A method and apparatus for dynamic adjustment of temperature field for selective laser sintering

Abstract

The present application relates to the technical field of selective laser sintering, and discloses a temperature field dynamic adjustment method and device for selective laser sintering, which comprises the following steps: controlling a PLC to output control signals with preset duty cycles to a heating circuit respectively; obtaining current values of the heating circuit sent by a current collection module under control signals with different preset duty cycles; performing abnormality judgment on a heating tube based on the current values of the heating circuit; if the heating tube is in an abnormal state, calculating a heating tube power loss rate based on the current values of the heating circuit; determining a temperature field adjustment duty cycle based on the heating tube power loss rate, and dynamically adjusting the temperature field based on the temperature field adjustment duty cycle. The present application realizes accurate early warning of abnormal states of heating equipment, ensures normal production of the heating equipment, thereby improving the production efficiency of the heating equipment and reducing economic losses of customers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of selective laser sintering, in particular to a temperature field dynamic adjustment method and device for selective laser sintering. BACKGROUND

[0002] The basic process of selective laser sintering heating is: before selective laser sintering, first, the pre-sintering powder is preheated by the heating temperature field to make the powder surface uniformly reach the best sintering temperature, and to eliminate the powder surface stress to a certain extent; second, after the powder is preheated, the heating temperature field needs to heat and keep the powder in the forming cavity and the sintered powder, so as to reduce the temperature difference between the sintered surface and the powder, eliminate the powder surface stress to a certain extent, and make the powder surface better sintered and formed. Temperature control plays a crucial role in ensuring printing quality, improving printing efficiency and expanding application fields.

[0003] In the selective laser sintering heating process, the heating and keeping warm purposes are achieved by the heating device. However, when the heating device is abnormal, the abnormal heating pipe cannot be accurately identified, which affects heating, causes the temperature field to be uncontrollable, and further affects the product quality and efficiency of the equipment, resulting in economic losses. SUMMARY

[0004] Therefore, the present application provides a temperature field dynamic adjustment method and device for selective laser sintering to solve the problem that when the heating device is abnormal, the abnormal heating pipe cannot be accurately identified, which affects heating and causes the temperature field to be uncontrollable.

[0005] In a first aspect, the present application provides a temperature field dynamic adjustment method for selective laser sintering, applied to an upper computer in a heating device, wherein the heating device comprises an upper computer, a PLC, a current acquisition module and a plurality of heating loops, the heating loops are connected with the PLC and the current acquisition module respectively, and the upper computer is connected with the PLC; the heating loop comprises a solid-state relay and a heating pipe, and the solid-state relay is connected with the heating pipe; the method comprises:

[0006] controlling the PLC to output a control signal with a preset duty ratio to the heating loop;

[0007] obtaining the current value of the heating loop sent by the current acquisition module under the control signal with different preset duty ratios, and performing abnormality judgment on the heating pipe based on the current value of the heating loop;

[0008] if the heating pipe is in an abnormal state, calculating the power loss rate of the heating pipe based on the current value of the heating loop;

[0009] determining the temperature field adjustment duty ratio based on the power loss rate of the heating pipe, and dynamically adjusting the temperature field based on the temperature field adjustment duty ratio.

[0010] The embodiment provides a kind of warm field dynamic adjustment method for selective laser sintering, host computer controls PLC to respectively output preset duty ratio control signal to heating circuit, can control the output power of heating tube by solid-state relay, then the current value of heating circuit is obtained by current acquisition module, the abnormality of heating tube is judged by the current value of heating circuit, greatly shorten the problem time and reduce the difficulty of abnormal processing, realize the accurate early warning to heating equipment, and, determine the duty ratio of warm field adjustment based on the power loss rate of heating tube, based on the duty ratio of warm field adjustment, dynamically adjust the warm field, ensure that heating equipment normal production, then improve the production efficiency of heating equipment, reduce the economic loss of customer.

[0011] In an alternative embodiment, the current value of the heating circuit sent by the current acquisition module under different preset duty ratio control signals is obtained, and the abnormality of the heating tube is judged based on the current value of the heating circuit, including:

[0012] When the preset duty ratio is less than the determination duty ratio, the first heating current value of the heating circuit sent by the current acquisition module is obtained, and the first heating current value is compared with the duty ratio current value; if the first heating current value is greater than the duty ratio current value, the heating tube is in a solid-state breakdown state;

[0013] When the preset duty ratio is greater than the determination duty ratio, the second heating current value of the heating circuit sent by the current acquisition module is obtained, and the second heating current value is compared with the duty ratio current value; if the second heating current value is less than the duty ratio current value, the heating tube is in a short-circuit state or an open-circuit state.

