CN108127919B - Scraper calibration method, three-dimensional object manufacturing equipment and powder spreading device thereof - Google Patents
Scraper calibration method, three-dimensional object manufacturing equipment and powder spreading device thereof Download PDFInfo
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- CN108127919B CN108127919B CN201711377879.1A CN201711377879A CN108127919B CN 108127919 B CN108127919 B CN 108127919B CN 201711377879 A CN201711377879 A CN 201711377879A CN 108127919 B CN108127919 B CN 108127919B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
- B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
Abstract
The invention relates to a scraper calibration method, which comprises the following steps of 1) detecting and acquiring actual distance values of a plurality of to-be-detected points which are connected into a straight line in the area covered by a scraper on a powder paving surface in the moving process from a preset detection surface; 2) judging whether the scraper is damaged or worn according to the actual distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface and the preset theoretical distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface; and the preset detection surface is a plane parallel to the powder spreading surface. Compare manual observation and detect, according to predetermineeing the difference between actual distance value and the preset theoretical distance value between the detection face and the powder face of spreading between a plurality of the check points of treating, whether can in time discover the scraper damage or wear and tear, or whether keep the level, detect the accuracy height to guarantee printing quality. Also provides three-dimensional object manufacturing equipment and a powder laying device thereof.
Description
Technical Field
The invention relates to the field of additive manufacturing, in particular to a scraper calibrating method, three-dimensional object manufacturing equipment and a powder spreading device thereof.
Background
Additive Manufacturing (AM) is an advanced Manufacturing technology with the advantages of digital Manufacturing, high flexibility and adaptability, direct CAD model driving, rapidness, rich and diverse material types, and the like. Among them, Selective Laser Melting (SLM) is one of the additive manufacturing technologies that have been rapidly developed in recent years, in which a powder material is used as a raw material, and Laser is used to scan the cross section of a three-dimensional entity layer by layer to complete prototype manufacturing, which is not limited by the complexity of the shape, does not require any tooling mold, and has a wide application range.
The selective laser melting process includes feeding certain amount of powder to the bench, spreading one layer of powder material on the upper surface of the formed part in the forming cylinder, controlling the laser to scan the powder layer in the solid part according to the cross section contour of the layer to raise the temperature of the powder to the melting point, and melting and sintering the powder to adhere the formed part. After the sintering of one layer of section is finished, the workbench descends by the thickness of one layer, the powder laying device lays a layer of uniform and compact powder on the workbench, and the scanning sintering of the section of a new layer is carried out until the manufacturing of the whole three-dimensional object is finished.
At present, a scraper becomes a common component of a powder spreading device, the control precision of the scraper plays a crucial role in manufacturing the whole three-dimensional object, if the scraper is damaged or abraded, the printing quality of a workpiece is poor, and even printing failure is caused, so that huge loss is brought. Generally, during the printing process, an operator finds out that the scraper is damaged through observation and manually replaces the scraper, but the operator cannot find out the abrasion of the scraper and cannot find out the damage of the scraper in time, so that the quality of a workpiece is affected.
Disclosure of Invention
Therefore, the scraper calibration method, the three-dimensional object manufacturing equipment and the powder spreading device thereof are needed to be provided for adaptively detecting, adjusting and calibrating the damage and the abrasion of the scraper aiming at the problem that the quality of a workpiece is affected because the traditional scraper cannot be timely found out of the abrasion or the damage.
A blade calibration method for three-dimensional object manufacturing, comprising the steps of:
1) detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder spreading surface in the moving process from a preset detection surface;
2) judging whether the scraper is damaged or worn according to the actual distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface and the preset theoretical distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface;
and the preset detection surface is a plane parallel to the powder spreading surface.
The scraper calibration method for three-dimensional object manufacturing in this application compares manual observation and detects, according to predetermineeing the difference between the actual distance value between the detection face and the powder surface of spreading a plurality of points of waiting to detect and predetermineeing theoretical distance value, can in time discover whether the scraper damages or wearing and tearing, or whether keep the level, detects the accuracy height to guarantee printing quality.
In one embodiment, the step 2) specifically includes the steps of:
acquiring an actual absolute difference value between the actual distance value corresponding to each point to be detected and the preset theoretical distance value;
comparing the actual absolute difference value with a first preset absolute difference value and a second preset absolute difference value; when the actual absolute difference value corresponding to any one point to be detected in the multiple points to be detected is larger than or equal to a first preset absolute difference value and smaller than or equal to a second preset absolute difference value, judging that the scraper is worn; and when the actual absolute difference value corresponding to any one point to be detected in the plurality of points to be detected is larger than a second preset absolute difference value, judging that the scraper is damaged.
In one embodiment, the step 2) specifically includes the steps of:
establishing a two-dimensional coordinate graph according to the position information of each point to be detected along the longitudinal direction of the scraper, and the actual distance value and the preset theoretical distance value corresponding to each point to be detected;
and judging whether the scraper is damaged or abraded according to the two-dimensional coordinate graph.
