Chapter 1: Deep Dive: The Root Challenge of Traditional Casting Defects

1.1 Common casting defects and their deep causes

Casting defects are the direct cause of high scrap rates. These defects are not accidental, but are dictated by the physical and process limitations inherent in conventional casting processes.

firstlystomatogether withshrinkage. Porosity mainly originates from the involvement or inability to effectively discharge gases (e.g. hydrogen, mold outgassing) in the liquid metal during the pouring and solidification process. When the dissolved gases in the liquid metal are released due to reduced solubility during cooling and solidification, bubbles will form inside or on the surface of the casting if they are not discharged in time. Related to this is shrinkage, which is a natural phenomenon of volume contraction of the metal during solidification. If the cooling system is not properly designed, resulting in local mold temperature is too high, or insufficient complementary shrinkage, it will form internal voids or depressions, the so-called shrinkage holes.

Next.sandwichedtogether witherror type (math.). In conventional sand casting, sand molds and sand cores usually need to be assembled and bonded after being made from multiple pieces separately. In this process, any tiny rupture of the sand core or improper bonding may lead to sand particles being caught in the metal liquid, forming sand entrapment defects. In addition, if the mold parting surface or the sand core is not positioned accurately, it may also lead to the casting of the upper and lower parts of the misalignment of the mis-shape defects.

endcold storagetogether withcrackles. When the fluidity of the metal liquid is poor, the pouring temperature is too low, or the runner design is narrow, the two metal streams are solidified without being fully integrated at the leading edge, leaving a weakly connected cold segregation. And during cooling and solidification, if there are uneven stresses within the casting, thermal cracks may occur during shrinkage.

1.2 The traditional mold manufacturing "high cost" and "low efficiency" dilemma

Another core pain point of the traditional casting process is its mold manufacturing process. Traditional wood or metal core box manufacturing is a labor-intensive, highly skilled worker-dependent process with long lead times and significant costs. Any minor design change means that the mold needs to be rebuilt, resulting in high additional costs and weeks or even months of waiting time.

This over-reliance on physical molds also fundamentally limits the design freedom of castings. Traditional mold-making processes are unable to mold complex internal runners and hollow structures in one piece, which must be disassembled into multiple independent sand cores and then assembled by complex tooling and labor. ². This process limitation forces designers to compromise and sacrifice part performance for manufacturability, such as simplifying cooling channels to accommodate drilling processes that do not allow for optimal cooling.

To summarize, the high scrap rate of traditional casting is not an isolated technical problem, but a product of its core processes. The traditional "physical trial and error" mode makes the foundry in the discovery of defects, need to go through a long process of mold modification and retesting, which is a high-risk, inefficient cycle. 3D printing's revolutionary value is that it provides a "moldless" solution, fundamentally reshaping the entire production process, will be the traditional "physical trial and error" mode, will be the traditional "physical trial and error" mode, will be the traditional "physical trial and error" mode, will be the traditional "casting" high scrap rate is not an isolated technical problem, but its core process products. The revolutionary value of 3D printing is that it provides a "moldless" solution that fundamentally reshapes the entire production process, transforming the traditional "physical trial-and-error" model into a "digital simulation validation" that puts the risk in front of the process, thus eliminating most of the causes of scrap at the source.

Chapter 2: 3D Printing: A Revolutionary Breakthrough from Technology to Solution

2.1 Moldless production: eliminating the root causes of obsolescence

The core advantage of 3D printing is its "moldless" production method, which allows it to bypass all of the mold-related challenges inherent in traditional casting, thus radically reducing scrap rates.

Directly from CAD to sand mold. Binder Jetting in Additive Manufacturing is the key to making this happen. It works by precisely spraying liquid binder onto thin layers of powder (e.g. silica sand, ceramic sand) from an industrial-grade printhead based on a 3D CAD digital model. By bonding layer by layer, the 3D model in the digital file is constructed in the form of a solid sand mold or sand core. This process completely eliminates the need to rely on physical molds. Because there is no need for lengthy mold design and manufacturing, the mold-making cycle can be shortened from weeks or even months to hours or days, enabling "print-on-demand" and rapid response to design changes, dramatically reducing up-front investment and trial-and-error costs.

One-piece molding and complex structures. 3D printing's layered manufacturing approach gives unprecedented design freedom. It is able to mold complex sand cores that would traditionally have to be split into multiple parts, such as the meandering runners inside an engine, into a single monolithic piece. Not only does this simplify the casting process, but more importantly, it completely eliminates the need for core assembly, bonding and misalignment, thus eradicating common defects such as sand entrapment, dimensional deviations, and misshaping caused by such issues.

