Sand 3D printing: putting an engine in the traditional foundry

March 30, 2024

By Jeff wei

3D printing technology is leading a revolution in today’s rapidly evolving manufacturing sector with its unique benefits and potential. As part of this revolution, sand 3D printing technology is emerging as a new favourite in the manufacturing industry. This technology not only drives innovation, but also brings unprecedented efficiency and flexibility to the traditional casting process.

What is sand 3D printing?

Sand 3D printing is an advanced additive manufacturing technology. This technology uses binder jetting to build sand moulds and cores, a process that is not only precise but also allows for the creation of complex geometries without sophisticated tooling, and these printed sand moulds and cores are subsequently used to cast a variety of metal parts.

Sand 3D printing technology is becoming more and more widely used in the manufacturing industry, especially when rapid prototyping, complex geometric designs or small batch customised production is required. It not only improves productivity and reduces costs, but also offers more possibilities for design innovation. With the continuous development of technology, sand 3D printing is expected to further change the traditional casting industry and promote the manufacturing industry to a more digital and automated direction.

Workflow of sand 3D printing

Sand 3D printing is an advanced technology for manufacturing metal casting sand moulds, which can achieve rapid manufacturing of complex shaped metal casting sand moulds by combining 3D printing technology with traditional casting process. The following is the general workflow of sand 3D printing:

Step 1: Design the model

First, a 3D model of the part to be cast needs to be created using computer-aided design (CAD) software. This model should contain all the necessary details and geometry, taking into account factors such as shrinkage, cooling and venting of the casting.

Step 2: Print preparation

Selection of material: Select the appropriate sand material and binder according to the needs of the printed part.

Load material: Fill the 3D printer’s silo with sand material and make sure the binder supply is sufficient.

Step 3: Printing Process

Laying the sand layer: the printer’s sand laying device lays a thin layer of sand material on the build platform.

Spraying binder: The print head selectively sprays binder onto specific areas of the sand layer along a path generated by the slicing software. Upon contact with the sand particles, the binder hardens and bonds the surrounding sand particles to form a layer of the model.

Build Layer by Layer: The process of laying the sand layer and spraying the binder is repeated, with the build platform dropping one layer thickness away for each completed layer, until the entire model build is complete.

Step 4: Post-processing

Remove excess sand: After printing, separate the printed sand mould from the uncured sand.

Curing: Place the sand mould in an oven for heat treatment or use other methods to cure the binder to enhance its strength and durability.

Cleaning and dressing: the sand mould is cleaned to remove any excess binder or sand particles and the mould is dressed as necessary to ensure it is ready for casting.

Step 5: Casting

Prepare for casting: Place the cured sand mould in the casting machine and prepare the molten metal.

Pouring the metal: Pour the molten metal into the sand mould to fill the cavities of the mould.

Cooling and demoulding: Wait for the metal to cool and solidify, then remove the metal casting from the sand mould.

Step 6: Subsequent processing

Sprue and Fly Edge Removal: Remove excess metal such as sprues and fly edges from the casting.

Surface Preparation: The casting is ground, polished or otherwise surface treated to achieve the desired surface quality.

Inspection and Testing: Quality inspection and performance testing of castings to ensure they meet design specifications.

3D printed sand mould casting process
3D printed sand mould casting process

The workflow of sand 3D printing combines advanced digital technology with traditional casting processes to provide an efficient and cost-effective solution for manufacturing complex and customised metal parts. As technology continues to advance, this process is expected to become even more streamlined and automated.

Technological Advantages of Sand 3D Printing

Sand 3D printing technology has demonstrated many advantages in modern manufacturing, especially in the foundry sector. Here are some of the key technical advantages of sand 3D printing:

  1. Design Freedom
    Sand 3D printing allows for the creation of highly complex geometries, including internal passages and cavities, which are difficult or impossible to achieve in traditional casting methods.Designers can create optimised lightweight structures that improve product performance and reduce material usage.
  2. Rapid Prototyping
    The time from design to prototype is dramatically reduced, accelerating the product development cycle and enabling organisations to respond quickly to market changes.It is easy for designers to iterate designs and quickly test and validate new concepts.
  3. Cost Reduction
    Reduces the cost of manufacturing expensive moulds in traditional casting, especially in small production runs and custom projects.Reduces overall material costs by reducing material waste and optimising design.
  4. Increase productivity
    Sand 3D printing allows moulds to be produced directly from a digital model, reducing manual handling and preparation.
    In some cases, subsequent processing steps, such as machining, can be reduced or eliminated, further increasing productivity.
  5. Customised production
    Sand 3D printing technology supports on-demand production, making it cost-effective to produce customised products even in single or small batches.It offers more possibilities for customised and personalised products.
  6. Material compatibility
    Sand 3D printing technology allows the use of many types of sand materials, including refractory and speciality sands, to meet different casting requirements.Compatible with a variety of binder systems, you can choose the right binder according to the application of the final product.
  7. Support for multi-material manufacturing
    Some advanced sand 3D printing systems are able to use multiple sand materials with different properties in the same printing process, increasing manufacturing flexibility.