[0014] The embodiment provides a kind of warm field dynamic adjustment method for selective laser sintering, by comparing the preset duty ratio with the determination duty ratio, and the current value of the heating circuit with the duty ratio current value, accurate determination of the abnormal state of the heating tube is realized, and accurate early warning of the heating equipment is realized.

[0015] In an alternative embodiment, the current value of the heating circuit sent by the current acquisition module under different preset duty ratio control signals is obtained based on the current value of the heating circuit to judge the abnormality of the heating tube, and further comprising:

[0016] The actual current value of the heating circuit under different preset duty ratio control signals is obtained by the current acquisition module, and the current deviation is determined based on the actual current value and the theoretical current value;

[0017] The current deviation is compared with the preset error range; if the current deviation does not match the preset error range, the heating tube is in an aging state.

[0018] The embodiment provides a kind of warm field dynamic adjustment method for selective laser sintering, by the current deviation between the actual current value of heating loop and the theoretical current value of different preset duty cycle control signal, with preset error range is compared, the accurate determination and early warning of the aging state of heating tube in heating loop are realized.

[0019] In an alternative embodiment, if the heating tube is in an abnormal state, the heating tube power loss rate is calculated based on the current value of the heating loop, comprising:

[0020] The heating tube power and the heating tube voltage are obtained, and the heating tube power loss rate is calculated based on the current deviation, the heating tube power and the heating tube voltage.

[0021] In an alternative embodiment, before the control PLC outputs the control signal of the preset duty cycle to the heating loop, it further comprises:

[0022] When the heating device is in standby state, the initial current value of the heating loop sent by the current acquisition module is obtained, and the initial current value is compared with the duty cycle current value.If the initial current value is greater than / equal to the duty cycle current value, the heating tube is in solid state breakdown state.

[0023] The embodiment provides a kind of warm field dynamic adjustment method for selective laser sintering, by comparing the initial current value with the duty cycle current value when the heating device is in standby state, the determination of the abnormal state of heating tube before heating of the heating device is realized, and then the normal production of the heating device is ensured by replacing the heating tube, and the economic loss is reduced.

[0024] In an alternative embodiment, the warm field adjustment duty cycle is determined based on the heating tube power loss rate, and the warm field is dynamically adjusted based on the warm field adjustment duty cycle, comprising:

[0025] The default duty cycle of the warm field is obtained, and the average value of the duty cycle is determined based on the default duty cycle of the warm field and the heating tube power loss rate;

[0026] The average value of the duty cycle is used as the warm field adjustment duty cycle, and the warm field is dynamically adjusted using the warm field adjustment duty cycle.

[0027] The embodiment provides a kind of warm field dynamic adjustment method for selective laser sintering, by warm field default duty cycle and heating tube power loss rate to determine the average value of the duty cycle, and then the average value of the duty cycle is used as the warm field adjustment duty cycle, and the warm field is dynamically adjusted using the warm field adjustment duty cycle, to realize the dynamic balance of warm field power demand, and ensure the stability of powder sintering warm field.

[0028] In a second aspect, the present application provides a kind of warm field dynamic adjustment device for selective laser sintering, applied to the host computer in heating equipment, and the device comprises:

[0029] a control module configured to control the PLC to output control signals with preset duty ratios to the heating circuit respectively;

[0030] an abnormality judging module configured to judge the heating tube to be abnormal based on the current value of the heating circuit according to the current value of the heating circuit sent by the current collecting module under the control signals with different preset duty ratios;

[0031] a calculating module configured to calculate the power loss rate of the heating tube based on the current value of the heating circuit if the heating tube is in an abnormal state;

[0032] a dynamic adjusting module configured to determine the temperature field adjusting duty ratio based on the power loss rate of the heating tube and to dynamically adjust the temperature field based on the temperature field adjusting duty ratio.

[0033] In a third aspect, the present application provides a computer device, comprising a memory and a processor, the memory and the processor are communicatively connected with each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the temperature field dynamic adjusting method for selective laser sintering of the first aspect or any of the corresponding embodiments thereof.

[0034] In a fourth aspect, the present application provides a computer readable storage medium, which stores computer instructions, and the computer instructions are used to make a computer execute the temperature field dynamic adjusting method for selective laser sintering of the first aspect or any of the corresponding embodiments thereof.

