Investment Casting

Overview

PUNI produces precision investment castings (lost-wax / 熔模铸造) using low-temperature and middle-temperature wax patterns. The process delivers near-net-shape components with excellent surface finish and tight dimensional tolerances, minimising machining and material waste.

Process Features

• Low-to-medium temperature wax injection with both manual and automated pattern assembly
• Multi-layer ceramic shell building (typically 4-8 layers depending on weight and material)
• Steam autoclave dewaxing at 150-180°C for clean wax recovery
• Vacuum and gravity pouring through medium-frequency induction furnaces
• Heat treatment capabilities: normalizing, quenching & tempering, solution treatment

Equipment List

• 8 sets of wax injection machines (capacity 50-500 g per shot)
• 6 sets of ceramic slurry tanks with controlled humidity dipping rooms
• 3 sets of steam dewaxing autoclaves (1.5 m³ / 3 m³ / 5 m³)
• 4 sets of medium-frequency induction furnaces (250 kg / 500 kg capacity)
• Automated robotic pouring stations for consistent melt quality
• Vibratory finishing, shot blasting and grinding workstations

Capability Range

• Weight per piece: 0.05 kg to 80 kg
• Maximum dimension: 600 × 600 × 400 mm
• Dimensional tolerance: CT5-CT7 per ISO 8062 (DIN/equivalent)
• Surface roughness as-cast: Ra 3.2 - 6.3 μm
• Minimum section thickness: 1.5 mm (subject to material)

Materials We Cast

• Carbon steel & alloy steel (WCB, WCC, LCC, 16Mn, 20#-45#, 40Cr, 42CrMo)
• Stainless steel: 304, 316, 316L, 321, 2205 duplex, 17-4PH
• Heat-resistant steel: HK, HP series for high-temperature service
• Gray iron & ductile iron (HT200, HT250, QT400, QT500, QT600)
• Copper alloys: tin bronze, aluminum bronze, brass
• Aluminum alloys (limited size range)

Typical Applications

Valve bodies and bonnets, pump impellers and casings, marine hardware, architectural fittings, automotive structural parts, agricultural wear parts, food processing machinery components, and general industrial OEM components.

Our Strengths

• 20+ years of pattern-making experience reduces your tooling risk on new programs
• In-house metallurgical lab with spectrometer for incoming material verification and final chemistry check
• Integrated CNC finishing — castings ship to the same workshop for machining, eliminating transit time and quality risk
• Full traceability per heat number with MTC per EN 10204-3.1
• Engineering support for DFM optimisation (wall thickness, draft angles, parting line selection)

Quality Control

All castings are dimensionally inspected using CMM, with surface roughness verified on profilometer. Material certificates include chemistry and mechanical properties per ASTM/EN/JIS standards. Critical orders receive 100% inspection; standard orders receive AQL 2.5 sampling per ISO 2859-1.