Lost foam-casting-process-implementation-challenges - SlideShare

• 1. Lost Foam Casting Implementation Challenges Sunil Mohite, Jayshree Machines & Tools, www.foamcast.in foamcast
• 2. Variants of the Lost Foam Process • Vacuum Lost Foam Casting (V-LFC) • Lost Foam Sintered Shell Process (LFS2/foamcast®/Replicast®) • Full Mold Casting Process (FMC) • foamcast® is the registered of Jayshree Machines & Tools, India • Replicast® is the registered of Castings Technology International, UK www.foamcast.in foamcast
• 3. Brief Process Steps V-LFC | LFS2/foamcast | FMC Process Comparison between all variants of LFC foamcast
• 4. Vacuum Lost Foam Casting (V-LFC) www.foamcast.in foamcast
• 5. Lost Foam Sintered Shell Process(LFS2/foamcast) www.foamcast.in foamcast
• 6. Full Mold Casting Process (FMC) www.foamcast.in foamcast
• 7. Process Comparison Vacuum Lost Foam Casting (V-LFC) Lost Foam Sintered Shell Process (LFS2/foamcast®) Full Mold Casting Process (FMC) Pattern Media EPS/STMMA Foam EPS Foam EPS Foam Pattern Mfg. Process Foam Injection Mold Foam Injection Mold Fabrication of Foam Foam Pattern Density 18-20.0 Kgs/m3 45.0 Kgs/m3 18-20.0 Kgs/m3 Foam Pattern Coating Single Coat Multiple Coats + Stuccoing Single Coat Shell Sintering Not Required Firing in furnace @ o C Not Required Silica Sand Free Flow 30 AFS Free Flow 45 AFS Free Flow 45 AFS Sand Compaction Required Required Required Vacuum Required Required Required Suitable for Metals that allow Carbon, CI, DI, GI & Aluminium Stainless Steels, Carbon Sensitive Alloys, All Ferrous & Non-Ferrous CI, DI, GI & Aluminium Typical Castings Auto parts, Pumps, Valves & Pipe Fittings Aerospace, Propulsion, Flow Control, Pumps & Valves Automobile Press Dies, Machine Tools Casting Weight Range 5 to 250 kg. net wt./piece 40 to 2,500 kg. net wt./piece ≥ 100 kg. net wt./piece www.foamcast.in foamcast
• 8. Questions that every foundry asks Which castings should be produced using LFC? Why LFC has not replaced traditional processes?* foamcast
• 9. Which castings should be produced using LFC? • Castings produced using the lost foam process should ideally be sold as machined castings regardless of alloy I. Due to process advantages lost foam castings are lighter in weight as compared to other casting process. Features like casting with holes, without draft angles, reduced machining allowance, etc. reduce the weight of the casting II. Therefore if you are selling castings by weight you are not able to unlock the true value of the casting which machining can. Furthermore due to lesser machining allowances, machining time is saved which in turn reduces tool wear out • Stainless Steels or some carbon sensitive alloys are materials which generally are a challenge to pour in most foundry processes. However in LFS2 it is not as challenging • Parts with a high core to metal ratio are suitable however not all. Classic example is Brake Disc, it has high core to metal ration but still it is viable in DISA line not LFC • Valve Bodies, Pump Casings and Impellors are ideal castings for LFS2 process www.foamcast.in foamcast
• 10. Why LFC has not replaced traditional processes?* • It is not cost effective to cast all castings in LFC • There many castings that are viable specific to process like: I. Crankshaft or brake disc the most economical method is using green sand in a DISA line II. For a simple Hub, Green Sand molding in a normal horizontally parted molding line is economical III. Likewise for forklift counter weight casting VPC is suitable • Even in China there are large foundries still using operating using the sand casting process *Siamak Khalichi www.foamcast.in foamcast
• 11. Commercial Challenges Investment in Foam Pattern Molding Setup Lost Foam Pattern Mold Cost Difficult to arranging Lost Foam Foundry Visit Lost Foam Pattern Mold Cost foamcast
• 12. Investment in Foam Pattern Molding Setup • To begin with foam pattern molding has to be a in-house process you cannot outsource foam patterns • It is the most critical process of Lost Foam process and is a multistage process where the bead is pre-expanded first and then injected in mold • Lost foam pattern molding is not like Thermocole packaging molding. The process is similar but for foam pattern molding there a many parameter that need strict control which are insignificant for Thermocole packaging molding. • One of the most critical parameter that requires critical machinery and process control is the foam bead pre-expansion process which determines the density of the foam pattern • Without precise and consistent density control there can be many casting defects in the foam pattern www.foamcast.in foamcast
• 13. Difficult to arrange Lost Foam Foundry Visit • Seeing is believing, most foundry owners prefer to see the process live in the flesh, which is not possible • Lost Foam foundry owners are worried that the visiting foundry owners focus is not limited to the lost foam process and they are worried that their productions process & methods are at risk • It is a general perception in casting buyers mind that lost foam castings are cheaper to produce and expect foundry to pass entire cost saving benefit to them. • Therefore many foundries using lost foam do not publicize their lost foam casting capability. They do not sell their casting as “lost foam casting” so that the buyer does not further negotiate pricing this is common with investment casting foundries having lost foam process www.foamcast.in foamcast
• 14. Lost Foam Pattern Mold Cost • The die/tool/mold used for molding the foam pattern is made from aluminum and is similar to investment casting tool. However the lost foam tool is hollow to pass steam and the investment casting tool is solid to transfer heat. • Although the Lost Foam Process is coreless the aluminum tools that mold the foam pattern have cores. • The tool development cost is approx. 15-20% more than an aluminum pattern with core box which is used in the sand casting process • Aluminum tools are required for each casting like-wise in any foundry process you require wood/aluminum patterns in any process • Even though the development cost is high the tool life too is infinite (subject to proper preventive maintenance) unlike wood/aluminum patterns which require replacement due to wear out caused by the sand www.foamcast.in foamcast