2.2 Optimization process: data to guarantee casting quality

The value of 3D printing goes beyond "moldlessness" itself. It elevates the manufacturing process to a whole new digital dimension, allowing data to be verified and optimized before physical manufacturing, turning "after the fact" into "before the fact".

Digital Simulation and Design. During the digital design phase prior to 3D printing, engineers can use advanced Finite Element Analysis (FEM) software to perform accurate virtual simulations of the pouring, make-up shrinkage and cooling processes. This makes it possible to anticipate and correct potential defects that could lead to porosity, shrinkage or cracks before actual production. For example, by simulating the flow of the liquid metal in the runners, the design of the pouring system can be optimized to ensure smooth filling and effective venting. This digital foresight greatly improves the success rate of the first trial run and guarantees casting yields at the source.

Excellent sand properties. 3D printed sand molds, due to their layer-by-layer construction, can achieve uniform densities and air permeability that are difficult to achieve with traditional processes. This is crucial for the casting process. Uniform gas permeability ensures that gases generated inside the sand mold can escape smoothly during the pouring process, significantly reducing porosity defects caused by poor venting.

Cooling with shape. Conformal cooling technology is another revolutionary application of 3D printing in the field of casting molds. Mold inserts manufactured through metal 3D printing have cooling runners that can be designed to exactly mimic the surface contours of the casting. This achieves fast, uniform cooling, significantly reducing deformation and shrinkage due to uneven shrinkage, thus dramatically reducing the scrap rate. According to data, molds with follow-through cooling can reduce injection cycle times by as much as 70%, while significantly improving product quality.

From "physical trial and error" to "digital foresight". The core contribution of 3D printing is to transform the traditional foundry model of "trial and error" into "anticipatory manufacturing". It enables foundries to perform numerous iterations in a digital environment in a cost-effective manner, which is a fundamental shift in mindset and business process. This "hybrid manufacturing" model makes 3D printing easier to adopt by traditional foundries and enables the most efficient production. For example, 3D printing can be used to create the most complex and error-prone sand cores, and then combined with sand molds made using traditional methods to "build on the strengths".

Chapter 3: SANTI TECHNOLOGY: A Digital Engine to Empower the Foundry Industry

3.1 Core equipment: "hard power" for casting innovation

As a pioneer and leader in the field of additive manufacturing in China, 3DPTEK provides strong "hard power" support for the foundry industry with its self-developed core equipment.

The company's core product lines are3DP Sand Printerthat highlights its leadership in technology. Flagship devices3DPTEK-J4000With an extra-large molding size of 4,000 x 2,000 x 1,000 mm, it is highly competitive on a global scale. This extra-large size allows large, complex castings to be molded in one piece without the need for splicing, further eliminating potential defects caused by splicing. At the same time, for example

3DPTEK-J1600PlusDevices such as these offer high accuracy of ±0.3 mm and efficient printing speeds, ensuring that superior quality is achieved while producing quickly.

In addition, SANTI Technology'sSLS (Selective Laser Sintering) Equipmentseries, such asLaserCore-6000The machines are also excellent in the field of precision casting. This series of equipment is particularly suitable for the manufacture of wax molds for investment casting, providing a more accurate solution for high-end, fine parts in aerospace, medical and other fields.

It is worth mentioning that SANDI Technology is not only an equipment supplier, but also an expert in material and process solutions. The company has developed more than 20 binders and 30 material formulations, compatible with cast iron, cast steel, aluminum, copper, magnesium and other casting alloys. This ensures that its equipment can be seamlessly integrated into a wide range of casting applications, providing customers with comprehensive technical support.

3.2 All-link services: integrated casting solutions

The competitive advantage of SANDI Technology lies not only in its hardware, but also in the integrated solutions it provides along the whole chain. The company has a strong "Trinity" innovation system - "research institute + post-doctoral workstation + R&D team". This model ensures continuous technology iteration and innovation momentum, and its accumulation of more than 320 patents is a strong proof of its technological leadership.

The company offers a "one-stop" turnkey service from design and 3D printing to casting, machining and inspection. This vertically integrated model greatly simplifies the customer's supply chain management, reduces communication costs and risks, and allows the foundry to focus on its core business.

3.3 Classic Case: Data-Driven Proof of Value

Successful cases are the most persuasive tool to convince potential customers. Through a series of real-world projects, SANDY Technology has quantified the significant business value that 3D printing technology brings.

in order toAutomotive water-cooled motor housingAs an example, this case perfectly demonstrates how the 3DP sand casting process solves the one-piece molding problem of "large size, thin wall, complex spiral cooling channels". ²¹. The successful application of this technology in the field of new energy vehicles has proved its significant advantages in the production of high-performance, complex structure castings.

