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标题: 200,000 Bends Without Deformation: TPM3D Combines SLS with Supercritical Foaming to Address the Mass-Production Challenge for 3D-Printed Shoes [打印本页]

作者: admin 时间: 2026-11-12 10:33
标题: 200,000 Bends Without Deformation: TPM3D Combines SLS with Supercritical Foaming to Address the Mass-Production Challenge for 3D-Printed Shoes
Introduction: The history of shoemaking is also a history of advances in materials and forming processes, from vulcanized rubber in 1839 to EVA foam and, in recent years, photopolymer-printed lattice midsoles. Each shift brought better performance along with new compromises.

On November 10, 2026, Nanjixiong learned that as photopolymer 3D-printed shoes face fatigue-resistance and mass-production limits, TPM3D is combining selective laser sintering (SLS) powder-bed fusion with supercritical physical foaming. The company is pursuing a sixth manufacturing-process shift to address the industry's “looks good but is hard to wear; can be printed but breaks easily” problem with 3D-printed midsoles.

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Looking back: six process shifts in 180 years

Shoemaking has undergone six major changes over nearly two centuries:

- 1839, vulcanized rubber: rubber could be used for soles for the first time, but they were heavy and stiff.
- 1850s–1920s, stitching and adhesive bonding: assembly lines enabled separate production of uppers and outsoles.
- 1930s–1970s, the EVA foaming revolution: chemical foaming made midsoles light and springy, but compression set over time and environmental pressures became problems.
- 1980s–2000s, injection molding and air-cushion technology: air-cushion systems emerged, but extremely high tooling costs—hundreds of thousands per mold and 6–12 months for a mold—made individual customization impractical.
- 2010s, exploration of photopolymer 3D printing: complex lattice midsoles became commercializable, but material choice, long-term fatigue resistance, and manufacturing cost remained major challenges. For example, photopolymer midsoles such as Adidas 4DFWD can develop cracks after tens of thousands of bending cycles.

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The first five shifts were significant but each had limitations. The sixth is the combination of SLS and supercritical physical foaming.

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△ Adidas 4DFWD photopolymer lattice midsole (2021)

The approach: combining macro-scale targeted support with high-performance micro-scale cushioning

TPM3D's solution is not simply a material change; it reworks the system from design through post-processing. It combines SLS printing of high-performance PEBA elastomer with supercritical CO₂ foaming:

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- Parametric lattice design: plantar-pressure data guide zoned topology. The heel has a dense cushioning structure, the arch medium-density support, and the forefoot a lower-density, high-rebound design. Instead of uniform “dead” material, the sole becomes a customized mechanical system.
- SLS laser sintering (macro-scale framework): PEBA powder is sintered layer by layer with an infrared laser. No support structures are needed, so complex lattices can be formed in one piece. Unfused powder can be recycled, enabling high material utilization.
- Supercritical CO₂ foaming (micro-scale performance): supercritical fluid penetrates between molecular chains to form uniform micron-scale closed cells. The all-physical process leaves no chemical residue and reaches a volumetric expansion ratio of 2.5×.

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The precision lattice framework made by SLS carries mechanical loads, while the bubbles introduced by supercritical foaming add light weight and rebound. Together, they aim to provide both a lightweight structure and strong energy return.

Three engineering metrics aimed at professional sports footwear

Technology must work on people's feet and on production lines, not just in presentations. TPM3D reports three metrics:

- Foaming expansion ratio increased to 2.5×, substantially reducing density while retaining the macro-scale mechanical structure.
- Low compression set of 22%–26%. Conventional EVA midsoles typically exceed 40%; TPM3D's midsole is said to retain high rebound after extreme impact, with energy return exceeding 70%.
- No deformation after 200,000 dynamic bending cycles. Conventional DLP photopolymer midsoles can crack after 50,000–100,000 cycles. TPM3D says its product completed 200,000 demanding fatigue-test cycles without irreversible collapse or fracture, addressing the stereotype that 3D-printed shoes are not durable.

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Core process receives a national invention patent

TPM3D's independently developed “fume polishing and supercritical foaming process for 3D-printed parts” has received an invention patent from the China National Intellectual Property Administration (Patent No. ZL202411423188.0). The patent covers the process chain from post-print fume polishing to controlled microcellular foaming, forming a core intellectual-property barrier for 3D-printed footwear.

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Looking ahead: green manufacturing from feedstock to recycling

TPM3D says it has incorporated ESG principles across the process. PEBA thermoplastic powder does not release chemical monomers; physical CO₂ foaming is non-toxic and leaves no residue; unsintered powder can be fully recycled; and worn-out shoes can be physically ground and re-pelletized.

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Nanjixiong's view: the future of 3D-printed shoes depends on mass-production economics

Nanjixiong has previously reported on photopolymer 3D-printed shoes. The industry's persistent concern is that although photopolymerization can form extremely complex lattices, material brittleness and fatigue resistance make it difficult to cross the threshold for everyday wear, let alone mass production.

TPM3D's combination of SLS and supercritical foaming has a clear rationale. SLS reconciles PEBA material with complex structures without tooling. Supercritical foaming gives the material properties associated with athletic footwear: light weight, rebound, and durability. Most importantly, the process avoids molds for personalization and recycles unfused powder at a high rate, aiming to reduce unit cost and production time while meeting professional sports requirements.

After more than 20 years focused on SLS, TPM3D is seeking to reshape how people's feet interact with the ground. This time it is presenting a production-oriented process with both manufacturing economics and performance, rather than just a concept shoe.

AI-translated from an article by Xiaoruanxiong on Nanjixiong, originally published on 2026-11-10. Text and images retain the original source attribution.
Read the original Chinese article

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