A mixing and adjusting method for foundry sand includes calculating a total supplied water amount until a compactability (CB) value of mixed sand becomes larger than a lower limit value of a target CB value range, determining the total supplied water amount as a predetermined amount of water associated with an electric resistance of the foundry sand, and determining a ratio of a variation in the CB value corresponding to an additionally supplied water amount from the additionally supplied water amount during an additional water pouring and the CB value of the mixed sand.

Teaching storage means stores teaching data created on the basis of signals from a first pulse generator, a first shaft detector, a second pulse generator, and a second shaft detector, in a storage unit as a sequence control program of molding operation of a self-hardening mold when teaching operation of throwing kneaded self-hardening foundry sand from a discharge port into a molding flask is performed by manually moving a conveyor arm and a kneading arm. Molding playback means reads out the sequence control program from the storage unit to control and drive a first pivot motor and a second pivot motor on the basis of the sequence control program to pivot the conveyor arm and the kneading arm, and then throws the self-hardening foundry sand from the discharge port of the kneading arm into the molding flask to reproduce the molding operation.

Teaching storage means stores teaching data created on the basis of signals from a first pulse generator, a first shaft detector, a second pulse generator, and a second shaft detector, in a storage unit as a sequence control program of molding operation of a self-hardening mold when teaching operation of throwing kneaded self-hardening foundry sand from a discharge port into a molding flask is performed by manually moving a conveyor arm and a kneading arm. Molding playback means reads out the sequence control program from the storage unit to control and drive a first pivot motor and a second pivot motor on the basis of the sequence control program to pivot the conveyor arm and the kneading arm, and then throws the self-hardening foundry sand from the discharge port of the kneading arm into the molding flask to reproduce the molding operation.

Provided is a method of producing foamed sand (s) for forming a sand mold. The foamed sand (s) includes sand particles (p) and foam (f) adhering to surfaces of the sand particles (p). The foam (f) contains water glass (b), water (w), and a surfactant (c). According to the method, an aqueous surfactant solution (e) in which the surfactant (c) is dissolved is frothed to generate froth (d) from the aqueous surfactant solution (e). Then, the generated froth (d), the water glass (b), and the water (w) are kneaded with the sand constituted by the sand particles (p).

Provided is a method of producing foamed sand (s) for forming a sand mold. The foamed sand (s) includes sand particles (p) and foam (f) adhering to surfaces of the sand particles (p). The foam (f) contains water glass (b), water (w), and a surfactant (c). According to the method, an aqueous surfactant solution (e) in which the surfactant (c) is dissolved is frothed to generate froth (d) from the aqueous surfactant solution (e). Then, the generated froth (d), the water glass (b), and the water (w) are kneaded with the sand constituted by the sand particles (p).

To provide a device and a method for detecting, before pouring starts, any misalignment between a cope and a drag that have been molded by a flaskless molding machine and then assembled. The device (40) that can detect any misalignment between the cope (2) and the drag (3) that have been molded by the flaskless molding machine (1) and then assembled and that are being transported to the position for pouring comprises a plurality of means (51), (52), (53) for measuring distances to the cope and the drag that measures the distances (S11), (S12), (S13), (S21), (S22), (S23) to the cope and the drag, and a means (48) for calculating a degree of a misalignment between the cope and the drag on a basis of the distances to the cope and the drag that have been measured by the means for measuring distances to the cope and the drag.

To provide a device and a method for detecting, before pouring starts, any misalignment between a cope and a drag that have been molded by a flaskless molding machine and then assembled. The device (40) that can detect any misalignment between the cope (2) and the drag (3) that have been molded by the flaskless molding machine (1) and then assembled and that are being transported to the position for pouring comprises a plurality of means (51), (52), (53) for measuring distances to the cope and the drag that measures the distances (S11), (S12), (S13), (S21), (S22), (S23) to the cope and the drag, and a means (48) for calculating a degree of a misalignment between the cope and the drag on a basis of the distances to the cope and the drag that have been measured by the means for measuring distances to the cope and the drag.

When pressing kneaded sand in a kneading sand tank into a mold by a pressing member, a pressing force applied to a kneaded sand layer in the kneading sand tank is monitored and a moving position of the pressing member is monitored from when the pressing member starts to move. A pressing start time at which the kneaded sand starts to flow into the mold is identified based on the pressing force applied to the kneaded sand layer in the kneading sand tank, and a pressing starting position of the pressing member at the pressing start time is identified. As a result, the pressing start time and the pressing starting position of the pressing member when the kneaded sand starts to flow into the mold are accurately identified, so the reliability of a filling evaluation of the kneaded sand into the mold is improved.

When pressing kneaded sand in a kneading sand tank into a mold by a pressing member, a pressing force applied to a kneaded sand layer in the kneading sand tank is monitored and a moving position of the pressing member is monitored from when the pressing member starts to move. A pressing start time at which the kneaded sand starts to flow into the mold is identified based on the pressing force applied to the kneaded sand layer in the kneading sand tank, and a pressing starting position of the pressing member at the pressing start time is identified. As a result, the pressing start time and the pressing starting position of the pressing member when the kneaded sand starts to flow into the mold are accurately identified, so the reliability of a filling evaluation of the kneaded sand into the mold is improved.

The moulding machine includes a moulding chamber having at least one chamber end wall provided with a pattern plate adapted to form a pattern in a mould part and associated with a reference pattern block positioned in fixed relationship to a pattern of said pattern plate and adapted to form a reference pattern in an external face of a mould part. The reference pattern block includes a face having a tangent varying in a longitudinal direction of the moulding chamber and being adapted to form a corresponding reference pattern in the sand mould part. A non-contact detection system (87) detects the position of a number of different points (P.sub.1, P.sub.2) distributed over the pattern face of the reference pattern in the longitudinal direction of the sand mould part, and the tangent (T.sub.1, T.sub.2) in the longitudinal direction of the sand mould part is different between at least two of said points.