China OEM custom lost foam casting products of gray cast iron according to your drawings and requirements (chemical composition of the material, required mechanical properties, tolerances, heat treatment and surface treatment), used for heavy duty truck gear box cover.
Lost Foam Casting, also called Lost Foam Casting (LFC) or Full Mold Casting, is a kind of Evaporative Pattern Casting (EPC) with dry sand casting process. The EPC is sometimes could be short for Expendable Pattern Casting because the lost foam patterns could be used only once. After the foam patterns are finished by special machined, then the foamed plastic patterns are coated with refractory coating to form a strong shell to withstand the molten metal. The foam patterns with shells are put into the sand box, and fill it with dry sand sand around them. During pouring, the high-temperature molten metal makes the foam pattern pyrolyzed and “disappears” and occupies the exit cavity of the patterns, and finally the finished desired castings are obtained.
| Lost Foam Casting vs Vacuum Casting | ||
| Item | Lost Foam Casting | Vacuum Casting |
| Suitable Castings | Small and medium-sized castings with complex cavities, such as engine block, engine cover | Medium and large castings with few or no cavities, such as cast iron counterweights, cast steel axle housings |
| Patterns and Plates | Foam patterns made by moldings | Template with suction box |
| Sand Box | Bottom or five sides exhaust | Four sides exhaust or with exhaust pipe |
| Plastic Film | The top cover is sealed by plastic films | All sides of both halves of sand box are sealed by plastic films |
| Coating Materials | Water-based paint with thick coating | Alcohol-based paint with thin coating |
| Molding Sand | Coarse dry sand | Fine dry sand |
| Vibration Molding | 3 D Vibration | Vertical or Horizontal Vibration |
| Pouring | Negative Pouring | Negative Pouring |
| Sand Process | Relieve negative pressure, turn over the box to drop sand, and the sand is then reused | Relieve negative pressure, then the dry sand falls into the screen, and the sand is recycled |
Cast iron is an iron-carbon cast alloy with other elements that is made by remelting pig iron, scrap, and other additions. For differentia- tion from steel and cast steel, cast iron is defined as a cast alloy with a carbon content (min 2.03%) that ensures the solidification of the final phase with a eutectic transformation. Depending on chemical specifications, cast irons can be non- alloyed or alloyed. The range of alloyed irons is much wider, and they contain either higher amounts of common components, such as silicon and manganese, or special additions, such as nickel, chromium, aluminum, molybdenum, tungsten, copper, vana- dium, titanium, plus others. Generally speaking, the cast iron could be divided into gray iron, ducitle iron (nodular iron), white cast iron, compacted graphite iron and malleable cast iron.
The Steps of Lost Foam Casting：
1- Use foam molds to produce foam patterns and casting gating systems
2- Bond the patterns and runners to form a mold bundle module
3- Dip paint on the module
4- Dry the paint
5- Put the module into the sand box and fill it with dry sand
6- Vibrate molding in order to fill the cavity with dry sand and then compact the molding sand
7- Pouring molten metal to vaporize the foam and then forming the desired castings
8- After the castings have cooled, clean the castings. The dry sand can be recycled
Advantages of Lost Foam Casting：
✔ Greater design freedom for complex structural castings
✔ No draft angle is needed to save lots of cost.
✔ Function integrated foam patterns could be assembled from several pieces of foam patterns.
✔ Lost foam castings are near-net-shape process
✔ High flexibility through short set-up times
✔ Longer EPS mould service lives, hence lower proportionate tool costs
✔ Assembly and treatment costs are reduced by the omission of the treatment process, installation parts, screw connections, etc.
✔ Expansion of the scope of applications
Metals and Alloys Could Cast by Lost Foam Casting Process：
• Gray Cast Iron, Ductile Cast Iron
• Carbon Steel: Low carbon, medium carbon and high carbon steel
• Cast Steel Alloys: Low alloy steel, high alloy steel, special alloy steel
• Aluminium and their alloys
• Brass & Copper.
Industries The Lost Foam Castings Used For：
Just as mentioned above, the lost foam casting is specially suitable to produce the large and thick-wall castings. They are serving mostly the trucks, railroad trains, construction machineries and other heavy machineries with the requirements of complex structure of the desired castings.
Casting Tolerances Reached by Lost Foam Casting Process：
Generally speaking, the casting tolerances of lost foam castings are better than sand casting, but worse than shell mold casting and no-bake casting processes. For our foundry, we basically could achieve the following casting grades. But we would like to talk with you the specific castings and then decide what numbers we can provide for you.
✔ DCT Grade by Lost Foam Casting: CTG9 ~ CTG13
✔ GCT Grade by Lost Foam Casting: CTG5 ~ CTG8
| Production Process | Annual Capacity / Tons | Main Materials | Casting Weights | |
| Sand Casting | 6000 | Gray Iron, Ductile Iron, Aluminium, Brass | 0.3 kg to 200 kg | |
| 0.66 lbs to 440 lbs | ||||
| Lost Foam Casting | 4000 | Gray Iron, Ductile Iron, Steel Alloys | 10 kg to 300 kg | |
| 22 lbs to 660 lbs | ||||
| Investment Casting (Lost Wax Casting) | Water Glass Casting | 3000 | Carbon Steel, Steel Alloys, Stainless Steel, Brass | 0.1 kg to 50 kg |
| 0.22 lbs to 110 lbs | ||||
| Silica Sol Casting | 1000 | Carbon Steel, Steel Alloys, Stainless Steel, Brass | 0.05 kg to 50 kg | |
| 0.11 lbs to 110 lbs | ||||
Foam Patterns for Casting
Lost Foam Casting Pattern
Post-Machining Services
Ductile Iron Machining Products