On the otherIndustrial pump bodyIn the case of SANDI, SANDI adopted the hybrid manufacturing model of "3DP outer mold + SLS inner core". This complementary strategy shortened the production cycle by 80%, and at the same time improved the dimensional accuracy of the castings to CT7 level, which perfectly proved the powerful effect of the hybrid manufacturing mode.

The joint venture project with Xinxin Foundry provides the strongest business argument. By introducing 3D printing technology, the foundry achieved a turnover increase of 1,35%, doubled its profitability, halved its lead time and reduced its costs by 30%. This series of quantitative data provides irrefutable proof of the return on investment of 3D printing technology in the foundry industry.

The following table visualizes how 3D printing can address the pain points of the foundry industry on both a technical and business value level:

Chapter 4: Looking to the future: digitalization and sustainability in the foundry industry

3D printing technology is leading the foundry industry from the traditional "manufacturing" to "smart manufacturing" fundamental transformation. According to the relevant report, the scale of China's additive manufacturing industry continues to grow at a high rate, and in 2022 it will exceed RMB 32 billion. This data clearly shows that digital transformation has become an irreversible industry trend.

In the future, 3D printing will be deeply integrated with artificial intelligence (AI), IoT and other technologies to achieve full automation and intelligent management of production lines. Foundries can use AI algorithms to optimize casting parameters and IoT sensors to monitor the production process in real time, thus further improving yield rates and production efficiency.

In addition, the unique advantages of 3D printing in realizing complex lightweight design will help automotive, aerospace and other downstream industries to improve product performance and reduce energy consumption, which is a perfect fit for the requirements of global sustainable development. 3D printing's on-demand production mode and extremely high material utilization (can be recycled more than 90% unbonded powder), also significantly reduces the generation of waste, for the casting industry to bring the environmentally friendly development path for the foundry industry.

concluding remarks 3D printing is not the end of casting, but its innovator. It gives the traditional foundry industry unprecedented flexibility, efficiency and quality assurance through its two core advantages of "moldless" and "digital". It enables foundries to free themselves from the plight of high scrap rates and enter a new era of greater efficiency, competitiveness and embrace of innovation. For any foundry seeking to stand out in a competitive market, embracing 3D printing technology, represented by SanDi Technology, is no longer an optional choice, but a necessary path to the future.

3D打印如何解決鑄造高報廢率問題：革新鑄造工藝，提升品質與效率最先出現在三帝科技股份有限公司。

principle

3D printed sand casting is based on a digital three-dimensional model. First of all, the 3D printing equipment is used to print out the sand mold (including upper and lower sand molds, cores, etc.) by stacking special sand materials (usually resin sand containing binder, etc.) layer by layer in accordance with the cross-section information of the model. Then, liquid metal is cast into the cavity formed by the sand mold, and after the liquid metal cools and solidifies, the sand mold is removed to obtain the desired metal casting.

workflows

1. 3D modelingThe casting model is designed using professional 3D modeling software (e.g. SolidWorks, UG, etc.), and at the same time, the casting process requirements, such as parting surfaces, draft slopes, machining allowances, etc., need to be taken into account, and then the model is converted into a file format suitable for 3D printing (e.g. STL format).
2. Sand Printing: The printing materials (sand and binder) are loaded into the silo of the 3D printing equipment, and under the control of the computer, the nozzle selectively sprays the binder onto the sand layer in accordance with the cross-section data of the model, so that the sand grains are bonded together and build up layer by layer to form the sand pattern. After the printing is completed, the sand model is subjected to appropriate post-processing, such as removing excess sand particles and reinforcing weak parts.
3. Preparation for casting: The printed sand molds are assembled and placed in the casting equipment to prepare the metal liquid for casting. At the same time, the raw metal is melted and treated to achieve the proper casting temperature and composition requirements.
4. Casting and cooling: Slowly pour the treated liquid metal into the cavity of the sand mold to ensure that the liquid metal fully fills the cavity. After casting, wait for the liquid metal to cool and solidify naturally.
5. Sand Cleaning and Post-treatment: After the castings are cooled, the sand mold is removed by vibration, sandblasting, cutting, etc. to obtain the castings. Then the castings are cleaned, polished, heat-treated, machined and other post-treatment processes to meet the final product quality requirements.

dominance

1. High degree of design freedom

Complex structure molding capabilityTraditional sand casting in the manufacture of complex shapes, such as sand molds with internal cavities, curved channels, shaped surfaces and other structures, by the limitations of the mold manufacturing technology, it is difficult to achieve or the cost is extremely high. The 3D printing sand casting can be based on digital three-dimensional model, easily and accurately print out a variety of complex shapes of sand, for the production of castings with complex structure provides a possibility. For example, the complex cooling channels of aircraft engine blades, automotive parts with fine internal structure, etc., can be realized by 3D printing sand casting.

