MANUFACTURING METHOD OF THERMOSET POLYMERS AND LOW-PRESSURE METERING AND MIXING MACHINE IMPLEMENTING SAID MANUFACTURING METHOD

Abstract

The invention relates to a manufacturing method and a dispensing machine comprising a metering step and particularly a calibration of mass flow of each component, which is completely automatically implemented. Therefore, said dispensing machine of the invention guarantees a reliable calibration, free of operational or input error and is saving operator time.

Claims

1. A manufacturing method of a thermoset polymer comprising at least two components, said manufacturing method comprising: metering each component in accordance with instructions received from a control unit of a dispensing machine, conveying each component to a mixing chamber of the dispensing machine via a conveying member in accordance with instructions received from the control unit, mixing metered components via a mixing element of the mixing chamber to form a mixture in accordance with instructions received from the control unit, dispensing the mixture obtained to a mold or to a container via a dispensing device in accordance with instructions received from the control unit, wherein the manufacturing method comprises at least one calibration step of each component comprising: a) pouring a test-quantity of a component determined by initial parameters to a container arranged on a weighing device of the dispensing machine via a mixing head in accordance with instructions received from the control unit, in order to obtain an actual volume of the component, b) weighing the actual volume via the weighing device of the dispensing machine, c) comparing an actual mass of the actual volume with a theoretical mass determined from the initial parameters used in step a) by using initial relation data between pump size, pump speed and gravity value determined by default during a determined pouring time in accordance with instructions received from the control unit, d) determining, via the control unit, a correction factor from the comparison in step c) and, e) using the correction factor obtained in step d) to modify the initial relation data in a final relation data between output flow rate and pump speed in accordance with instructions received from the control unit, said calibration step being implemented for at least one measuring point defined by a set of different parameters, wherein the metering step is implemented by controlling pump speed to obtain a desired mass flow of the component, the control unit controlling the pump speed by using the final relation data obtained in step e).

2. The manufacturing method according to claim 1, wherein the initial parameters comprise pump speed, pouring time, pump pressure, or a combination thereof.

3. The manufacturing method according to claim 1, wherein the calibration step is implemented for several measuring points.

4. The manufacturing method according to claim 1, wherein steps a) to e) are implemented consecutively.

5. The manufacturing method according to claim 1, wherein the at least one measuring point comprises different pump speeds and wherein pressure is not an initial parameter due to the use of a dynamic pressure regulator on each inlet.

6. The manufacturing method according to claim 1, comprising a step g) wherein the control unit comprises a memory, which records history of final relation data for each component.

7. The manufacturing method according to claim 6, comprising a step h) wherein the control unit uses history records of final relation data to recognize components already calibrated, and a step i) wherein the control unit suggests indications for calibration adjustments and/or pressure adjustments depending upon history records used in step h).

8. The manufacturing method according to claim 1, wherein the dispensing machine and the control unit are designed to dispense multiple outputs with different back pressures generated by the molds.

9. A dispensing machine being configured to manufacture thermoset polymers based on at least two different components, the dispensing machine comprising at least: a control unit, a man-machine interface connected to the control unit, a mixing head equipped with at least two inlets for the at least two components and an outlet and a circuit for each of the at least two components, a pump configured to control the flow of the components, a mixing chamber equipped with a mixing element configured to mix the components together to form a mixture, a dispensing device configured to dispense the mixture obtained in the mixing chamber, wherein the dispensing machine comprises an integrated weighing device arranged in the dispensing device to be movable from at least an inactive position to at least one active position, wherein the weighing device is protrudable from the dispensing device by a translation motion and/or a rotation motion, wherein said weighing device is positioned under the mixing head when in the active position, and wherein the weighing device is connected to the control unit and the control unit is configured to control the weighing device.

10. The dispensing machine according to claim 9, configured to implements the manufacturing method according to claim 1.

11. The dispensing machine according to claim 9, comprising a dynamic pressure regulator.

12. The dispensing machine according to claim 11, wherein the dynamic pressure regulator maintains a constant pressure level independently of a pressure generated downstream from the mixing head.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The invention will be better-understood thanks to the detailed specification hereinafter, which describes an embodiment of the invention as example and based on the following figures.

[0045] FIG. 1 is a graphical representation of initial relation data between output flow rate and pump speed, final relation data and relation data without correction factor,

[0046] FIG. 2 is a side view of the dispensing machine according to the invention,

[0047] FIG. 3 is a perspective view of the dispensing machine according to the invention.

DETAILED DESCRIPTION

[0048] The dispensing machine 100 of the invention illustrated in FIGS. 2 and 3, is a low-pressure metering and mixing machine. The dispense machine 100 is configured to manufacture thermoset polymers based on at least two different components, by implementing a manufacturing method detailed herein after.