[0035] In a fifth aspect, the present application provides a computer program product, which comprises computer instructions, and the computer instructions are used to make a computer execute the temperature field dynamic adjusting method for selective laser sintering of the first aspect or any of the corresponding embodiments thereof. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 is a structural schematic diagram of a heating device according to an embodiment of the present application;

[0038] Figure 2 is a circuit diagram for realizing intelligent identification of heating tube loss and dynamic adjustment of temperature field for selective laser sintering according to an embodiment of the present application;

[0039] Figure 3 is a flowchart of a temperature field dynamic adjustment method for selective laser sintering according to an embodiment of the present application;

[0040] Figure 4 is a schematic diagram of a solid state relay input percentage and output power relationship curve according to an embodiment of the present application;

[0041] Figure 5 is a flowchart of another temperature field dynamic adjustment method for selective laser sintering according to an embodiment of the present application;

[0042] Figure 6 is a flowchart of still another temperature field dynamic adjustment method for selective laser sintering according to an embodiment of the present application;

[0043] Figure 7 is a structural block diagram of a temperature field dynamic adjustment device for selective laser sintering according to an embodiment of the present application;

[0044] Figure 8 is a hardware structure schematic diagram of a computer device of an embodiment of the present application. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions and advantages of embodiments of the present application clearer, the technical solutions in embodiments of the present application will be described clearly and completely below with reference to the drawings in embodiments of the present application. Obviously, the described embodiments are some but not all of embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0046] In the selective laser sintering heating process, the heating device is composed of a plurality of heating pipes, solid state relays, a PLC (Programmable Logic Controller) and temperature sensors. The plurality of heating pipes are fixedly arranged on the top of the working cavity in an array layout. Although the heating device can achieve the purposes of heating and heat preservation, when the heating pipes are abnormal, such as aging, short circuit, open circuit and solid state breakdown, the fault heating pipe cannot be accurately judged, and the solid state breakdown also cannot be judged. It is difficult to troubleshoot the problem for a long time. When the heating device is abnormal, it will directly affect the heating, cause the temperature field to be uncontrollable, and further affect the product quality, efficiency of the equipment and cause economic losses of customers.

[0047] To solve the above technical problems, an embodiment of the present application provides a temperature field dynamic adjustment method for selective laser sintering, which is applied to an upper computer 101 in a heating device, such as Figure 1As shown, the heating device includes a host computer 101, a PLC 102, a current collection module 103, and a plurality of heating circuits, such as Figure 2 As shown, the heating circuit is connected with the PLC 102 and the current collection module 103, and the host computer 101 is connected with the PLC 102; the heating circuit includes a solid-state relay 104 and a heating tube 105, and the solid-state relay 104 is connected with the heating tube 105.

[0048] The heating tube 105 is a heating element and serves as a heat source; the solid-state relay 104 adjusts the analog quantity to control the power output of the heating tube 105, so as to regulate the temperature of the temperature field; the PLC 102 serves as a controller to control the solid-state relay 104 through PID (Proportional Integral Derivative) regulation and output duty cycle, and then control the heating tube 105.

[0049] The heating device further includes an infrared sensor 106, which collects the temperature of the heating temperature field as the temperature feedback of the PLC-PID regulation, so as to form a closed-loop control of the whole heating temperature field.

[0050] The current collection module 103 includes a collection transmitter 107 and a current transformer 108, which are used to collect the current data of the heating tube. The current collection module 103 collects the current value of each current transformer; the current collection module 103 exchanges data with the PLC 102 and the host computer 101 through the MDBUS RTU protocol (a communication protocol widely used in the industrial control field, mainly used for data exchange between devices), and the PLC 102 and the host computer 101 exchange data, realize data processing and algorithm dynamic adjustment, judge the aging, short circuit, open circuit and solid-state breakdown of the heating tube 105, accurately output device warning, intelligently identify the loss of the heating tube and dynamically adjust the temperature field, and ensure the stability of the powder sintering temperature field.

[0051] According to the embodiment of the present application, a kind of temperature field dynamic adjustment method for selective laser sintering is provided, it needs to be explained, the steps shown in the flowchart of the drawing can be executed in computer system such as a group of computer executable instructions, and although logical order is shown in flowchart, in some cases, the steps shown or described can be executed in different order from here.

[0052] In the present embodiment, a kind of temperature field dynamic adjustment method for selective laser sintering is provided, which can be used in the above-mentioned host computer 101, Figure 3 It is a flowchart of a kind of temperature field dynamic adjustment method for selective laser sintering according to the embodiment of the present application, as shown in the figure, the flow includes the following steps: Figure 3

[0053] ​Step S301, the control PLC outputs control signals with preset duty cycles to the heating circuit respectively.

