I. Material BasicsPVC and CPVC are both thermoplastics; CPVC is chlorinated PVC with higher chlorine content (~67% vs ~56%).II. Key Differences (At a Glance)Feature PVC CPVCMax Temp 60°C (long-term 45°C) 110°C (long-term 95°C)Mechanical Strength Moderate Higher (tensile, flexural, impact)Flexibility...

CPVC fittings in service typically encounter five major issues: joint leakage, fitting cracking, environmental stress cracking, physical damage to the pipe body, and emergency leaks during operation. Joint leakage arises mainly from poor surface preparation, incorrect solvent cement, or insufficient curing time – solutions centre on thorough cleaning, using certified CPVC adhesives, and strictly observing cure schedules. Fitting cracking is often caused by low-temperature brittleness, installation-induced stress, or over-tightened threads; countermeasures include pre-heating in cold conditions, controlled insertion force, and proper threading practices. Environmental stress cracking results from chemical incompatibility, sustained mechanical stress, or UV degradation – addressing these requires checking chemical compatibility charts, installing expansion joints/loops, and applying UV-protective coatings. Physical damage usually stems from impacts, scratches, or substandard material quality – improved handling and selection of high-grade products are essential. For live-line leaks, a specialised on-stream repair clamp offers a quick and safe solution. In summary, the vast majority of CPVC fitting problems can be prevented by choosing quality materials, following standardised installation procedures, accommodating thermal movement, and protecting against environmental factors – thereby ensuring long-term reliability of the piping system.

Overview of PPR Pipe Fittings Applications PPR pipe fittings, short for Polypropylene Random Copolymer pipe fittings, are a new type of plastic fittings manufactured through injection molding using random copolymer polypropylene resin as the main raw material-13-2. Compared with traditional cast iron pipes, galvanized steel pipes, and cement pipes, PPR pipe fittings offer significant advantages including energy and material savings, environmental friendliness, lightweight with high strength, corrosion resistance, smooth inner walls that prevent scaling, easy installation and maintenance, and long service life-1-. They can withstand a maximum instantaneous temperature of 95°C and a long-term (50-year) service temperature of 70°C, with a service life of over 50 years under normal conditions-2-1. Thanks to these excellent properties, PPR pipe fittings are widely used in the following fields:

PVC pipe fitting molds are specialized tools for injection molding PVC connectors. Their quality directly determines fitting precision and piping system safety. Main types include elbow, tee, coupling, and reducer molds, classified by material as CPVC, UPVC, PPR, etc. They are widely used in building plumbing, agricultural irrigation, industrial transport, electrical conduits, and gas supply. Mold design must address PVC shrinkage compensation, venting, and heat sensitivity. Core components include mold base, core, gating, cooling, and ejection systems. Future trends focus on intelligentization, modular design, new materials, and green manufacturing. China’s Taizhou region has formed a major industrial cluster with global exports.

The main challenges in PVC pipe‑fitting injection molding stem from PVC’s poor thermal stability, narrow processing window, high melt viscosity, and tendency to generate shear heat. Mold‑related issues typically fall into five categories: gate cold‑slug marks, internal voids, corrosion and scaling, ejection deformation, and weak weld lines. A systematic approach to resolving these centers on four pillars: precise temperature control, adequate venting, optimized packing pressure, corrosion‑resistant materials, and proper ejection design. In practice, mold temperature should be kept at 40–60°C, melt temperature at 190–210°C, and packing pressure at 80–90% of injection pressure. Corrosion‑resistant steel or plated surfaces are recommended. Before each shutdown, the barrel must be purged with PS or PE, and the mold should undergo regular cleaning and stress‑relief treatment to reduce scrap rates and extend service life.

PP pipe fittings are widely used in water supply and drainage, HVAC, and industrial sectors due to their excellent corrosion resistance, electrical insulation, and long service life. Behind every high-quality PP pipe fitting, however, lies the precision engineering of its mould. Today, let’s explore several key technical aspects of PP pipe fittings moulds.