Three-dimensional shaping device and method for manufacturing three-dimensional shaped object
A three-dimensional shaping device includes a plasticization unit configured to plasticize a material into a shaping material using a rotating screw; a drive unit configured to rotate the screw; a supply flow path through which the shaping material flows; a nozzle configured to discharge the shaping material; a discharge amount adjusting mechanism configured to switch between stop and restart of discharge of the shaping material from the nozzle by a valve portion provided in the supply flow path; a pressure measuring portion configured to measure a pressure of the shaping material in the supply flow path between the plasticization unit and the valve portion; and a control unit configured to adjust rotation of the screw by controlling the drive unit according to a measured value of the pressure which is measured. The control unit controls the drive unit under a first control during a period when the discharge of the shaping material from the nozzle is not stopped, and controls the drive unit under a second control during a period when the discharge of the shaping material from the nozzle is stopped, and a degree of adjustment of the rotation of the screw under the second control is smaller than a degree of adjustment of the rotation of the screw under the first control.
1. A three-dimensional shaping device, comprising:
a plasticization unit having a screw and configured to plasticize a material into a shaping material using the screw;
a drive unit configured to rotate the screw;
a supply flow path communicating with the plasticization unit and through which the shaping material flows;
a nozzle communicating with the supply flow path and configured to discharge the shaping material;
a discharge amount adjusting mechanism having a valve portion provided in the supply flow path, and configured to switch between stop and restart discharging of the shaping material from the nozzle by driving the valve portion;
a suction portion coupled to the supply flow path between the valve portion and the nozzle, the suction portion being configured to suck the shaping material;
a pressure measuring portion configured to measure a pressure of the shaping material in the supply flow path; and
a control unit configured to adjust rotation of the screw by controlling the drive unit according to a measured value of the pressure measured by the pressure measuring portion, wherein the screw of the plasticization unit is a flat screw having a groove forming surface on which a groove is formed through which the material is supplied, the plasticization unit includes a barrel having a facing surface which faces the groove forming surface, with an opening portion of the supply flow path being provided on the facing surface, and is configured to plasticize the material between the flat screw and the barrel into the shaping material, such that the shaping material flows from the opening portion into the supply flow path, the groove includes a first groove and a second groove, a depth of the first groove is greater than a depth of the second groove, and the second groove is located closer to a center of the flat screw than the first groove, and the control unit adjusts the rotation of the screw by controlling the drive unit without using the measured value which is measured during a period when the shaping material is sucked by the suction portion, wherein the control unit controls the drive unit under a first control during a period when the discharging of the shaping material from the nozzle is not stopped by the discharge amount adjusting mechanism, and controls the drive unit under a second control during a period when the discharging of the shaping material from the nozzle is stopped by the discharge amount adjusting mechanism, and a degree of adjustment of the rotation of the screw under the second control is smaller than a degree of adjustment of the rotation of the screw under the first control.
2. The three-dimensional shaping device according to claim 1 , wherein the control unit is configured to change a rotation speed of the screw according to the measured value under the first control, and rotate the screw at a preset rotation speed under the second control.
3. The three-dimensional shaping device according to claim 1 , wherein
the control unit is configured to,
decrease the rotation of the screw when the measured value exceeds a target value of the pressure, and
increase the rotation of the screw when the measured value falls below the target value.
4. The three-dimensional shaping device according to claim 1 , wherein
the control unit is configured to,
decrease the rotation of the screw when the measured value exceeds a first threshold value which is greater than a target value of the pressure,
increase the rotation of the screw when the measured value falls below a second threshold value which is smaller than the target value, and
not adjust the rotation of the screw when the measured value is equal to or less than the first threshold value and equal to or more than the second threshold value.
5. The three-dimensional shaping device according to claim 1 , wherein
the control unit calculates a moving average value of the pressure using a plurality of measured values, and adjusts the rotation of the screw by controlling the drive unit according to the moving average value.
6. The three-dimensional shaping device according to claim 1 , wherein
the valve portion has a recessed portion configured to communicate with the plasticization unit and the nozzle, and
the discharge amount adjusting mechanism rotates the valve portion about a rotation shaft intersecting a direction from the plasticization unit toward the nozzle to change a position of the recessed portion, so that a flow path cross-sectional area of the supply flow path is changed to adjust a flow rate of the shaping material to be supplied to the nozzle.
7. The three-dimensional shaping device according to claim 1 , wherein
the control unit adjusts the rotation of the screw by controlling the drive unit referring to a table in which a relationship between a rotation speed of the screw and the measured value is expressed.
8. The three-dimensional shaping device according to claim 1 , further comprising:
a heating portion configured to heat the shaping material of the supply flow path between the valve portion and the nozzle, wherein
the control unit adjusts a temperature of the heating portion according to the measured value.
9. The three-dimensional shaping device according to claim 1 , wherein the control unit controls the drive unit under a third control during a period after a maintenance operation of the three-dimensional shaping device and before starting shaping a three-dimensional shaped object, among a period when the discharge of the shaping material from the nozzle is not stopped by the discharge amount adjusting mechanism, and the degree of adjustment of the rotation of the screw under the first control is smaller than a degree of adjustment of the rotation of the screw under the third control.
10. The three-dimensional shaping device according to claim 1 , wherein the control unit is configured to, under the first control, decrease the rotation of the screw when the measured value exceeds a first threshold value which is greater than a target value of the pressure, and increase the rotation of the screw when the measured value falls below a second threshold value which is smaller than the target value, and under the second control, decrease the rotation of the screw when the measured value exceeds a third threshold value which is greater than the target value, and increase the rotation of the screw when the measured value falls below a fourth threshold value which is smaller than the target value, and a difference between the third threshold value and the fourth threshold value is greater than a difference between the first threshold value and the second threshold value.
11. The three-dimensional shaping device according to claim 1 , wherein the control unit is configured to, under the first control, decrease the rotation of the screw when the measured value exceeds a target value of the pressure, and increase the rotation of the screw when the measured value falls below the target value, and under the second control, decrease the rotation of the screw when the measured value exceeds a third threshold value which is greater than the target value, and increase the rotation of the screw when the measured value falls below a fourth threshold value which is smaller than the target value.
12. The three-dimensional shaping device according to claim 1 , wherein under the first control and the second control, the control unit calculates a moving average value of the pressure using a plurality of measured values, and adjusts the rotation of the screw by controlling the drive unit according to the moving average value, and the number of samples of measured values used to calculate the moving average value under the second control is larger than the number of samples of measured values used to calculate the moving average value under the first control.