In one embodiment, the plurality of detection points are located upstream of the powder laying surface in the powder laying direction.
In one embodiment, the method further comprises the steps of:
when the scraper is damaged, replacing the scraper, and adjusting the replaced scraper to be positioned at a preset mounting position; or
When the scraper is worn, the scraper is adjusted to be located at the preset installation position.
In one embodiment, the method further comprises a verification step of:
verifying whether the adjusted scraper is in a preset mounting position; and if the adjusted scraper is not at the preset installation position, readjusting the scraper until the scraper is at the preset installation position.
In one embodiment, the verifying step specifically includes the steps of:
powder spreading: laying a next layer of powder material on the cured layer;
a detection step: detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder spreading surface in the moving process from a preset detection surface;
acquiring an actual absolute difference value between an actual distance value of the point to be detected on the powder spreading surface after the powder spreading is carried out again and a preset detection surface and a preset theoretical distance value, and comparing the actual absolute difference value with a preset adjustment value; and if the actual absolute difference value is larger than the preset adjusting value, readjusting the scraper and returning to the powder spreading step until the scraper is at the preset mounting position.
In one embodiment, the connection lines of the points to be detected are straight lines, broken lines or curved lines.
Powder spreading device for manufacturing three-dimensional objects, comprising:
the detection unit is used for detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder laying surface in the moving process from a preset detection surface;
and the processing unit is connected with the detection unit and is used for judging whether the scraper is damaged or worn according to the actual distance value of the plurality of points to be detected on the powder spreading surface from the preset detection surface and the preset theoretical distance value of the plurality of points to be detected on the powder spreading surface from the preset detection surface.
In one embodiment, the processing unit includes:
the calculation unit is used for calculating and obtaining an actual absolute difference value between an actual distance value of each point to be detected on the powder spreading surface and a preset detection surface and a preset theoretical distance value;
the comparison and judgment unit is used for comparing the actual absolute difference value with a first preset absolute difference value and a second preset absolute difference value; when the actual absolute difference value corresponding to any one point to be detected in the multiple points to be detected is larger than or equal to a first preset absolute difference value and smaller than or equal to a second preset absolute difference value, judging that the scraper is worn; and when the actual absolute difference value corresponding to any one point to be detected in the plurality of points to be detected is larger than a second preset absolute difference value, judging that the scraper is damaged.
In one embodiment, the method further comprises:
a powder groove seat;
the scraper mounting seat is arranged on the powder groove seat, and the plurality of scrapers are arranged on the scraper mounting seat so as to be capable of operably replacing the next scraper and enable the powder material to be paved on a powder paving surface;
the detection unit comprises at least one distance sensor arranged on the powder groove seat, and the at least one distance sensor is electrically connected with the processing unit.
In one embodiment, the powder spreading machine further comprises a driving mechanism connected with the processing unit, wherein the driving mechanism is installed on the powder groove seat and connected with the scraper installation seat to drive the scraper installation seat to move, so that the next scraper is replaced, and the driving mechanism is further used for spreading powder materials to a powder spreading surface.
In one embodiment, the device further comprises a scraper height adjusting mechanism connected with the processing unit, wherein the scraper height adjusting mechanism is used for adjusting the height of the scraper to be kept horizontal and adjusting the height of the scraper along the vertical direction.
In one embodiment, the powder groove cleaning device further comprises a distance sensor moving mechanism, wherein the distance sensor moving mechanism is arranged on the powder groove seat and used for driving the distance sensor to move in a preset range along the lengthwise direction of the scraper.
The three-dimensional object manufacturing equipment comprises the powder laying device for manufacturing the three-dimensional object.
Drawings
FIG. 1 is a flow chart of a blade calibration method for three-dimensional object manufacturing in one embodiment of the present invention;
FIG. 2 is a flow chart of a blade calibration method for three-dimensional object manufacturing in another embodiment of the present invention;
fig. 3 is a two-dimensional coordinate diagram of the position information of the point to be detected along the longitudinal direction of the scraper when the scraper is in a normal state, and the actual distance value and the preset theoretical distance value corresponding to the point to be detected in the embodiment of the present invention;
FIG. 4 is a diagram illustrating a state of a powder spreading surface after powder spreading when the scraper is in a damaged state according to an embodiment of the present invention;
fig. 5 is a two-dimensional coordinate diagram of the position information of the point to be detected along the longitudinal direction of the scraper, the actual distance value and the preset theoretical distance value corresponding to the point to be detected when the scraper shown in fig. 4 is in a damaged state;
fig. 6 is a two-dimensional coordinate diagram of the position information of the point to be detected along the longitudinal direction of the scraper when the scraper is in a worn state and the actual distance value corresponding to the point to be detected in the embodiment of the present invention;
FIG. 7 is a block diagram of a powder laying apparatus for fabricating a three-dimensional object according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a powder laying device for manufacturing a three-dimensional object according to an embodiment of the present invention.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Before describing the blade calibration method in detail, the related contents of the three-dimensional object sintering apparatus using the selective laser sintering process will be described first, so as to better understand the technical solution of the blade calibration method in the present invention.
