GMM - Gravellona Macchine Marmo








Average size sawing machine, accurate and fast thanks to brushless motors and rotating elements guides, appropriate both for repetitive processing and for processing of single parts also with vertical or inclined cuts, parallel, orthogonal and oblique. It meets the production needs of small and large series, of complex moulding of profiles, contouring, and of cuts with blade of circumferences.

Mains structures of the machine in cast iron for maximum resistance through time to corrosion, perfect dimensional stability, minimum acoustic resonance; blade cover casing and protection of guides in stainless steel for maximum duration. The superficial protection cycle of the machine includes stripping and immersion in melted zinc bath and double painting layer.

All the motion axes of the machine are run by brushless motors with absolute resolver and Siemens drives.

The horizontal motion of the blade-holder slide (axis X) on ball guides with centralized greasing is driven by a brushless motor and a pinion-rack precision couple synchronized and without play. Guides are protected with casings against water and dust infiltrations. Cut and return speeds of the blade-holder head are electronically regulated independently from the pushbutton station. The cut and return end of stroke of the head can be programmed.

Bridge transfer (axis Y) on ball guides with oil bath and brushless motor and two pinion-rack precision couples synchronized and without play. The fast shifts can be obtained electrically at a variable speed controlled through the relative buttons or automatically according to an adjustable program.

The blade-holder head in the blade upward/downward motion (axis Z) runs vertically on a chrome-plated sleeve of large diameter shifted by a ball screw with adjustable upward and downward end of stroke.

The blade can be inclined (axis R) from 0 to 90 with a reducer without play and can be locked in any position.

The patented spindle motor unit is particular in that the tilt pins are directly obtained in the frame of the motor to obtain a unique mechanical rigidity. Flanged and directly connected to the blade, it has an electronic regulator of rotation speed for the optimal use of tools of different diameter on materials with different characteristics. To execute inclined cuts also with successive strokes, as requested by the hardest materials, the upward/downward motion is interpolated with the tilt on the R axis.

In order to increase productivity in the cutting strokes of hard materials, vertical increases are also interpolated with the horizontal motion, so that the head starts the downward motion even before inverting the stroke.

The blade holder head can be oriented around its vertical axis (axis W) from 0 to 370 with respect to the direction of bridge motion. Head orientation allows the machine to execute parallel, orthogonal and diagonal cuts with respect to bridge direction, without turning the part-holder table, interpolating adequately the motions of the head and of the bridge along the axes X and Y. A laser beam collimator, applied on the blade cover protection to follow its motions, facilitates the operator in the positioning of the blade on the cutting line.

The table is a fixed structure in hot zinc-plated steel with wooden or PVC worktop.

The electrical panel on the floor is equipped with the panel with the basic controls and includes the drives, remote switches, thermal protections, general isolating switch with door locking and operating electronics.

The suspended pushbutton station has a USB connection and 15" touchscreen TFT colour display with double function, display of motion axes positions and control and programming keyboard; the flexible arm supporting the pushbutton allows the operator to approach the table during work preparation; in addition it has a connection to a LAN company network to transfer directly to the machine drawings and works from company computer and also to display the operation of the sawing machine from a remote station far from the working area.

The software of the machine controls the motion axes with the programs for the automatic cut of marbles and granites, in a single stroke or with little increases, in full automatism, also without the operator.

The Tool Point control on rotation (W) and tilt (R) motions of the blade maintains steady the contact point of the diamond segment on the material, adjusting in real time the position on the other axes: the use in manual of the machine becomes easier and faster for the operator and in automatic cycle the execution time is reduced.

With butt cutting cuts can be made between two fixed ends, apart from the vertical position of the blade, essential to obtain accurate dead slots and through cavities of a preset length.

The machine reads directly the .dxf files in cuts from CAD, a function that allows the tilt of each single cut at different angles. The cuts in curve can be set directly in the machine simply storing the arc with 3 points. Profiles and arc templates can be set directly from the pushbutton station. Profiles and templates can be drawn with CAD also associated between them and templates can be trowelled as well. All the machining operations can be made with any orientation angle (W) of the blade and without turning the table, since the software constantly interpolates the shifts of the blade and of the bridge.

Machine safety: pursuant to EC standards with safety barrier with panels, with folding opening, against the shot of fragments, controlled by safety micros and by an intrinsic safety circuit protect the danger area around the blade.

Blade cover casing internally coated by soundproof material.

Safety pressure switch to stop the machine in case of blade refrigeration water failure.

Under-head sensor to stop the machine in case of overload due for example to high forward speed or excessive stroke depth. Load reducer to set the maximum threshold of electrical absorption of blade motor so to protect the tool from stresses higher than the preset value. Electrical and water supplies supported and protected by nylon cable-holder chains from the connection point to machine base down to the electrical panel and from the latter to the operating head.

The refrigeration water supply system of the tool is automatically triggered.

The main points of the machine are supplied by an automatic system of centralized greasing.

On demand the machine can be equipped also with:

- spindle for the use of slot mills and relative programs to carry out contouring works both from .dxf file and from ISO file reading (in this case the work is run by an external CAD-CAM software excluded from the supply)

- SLAB-CAM with camera to detect a slab and position on it as preferred the parts to obtain according to streaks or defects of the material or to reduce the waste to the minimum.