• 15. Technical Challenges Critical Castings in VLFC require STMMA Lost Foam Process Cost foamcast
• 16. Critical Castings in VLFC require STMMA • The pattern raw material used is all lost foam processes is EPS – Expandable Polystyrene which is a petroleum product high in carbon • A novel material STMMA – Styrene Methyl Methacrylate which is a co-polymer and has very low carbon content is now available to foundries for molding foam patterns • Prevention is better than cure. Particularly the VLFC & FMC process requires lot of process controls to tackle the issue of carbon generated by EPS during the pouring stage. These can be easily negotiated if STMMA is used instead of EPS. • However the cost of STMMA is over four times higher than EPS and the material has to be imported from Japan/Europe www.foamcast.in foamcast
• 17. Lost Foam Process Cost • Process cost of VLFC including the cost of STMMA at 75% yield is approx. Rs. 20.0/Kg of finished casting • Process cost of LFS2/foamcast® at 60% yield is Rs. 40.0/Kg of finished casting • Above costs do not include metal melting and fettling/finishing cost • Important to note here that the salvage cost of the castings is negligible as compared to other foundry processes • It is very unfair that many foundries do not count casting salvage cost which the foundry has to spend in the form of welding and chemical impregnation to make the casting saleable • If you sell machined castings the incremental process cost can easily be absorbed by the savings achieved in the machining process www.foamcast.in foamcast
• 18. Current Status of Lost Foam Process in India Lost Foam Foundries in India Failed Attempts at setting up LFC plants foamcast
• 19. Lost Foam Foundries in India • It is still believed that Lost Foam is a new process to India but it is not • We ourselves have installed 12 plants in India with first one being PTC Industries, Lucknow in • Some of the foundries like Kirsloskar Brother Ltd., Kirloskarwadi and SAM Turbo Pumps P Ltd., Coimbatore are captive foundries • Foundries having investment casting process have added lost foam process like Castech Foundries P Ltd., Junagadh, Sri Alka Industries, Ahmedabad and Amruta Industries, Kolhapur • Sand casting foundries have also added lost foam process like Sueera Global Alloys P Ltd., Coimbatore and Gujrat Metal Casting Industries Ltd., Vadodara www.foamcast.in foamcast
• 20. Failed Attempts at setting up LFC plants • The first failed attempt at LFC was by Alexcon Foamcast Ltd., Khopoli. The equipment was imported for Vulcan Engineering, US. • The foundry was way ahead of its time and stopped operations in -98 due to financial difficulties and NOT PROCESS FAILURE • Some foundries and Pune, Kolhapur & Raipur regions imported Chinese equipment from different manufacturers after doing some online research/visit to China. The equipment manufactures chosen were not able to support the buyers technically due to lack of knowledge of the process and language difficulties. • A foundry in Karnataka tried to setup a lost foam foundry by importing the foam patterns, which was not viable www.foamcast.in foamcast
• 21. How to implement the Lost Foam Process? Selection of correct variant of lost foam Selecting a suitable part & sizing of plant capacity Investing in the right machinery foamcast
• 22. Selection of correct variant of lost foam • The three variants of lost foam are V-LFC, LFS2/foamcast & FMC • V-LFC & LFS2/foamcast are the only two suitable for mass production of castings • V-LFC is suitable for metals that allow Carbon, CI, DI, GI & Aluminium • However it is advisable to use STMMA instead of EPS to reduce the number of parameters required for process control • If availability/cost of STTMMA is a concern EPS can be used however you will have to select the castings accordingly. • If EPS is used there is failure in thin wall (≤ 6mm)/critical V-LFC casting • LFS2/foamcast is suitable for all metals especially Stainless Steels • Exothermic sleeves can be used for pouring in LFS2/foamcast • Methoding/gating is similar to sand casting in LFS2/foamcast and can be further optimized using software to improve yields • All raw materials required for LFS2/foamcast are abundantly available in India www.foamcast.in foamcast
• 23. Selecting a suitable part & sizing of plant capacity • Part that is in production in foundry should be selected for migration to LFC • The advantage of selecting proven part is you need not experiment with the methoding of the casting • Ideally part in the weight range of 10-100kgs. is suitable for trial • Implementing of LFC becomes faster & easier if trial time is short • Ideally to start with a plant capacity of 100MT/Month is sufficient to produce desired casting quality and prove productivity of part • Plant capacity can be designed for scaling up within short time • Green field stand alone lost foam casting projects should be avoided • It is better to implement lost foam process in existing foundry parallel with running process to reduce cost of initial investment • After success of Lost Foam Process suitable castings can be selected from existing process for migration to LFC www.foamcast.in foamcast
• 24. Investing in the right machinery • Machinery selection is critical and key to success of LFC, especially foam processing and molding equipment • Equipment used for molding packaging material is not suitable for LFC • Pre-Expansion machines should be able consistently produce desired density of expanded bead • Foam Molding machine should be able to handle multiple cores in aluminum tool to keep gluing of pattern to minimum requirement • Vacuum Flask/Molding Boxes should be designed for hassle free maintenance since sand is prone to clogging in vacuum chamber • Vibrating station should be programmable so that cycles can be set and saved based on casting types to avoid damage to patterns • Proper sand handling equipment should be designed to maintain sand temperature, remove lumps & dust www.foamcast.in foamcast