The selective laser sintering is to finish the manufacture of the whole three-dimensional object by adopting a layer-by-layer sintering and stacking method, namely, after the sintering of one layer of cross section is finished, the workbench descends by the thickness of one printing layer, the powder laying device lays a layer of uniform and compact powder on the powder laying layer, the scanning sintering of the cross section of a new layer is carried out, and the whole three-dimensional object is manufactured after the scanning stacking of a plurality of layers.
The powder spreading device generally comprises a powder feeding box and a powder spreading roller and a scraper mechanism which are arranged below the powder feeding box, powder in the powder feeding box falls down through a gap between the powder spreading roller and the scraper mechanism and one side wall of the powder feeding box to finish powder feeding, and the scraper mechanism finishes laying uniform and compact powder. The applicant of the application finds that in the printing process, the scraper is in contact with a powder material, and even the sintered section is warped due to the heat effect, so that the powder spreading movement of the scraper is blocked, the scraper is possibly abraded, damaged or inclined, and the printing quality is affected. At present, the prior art judges whether the scraper is damaged through the naked eye, and carries out the change and the regulation of scraper by hand, and it is relatively poor to detect the accuracy, and the change process is loaded down with trivial details, and can't discover the wearing and tearing of scraper, leads to printing quality to receive the influence.
Therefore, the invention provides a scraper calibration method for self-adaptively detecting, adjusting and calibrating the damage and the abrasion of the scraper, three-dimensional object manufacturing equipment and a powder spreading device thereof.
As shown in fig. 1, a doctor blade calibration method in an embodiment of the present invention includes the following steps:
s120: detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder spreading surface in the moving process from a preset detection surface;
the powder spreading surface is a cross section surface of the three-dimensional object to be manufactured corresponding to the working plane, and the preset detection surface is a plane which is fixed with the scraper in distance and is parallel to the powder spreading surface.
In one embodiment, the three-dimensional object manufacturing apparatus has a forming cylinder with an upward opening, in which a support for supporting a three-dimensional object to be formed is disposed, the support being movable up and down in the forming cylinder in a vertical direction. The upper edge of the forming cylinder defines the working plane, a scanning laser is arranged on the working plane, emitted scanning beams are guided into the working plane through a scanning deflection mirror to be scanned, and the scanning area position is the cross section position of the three-dimensional object to be manufactured corresponding to the working plane.
The preset detection surface can be a plane where a detection end of the distance detection device positioned above the powder spreading surface is located, the powder spreading surface is provided with a plurality of points to be detected in a coverage area in the moving process of the scraper, and the distance detection device can be used for detecting and acquiring actual distance values of the points to be detected from the preset detection surface.
The connecting line of the plurality of points to be detected can be a straight line, a broken line or a curve. In one embodiment, the distance detection device is fixedly or movably arranged on the powder spreading device, the powder spreading device stops at a preset position along the powder spreading direction, the plurality of points to be detected can be arranged at intervals or continuously along the longitudinal direction of the scraper corresponding to the distance detection device, and the connecting line is a straight line of the points to be detected.
For example, in another embodiment, the distance detection devices are arranged at two sides of the scraper in a staggered manner along the longitudinal direction of the scraper, and the distance detection points to be detected and the distance detection devices correspond to the detection points to be detected at two sides of the scraper in a one-to-one manner in a staggered manner along the longitudinal direction of the scraper. At this time, the connection lines of the points to be detected are broken lines.
In another embodiment, the distance detection device is fixedly or movably disposed on the powder spreading device, and the powder spreading device simultaneously detects the powder in the powder spreading direction, so that the plurality of points to be detected may also be the detection points which are continuously arranged in the area covered by the scraper corresponding to the distance detection device in the moving process. At this time, the connection line of the plurality of points to be detected is a curve.
It should be understood that the plurality of points to be detected may be a plurality of points to be detected spaced apart by a predetermined distance in the width direction of the powder spreading surface (the longitudinal direction of the scraper), or may be a plurality of points to be detected continuously in the area covered by the scraper during the movement of the scraper, which is not limited herein. For example, in one embodiment, a plurality of distance detection devices are fixedly arranged in the area covered by the scraper in the moving process on the powder spreading device, and the plurality of points to be detected are detection points corresponding to the plurality of distance detection devices one to one, and at this time, the plurality of points to be detected are arranged at intervals. In another embodiment, a distance detection device is movably arranged on the powder spreading device in the area covered by the scraper in the moving process, and the points to be detected are a plurality of continuous points to be detected corresponding to the distance detection device.
It is emphasized that the detection range of the distance detection means should cover the length range of the doctor blade or be arranged in the longitudinal direction of the doctor blade. Correspondingly, a plurality of points to be detected are arranged from one side edge of the powder spreading surface to the opposite other side edge, so that the completeness of scraper damage or abrasion detection is ensured.
