Why Lost Foam?

Marshall Miller

With competitive price and timely delivery, Ruiou sincerely hope to be your supplier and partner.

The use of foam patterns in metalcasting first began in . While it is not as widely used as other processes like bonded sand, permanent mold or diecasting, lost foam casting provides advantages for casting intricate patterns using precision molding tools to totally pattern-less castings using machined foam patterns that are not feasible with other processes.

Designing for other casting processes, such as sand casting, has restrictions. Because most casting methods require reusable patterns that must be withdrawn from the mold prior to casting, the removal of the pattern from the mold must be taken into consideration when planning the pattern layout. Contrarily, using foam patterns that remain in the mold during casting and are evaporated helps reduce some of these limitations.

In the lost foam casting process, polystyrene or co-polymer beads are expanded in an aluminum tool and bonded together to form complete patterns or sections that are assembled into a foam pattern. These pieces are then glued together to form a replica of the final cast component to be made. This foam pattern with rigging is then coated with a refractory, placed in a flask and surrounded in unbonded sand and compacted. Molten metal is poured onto the foam pattern, evaporating the foam and forming the part.

With lost foam assemblies, major opportunities for mass reduction, cast-in inserts and component integration are offered. Further, metalcasters can cast components with complex shapes unthinkable in other processes. For instance, engineers can create designs with little to no draft and it is common to see uniform wall thicknesses and excellent surface finish on the end product.

Although the lost foam process may be more expensive than other casting methods, it leads to reduced costs over time, as extra labor in casting and machining processes is eliminated, as is the cost for tooling.

Advantages

The lost foam process holds unique advantages over other manufacturing and casting processes. 

The freedom to design complex internal passages that are impossible or not easily manufactured in other processes is a primary advantage guiding customers to select the lost foam process. It is useful for part consolidation and the elimination of finishing and machining steps. 
In the case of an iron stalk roll for 360 Yield Center, lost foam casting process was the only option (Fig. 1). This component features backdrafted teeth that come to tiny points. The teeth also have a small cup under the backside. The casting supplier, AFS Corporate Member Grede Columbiana (Columbiana, Alabama), made prototypes using a cut foam process where it had foams and patterns machined out of foam billet and used for test castings just to prove they could cast the product. 

However, lost foam castings do not have to be complex to be successful. For example, one part for an oil drain was relatively simple. Originally made with green sand molds and a core used to make the vents, the component ran into issues during machining, when the vents were obliterated. It was a part with a high scrap rate. Converting it to lost foam casting eliminated the issue and was less expensive than the green sand cast part. 

Beyond the design advantages, lost foam has process advantages, as well. The typical lost foam casting line is usually about 100 feet long. It&#;s a compact, usually highly automated process that has the capability of single part flow. Plus, process control is simpler. However, some of the largest lost foam foundries in the world were able to design and construct their own systems that are incredibly simple but effective.
Benchmarked vs. sand casting, lost foam achieves energy savings, improved labor productivity, material reduction, reduced stock, reduced scrap, and improved safety. Lost foam tooling can last 400,000-750,000 cycles. In iron lost foam foundries, four-week lead times are normal since patterns can be stored for months and clustered when needed. Core and mold manufacturing do not have to occur ahead of time.
The process advantages lead to cost savings. Lost foam tooling has an extremely long life, labor costs are lower, and the aggregate used is easily recycled and lends itself too ready adoption of synthetic aggregate eliminating silica issues. Waste disposal is inexpensive and clean. Finishing costs are reduced with the major effort being gaging, and lower capital cost is required. It&#;s a high-productivity process with lower energy consumption and higher yield.

Quality improvements include no binder-related defects, long-term repeatability, no core defects, no mold shift, close dimensional tolerances, excellent surface finish and improved pressure tight castings.

Tackling the Cost of Tooling

One of the negatives about lost foam is the cost of the tools. The automotive industry has used the lost foam process heavily at high volumes, and those companies are less sensitive to tooling costs. However, the average customer is put off by the high upfront tooling cost. A current research project funded by the American Foundry Society is exploring how to reduce the cost of a tool to compete with a typical matchplate automated sand casting line. First cut tests of 3D printed aluminum molds yielded a functional tool at half the manufacturing cost. Now, AFS is funding printed titanium tools to create a lost foam tool that is expected to eliminate stress cracking and corrosion cracking.
The project entails producing and testing printed lost foam molds and expanding patterns. First, the project examined laser-printed aluminum tools using a 12 x 15 in. piece. Based on preliminary results, it appears that using an additively manufactured tool would reduce the cost about 50% (Fig. 2).

Taking the project a step further, the research team used software to redesign the tool and reduce the thickness of the tool by half. They added ribbing on the back for strength. There were no negative issues in the pattern molding process.
The same Software also was used to maximize heat transfer and reduce cycle time. The target is to halve the typical cycle time. Simulations were run to ensure strength was not lost. Titanium tools are now under design for printing.

AFS is also jointly developing printed lost foam polymer tools in various materials. The effort is to produce functional tools at 25% of the cost of conventional tools. This project utilizes the same software to design for Additive Manufacturing. Molds will begin printing in April with testing following. 