Personalization3D printing sand casting has a unique advantage for the production of some small batch, customized needs of castings. It can be based on customer-specific requirements, quickly design and print out the corresponding sand, to meet the personalized needs of different customers, to avoid the traditional mold manufacturing needs to open the mold, mold repair and other cumbersome processes, greatly reducing the production cycle of customized products.

2. Reduced production cycle time::

Simplification of the mold manufacturing process: Traditional sand casting requires the production of molds first, and then the molds are used to manufacture the sand molds, and the process of designing, manufacturing and commissioning of the molds often takes a lot of time and manpower. And 3D printing sand casting directly based on the digital model for printing, no need to make molds, eliminating the link of mold manufacturing, greatly reducing the entire production cycle 25.

Rapid iteration and modification: In the product development and design phase, if it is found that the design of the casting needs to be modified, traditional sand casting requires the re-making of molds, which is costly and time-consuming. 3D printing sand casting only needs to modify the digital model on the computer, and then reprint the sand model can be, can quickly realize the design iteration and modification, speed up the product development process45.

3. Improved precision and quality::

High dimensional accuracy3D printing technology can accurately control the size and shape of the sand mold, reducing the casting dimensional deviation caused by mold manufacturing errors, parting surface fit and other problems, and improving the dimensional accuracy of the castings. The smooth surface of the printed sand mold makes the surface quality of the final casting better and reduces the subsequent processing and treatment workload4.

Good internal quality: 3D printing sand casting can realize the uniform tightness of the sand pattern, avoiding the local loosening, sand entrapment and other defects that may occur in traditional sand casting, and improving the internal quality of the castings. At the same time, through precise control, the solidification process of the casting can be optimized to reduce the generation of defects such as shrinkage holes and shrinkage loosening.

4. cost-effectiveness::

High material utilization: 3D printing sand casting is on-demand printing, using only the required materials, avoiding the waste of materials in traditional mold manufacturing. Moreover, during the printing process, the distribution of materials can be precisely controlled according to the structure and strength requirements of the sand mold, further improving the utilization of materials.

Reduced labor costs: Traditional sand casting requires a large number of manual operations, such as mold making, sand modeling, mold repair, etc., with high labor costs. The 3D printing sand casting mainly relies on automated equipment for printing, greatly reducing the involvement of manual labor and reducing labor costs. At the same time, it also reduces the errors and uncertainties brought about by manual operation, and improves the stability and consistency of production.

5. green::

Reduction of waste emissions: Traditional sand casting produces a large amount of waste in the process of mold manufacturing and sand processing, such as discarded mold materials, waste sand, etc., which causes a certain amount of pollution to the environment. The 3D printing sand casting produces less waste, and the remaining materials can be recycled and reused, in line with the requirements of green environmental protection.

Improvement of the production environment: 3D printing sand casting process does not require the use of a large number of chemical reagents and binders, reducing the pollution of the environment and health hazards to the operator. At the same time, the automated production method also reduces the generation of dust and noise, improving the production environment.

Application Areas

Aerospace: Used in the manufacture of aero-engine blades, turbine disks, aircraft structural components and other complex parts to meet the requirements of high strength, lightweight and high performance.

automobile industry: Production of engine blocks, cylinder heads, transmission cases and other components, especially for high-performance engines and new automotive design of complex structural components.

Energy: Applied in the manufacture of key components for gas turbines, power generation equipment, etc. to improve component performance and reliability.

Medical Device Field: Manufacture of customized medical devices such as orthopedic implants and dental prostheses to meet individual patient needs.

summarize

3D printed sand casting, as an advanced casting technology, synthesizes the advantages of 3D printing and traditional sand casting. It shows excellent performance in design, production cycle, quality, cost and environmental protection, and brings new ideas and methods for modern industrial manufacturing. With the continuous development and improvement of the technology, 3D printing sand casting is expected to be widely used in more fields, and promote industrial production in the direction of more efficient, more accurate and more environmentally friendly.

3D打印砂型鑄造：原理、流程、優勢最先出現在三帝科技股份有限公司。