These advantages of sand 3D printing technology make it an attractive solution in the manufacturing industry, especially for industries that require rapid innovation and highly customised products. As the technology continues to advance and costs decrease, the applications of sand 3D printing are expected to expand further.

How does sand 3D printing compare cost-effectively to traditional casting processes?

Sand 3D printing has its own unique advantages and challenges in terms of cost-effectiveness compared to traditional casting processes. Below is a comparison of the two processes in terms of cost:

Initial investment and equipment costs

Sand 3D printing: requires investment in specialised 3D printing equipment, which can be relatively costly, especially for industrial-grade, high-precision printers. However, as the technology develops and the market expands, equipment costs are gradually decreasing.

Traditional casting: The initial investment in a traditional casting process may include a large number of skilled workers, casting furnaces, mould making equipment and other associated production machinery. For large-scale production, these initial costs can be very high.

Mould and tooling costs

Sand 3D Printing: There is no need for expensive initial mould making, which is particularly cost effective when producing small batches or custom parts. 3D printing allows for rapid prototyping and design iteration without the need for additional mould costs.

Traditional casting: the cost of manufacturing moulds and tools can account for a significant portion of the total cost, especially when producing small batches or complex designs. There are also additional costs for mould wear and maintenance.

Material costs

Sand 3D printing: the sand material used is relatively cheap and much of it can be recycled, reducing material waste.

Traditional casting: Material costs depend on the type of metal used, which is usually more expensive than sand materials. In addition, material waste can be higher in traditional casting processes.

Labour and operating costs

Sand 3D printing: although the operation of 3D printing equipment may require specialised skills, the high level of automation can reduce labour costs. Also, operating costs may be lower due to increased productivity.

Conventional casting: more manual involvement may be required, especially in the mould making and post-processing stages. In addition, energy consumption is usually higher in conventional casting, which can also increase operating costs.

Post-processing and finishing costs

Sand 3D printing: Printed sand moulds may require subsequent cleaning and curing processes, but typically have lower post-processing costs than traditional casting.

Conventional casting: castings usually require extensive post-processing such as cutting, grinding and painting, which add additional costs.

To summarise

Sand 3D printing offers significant cost advantages for small volume production, rapid prototyping and customised products. It reduces mould costs, material wastage and post-processing requirements, thereby reducing overall costs. However, for mass production, traditional casting may be more advantageous in terms of cost per unit of product, especially if the initial mould costs have been amortised.

As 3D printing technology continues to advance and costs decrease, the advantages of sand 3D printing in terms of cost-effectiveness will become more apparent, especially in application scenarios that require rapid innovation and design iteration. When choosing a production process, companies should consider factors such as the design complexity of the product, production volume, material selection and market requirements.

AFS has developed a variety of sand 3D equipment, with excellent core technology, high cost-effective, in the foundry field has been fully recognised by customers around the world. Click on the equipment model to learn more:

What are the significant environmental advantages of sand 3D printing over traditional casting processes?

1. Reduced material waste:

   Sand 3D printing is an additive manufacturing process that adds material only where it is needed, thus reducing the use and waste of raw materials.

   In contrast, traditional casting processes can produce large amounts of waste and swarf during mould making and melting.

2. Reduced energy consumption:

   Energy consumption during sand 3D printing is typically lower than the high-temperature melting process in traditional casting.

   Conventional casting requires heating the metal material to its melting point, which not only consumes a lot of energy, but can also lead to energy waste.

3. Reduction of harmful emissions:

   The binder used in the sand 3D printing process is usually water-based, which reduces harmful emissions compared to the harmful chemicals used in traditional casting.

   Conventional casting can produce harmful emissions and dust during the melting and burning process.

4. Improved material utilisation:

   Sand 3D printing allows for more precise material placement, reducing the amount of material that needs to be removed during subsequent processing.

   Traditional casting processes often require the removal of large amounts of material to obtain the desired shape and size, which increases material waste.

5. Support for material recycling:

   Sand materials used for sand 3D printing can be recycled and reused after printing, reducing the need for new resources.

   While waste sand and scrap from traditional casting processes can also be recycled, sand 3D printing offers a higher rate of material recycling.

6. Reduced logistics and transport:

   Sand 3D printing can take place close to the location of demand, reducing the need to transport raw materials and finished products, and thus reducing carbon emissions from the logistics process.

   Conventional casting may require transporting raw materials and finished products over long distances, which adds to the environmental burden.

7. Promoting sustainable development:

   The development and application of sand 3D printing technology is helping to drive manufacturing in a more sustainable and environmentally friendly direction.

While traditional casting processes are also being improved to reduce environmental impact, sand 3D printing offers a new, more sustainable way of production.