[0054] Specifically, as shown in the figure, Figure 2 The device pre-builds into a heating self-checking mode, calculates the target number of self-checking automatically according to the number of heating circuits set by the upper computer and the number of circuits per round of heating, and outputs control signals with duty cycles of 40%, W%, E% and R% for 160s after receiving the self-checking enable command sent by the upper computer, wherein 40

[0055] Step S302, the current values of the heating circuit sent by the current acquisition module under different preset duty cycles are obtained, and the heating tube is abnormally judged based on the current values of the heating circuit.

[0056] Specifically, as shown in the figure, Figure 1 The PLC as a controller controls the solid-state relay through PID control to output duty cycles, as shown in the figure, Figure 4 The solid-state relay controls the power output of the heating tube according to the input percentage and output power relationship curve, and the current acquisition module acquires the real-time current values of the heating tube at each power stage (i.e. the current values of the heating circuit).

[0057] Step S303, if the heating tube is in an abnormal state, the power loss rate of the heating tube is calculated based on the current values of the heating circuit.

[0058] Specifically, the abnormal state of the heating tube includes solid-state breakdown state, short-circuit state, open-circuit state and aging state.

[0059] Step S304, the temperature field adjustment duty cycle is determined based on the power loss rate of the heating tube, and the temperature field is dynamically adjusted based on the temperature field adjustment duty cycle.

[0060] The temperature field dynamic adjustment method for selective laser sintering provided in the embodiment, the upper computer controls the PLC to output control signals with preset duty cycles to the heating circuit, the output power of the heating tube can be controlled through the solid-state relay, and then the current values of the heating circuit are obtained through the current acquisition module, the heating tube is abnormally judged through the current values of the heating circuit, which greatly shortens the problem solving time and reduces the difficulty of abnormal processing, realizes the accurate early warning of the heating equipment, and based on the power loss rate of the heating tube, the temperature field adjustment duty cycle is determined, and the temperature field is dynamically adjusted based on the temperature field adjustment duty cycle, which ensures the normal production of the heating equipment, and then improves the production efficiency of the heating equipment and reduces the economic loss of the customer.

[0061] A temperature field dynamic adjustment method for selective laser sintering is provided in the embodiment, which can be used for the upper computer 101 described above, Figure 5 is a flowchart of a temperature field dynamic adjustment method for selective laser sintering according to an embodiment of the present application, as shown in the figure, the flow includes the following steps: Figure 5

[0062] Step S501, control the PLC to output the control signal of the preset duty ratio to the heating circuit respectively. For details, please refer to step S301 of the embodiment shown in Figure 3 , which will not be repeated here.

[0063] Step S502, acquire the current value of the heating circuit sent by the current acquisition module under different preset duty ratio control signals, and perform abnormality judgment on the heating tube based on the current value of the heating circuit.

[0064] Specifically, the above step S502 includes:

[0065] Step S5021, when the preset duty ratio is less than the judgment duty ratio, acquire the first heating current value of the heating circuit sent by the current acquisition module, compare the first heating current value with the duty ratio current value, and if the first heating current value is greater than the duty ratio current value, the heating tube is in a solid-state breakdown state.

[0066] Specifically, assuming that the judgment duty ratio is 20%, when the preset duty ratio output by the PLC is less than 20%, and the first heating current value of the heating circuit is greater than the current value of 20% duty ratio, the heating tube is in a solid-state breakdown state, which further causes the heating tube to abnormally heat.

[0067] Further, when the heating device is in standby state, acquire the initial current value of the heating circuit sent by the current acquisition module, compare the initial current value with the duty ratio current value, and if the initial current value is greater than / equal to the duty ratio current value, the heating tube is in a solid-state breakdown state.

[0068] Further, when the heating device is in standby state, the heating device is not heated under the condition of enabling, and no control signal of the preset duty ratio is output, and when the initial current value collected by the current acquisition module is greater than or equal to the current value of 20% duty ratio, it is determined that there is a solid-state breakdown causing the heating tube to abnormally heat automatically;

[0069] Step S5022, when the preset duty ratio is greater than the judgment duty ratio, acquire the second heating current value of the heating circuit sent by the current acquisition module, compare the second heating current value with the duty ratio current value, and if the second heating current value is less than the duty ratio current value, the heating tube is in a short-circuit state or an open-circuit state.

[0070] ​Specifically, in the case of starting heating, when the PLC output duty cycle is greater than 20%, and the second heating current value collected by the current collection module is less than 0.5A, the heating tube is in a short-circuit state or an open-circuit state, and after a delay, an alarm is triggered by the upper computer.

[0071] In step S5023, the actual current value of the heating circuit under different preset duty cycles is obtained by the current collection module, and the current deviation is determined based on the actual current value and the theoretical current value.

