Analysis of 3DP sand type inkjet printing technology

May 27, 2022

With the rapid development of the national economy, the traditional foundry industry has brought great impact, especially in clean production, intelligent casting has put forward higher requirements, and rapid prototyping sand technology is an effective way to introduce intelligent technology into the foundry industry.

Sand rapid prototyping technology is currently the main three-dimensional inkjet printing (3DP) technology and selective laser sintering (SLS) technology. Among them, sand-based inkjet printing technology has the advantages of high forming efficiency, large forming size, low thermal stress, etc., and is more suitable for large-scale, flexible, rapid and intelligent production.

The origin of 3DP sand-based inkjet printing technology

3DP sand-based inkjet printing technology was invented by Professor Emanuel and others at MIT in the U.S. A patent application was submitted in 1989 and a patent was granted in 1993. The method used in this technology utilizes a nozzle that jets a liquid binder to bond the powder laid on the powder bed into shape.

sand inkjet printing process

Schematic diagram of the sand inkjet printing process

The technology works on the principle that the system first lays a layer of powder on the table (the powder is pre-mixed and cured, and the inkjet print head sprays bonding agent (furan resin) on the powder bed according to the shape of the cross-section generated from CAD data to print a cross-section; the working cylinder drops a layer thickness (0.2~0.4mm thickness of the sand type layer); the system keeps repeating the above steps until all cross-sections are printed; finally the cured sand type is removed from the The final cured sand pattern is removed from the working cylinder, and the uncured excess powder is removed to obtain the final sand pattern.

Advantages and applications of 3DP sand inkjet printing technology

1. Shorten the casting production process.

The casting process creates complex sand patterns directly from 3D graphic data, changing the traditional casting method of using molds, making cores, molding, and closing boxes.

2. Improve the quality of castings and increase production efficiency.

The products produced by this technology are highly accurate, and the sand mold and core are quickly formed in one piece, which significantly 3. shortens the product development and production cycle.

3.More flexible design, cost saving and reduced manufacturing difficulty.

The technology has advantages such as flexible modification of model design, which has outstanding effect on improving product precision and reducing sand-iron ratio, especially suitable for the production of complex castings with internal structure.

4. People-oriented, green casting, intelligent casting.

Significantly improve the casting site environment, reduce the labor intensity of workers; machine for human, labor costs drop significantly; typical digital manufacturing, improve the intelligence level of casting production.

5. The industrial application of casting additive manufacturing technology

The industrial application of foundry additive manufacturing technology will have transformative significance and far-reaching impact on the transformation and upgrading of the foundry industry, foundry smart manufacturing and the construction of future foundry smart factories.

Beijing Longyuan Automatic Molding System Co., Ltd. (hereinafter referred to as “Longyuan AFS”), a subsidiary of China’s leading 3D printing company Sandi Technology, made an ECU bracket for a diesel car company. This product is a small batch of rapid trial production, from receiving customer drawings to Delivery of the finished part in just 4 days, the casting material is 250 grey iron.

Small batch automotive bracket castings
Figure: Small batch automotive bracket cast by 3DP sand printing technology of Longyuan AFS

This article describes some of the applications of 3DP sand-based 3D printing technology.

In the aerospace, automotive, marine pump and valve industries, this technology is suitable for the R&D and manufacturing of prototype parts and the production of small and medium batch castings, eliminating the long mold opening time and high mold opening costs. It also eliminates the need for lengthy mold opening times and high mold opening costs. The technology also allows designers to design castings exactly according to the optimal solution, regardless of the shape of the casting, and is no longer limited by machining requirements. Learn more about Beijing Longyuan’s 3DP equipment.

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Longyuan AFS Co., Ltd. is a leading provider of 3D printing equipment and manufacturing services in China, providing high-quality R&D pilot production and rapid manufacturing services for small-lot, multi-species and complex structure metal products based on the integrated technology of "3D printing, casting, machining and inspection".

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