Lost foam casting is an innovative and cost-effective casting process that has gained popularity in recent years due to its ability to create highly precise and complex parts quickly. By using a foam pattern that is coated in a ceramic shell and then melted away. This process eliminates the need for expensive tooling and produces near-net-shape parts with exceptional quality and accuracy. In this article, we will take an in-depth look at the lost foam casting process, its advantages, and how it compares to other casting methods.

Goto Ruiou to know more.

What is Lost Foam Casting?

In lost foam casting, a foam pattern is used to create a mold for metal parts. The foam is first sculpted into the desired shape and then coated in a ceramic material, which hardens to create the mold. The mold is then filled with molten metal, causing the foam to vaporize and be replaced by the metal. With the ability to eliminate the need for expensive tooling, foam casting has become an increasingly popular method of creating intricate and complex parts with high accuracy. In addition to its precision, foam casting is also known for being a cost-effective and eco-friendly casting process that has found widespread use in various industries such as automotive, aerospace, and marine engineering.

Lost Foam Casting Process

This casting process is a manufacturing process that has gained popularity due to its precision, cost-effectiveness, and eco-friendliness. In this process, a foam pattern is used to create a mold for casting metal parts. The pattern is first cut to the required shape and then coated in a ceramic material, which hardens to form the mold. Molten metal is then poured into the mold, causing the foam to vaporize and be replaced by the metal. The process eliminates the need for expensive tooling, and the resulting parts are of exceptional quality and accuracy. Because of its advantages, Foam casting is widely used in various industries, including automotive, aerospace, and marine engineering.

The following are the process steps of the Foam Casting Process

Process Steps of Foam Casting

The foam Casting process has basically nine process steps.

Here we are describing one by one process steps. You can follow these steps when you use this casting process.

Pattern Creation

The process of creating a foam pattern involves shaping or carving expanded polystyrene (EPS) foam into the desired shape, resulting in an exact replica of the final desired product.

Pattern Assembly

If necessary, the foam pattern can be assembled with other foam components to create a more complex pattern. Foam-friendly glue or adhesive is utilized to securely join the foam pieces together.

Pattern Coating

After assembling the foam pattern, a refractory material, such as a ceramic slurry or refractory coating, is applied to coat it. This coating serves to create a protective layer around the foam pattern during the casting process.

Mold Formation

Once the foam pattern is coated, it is embedded in a casting flask. The casting flask is then filled with unbonded sand or another refractory material. The sand serves the purpose of supporting the foam pattern and providing stability during the casting process.