S130: judging whether the scraper is damaged or worn according to the actual distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface and the preset theoretical distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface;
although not wishing to be bound by theory, the applicant has found in its research that, in an ideal situation, the doctor blade uniformly spreads the powder over the upper surface of the support or the solidified powder layer by the thickness of the printing layer, and the height of the drop of the support should be the thickness of the printing layer, at which time the distance of the predetermined detection surface from the powder spreading surface should have a theoretical constant value. Repeated research and verification show that the flatness and the thickness of the powder spreading surface change after the scraper is damaged or worn, and the flatness and the thickness of the powder spreading surface also change when the scraper is not kept horizontal.
Therefore, when the actual distance value detected by the point to be detected is different from the preset theoretical distance value, whether the scraper is damaged or abraded can be judged according to the difference, or whether the scraper is kept horizontal can be judged, and when the scraper is normal, powder can be laid next time. Compared with manual observation and detection, the scraper calibration method in the embodiment can find whether the scraper is damaged or worn or whether the scraper keeps horizontal or not in time according to the difference between the actual distance value and the preset theoretical distance value between the preset detection surface and the plurality of points to be detected on the powder spreading surface, and the detection accuracy is high, so that the printing quality is ensured.
Referring to fig. 2, in an embodiment, the step S130 includes:
s132: acquiring an actual absolute difference value between the actual distance value corresponding to each point to be detected and the preset theoretical distance value;
the position variable of a plurality of points to be detected along the longitudinal direction (the width direction of the powder spreading surface) of the scraper is l, and the preset theoretical distance value of each point to be detected is D0lThe actual distance value of each point to be detected is D1lThen the actual absolute difference between the two is Δl＝D1l-D0l. In one embodiment, the distance detection device is movable along the longitudinal direction of the scraper, so that the actual distance value and the preset theoretical distance value of a plurality of continuous points to be detected within the length range of the scraper can be detected and obtained, and the actual absolute difference value of the actual distance value and the preset theoretical distance value is obtained through calculation. Of course, in other embodiments, the actual absolute difference values of the multiple points to be detected within the range of the length of the scraper may be obtained by multiple fixed distance detection devices.
S134: comparing the actual absolute difference value with a first preset absolute difference value and a second preset absolute difference value;
when the actual absolute difference value corresponding to any one point to be detected in the multiple points to be detected is larger than or equal to a first preset absolute difference value and smaller than or equal to a second preset absolute difference value, judging that the scraper is worn; and when the actual absolute difference value corresponding to any one point to be detected in the plurality of points to be detected is larger than a second preset absolute difference value, judging that the scraper is damaged.
In an ideal state, when the actual distance value of each point to be detected is equal to the preset theoretical distance value, namely the absolute difference value of the actual distance value and the preset theoretical distance value is 0, the scraper is not damaged or abraded and is kept horizontal; when the scraper is damaged (chipped) or worn, the actual absolute difference value of at least one point to be detected is not 0. However, due to various factors such as the detection accuracy of the distance detection means and the moving accuracy of the support for supporting the three-dimensional object to be molded in the molding cylinder, the actual absolute difference is allowed to fluctuate within a certain tolerance range in order to ensure the printing quality, and therefore, there exist a lower limit threshold value and an upper limit threshold value, i.e., the aforementioned first preset absolute difference value and the second preset absolute difference value.
In one embodiment, the second predetermined absolute difference is one powder coating thickness, but in other embodiments, the first predetermined absolute difference and the second predetermined absolute difference may be set according to specific situations, and are not limited herein. When the actual absolute difference value corresponding to any one of the multiple points to be detected is greater than a second preset absolute difference value (one powder spreading layer is thick), the scraper can be determined to be damaged (with a gap), and when the actual absolute difference value corresponding to any one of the multiple points to be detected is greater than or equal to the first preset absolute difference value and less than or equal to the second preset absolute difference value, the scraper is determined to be worn.
In particular, in order to facilitate an operator to acquire the condition that the scraper is damaged or worn, the actual distance value, the preset theoretical distance value and the actual absolute difference value of each point to be detected can be recorded and displayed in a chart form, and the comparison result of the actual absolute difference value and the preset theoretical difference value is displayed in the chart.
In another embodiment, the step S130 includes the steps of:
establishing a two-dimensional coordinate graph according to the position information of each point to be detected along the longitudinal direction of the scraper, and the actual distance value and the preset theoretical distance value corresponding to each point to be detected;
judging whether the scraper is damaged or abraded according to the two-dimensional coordinate graph;
for convenience of explanation, please refer to fig. 3 to 6, wherein fig. 3 shows a two-dimensional coordinate graph of the position information of the point to be detected along the longitudinal direction of the scraper when the scraper is in a normal state, and an actual distance value and a preset theoretical distance value corresponding to the point to be detected; FIG. 4 is a view showing a state of the powder spreading surface after the powder spreading when the scraper is in a damaged state; FIG. 5 is a two-dimensional graph showing the position information of the point to be detected along the longitudinal direction of the scraper when the scraper is in a damaged state, and the actual distance value and the preset theoretical distance value corresponding to the point to be detected; fig. 6 shows a two-dimensional graph of the position information of the point to be detected in the longitudinal direction of the doctor blade in a worn state and the actual distance value corresponding to the point to be detected.