[0072] Specifically, the aging logic of the heating tube is entered within the last 5S of each control stage, that is, after completing the current round, the duty cycle on the PLC is uploaded, and it is judged whether the deviation of the actual current value of the heating circuit under each output duty cycle in the last 5S from the theoretical current value exceeds the allowable error ±0.5A. If the current deviation of the same heating tube under two or more than two ratio rated power exceeds the allowable error, it is considered that the heating circuit of this road is aging, and the upper computer alarms the aging of the heating circuit.

[0073] In step S5024, the current deviation is compared with the preset error range, and if the current deviation does not match the preset error range, the heating tube is in an aging state.

[0074] In step S503, if the heating tube is in an abnormal state, the heating tube power loss rate is calculated based on the current value of the heating circuit.

[0075] Specifically, the heating tube power and the heating tube voltage are obtained, and the heating tube power loss rate is calculated based on the current deviation, the heating tube power and the heating tube voltage.

[0076] Further, the heating equipment is pre-built into a heating self-checking mode, the upper computer performs heating self-checking, and when the heating tube is aging (not including short circuit, open circuit and solid state breakdown), the heating tube power loss rate is automatically calculated by the current value of the heating circuit. The calculation formula of the heating tube power loss rate η is as follows:

[0077] η=U*△I / P*100% (1)

[0078] △I=I-I1 (2)

[0079] Wherein, U represents the heating tube voltage, △I represents the current deviation, P represents the heating tube power, I1 represents the actual current value, and I represents the theoretical current value.

[0080] Further, if the heating tube power loss rate is greater than the set value X=45%, the upper computer prompts to replace the heating tube, X=(45-60); if the heating tube power loss rate is less than the set value X%, the temperature field is dynamically adjusted.

[0081] Step S504, determine the temperature field adjustment duty cycle based on the heating tube power loss rate, and dynamically adjust the temperature field based on the temperature field adjustment duty cycle. For details, please refer to Figure 3 Step S304 of the embodiment shown will not be described here.

[0082] The embodiment provides a temperature field dynamic adjustment method for selective laser sintering. By comparing the preset duty cycle with the determination duty cycle and the current value of the heating loop with the duty cycle current value, accurate determination of the abnormal state of the heating tube and accurate early warning of the heating device are realized. Secondly, by comparing the current deviation between the actual current value and the theoretical current value of the heating loop under the control signal of different preset duty cycles with the preset error range, accurate determination and early warning of the aging state of the heating tube in the heating loop are realized. Finally, by comparing the initial current value with the duty cycle current value when the heating device is in the standby state, determination of the abnormal state of the heating tube before the heating device heats is realized, and then the heating device can be ensured to produce normally by replacing the heating tube, thereby reducing economic losses.

[0083] In the embodiment, a temperature field dynamic adjustment method for selective laser sintering is provided, which can be used for the host computer 101 described above, Figure 6 is a flowchart of a temperature field dynamic adjustment method for selective laser sintering according to an embodiment of the application, as shown in Figure 6 The flowchart includes the following steps:

[0084] Step S601, the PLC outputs control signals of preset duty cycles to the heating loop respectively. For details, please refer to Figure 5 Step S501 of the embodiment shown will not be described here.

[0085] Step S602, acquire the current value of the heating loop sent by the current acquisition module under the control signal of different preset duty cycles, and determine the abnormality of the heating tube based on the current value of the heating loop. For details, please refer to Figure 1 Step S502 of the embodiment shown will not be described here.

[0086] Step S603, if the heating tube is in an abnormal state, calculate the power loss rate of the heating tube based on the current value of the heating loop. For details, please refer to Figure 5 Step S503 of the embodiment shown will not be described here.

[0087] Step S604, determine the temperature field adjustment duty cycle based on the heating tube power loss rate, and dynamically adjust the temperature field based on the temperature field adjustment duty cycle.

[0088] Specifically, the above step S604 includes:

[0089] In step S6041, the default duty ratio of the temperature field is obtained, and the average duty ratio is determined based on the default duty ratio of the temperature field and the power loss rate of the heating pipe.

[0090] Specifically, the calculation formula of the power P1 of the heating pipe after loss is as follows:

[0091] P1 = P * (1 - η) (3)

[0092] Further, assuming that the default duty ratio of the temperature field is Z, the duty ratio of the heating pipe power loss output is Z1, and the expression of the dynamic balance of the power demand of the temperature field is as follows:

[0093] P * Z = P1 * Z1 (4)

[0094] Further, the calculation formula of the duty ratio of the heating pipe power loss output after dynamic adjustment of the temperature field is as follows:

[0095] Z1 = Z / (1 - U * (I - I1) / P * 100%) (5)

[0096] Further, the calculation formula of the duty ratio of the heating pipe power loss after dynamic adjustment of the temperature field, i.e., the average duty ratio, is as follows:

[0097] ΣZ = (Z1 + Z2 +... + Zn) / n) (6)

[0098] Wherein, n is the number of duty ratio output stages.