Foam Pattern Removal

By heating the mold to a high temperature, the foam pattern within the mold vaporizes. This vaporization process leads to the escape of gases, which, in turn, creates channels within the mold. These channels serve the purpose of allowing the molten metal to flow into the mold during the casting process.

Metal Pouring

After removing the foam pattern from the mold, the mold is prepared for metal pouring. The molten metal is then poured into the mold through the sprue, effectively filling the cavity that was left behind by the vaporized foam pattern.

Cooling and Solidification

Once poured, the molten metal fills the mold cavity and initiates the cooling and solidification process. The duration of cooling varies, depending on factors such as the type of metal being used and the complexity of the casting.

Shakeout and Finishing

Once the metal has completely solidified, the mold is broken or shaken to remove the sand and reveal the cast metal part. The cast part may require additional finishing processes, such as trimming, grinding, or machining, to achieve the desired shape and surface quality.

Inspection and Quality Control

After completion, the finished casting undergoes inspection to identify any defects or imperfections. Quality control measures are implemented to ensure that the casting meets the required specifications and standards.

Foam Casting Materials

For the Lost Form casting process following material will be needed.

• Expanded Polystyrene (EPS) Foam
• Refractory Coating (ceramic slurry or refractory coating)
• Casting Flask
• Unbonded Sand
• Sprue
• Molten Metal (aluminum, iron, steel, copper alloys, etc.)
• Release Agents
• Venting Materials (expendable foam or other materials for creating vents)
• Degassing Agents (to remove gas bubbles from the molten metal)
• Insulating Materials (to protect the surrounding area from heat)
• Fluxes (to remove impurities from the molten metal)
• Cooling Media (for post-casting cooling processes)
• Cleaning Agents (to remove any residual materials or coatings)
• Quality Control Tools and Instruments (visual inspection tools, measuring instruments, non-destructive testing equipment, etc.)

Metals Commonly used in Lost Foam Casting

Here is a list of metals commonly used in lost foam casting

• Aluminum Alloys
• Copper Alloys
• Magnesium Alloys
• Nickel-Based Alloys
• Steel Alloys

Polyurethane Foam Casting

Polyurethane foam casting is a specialized type of lost foam casting that uses polyurethane foam to create molds for metal parts. The process begins with creating the desired shape of the part using foam. The foam pattern is then coated with a ceramic material to create a shell, which is used as the mold for casting metal.

Once the shell is created, molten metal is poured into it, vaporizing the foam pattern and leaving behind a high-quality metal part. This method offers many benefits, including the ability to create complex and intricate parts with great accuracy, rapid prototyping, and cost-effectiveness. Additionally, Polyurethane foam casting is commonly used in a variety of industries. For instance, automotive, aerospace, and medical engineering, to create prototypes and short-run production parts.

Lost Foam Casting Products

Lost foam casting, a casting process, utilizes a foam pattern to form a mold for metal casting. In this process, the foam pattern is coated with refractory material. Subsequently, as the molten metal is poured into the mold, the foam pattern undergoes vaporization, making way for the molten metal. Consequently, this method facilitates the casting of complex shapes and intricate details. There are a lot of applications for Lost Foam Casting. For examples;

• Engine blocks
• Pump and valve bodies
• Impellers
• Cylinder heads
• Artistic sculptures
• Manhole covers
• Aerospace components (turbine blades, intake manifolds, structural parts)
• Industrial machinery parts
• Automotive parts (transmission cases, gearbox housings, suspension components)
• Agricultural equipment components
• Marine parts (propellers, marine engine components)
• Electrical motor housings
• Medical equipment components
• Oil and gas industry components (valve bodies, pipe fittings)
• Foundry patterns and molds (used in other casting processes)

Lost Foam Casting Engine Block

Lost foam casting is a popular method for producing engine blocks due to its ability to create complex and highly accurate parts. In this process, a foam pattern is made into the shape of the engine block. The pattern is then coated with a ceramic shell and heated to a high temperature, causing the foam to vaporize and leaving a void in the shell. Molten metal is then poured into the shell, occupying the space left by the foam.

This method allows for the creation of highly precise engine blocks with large and intricate designs that are difficult to manufacture using traditional casting methods. Additionally, lost foam casting minimizes the need for tooling, making it a cost-effective production method for engine blocks. The automotive industry commonly uses lost foam casting to create engine blocks that are both durable and efficient while keeping production costs.

Want more information on Complete equipment for lost foam casting? Feel free to contact us.

Advantages and Disadvantages of Foam Casting

Lost Foam Casting process has both advantages and disadvantages.

Advantages of the Casting Process

There are several advantages of the Lost Foam Casting Process.