[0049] According to the invention and as illustrated in FIGS. 2 and 3, the dispensing machine 100 a control unit 101, a man-machine interface 102 connected to the control unit 101. The dispensing machine 100 comprises a mixing head 103 equipped with at least two inlets 103a for the at least two components and a circuit 103b for each of the at least two components. The components are stored in containers 107. The dispensing machine 100 further comprises a pump 104 configured to control the flow of the components arriving in the mixing head 103, a mixing chamber 105 equipped with mixing element (not illustrated) configured to mix the components together, and a dispensing device (not illustrated) configured to dispense the mixture obtained in the mixing chamber 105 in a mold or a container (not illustrated).

[0050] According to the invention, the dispensing machine 100 comprises a slidably integrated weighting device 106. The weighting device 106 comprises an arm 106a at one extremity of which, a weighting sensor 106b is arranged. The weighting device 106 is configured to be movable from at least an inactive position (illustrated in dotted line in FIG. 2), wherein said weighting device 106 is arranged in the dispensing device 100, to at least one active position wherein the weighting device 106 is protruding from the dispensing device 100 by a translation and/or a rotation. As shown in FIGS. 2 and 3, the weighting device 106 is positioned under the mixing head 103 in the active position.

[0051] The control unit 101 is configured to control all the elements of the dispensing machine 100 such as the mixing head 103 and his inlets preferably equipped with dynamic pressure regulator 103a, the pump 104, the weighting device 106, the mixing chamber 105, the man-machine interface 102.

[0052] In order to manufacture a thermoset polymer, the dispensing machine 100 implements a manufacturing method, which will be described above. First, the operator needs to select or enter the components to be calibrated. This selection or this entry can be implemented in the control unit 100 via the man-machine interface 102. Then, if the inlet 103a are preferably equipped with dynamic pressure regulator the operator can adjust a working pressure above the back pressure needed for the casting process.

[0053] Then, the control unit 101, engages a calibration step calibration for each component. In order to do this, the control unit orders to the weighting device 106 to move into an active position or the operator move the weighting device 106 in an active position. Once the weighting device 106 in an active position, the control unit 101 orders to the mixing head 103 to pour a test-quantity of component determined by initial parameters in a container 1 arranged on a weighting device 106 of the dispensing machine 100, in order to obtain an actual volume of component, as seen in FIGS. 2 and 3. This order is executed only if a container 1 is detected on the weighting device 106. When the container 1 is positioned on the weighting sensor 106b, the presence of said container 1 is detected and the control unit 101 receives such information to start the calibration step.

[0054] The test-quantity of component is poured and the weighting device 106 weights the actual volume of said test-quantity of component. The weighting device 106 sends the weight information to the control unit 101.

[0055] The control unit 101 compares the actual mass of the actual volume with a theoretical mass determined from the initial parameters by using initial relation data between output flow rate and pump speed. The initial relation data is illustrated in FIG. 1 via an interpolation curve represented with squared dots while the actual mass is represented with triangles. For simplification purpose in order to better display the non-linear deviation, the deviation is shown with a multiplication factor and the determined gravity value is 1. The deviation is represented with crosses, and illustrates the difference between the real output and the theoretical output.

[0056] Then, the control unit 101 determines a correction factor at a determined pump speed for the calibration, in the graph it is at 30% of full pump speed, corresponding to the deviation, on the graph 2%.

[0057] As the deviation is not constant and may change with pump speed, for better results, the calibration step is implemented for several measuring points defined by a set of different pump speeds. In a preferred embodiment, if the pressure of each component is stable thanks to the dynamic pressure regulator, it is not necessary to perform calibration points at different pressures. Only the pump speed parameter is enough to get all necessary correction factors. For each zone of the pump speed range, the control unit will be able to meter the component taking into account the appropriate correction factor to deliver the mass flow rate and the amount of product according to the formulation of the component.

[0058] When all measuring points of a component is calibrated, depending upon the operator's choice the control unit may engages the same calibration procedure for the other(s) component(s).

[0059] Then, the control unit orders to at least one conveying member to convey each component in a mixing chamber 105 of the dispensing machine 100 and to a mixing element of the mixing chamber 105 to mix the components metered. Finally, the mixture obtained is dispensed or injected in a mold or in a container.

[0060] The invention is applicable to any low pressure metering and mixing machine, in the example of a three or four component machine which can process a wide range of formulations at different outputs and with different back pressures generated by the molds, if the machine is equipped with the dynamic pressure regulators, the invention is giving a novel, simple (only 3 to 8 measuring points) and automatic way of the calibration with a superior accuracy versus traditional methods.

[0061] Obviously, the invention is not limited to the embodiments described and represented with the annexed drawings. Modifications remain possible, in particular from the point of view of the constitution of the each element or by substitution of technical equivalents, without leaving for all that the scope of the invention.