As can be seen from fig. 3, when the scraper is in a normal state, the actual distance value of each point to be detected coincides with the two-dimensional point of the preset theoretical distance value in the two-dimensional coordinate graph, that is, the actual distance value and the preset theoretical distance value corresponding to the point to be detected are connected to form a straight line along with the change of the position information of the point to be detected. As can be seen from fig. 4, when the scraper is damaged, the scratch a is caused on the powder spreading surface 20, and referring to fig. 5, when the scraper is damaged, the damaged position of the scraper is a broken line on the connection line of the ordinate corresponding to the abscissa in the two-dimensional coordinate graph, and meanwhile, the actual absolute difference value of at least one point to be detected is greater than one powder spreading layer thickness (0.1 mm). As can be seen from fig. 6, after the scraper is worn, the actual distance value corresponding to the point to be detected changes along with the position information of the point to be detected, and the vertical coordinate, that is, the actual absolute difference value (0.05 mm) corresponding to any point to be detected in the plurality of points to be detected is greater than the first preset absolute difference value and less than the thickness (0.1 mm) of the powder spreading layer.
Thus, whether the scraper is damaged or abraded can be judged.
Further, the coordinate points in the interval which is greater than or equal to the first preset absolute difference value and less than or equal to the second preset absolute difference value and the coordinate points in the interval which is greater than the second preset absolute difference value are visually displayed so as to visually acquire the judgment information. In particular, in the embodiment, the visual display can be realized through the differentiation of colors.
In one embodiment, the plurality of points to be detected are located at upstream positions on the dusting surface 20 in the dusting direction.
Taking the powder feeding as an example, in one embodiment, the powder feeding box stores powder for sintering the workpiece, and the powder paving device completes powder paving during movement along the working plane. In another embodiment, the powder is supplied by upward movement of the support of the powder supply cylinder.
The applicant researches and discovers that the situation that the powder is insufficient in the powder paving process can exist in both the upper powder feeding mode and the lower powder feeding mode, and the accuracy of the detection and calibration result can be ensured only when the powder paving surface 20 is fully paved with the powder. Therefore, the plurality of points to be detected are located at the upstream position of the powder spreading surface 20 along the powder spreading direction, so that the powder layer can be fully spread on the powder spreading surface 20 in the region corresponding to the detection position, and the detection and calibration precision is improved.
It should be noted that the upstream position of the powder placement surface 20 in the powder placement direction is specifically a position located forward (near the initial powder placement position) of the middle position of the powder placement surface 20.
In one embodiment, the step S120 further includes the steps of:
s110: laying down a next layer of powder material on the carrier or the cured layer;
specifically, when the scanning sintering of one layer of section of the three-dimensional object to be manufactured is finished, the powder laying device lays a layer of uniform and compact powder on the solidified layer, and the scanning sintering of the section of a new layer is carried out.
Referring to fig. 2, in one embodiment, the method for calibrating the scraper further includes the steps of:
s140: when the scraper is damaged, replacing the scraper, and adjusting the replaced scraper to be positioned at a preset mounting position; or
S150: when the scraper is worn, the scraper is adjusted to be located at a preset installation position.
The preset installation position is a position which enables the powder spreading surface 20 (the bottom surface of the scraper) of the replaced scraper or the adjusted scraper to be kept horizontal and to be away from the working plane by a certain distance, so that the effects of leveling and uniform powder spreading and consistent powder spreading layer thickness are achieved. In particular to the embodiment, the preset mounting position is a position with a fixed height from the working plane.
Taking the wear of the blade as an example, the wear amount of the blade is DWear and tearThen the scraper is adjusted to descend DWear and tearAnd keeping the distance to be horizontal, so that the distance from the bottom of the scraper to the working plane is within an error allowable range; taking the scraper damaged as an example, the replaced scraper is adjusted to keep the scraper horizontal, and the distance from the bottom of the scraper to the working plane is within an error allowable range.
In one embodiment, the method further comprises the step of verifying:
s160: and verifying whether the adjusted scraper is in a preset mounting position, and if not, readjusting the scraper until the scraper is in the preset mounting position.
And if the adjusted scraper is positioned at the preset installation position, performing powder laying detection for the next time or finishing the detection and adjustment of the scraper.