Complex Geometries

Lost foam casting allows for the production of intricate and complex shapes that may be difficult or costly to achieve using other casting methods.

Design Flexibility

The process enables designers to incorporate intricate details, thin walls, and complex internal features into the foam pattern, resulting in high-precision castings.

Cost-Effective

Lost foam casting can often reduce production costs since it eliminates the need for cores, reduces machining requirements, and minimizes the need for assembly.

Reduced Post-Casting Operations

The dimensional accuracy and surface finish achieved through lost foam casting often reduce the need for extensive post-casting machining or finishing operations.

Material Savings

Lost foam casting typically requires less material compared to other casting methods since there are no cores or gating systems involved.

Environmental Benefits

The process generates less waste, as the foam pattern is vaporized and consumed during casting, minimizing the need for pattern disposal or reclamation.

Disadvantages of the Casting Process

The suitability of this process depends on the application of the process. Generally, there are some disadvantages to this process.

Pattern Fragility

Foam patterns used in lost foam casting can be fragile and susceptible to damage during handling, transportation, or the molding process.

Pattern Production Complexity

Creating foam patterns with intricate designs can be time-consuming and require skilled craftsmanship or specialized equipment.

Limited Material Compatibility

Lost foam casting is best suited for non-ferrous metals, such as aluminum, magnesium, or copper alloys. It may not be suitable for high-temperature or reactive materials like steel or iron.

Surface Finish Limitations

Achieving a smooth surface finish on castings may be challenging with lost foam casting, particularly for complex geometries or internal features.

Casting Size Limitations

Lost foam casting is more suitable for smaller to medium-sized castings. Producing large or heavy castings through this method can be challenging due to the handling and structural integrity of the foam patterns.

Process Control

Lost foam casting requires precise control of process parameters, such as temperature, gas flow, and metal pouring, to ensure consistent casting quality, which may require skilled operators and advanced equipment.

Comparison with Other Casting Processes

Generally, there are more common casting processes like Sand Mold Casting, Pressure Die Casing, and Investment Casting, and Gravity Casting. Lost Foam Casting is also a popular casting process in the manufacturing industry. Foam casting has several advantages over other casting processes, making it a popular choice, especially for creating complex parts. Unlike traditional casting methods, which rely on permanent molds and patterns, foam casting uses a foam pattern that is coated with a ceramic material to create a mold, which is then filled with molten metal. 

The Foam Casting Process can compare with other casting processes. For Example the followings are some common casting processes.

• Sand Casting
• Investment Casting
• Die Casting
• Centrifugal Casting
• Continuous Casting
• Shell Molding
• Vacuum Casting
• Permanent Mold Casting
• Electroslag Casting
• Squeeze Casting
• Continuous Belt Casting
• Ceramic Mold Casting
• Plaster Casting
• Slush Casting

The following table compares the common casting processes.

Lost Foam Casting Tips

Here are some neutral Lost Foam Casting tips

• Select the appropriate foam type, density, and thickness for your specific part design.
• Keep foam patterns clean and avoid punctures or dents that could affect the final metal product.
• Use a high-quality ceramic material for coating the foam pattern to ensure a durable and long-lasting mold.
• Allow enough time for the ceramic to cure properly before pouring the molten metal.
• Use a suitable gating and riser system to ensure proper flow of the molten metal and prevent shrinkage and porosity.
• Ensure that the metal temperature and pouring speed are optimal for the specific metal being used and the size and complexity of the part being cast.
• Maintain proper ventilation to avoid air entrapment in the mold and ensure a high-quality final product.
• Implement quality control measures to test for defects in the final metal product and make improvements for future castings.
• Partner with a reputable foundry that has experience with lost foam casting to ensure the highest quality and accuracy.

Conclusion

In conclusion, lost foam casting is an innovative and cost-effective method of creating highly precise and complex metal parts. This casting process has rapidly gained popularity in recent years due to its many advantages, including cost savings, faster lead times, and the ability to produce intricate designs with precision. It is a popular choice for various industries. For example; automotive, aerospace, and marine engineering, among others. As technology advances and new materials become available, lost foam casting is sure to continue to evolve and adapt, making it an exciting and promising casting process for the future.

Thank you for taking the time to read this article on lost foam casting. We hope that you found the information provided both informative and useful. At the end of the day, our goal is to provide accurate and insightful content on a wide range of topics to our readers. If you have any questions or comments on this article or any other topic related to this subject, please do not hesitate to reach out to us. We appreciate your interest and support and look forward to bringing you more valuable content in the future. Once again, thank you for your time and attention, and we look forward to bringing you more informative content in the future.

For more How much does the lost foam casting equipmentinformation, please contact us. We will provide professional answers.