TF COMBO BAG (Thermally Formed Combo Bag)

TF Combo Bag is a one-piece thermoformed integrated fiberglass filter and flow control bag, specially engineered for high-standard molten aluminum purification used in permanent mold casting, gravity die casting, and vertical DC billet casting.

Unlike traditional manually sewn filter bags, the TF Combo Bag adopts full hot-press integral molding technology. There are no sewing threads, stitching gaps or loose fiber residues on the whole bag body. The bag is impregnated with imported high-temperature smokeless phenolic resin and treated by high-pressure carbonization. This treatment delivers permanent shape fixation, excellent high-temperature rigidity, oxidation resistance, and ultra-low smoke emission during aluminum pouring.

1. Raw Material Composition & Grade Standard

● Base material: Premium alkali-free E-glass fiber woven fabric with low iron content

● Double-layer composite construction:

      1. Outer layer: Thick high-tensile fiberglass mesh for large slag interception and structural support

      2. Inner layer: Fine uniform mesh for deep filtration of micro inclusions

● Impregnating agent: Low-smoke flame-retardant modified phenolic resin, casting grade compliant with European standards

● Production workflow: Dipping → high-temperature drying → high-pressure thermoforming → secondary carbonization curing → final hardening

● The formulation strictly controls iron content and volatile substances. It brings no secondary contamination to molten aluminum, with no black smoke, strange odors or fiber shedding under high casting temperatures.

2. Core Physical & High-Temperature Performance Parameters

● Maximum continuous working temperature: 1000°C

● Instant temperature resistance: up to 1150°C

● High-temperature rigidity retention: maintains shape for 90–120 minutes in molten aluminum at 720–760°C

● Tensile strength (dry and hot state): ≥8.5 kg per strand, no deformation or expansion under long-term scouring of molten metal

● Filtration precision range: 5μm–50μm

● Standard mesh aperture: 1.5×1.5mm / 2.0×2.0mm / 2.5×2.5mm

● Liquid permeability: consistent flux, no localized clogging and stable flow rate of molten aluminum

● Combustion property: low smoke, non-flammable, no dripping residues

3. Structural Design Principle: Combo Multi-Function Integration

The term "Combo" stands for three core functions combined within one single product:

● Filtration: Double-layer gradient filtration removes alumina slag, oxide films, suspended particles and tiny non-metallic inclusions.

● Flow stabilization: Integrated cavity structure eliminates liquid turbulence, splashing and swirling flow of molten aluminum.

● Diversion & distribution: Optimized internal channels enable even mold filling, balance temperature differences and improve the consistency of finished castings.

The seamless monolithic structure completely solves common defects found in traditional sewn bags: thread shedding, floating fibers and slag leakage through stitching gaps.

4. Key Advantages Over Traditional Sewn Filter Bags

1. Zero inclusion-related defects:

Without sewing threads or loose fibers, threads will not break under high heat.

It fundamentally prevents thread residues from mixing into molten aluminum, which causes pinholes, slag holes and blowholes in wheel hubs and castings.

2. Sustained three-dimensional rigidity at high temperature:

Conventional soft sewn bags soften, expand, sag or deform once exposed to hot aluminum liquid, resulting in unstable flow and sudden slag leakage.

TF thermoformed bags retain their full 3D shape throughout the whole casting cycle.

3. Ultra-low smoke and eco-friendly pourin:

Formulated with low-volatility carbonized resin.

It generates almost no smoke or pungent odor during pouring and meets EU environmental standards for manufacturing workshops.

4. No preheating required for higher efficiency:

Great thermal shock resistance. It can be installed and used directly without preheating, reducing process steps and shortening casting cycle time.

Uniform flow and suppressed oxidation.

It restrains liquid turbulence and reduces secondary oxide slag formation, greatly improving casting surface finish and internal compactness.

5. Industrial Application Scenarios:

● Gravity casting of aluminum alloy automotive wheel hubs

● Casting of automotive engine blocks, cylinder heads and aluminum brackets

● Vertical DC casting of aluminum billets, round bars and flat ingots

● Low-pressure die casting and precision aluminum casting

● High-end aluminum profiles and semi-finished aerospace aluminum castings

6. Customization Capability

● Full-size customization: inch and metric dimensions to match customer launders and molds

● Custom mesh density and double-layer matching ratio

● Custom diversion nozzles, bottom holes and side hole structures

● Custom hardness and rigidity holding time

● OEM logo printing and neutral export packaging

● Reinforced high-temperature version available for long-cycle casting

7. Quality Certification & Industrial Standards

Compliant with international casting industry specifications:

✅ISO 9001 Quality Management System

✅ISO 14001 Environmental Management System

✅ISO 45001 Occupational Health and Safety Management System

✅All raw materials are tested with MSDS safety data sheets