In one embodiment, the verifying step S160 specifically includes the steps of:
s162: laying a next layer of powder material on the cured layer;
s164: detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder spreading surface in the moving process from a preset detection surface;
s166: acquiring an actual absolute difference value between an actual distance value of the point to be detected on the powder spreading surface after the powder spreading is carried out again and a preset detection surface and a preset theoretical distance value, and comparing the actual absolute difference value with a preset adjustment value; and if the actual absolute difference value is larger than the preset adjusting value, readjusting the scraper and returning to the step S162 until the scraper is at the preset mounting position.
Specifically, after the scraper is replaced or adjusted, the powder is spread again and is detected, and if the actual absolute difference value between the actual distance value from the point to be detected on the powder spreading surface 20 to which the powder is spread again and the preset detection surface is detected to be larger than the preset adjustment value, the scraper is adjusted again. And when the sum of the actual absolute difference value between the actual distance value of the point to be detected on the powder spreading surface 20 after the powder is re-spread and the preset detection surface and the preset theoretical distance value is less than or equal to the preset adjustment value, finishing the replacement of the scraper or finishing the adjustment of the scraper.
Therefore, the scraper can be ensured to be horizontal, the flatness and the thickness of the powder spreading surface 20 are improved, the sintering quality of workpieces is improved, and the sintering success rate is improved.
It should be noted that the preset adjustment value is an upper limit value of the adjustment range of the height of the scraper, and may be determined according to the characteristics of the scraper, and is not limited herein. Generally, to ensure the accuracy, the preset adjustment value is smaller than the second preset absolute difference value.
As shown in fig. 7, another embodiment of the present invention also provides a powder laying device 10 for manufacturing a three-dimensional object, the powder laying device 10 including:
the detection unit 12 is used for detecting and acquiring actual distance values of a plurality of to-be-detected points which are connected in a straight line in a coverage area in the movement process of the scraper on the powder laying surface 20 from a preset detection surface;
and the processing unit 14 is connected with the detection unit 12, and the processing unit 14 is used for judging whether the scraper is damaged or worn according to the actual distance value of the plurality of points to be detected on the powder spreading surface 20 from the preset detection surface and the preset theoretical distance value of the plurality of points to be detected on the powder spreading surface 20 from the preset detection surface.
Compared with manual inspection, the powder spreading device 10 for manufacturing the three-dimensional object in the embodiment can find whether the scraper is damaged or worn or whether the scraper is kept horizontal or not in time according to the difference between the actual distance value and the preset theoretical distance value between the preset detection surface and the plurality of points to be detected on the powder spreading surface 20, and has high detection accuracy, so that the printing quality is superior to that of the prior art.
In one embodiment, the processing unit 14 includes:
a calculating unit 142, configured to calculate and obtain an actual absolute difference between an actual distance value from a point to be detected on the powder spreading surface 20 to a preset detection surface and a preset theoretical distance value;
and a comparison and judgment unit 144 for comparing the actual absolute difference value with a preset absolute difference value to judge the blade damage or wear.
In one embodiment, the comparing and determining unit 144 is specifically configured to compare the actual absolute difference value with a first preset absolute difference value and a second preset absolute difference value; when the actual absolute difference value corresponding to any one point to be detected in the multiple points to be detected is larger than or equal to a first preset absolute difference value and smaller than or equal to a second preset absolute difference value, judging that the scraper is worn; and when the actual absolute difference value corresponding to any one point to be detected in the plurality of points to be detected is larger than a second preset absolute difference value, judging that the scraper is damaged.
In another embodiment, the processing unit 14 includes:
the image generating unit is used for establishing a two-dimensional coordinate graph according to the position information of each point to be detected along the longitudinal direction of the scraper, and the actual distance value and the preset theoretical distance value corresponding to each point to be detected;
and the analysis unit judges whether the scraper is damaged or worn according to the two-dimensional coordinate graph.
In one embodiment, the analyzing unit is specifically configured to determine that the scraper is normal when the actual distance value of each point to be detected coincides with a two-dimensional point of a preset theoretical distance value in a two-dimensional coordinate graph, that is, a connection line between the actual distance value and the preset theoretical distance value corresponding to the point to be detected changes along with the position information of the point to be detected is a straight line. And when the connecting line of the scraper on the ordinate corresponding to the abscissa in the two-dimensional coordinate graph is a broken line and/or a curve and the actual absolute difference value of at least one point to be detected is larger than the thickness of one powder spreading layer, judging that the scraper is damaged (has a gap). When the actual distance value corresponding to the point to be detected changes along with the position information of the point to be detected, the connecting line is a straight line, and the ordinate, namely the actual absolute difference value corresponding to any point to be detected in the plurality of points to be detected is smaller than the thickness of one powder spreading layer and larger than a first preset absolute difference value, the scraper abrasion is judged.
It should be understood that the comparison determination unit 144 and the analysis unit in the above embodiments are not necessary, and may also be determined by manual comparison, and are not limited herein.