[0099] In step S6042, the average duty ratio is taken as the temperature field adjustment duty ratio, and the temperature field is dynamically adjusted using the temperature field adjustment duty ratio.

[0100] Specifically, the average duty ratio of the heating equipment after entering the steady state after the loss of the heating pipe is taken as the final duty ratio of the dynamically adjusted temperature field.

[0101] The temperature field dynamic adjustment method for selective laser sintering provided in this embodiment determines the average duty ratio based on the default duty ratio of the temperature field and the power loss rate of the heating pipe, and then takes the average duty ratio as the temperature field adjustment duty ratio, and dynamically adjusts the temperature field using the temperature field adjustment duty ratio, thereby achieving dynamic balance of the power demand of the temperature field and ensuring the stability of the powder sintering temperature field.

[0102] The specific steps of the temperature field dynamic adjustment method for selective laser sintering will be described below through specific embodiments.

[0103] Embodiment 1:

[0104] The specific steps of the selective laser sintering intelligent identification of the loss of the heater and the dynamic adjustment of the temperature field include:

[0105] The theoretical current value of the heating tube at each power is shown in Table 1 as a heating self-checking function to judge the aging of the heating tube and the reference value of the heating tube temperature field control self-adjusting function.

[0106] Table 1:

[0107]

[0108] As shown in Table 2, the heating tube short circuit, open circuit, and solid state breakdown are judged. In the first heating circuit, the detection current is about 5.5 A under different duty cycle control conditions. The current collected by the current collection module is greater than or equal to the current value of 20% duty cycle, indicating that the heating circuit is solid state breakdown. In the first heating circuit, the detection current is 0 A under different duty cycle control conditions. The PLC output duty cycle is greater than 20%, and the external current detection module channel current is less than 0.05 A, indicating that the heating tube is burned out.

[0109] Table 2:

[0110]

[0111] As shown in Table 3, the heater is aged and the temperature field is dynamically adjusted.

[0112] Table 3:

[0113]

[0114] The actual current value of the first heating tube under 40%, 60%, 80%, and 100% duty cycle output is compared with the theoretical current value, and the results are shown in Table 4:

[0115] Table 4:

[0116]

[0117] The current deviation of the above four groups of data is greater than 0.5 A, indicating that the lamp tube is aged. At this time, the host computer warns that the heating tube is aged.

[0118] The heating tube loss rate in the four stages is less than the set value X (45%), and the host computer judges to directly enter the dynamic adjustment of the temperature field self-adjusting. The default duty cycle of the temperature field is Z = 45%, Z1 = 59.3%, Z2 = 55.9%, Z3 = 63.8%, Z4 = 55.6%, ΣZ = (59.3% + 55.9% + 63.8% + 55.6%) / 4 = 58.6%, and the dynamic adjustment of the temperature field output duty cycle is 58.6%, so that the heating equipment can ensure normal temperature field stable control and ensure production quality.

[0119] In the above embodiments, by increasing the hardware and experimental measured data, the current value is judged, the abnormality of the heating loop element such as aging, short circuit, open circuit, and solid state breakdown is intelligently identified and dynamically adjusted, wherein the heating tube aging, short circuit, open circuit, and solid state breakdown are intelligently identified by the current value judgment, the device warning is accurately output, the problem troubleshooting time is greatly shortened, and the difficulty of abnormal processing is reduced; the heating loss is intelligently identified and the temperature field is dynamically adjusted to ensure normal production of the device, thereby improving the production efficiency of the device and reducing the economic loss of the customer.

[0120] In the present embodiment, a temperature field dynamic adjustment device for selective laser sintering is also provided, which is used to realize the above embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and contemplated.

[0121] The present embodiment provides a temperature field dynamic adjustment device for selective laser sintering, as shown in Figure 7 , comprising:

[0122] The control module 701 is used to control the PLC to output control signals with preset duty cycles to the heating loop respectively;

[0123] The abnormality judgment module 702 is used to acquire the current value of the heating loop sent by the current acquisition module under different preset duty cycles of the control signal, and to judge the abnormality of the heating tube based on the current value of the heating loop;

[0124] The calculation module 703 is used to calculate the power loss rate of the heating tube based on the current value of the heating loop if the heating tube is in an abnormal state;

[0125] The dynamic adjustment module 704 is used to determine the temperature field adjustment duty cycle based on the power loss rate of the heating tube, and to dynamically adjust the temperature field based on the temperature field adjustment duty cycle.

