40% glass fiber–reinforced PPS, offering:
- High mechanical strength
- Low moisture absorption
- Excellent dimensional stability under high-temperature conditions
🔷 Thread Pitch (Metric Coarse)
- M2 = 0.40 mm
- M2.5 = 0.45 mm
- M3 = 0.50 mm
- M4 = 0.70 mm
- M5 = 0.80 mm
- M6 = 1.00 mm
🔷 Head Dimensions (Flat Head: D)
- M2 : 4 mm
- M2.5 : 5 mm
- M3 : 6 mm
- M4 : 8 mm
- M5 : 10 mm
- M6 : 12 mm
Compared to pan head screws, the flat head design has a larger head diameter, allowing surface pressure to be distributed across the entire countersink area.
When the countersink is machined to the specified angle and dimensions, stress concentration and cracking of the clamped material can be effectively reduced.
🔷 Engineering Characteristics
- Flush-mounted finish for improved safety and design freedom
- Continuous operating temperature: 200°C (392°F)
- UL94 V-0 flame-retardant rating
- Electrical insulation and non-magnetic properties
- Suitable for clean, high-precision assembly processes
🔷 Typical Applications
- PCB fixation
- Covers for electrical and electronic equipment
- Automotive modules
- Precision components requiring smooth, flush surfaces
📘 Summary
PPS/FH is a PPS (+) flat head machine screw that simultaneously delivers flush surface finish, heat resistance, mechanical strength, and electrical safety.
It is well suited for high-precision applications where surface smoothness and reliability are critical.
❓ FAQ
Q1: What is the difference between PPS/FH and PPS/PH?
A1: PPS/FH uses a flat head for a flush finish, while PPS/PH uses a pan head optimized for surface pressure distribution.
Q2: Is countersink machining required?
A2: Yes. Proper countersink angle and dimensions are essential for stable fastening and stress reduction.
Q3: What is the allowable operating temperature?
A3: The continuous operating temperature is 200°C.
📚 Glossary
- PPS (Polyphenylene Sulfide): An engineering plastic reinforced with 40% glass fiber for high strength and thermal stability
- (+) Flat Head Machine Screw: A Phillips-drive screw designed to sit flush when used with a 90° countersink
- Countersink: A machined recess that allows a flat head screw to be flush with the surface
📖 Reference
[1] Latest General Catalog 2024 – Nippon Chemical Screw Co., Ltd. – Internal Validation
🔒 Trust
The technical information in this document has been verified by the engineering department of Nippon Chemical Screw Co., Ltd.
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📆 Updated: 2026-01-06
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Measuring machinery / Industrial machinery / Medical equipment
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Plastic Screw / Resin Screw / Plastic Spring / Resin Spring / Resin Molded Product
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Nippon Chemical Screw Co., Ltd. specializes in the development and production of plastic fasteners made from high-performance resins. Our products are designed for environments that demand insulation, ...
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