In one embodiment, referring to fig. 8, the powder spreading device 10 for manufacturing a three-dimensional object further includes a powder groove base 16 and a scraper mounting base 18, wherein the scraper mounting base 18 is installed on the powder groove base 16, and a plurality of scrapers are installed on the scraper mounting base 18 so as to be capable of operatively replacing the next scraper to spread the powder material onto the powder spreading surface 20. The detecting unit 12 includes at least one distance sensor 15 disposed on the powder tank base 16, and the at least one distance sensor 15 is electrically connected to the processing unit 14.
Specifically, in the embodiment, the powder spreading device 10 further includes a roller with a plurality of grooves and an inner partition plate, inner walls of two sides of the powder chute base 16 respectively extend inwards to form a first inner cavity and a second inner cavity in sequence from top to bottom inside the powder chute base 16, and a through hole is formed between the first inner cavity and the second inner cavity. The roller is located the second inner chamber, and roller and opening interference fit, and scraper mount pad 18 sets up in the second cavity, and the inner baffle is used for half surrounding scraper mount pad 18 and is located the roller below, and the inner wall of inner baffle and 16 both sides of powder groove seat forms first passageway and second passageway respectively to make the powder of storing in the first cavity fall from first passageway or second passageway under the motion of roller. The scraper comprises two or more sheets for spreading the powder falling from the first or second channel to the working plane.
The distance sensor 15 comprises a distance sensor 15, and the distance sensor 15 is movably arranged on the powder groove seat 16 along the lengthwise direction of the scraper and reciprocates within the length range (between the position B and the position C) of the scraper, so that the distance between a plurality of points to be detected on the powder laying surface 20 in the coverage area during the movement of the scraper and a preset detection surface is detected and obtained. Of course, in other embodiments, two or more distance sensors 15 may be provided, which is not limited herein.
It is understood that the powder laying device 10 may be configured in other forms, and is not limited herein.
It is understood that the distance sensor 15 may be plural, and plural distance sensors 15 are disposed on the powder tank seat 16 at intervals in the coverage area during the scraper moving process, which is not limited herein.
It is understood that the distance sensor 15 can be fixed on the powder tank seat 16, and is not limited herein.
Further, the powder spreading device 10 further comprises a driving mechanism 19 connected to the processing unit 14, wherein the driving mechanism 19 is installed on the powder tank base 16 and connected to the scraper mounting base 18 to drive the scraper mounting base 18 to move, so as to replace the next scraper, and further, the driving mechanism 19 is used for spreading the powder material to the powder spreading surface 20.
Specifically, the driving mechanism 19 includes a coupling and a motor connected to the processing unit 14, and a rotating shaft of the doctor mounting base 18 is connected to the motor through the coupling, so that the doctor mounting base 18 performs a rotating motion under the driving of the motor. In a preferred embodiment, the number of the scrapers is four, and the scrapers are uniformly and symmetrically arranged on the scraper mounting seat 18, so that when the scrapers are judged to be damaged, the motor drives the scraper mounting seat 18 to rotate, and the other scraper is switched.
So, but automated inspection, tool changing compare among the prior art manual tool changing, and the change process is simple and convenient, has improved efficiency, has guaranteed product quality.
It is understood that in other embodiments, the number of blades may be specifically selected according to design requirements, and is not limited herein.
In one embodiment, the powder spreading device 10 further comprises a scraper height adjusting mechanism 13 connected with the processing unit 14, wherein the scraper height adjusting mechanism 13 is used for adjusting the height of the scraper to be kept horizontal and to be adjusted in the vertical direction. Further, the adjusting member includes a driving member and a connecting member, the driving member is connected with the scraper mounting seat 18 through the connecting member to level and/or heighten. Specifically, the driving member may be a telescopic cylinder or a motor, which is not limited herein. In the embodiment, the two adjusting members are symmetrically arranged on the powder groove seat 16 by taking the center of the scraper as a reference, and are positioned above the scraper installation seat 18.
In one embodiment, the powder spreading device 10 further comprises a distance sensor moving mechanism 11, and the distance sensor moving mechanism 11 is used for driving the distance sensor 15 to move within a preset range along the longitudinal direction of the scraper. Specifically, the distance sensor moving mechanism 11 may be a ball screw mechanism.
The distance sensor moving mechanism 11 is connected to the processing unit 14.
The preset range refers to a length range of the doctor blade.
Based on the powder laying device 10, the invention also provides a three-dimensional object manufacturing device which comprises the powder laying device 10 in any one of the embodiments.
Compared with the prior art, the scraper calibration method, the three-dimensional object manufacturing equipment and the powder paving device 10 thereof have the following advantages:
1) compared with manual observation and detection, according to the difference between the actual distance value and the preset theoretical distance value between the preset detection surface and the plurality of points to be detected on the powder spreading surface 20, whether the scraper is damaged or abraded or whether the scraper is kept horizontal or not can be found in time, the detection accuracy is high, and therefore the printing quality is guaranteed;
2) but automated inspection, tool changing/accent sword compares manual tool changing/accent sword among the prior art, has improved efficiency, and has guaranteed to detect and tool changing/accent sword precision to printing quality has been improved.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A blade calibration method for three-dimensional object manufacturing, comprising the steps of:
1) detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder spreading surface in the moving process from a preset detection surface;
2) judging whether the scraper is damaged or worn according to the actual distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface and the preset theoretical distance value between the multiple points to be detected on the powder spreading surface and the preset detection surface;
and the preset detection surface is a plane parallel to the powder spreading surface.