[0126] In some optional embodiments, the abnormality judgment module 702 comprises:

[0127] The solid state breakdown judgment unit is used to acquire the first heating current value of the heating loop sent by the current acquisition module when the preset duty cycle is less than the judgment duty cycle, compare the first heating current value with the duty cycle current value, and if the first heating current value is greater than the duty cycle current value, the heating tube is in a solid state breakdown state;

[0128] The burnout judging unit is configured to, when the preset duty cycle is greater than the judging duty cycle, acquire the second heating current value of the heating loop sent by the current acquisition module, compare the second heating current value with the duty cycle current value, and if the second heating current value is less than the duty cycle current value, the heating tube is in a short-circuit state or an open-circuit state.

[0129] In some optional embodiments, the abnormality judging module 702 further includes:

[0130] The determining unit is configured to acquire actual current values of the heating loop under control signals of different preset duty cycles through the current acquisition module, and determine current deviations based on the actual current values and the theoretical current values;

[0131] The aging judging unit is configured to compare the current deviations with a preset error range, and if the current deviations do not conform to the preset error range, the heating tube is in an aging state.

[0132] In some optional embodiments, the calculating module 703 is specifically configured to acquire a heating tube power and a heating tube voltage, and calculate a heating tube power loss rate based on the current deviations, the heating tube power and the heating tube voltage.

[0133] In some optional embodiments, the device further includes:

[0134] The comparing module is configured to, when the heating device is in a standby state, acquire an initial current value of the heating loop sent by the current acquisition module, compare the initial current value with the duty cycle current value, and if the initial current value is greater than / equal to the duty cycle current value, the heating tube is in a solid-state breakdown state.

[0135] In some optional embodiments, the dynamic adjusting module 704 includes:

[0136] The acquiring unit is configured to acquire a temperature field default duty cycle, and determine a duty cycle average value based on the temperature field default duty cycle and the heating tube power loss rate;

[0137] The adjusting unit is configured to take the duty cycle average value as a temperature field adjusting duty cycle, and dynamically adjust the temperature field by using the temperature field adjusting duty cycle.

[0138] Further function descriptions of the above various modules and units are the same as those of the above corresponding embodiments, and will not be described here.

[0139] The temperature field dynamic adjusting device for selective laser sintering in the embodiment is presented in the form of functional units. The units herein refer to ASIC (Application Specific Integrated Circuit) circuits, processors and memories executing one or more software or fixed programs, and / or other devices that can provide the above functions.

[0140] This invention also provides a computer device having the above-described features. Figure 7 The diagram shows a dynamic temperature field adjustment device for selective laser sintering.

[0141] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of a computer device provided in an optional embodiment of the present invention, such as... Figure 8 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 8 Take a processor 10 as an example.

[0142] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0143] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0144] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0145] The memory 20 can include a volatile memory, such as a random access memory, and / or can include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive. The memory 20 can also include a combination of the above-mentioned types of memories.

[0146] The computer device also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 can be connected by a bus or other means, Figure 8 The connection by bus is taken as an example.

[0147] The input device 30 can receive inputted digital or character information, and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touchpad, a pointing stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), a tactile feedback device (e.g., a vibration motor), etc. The display device includes, but is not limited to, a liquid crystal display, a light emitting diode, a display and a plasma display. In some alternative embodiments, the display device can be a touch screen.

[0148] The embodiments of the present application also provide a computer readable storage medium, and the method according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or stored in a remote storage medium or a non-transitory machine readable storage medium and downloaded from a network and stored in a local storage medium, so that the method described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor or programmable or special purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk or a solid state disk, etc. Further, the storage medium can also include a combination of the above-mentioned types of memories. It can be understood that the computer, the processor, the microprocessor controller or the programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, the processor or the hardware, the method shown in the above embodiments is implemented.

[0149] Part of the present application can be applied as a computer program product, for example, computer program instructions, when executed by a computer, through the operation of the computer, can invoke or provide the method and / or technical solutions according to the present application. Those skilled in the art should understand that the form of computer program instructions in computer readable medium includes but is not limited to source files, executable files, installation package files and the like, and accordingly, the way of computer program instructions executed by computer includes but is not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer readable medium can be any available computer readable storage medium or communication medium accessible to the computer.

