The foundry industry is experiencing escalating pressure to mitigate its environmental impact through increased material recovery and reduced process emissions, writes Andrew Tagg, John Winter & Co Ltd. Concurrently, there is heightened awareness of the chronic health hazards associated with prolonged exposure to volatile organic compounds (VOCs), combustion by-products and particulate matter generated during moulding and casting operations.
Silica sand – the predominant moulding and core making medium – has come under intensified regulatory scrutiny due to the classification of respirable crystalline silica (RCS) as a carcinogenic substance. This classification significantly elevates occupational health and safety liabilities for foundry operators, particularly regarding potential compensation claims and compliance obligations related to worker exposure monitoring, engineering controls and dust mitigation systems.
To mitigate this risk, foundries are being forced to invest more heavily in local exhaust ventilation (LEV) and personal protective equipment (PPE), even as occupational exposure levels continue to tighten. Although several crystalline silica free moulding aggregates are commercially available, their considerably higher material cost renders them economically impractical unless sand reclamation technologies can be optimised to deliver recovery efficiencies above 93 per cent. Additionally, one of the more cost effective alternatives, olivine sand, exhibits poor compatibility with most organic binder systems, limiting its use.
Achieving high levels of reclamation is feasible through the application of thermal reclamation, particularly in systems bonded with PUNB or furan resins. Although multi-stage mechanical attrition processes claim comparable performance, they are associated with sand grain degradation causing loss through dust generation. Although the adoption of thermal reclamation enables replacement of silica sand and the associated health liabilities caused, it does not mitigate hazards from fumes associated during sand mixing, moulding, pouring and knock out. The volatile and thermal decomposition products – including phenol, furfuryl alcohol (EU Category 2 carcinogen), formaldehyde (human carcinogen), sulphur dioxide (a toxic gas) and numerous organic compounds – are generated during binder pyrolysis.
Controlling worker exposure in jobbing foundries remains challenging because of the wide variation in mould sizes (from 0.5m to several metres). This variability makes it difficult to standardise pouring locations and limits the use of LEV systems. Consequently, emissions are often vented through roof exhausts, raising additional concerns about the release of odours and toxic substances into the surrounding environment. In some situations, PPE becomes the primary means of exposure control.
Inorganic binder systems represent a promising approach to reducing fume related risks. Nevertheless, their application is constrained by the difficulty of achieving the high reclamation rates economically, preventing the adoption of the higher cost non crystalline silica aggregates.
HWS V-PROCESS
The V-Process offers a sustainable approach for foundries seeking to minimise long term health liabilities. By eliminating the use of sand binders, the process enables exceptionally high levels of moulding aggregate reuse and can accommodate a wide range of thermally stable aggregates. For example, olivine sand – characterised by superior refractory properties, lower thermal expansion and comparatively low cost – represents a viable alternative to silica.
In addition to enhanced aggregate performance, the V-Process generates significant raw material cost savings through the elimination of binders, catalysts and associated coatings. Despite these advantages, the process has seen limited adoption. This is likely attributable to earlier evaluations in which health, safety and sustainability considerations were undervalued, leading to the perception that its benefits were restricted to cost reduction alone. A direct comparative assessment of conventional methods and the V-Process is therefore essential to fully demonstrate its potential for enabling a sustainable and safe foundry environment.
ORIGINS
The V-Process was developed in Japan in the early 1970s to address shortcomings of conventional chemically bonded sand systems, associated with the poor quality of silica sand resulting in high binder levels and the related emissions, dimensional variability and rework. By combining controlled vacuum with a thermoplastic pattern film, the process forms moulds without chemical binders, creating very high packing density with the associated improved casting dimensional accuracy and surface finish. As patterns are not subjected to chemical attack, abrasion, vibration or impact in moulding pattern stripping, damage and wear is minimised.
The technology has been adopted globally with sixty plants supplied by Heinrich Wagner Sinto (HWS) in the United States, Russia and Europe, particularly in mechanical engineering, valves, railway and structural applications. Today, the V-Process is a mature moulding method well suited to large castings, thin-walled structures and components with demanding surface and dimensional specifications.
SUMMARY OF THE PROCESS
The V-Process employs vacuum to produce dimensionally stable, high density moulds. A thin thermoplastic film is thermoformed over the pattern, allowing the applied vacuum to consolidate and retain the dry, unbonded sand. Following solidification and casting removal, the vacuum is released, enabling the mould to collapse cleanly. This process facilitates exceptionally high reclamation levels, with up to 98 per cent of the sand being immediately reusable.
COMPARISONS BETWEEN V-PROCESS AND OTHER SUSTAINABLE FOUNDRY SYSTEMS
The sustainability potential of the V-Process must be evaluated on equal terms with other moulding technologies. In a conventional foundry, achieving 98 per cent sand reuse requires substantial investment in reclamation systems. Historically, process comparisons were often based on simplified assumptions regarding productivity, capital cost and energy demand – meaning many evaluations were not genuinely like for like.
In practice, the only systems capable of sustaining such high levels of aggregate recovery are chemically bonded processes using ceramic sand combined with thermal reclamation. Even silica sand struggles to reach comparable reuse rates due to grain degradation during mechanical and thermal reclamation. Additionally, the energy consumption associated with these reclamation steps is significant.
It has been assumed that the V-Process requires higher energy consumption because comparisons have been made between a simple no-bake moulding process with simple single attrition sand reclamation. However, when you incorporate the use of thermal reclamation, fume extraction plant and then the energy, the difference is significantly less.
SUMMARY
The V-Process presents a distinct opportunity to achieve full sustainability in foundry operations, specifically within the moulding process, while simultaneously delivering substantial advancements in environmental performance, health and safety standards and product quality. Historically, such considerations played only a limited role in investment evaluations, resulting in comparisons that were not conducted on an equivalent basis. Given the increasing emphasis on environmental compliance and health related liabilities in both present and future contexts, the HWS V-Process now represents a more economically viable and strategically sound option for modern foundry operations.
ACKNOWLEDGEMENTS
The author thanks Heinrich Wagner Sinto Maschinenfabrik Gmbh, Bahnhofstraße 101, D-57334, Bad Laasphe.
For the supporting images/figures, refer to the printed copy of the February/March 2026 issue of Foundry Trade Journal.