2. The blade calibration method for three-dimensional object manufacturing according to claim 1, characterized in that said step 2) comprises in particular the steps of:
acquiring an actual absolute difference value between the actual distance value corresponding to each point to be detected and the preset theoretical distance value;
comparing the actual absolute difference value with a first preset absolute difference value and a second preset absolute difference value; when the actual absolute difference value corresponding to any one point to be detected in the multiple points to be detected is larger than or equal to a first preset absolute difference value and smaller than or equal to a second preset absolute difference value, judging that the scraper is worn; and when the actual absolute difference value corresponding to any one point to be detected in the plurality of points to be detected is larger than a second preset absolute difference value, judging that the scraper is damaged.
3. The blade calibration method for three-dimensional object manufacturing according to claim 1, characterized in that said step 2) comprises in particular the steps of:
establishing a two-dimensional coordinate graph according to the position information of each point to be detected along the longitudinal direction of the scraper, and the actual distance value and the preset theoretical distance value corresponding to each point to be detected;
and judging whether the scraper is damaged or abraded according to the two-dimensional coordinate graph.
4. A blade calibration method for three-dimensional object manufacturing according to any of claims 1-3, characterized in that the method further comprises the steps of:
when the scraper is damaged, replacing the scraper, and adjusting the replaced scraper to be positioned at a preset mounting position; or
When the scraper is worn, the scraper is adjusted to be located at the preset installation position.
5. The blade calibration method for three-dimensional object manufacturing according to claim 4, characterized in that it further comprises a verification step of:
verifying whether the adjusted scraper is in a preset mounting position; and if the adjusted scraper is not at the preset installation position, readjusting the scraper until the scraper is at the preset installation position.
6. The blade calibration method for three-dimensional object manufacturing according to claim 5, characterized in that said verification step comprises in particular the steps of:
powder spreading: laying a next layer of powder material on the cured layer;
a detection step: detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder spreading surface in the moving process from a preset detection surface;
acquiring an actual absolute difference value between an actual distance value of the point to be detected on the powder spreading surface after the powder spreading is carried out again and a preset detection surface and a preset theoretical distance value, and comparing the actual absolute difference value with a preset adjustment value; and if the actual absolute difference value is larger than the preset adjusting value, readjusting the scraper and returning to the powder spreading step until the scraper is at the preset mounting position.
7. Powder spreading device for manufacturing three-dimensional objects, characterized in that it comprises:
the detection unit is used for detecting and acquiring actual distance values of a plurality of points to be detected in the area covered by the scraper on the powder laying surface in the moving process from a preset detection surface;
and the processing unit is connected with the detection unit and is used for judging whether the scraper is damaged or worn according to the actual distance value of the plurality of points to be detected on the powder spreading surface from the preset detection surface and the preset theoretical distance value of the plurality of points to be detected on the powder spreading surface from the preset detection surface.
8. A powder spreading device for manufacturing three-dimensional objects according to claim 7, further comprising:
a powder groove seat;
the scraper mounting seat is arranged on the powder groove seat, and the plurality of scrapers are arranged on the scraper mounting seat so as to be capable of operably replacing the next scraper and enable the powder material to be paved on a powder paving surface;
the detection unit comprises at least one distance sensor arranged on the powder groove seat, and the at least one distance sensor is electrically connected with the processing unit.
9. The powder spreading device for manufacturing the three-dimensional object according to claim 7, further comprising a scraper height adjusting mechanism connected with the processing unit, wherein the scraper height adjusting mechanism is used for adjusting the height of the scraper to be kept horizontal and adjusting the height of the scraper in a vertical direction.
10. Three-dimensional object manufacturing apparatus, comprising a powder spreading device for manufacturing three-dimensional objects according to any one of claims 7 to 9.
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| CN111230976B (en) * | 2020-01-14 | 2022-02-25 | 山东华滋自动化技术股份有限公司 | Control method and system for automatic sleeve cutting of die cutting machine |
| CN112810140B (en) * | 2020-12-28 | 2023-03-10 | 上海联泰科技股份有限公司 | Data processing method, system, storage medium, 3D printing device and control method |
| CN114228140B (en) * | 2021-11-19 | 2024-04-05 | 湖南华曙高科技股份有限公司 | Scraper detection method, three-dimensional object manufacturing equipment and powder paving device thereof |
| CN114603849B (en) * | 2022-04-14 | 2024-01-26 | 南京铖联激光科技有限公司 | Novel scraper device for additive manufacturing and powder spreading method |
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