Sand castings with two types of molds

Our molds are made of self-hardening and/or green sand. After pouring these sand castings, the molds are broken and the parts are removed. The sand is then regenerated.

This self-hardening system relies on the use of high furfurilic alcohol content, which is water and phenol-free, and catalyzed by a mild toluene sulfonic acid (TSA).

Sand regenaration

The regeneration of our self-hardening sand enables us to achieve six different objectives, namely:

• Improving the environmental conditions of our exploitation
• Ensuring the quality of our workplace
• Better controlling our production costs
• Ensuring compatibility with green sand
• Maintaining casting integrity
• Enhancing the quality of surface finish of our products.

Below are photos of the mechanical regeneration system used to produce our sand castings :

Improving the environmental conditions of our exploitation

Before the implementation of this furanic system, the silicate-bonded sand was disposed of as landfill and new sand from a local sandpit was introduced into the process daily.

The furanic resin sand system is equipped with programmable controllers and enables us to regenerate the sand through reliable mechanical processes. This new regeneration process allows us to stop releasing used sand into the environment, eliminating nearly 5,000 tons of waste, while reducing the exploitation of the local sandpit. Our current waste is composed only of small quantities of dust, granules and excess green sand, all of which is recycled into other external processes in compliance with applicable regulations. All the foundry processes now  comply with a certificate duly issued by Quebec's Ministry of Environment. This is an actual case where both environmental aspects and industrial concerns are taken into account in keeping with the concept of a lasting developmental approach.

Ensuring the quality of our workplace

For thirty years, the use of an inorganic no-bake sand binding system had helped us maintain unsurpassed quality standards in the workplace, due to the very low quantity of odorless fumes that were released during pouring. In addition, the binder used was hypo-allergenic. In a situation where work environment deterioration is unacceptable, switching to the use of organic binders can represent a great challenge. Our current experience with organic binders has taught us that while there are greater quantities of malodorous fumes than there were while using the former process, they are tolerable. As well, their effects are compensated for by the reduction of airborne dust at the cleaning zone. Here, the fumes are now collected at each individual point of release in the sand regeneration system.

Better controlling our production costs

Although the cost of silica-based sand, which we must now use, is higher than that of the local sand that was formerly used, the quantities needed have been drastically reduced by our regeneration process. This converted furan sand system also reduces the quantity of binder needed.

This molding sand allows us to have a better surface finish. It also reduces the need of using steel reinforcement in the cores.

Despite the additional costs incurred as a result of this new process, due to the necessary disposal of certain amounts of dust, granules, and excess green sand, the increase in the cost of sand has been lowered significantly. The result has been a direct economical advantage for Fonderie Saguenay's clients.

Ensuring compatibility with green sand

Fonderie Saguenay's diversified production requires the use of green sand, which costs much less than no-bake sand, while giving the various types of castings that we produce the highest level of quality possible.

However, this use of two different binder systems requires perfect compatibility between them.

The choice of a furan no-bake sand system provides us with unidirectional compatibility. Indeed, during shakeout operations, small quantities of used furan sand can find their way into the green sand without impairing its properties.

Maintaining casting integrity

Our choice of binder was guided by our desire to minimize the risk of gas defects often associated with organic binder sand systems. After successfully using inorganic binders for so many years, a compromise on this matter was out of the question, considering the kind of production that is called for in Fonderie Saguenay's corporate mission.

Extensive pre-selection trials followed by several months of actual production have clearly shown that the selected systems give our castings excellent integrity even for thick-wall ductile iron.

Enhancing the quality of the surface finish of our products

The previous binder system did not lend itself to efficient recycling, so it was necessary to find a compromise that would allow Fonderie Saguenay to use local sand, the refractory properties of which were far less than ideal. As a result, the surface finish of our castings was subject to penetration and washing by molten metal. To remedy this weakness, special workarounds had to be used, which made the process more prone to human error.

The new furan binder sand system allows for efficient regeneration. The addition of sand - in amounts far inferior to those that where previously needed - can now be made without compromise, using sand with a high silica content. This enables us to achieve the best possible surface finish.