To further reduce the barrier of entry to lost foam casting, researchers are also looking at eliminating the need for tooling altogether by directly printing the patterns. Castings could be ready in hours without expensive molding equipment. The industry has produced castings on a test basis successfully in bronze, aluminum, ductile iron and grey iron. Carbon and Stainless steel are next.  CS

Click here to see this story as it appears in the March/April issue of Casting Source.

Contact us to discuss your requirements of How much does the lost foam casting equipment. Our experienced sales team can help you identify the options that best suit your needs.

Nowadays, the profit of the foundry industry is getting lower and lower. In order to ensure the quality of castings, the caster must consider reducing the cost. Next, InterContinental Editor will help the caster to split the lost foam process cost to see how the lost foam process reduces the cost. .

Lost foam casting is especially suitable for castings with multi-parts, multiple cores, complex geometric shapes and complex cavities that are difficult to complete by ordinary casting. Therefore, the cost comparison should have a high degree, and the cost of a simple iron casting using a cupola and a pile of clay sand cannot be compared with the lost foam casting.

Cost analysis is very simple and can include two aspects, namely cost increase factors and cost reduction factors. The difference between these two factors is the amount of cost increase or decrease after the lost foam casting process is adopted.

Original cost minus EPC cost reduction factor + EPC cost increase factor = EPC cost

1. The cost increase factors of lost foam casting

The cost increase of lost foam casting mainly comes from two aspects: foam model and paint consumption.

Each ton of casting consumes 3,000 grams of foam type (including the pouring riser). If you produce the foam model yourself, the cost per gram is 0.02 yuan. That is, each ton of foam type consumes 60 yuan; if the foam model is purchased out, it is at most 0.03 to 0.05 yuan per gram. That is, it consumes 90 to 150 yuan per ton of castings. The paints are all self-made, the aggregate price is between 500 and 1,000 yuan, and the amount of other ingredients is less, calculated at 1,000 yuan per ton of dry powder coating, even for thin-walled parts, it can only consume 50-60 kg per ton, that is, no more than 100 yuan.

Therefore, the cost of lost foam casting increases, which can be defined as:

• &#; Self-made foam model: about 160 yuan; (changes with the market)
• &#;Buy bubble model: about 200-250 yuan (changes with the market)

2. Factors to reduce the cost of lost foam casting

• (1) Dry sand is repeatedly used, no core is required, and the consumption is small, so calculations can be omitted. Compared with cast steel, it can save more than 1.2 tons of molding sand per ton of castings. Compared with cast iron, it can save additional material cost, mold shell firing cost, core making cost, and core iron cost.
• (2) The styling efficiency is obviously improved, no styling workers are needed, and the labor can be saved by more than 40%-60%.
• (3) The cleaning man-hour can be saved by 90%, and the steel casting can save the gas consumption of cutting burrs.
• (4) The yield of molten iron is increased by 10-30%, especially for ductile iron parts, which can be poured without riser.
• (5) Stainless steel, high manganese steel and ductile iron can be solid-solution treated with waste heat, which greatly saves energy consumption.
• (6) Wooden molds are not required for a single product.
• (7) The improvement of casting precision can realize no-processing or micro-processing, which not only reduces the weight of the casting, but also saves the cost of mechanical processing man-hours.

In short, the cost of lost foam is significantly lower than that of traditional processes, which is beyond doubt.

Please keep the source and address of this article for reprinting: How Does The Lost Foam Process Reduce Costs?

Minghe Die Casting Company are dedicated to manufacture and provide quality and high performance Casting Parts(metal die casting parts range mainly include Thin-Wall Die Casting,Hot Chamber Die Casting,Cold Chamber Die Casting),Round Service(Die Casting Service,Cnc Machining,Mold Making,Surface Treatment).Any custom Aluminum die casting, magnesium or Zamak/zinc die casting and other castings requirements are welcome to contact us.

Under the control of ISO and TS ,All processes are carried out through hundreds of advanced die casting machines, 5-axis machines, and other facilities, ranging from blasters to Ultra Sonic washing machines.Minghe not only has advanced equipment but also have professional team of experienced engineers,operators and inspectors to make the customer&#;s design come true.

Contract manufacturer of die castings. Capabilities include cold chamber aluminum die casting parts from 0.15 lbs. to 6 lbs., quick change set up, and machining. Value-added services include polishing, vibrating, deburring, shot blasting, painting, plating, coating, assembly, and tooling. Materials worked with include alloys such as 360, 380, 383, and 413.

Zinc die casting design assistance/concurrent engineering services. Custom manufacturer of precision zinc die castings. Miniature castings, high pressure die castings, multi-slide mold castings, conventional mold castings, unit die and independent die castings and cavity sealed castings can be manufactured. Castings can be manufactured in lengths and widths up to 24 in. in +/-0. in. tolerance.  

What Can we help you do next?

&#; Go To Homepage For Die Casting China

&#;Casting Parts-Find out what we have done.

&#;Ralated Tips About Die Casting Services

By Minghe Die Casting Manufacturer |Categories: Helpful Articles |Material Tags: Aluminum Casting, Zinc Casting, Magnesium Casting, Titanium Casting, Stainless Steel Casting, Brass Casting,Bronze Casting,Casting Video,Company History,Aluminum Die Casting |Comments Off

Are you interested in learning more about EPS Forming Machine? Contact us today to secure an expert consultation!