Comparison between 3D printing workshop and traditional casting workshop
Comparison between 3D printing workshop and traditional casting workshop

In summary, the environmental benefits of sand 3D printing technology are mainly in terms of reducing material and energy consumption, lowering harmful emissions, improving material utilisation and supporting sustainable development. With the continuous progress of technology and cost reduction, these environmental advantages will become more significant and help promote the green transformation of the manufacturing industry.

Areas of application for sand 3D printing

Sand 3D printing is particularly used in the foundry industry, where it enables foundries to respond quickly to changes in the market and produce higher quality castings. In the automotive and aerospace industries, sand 3D printing is being used to create complex parts, improve performance and reduce weight. And in the art and design field, sand 3D printing offers unlimited creative possibilities for artists and designers. Here are some of the major application areas of sand 3D printing:

1. Automotive industry

Prototyping: Rapid prototyping of automotive parts to speed up the design and testing process.

Customised parts: Provide customised parts for limited edition cars or classic car restorations.

Lightweight design: Reduce material usage through optimised design to achieve lightweight automotive parts and improve fuel efficiency and performance.

Automotive applications: water-cooled motor housings for new energy commercial trucks
Automotive applications: water-cooled motor housings for new energy commercial trucks

2. Aerospace

Complex part manufacturing: Printing parts with complex internal passages, such as engine components and heat exchangers.

Weight Reduction: Improve aircraft fuel efficiency and performance by reducing component weight.

Rapid Manufacturing: Produce parts quickly, reducing downtime for maintenance and repair.

3. Industrial Machinery

Custom Moulding: Customising moulds and tools for specific production processes.

Complex gears and parts: Print complex gears and other mechanical parts to improve mechanical efficiency and durability.

4. Energy Industry

Oil & Gas: Manufacture customised parts for drilling and extraction operations.

Renewable energy: manufacture parts for wind turbines and solar energy systems.

5. Medical devices

Custom Implants: Customising orthopaedic implants and surgical instruments to meet specific patient needs.

Prototypes and Models: for testing and developing new medical device designs.

6. Art and Design

Artwork: Artists use sand 3D printing technology to create unique sculptures and artwork.

Design prototypes: designers use this technology to create prototypes for furniture, jewellery and other product designs.

7. Architecture

Architectural Modelling: Rapidly create detailed models of buildings and urban plans.

Customised components: produce bespoke architectural components for special building projects.

8. Education and Research

Teaching tools: production of teaching models and presentation tools in the field of education.

Research: Researchers use sand 3D printing for experiments and studies in the field of materials science and engineering.

The applications of sand 3D printing technology are expanding, and as technology advances and costs decrease, more industries are expected to begin adopting the technology to improve productivity, reduce costs and drive innovation.

3D printing technology, particularly sand 3D printing, is significantly driving the digital transformation of the foundry industry. This transformation is not only changing traditional manufacturing processes, but also bringing unprecedented design freedom, productivity and environmental sustainability to the industry. Here are predictions for future trends in sand 3D printing:

Technological innovation and development of new materials

As 3D printing technology continues to advance, it is expected that more types of materials and binders will be developed to meet the needs of different casting applications.

Further integration of intelligence and automation

The foundry industry will continue to integrate smart manufacturing and automation technologies, such as the Internet of Things (IoT) and Artificial Intelligence (AI), to improve productivity and quality control.

Supply chain optimisation

3D printing technology will facilitate the localisation and decentralisation of the supply chain, reducing logistics costs and time, and increasing supply chain flexibility and responsiveness.

Increased Cross-Industry Collaboration

The foundry industry will work more closely with other industries such as automotive, aerospace and medical to develop new applications and solutions.

Importance of education and training

As 3D printing technology becomes more widely used in the foundry industry, the demand for relevant expertise and skills will increase, and education and training will be key to the industry’s growth.

Developments in standardisation and regulation

As the technology develops, it is expected that more standards and specifications for 3D printed casting will emerge to ensure product quality and safety.

Challenges and future of sand 3D printing

Despite its enormous potential, sand 3D printing technology still faces challenges in terms of market acceptance (mainly because many senior leaders in companies do not know much about the technology). With the deepening of the research and the advancement of the technology and the popularity of the application, it is believed that many traditional foundry owners will gradually accept this new technology, coupled with the fact that many foundries have now benefited from this technology, we can expect that sand 3D printing will lead to more innovations and breakthroughs in the future, and will bring about wider impacts for the manufacturing industry.

Conclusion:

Sand 3D printing technology is changing the way we make things, providing new tools for designers and engineers as well as new opportunities for traditional manufacturing. As the technology continues to evolve and costs come down, sand 3D printing is expected to be a key pillar of the future of manufacturing. I encourage every reader interested in innovation and sustainability to further explore the endless possibilities of sand 3D printing.

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