[0150] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A method for dynamic adjustment of temperature field for selective laser sintering, characterized in that, The application is applied to a host computer in a heating device, wherein the heating device comprises the host computer, a PLC, a current collection module and a plurality of heating loops, the heating loops are connected with the PLC and the current collection module respectively, and the host computer is connected with the PLC; the heating loop comprises a solid-state relay and a heating tube, and the solid-state relay is connected with the heating tube; the method comprises: controlling the PLC to output a control signal with a preset duty cycle to the heating loop; acquiring a current value of the heating loop sent by the current collection module under a control signal with a different preset duty cycle, and performing an abnormality judgment on the heating tube based on the current value of the heating loop; wherein the abnormal state of the heating tube comprises a solid-state breakdown state, a short circuit state, an open circuit state and an aging state; if the heating tube is in the aging state, calculating a heating tube power loss rate based on the current value of the heating loop; determining a temperature field adjustment duty cycle based on the heating tube power loss rate, and dynamically adjusting the temperature field based on the temperature field adjustment duty cycle; the determination of the temperature field adjustment duty cycle based on the heating tube power loss rate and the dynamic adjustment of the temperature field based on the temperature field adjustment duty cycle comprise: acquiring a temperature field default duty cycle, and determining a duty cycle average value based on the temperature field default duty cycle and the heating tube power loss rate; wherein the calculation formula of the power P1 of the heating tube after loss is as follows: wherein P represents the heating tube power; and P represents the heating tube power loss rate. assuming that the temperature field default duty cycle is Z, the duty cycle output by the heating tube power loss is Z1, and the expression of the dynamic balance of the temperature field power demand is as follows: the calculation formula of the duty cycle output by the heating tube power loss after the dynamic adjustment of the temperature field is as follows: wherein U represents the heating tube voltage, I1 represents the actual current value, and I represents the theoretical current value; the calculation formula of the duty cycle average value is as follows: wherein n is the number of duty cycle output stages; the duty cycle average value is taken as the temperature field adjustment duty cycle, and the temperature field is dynamically adjusted by using the temperature field adjustment duty cycle.

2. The method of claim 1, wherein, the acquisition of the current value of the heating loop sent by the current collection module under a control signal with a different preset duty cycle and the abnormality judgment on the heating tube based on the current value of the heating loop comprise: when the preset duty cycle is less than a judgment duty cycle, a first heating current value of the heating loop sent by the current collection module is acquired, the first heating current value is compared with a duty cycle current value, and if the first heating current value is greater than the duty cycle current value, the heating tube is in a solid-state breakdown state; when the preset duty cycle is greater than the judgment duty cycle, a second heating current value of the heating loop sent by the current collection module is acquired, the second heating current value is compared with the duty cycle current value, and if the second heating current value is less than the duty cycle current value, the heating tube is in a short circuit state or an open circuit state.

3. The method of claim 2, wherein, the acquisition of the current value of the heating loop sent by the current collection module under a control signal with a different preset duty cycle and the abnormality judgment on the heating tube based on the current value of the heating loop further comprise: The current acquisition module obtains actual current values of the heating loop under control signals of different preset duty cycles, and determines a current deviation based on the actual current values and theoretical current values; The current deviation is compared with a preset error range, and if the current deviation does not match the preset error range, the heating tube is in an aging state.

4. The method of claim 3, wherein, If the heating tube is in the aging state, a heating tube power loss rate is calculated based on the current value of the heating loop, including: The heating tube power and the heating tube voltage are obtained, and the heating tube power loss rate is calculated based on the current deviation, the heating tube power and the heating tube voltage.

5. The method of claim 2, wherein, Before the control module controls the PLC to output the control signal of the preset duty cycle to the heating loop, the method further includes: When the heating device is in a standby state, an initial current value of the heating loop sent by the current acquisition module is obtained, and the initial current value is compared with the duty cycle current value, and if the initial current value is greater than / equal to the duty cycle current value, the heating tube is in a solid state breakdown state.

6. A temperature field dynamic adjustment device for selective laser sintering, characterized in that, The device is applied to an upper computer in a heating device, and the device includes: A control module configured to control a PLC to output a control signal of a preset duty cycle to a heating loop; An abnormality judgment module configured to obtain current values of the heating loop sent by a current acquisition module under control signals of different preset duty cycles, and to perform abnormality judgment on a heating tube based on the current values of the heating loop; wherein abnormal states of the heating tube include a solid state breakdown state, a short circuit state, an open circuit state and an aging state; A calculation module configured to calculate a heating tube power loss rate based on the current value of the heating loop if the heating tube is in the aging state; A dynamic adjustment module configured to determine a temperature field adjustment duty cycle based on the heating tube power loss rate, and to perform dynamic adjustment on a temperature field based on the temperature field adjustment duty cycle; The dynamic adjustment module includes: An obtaining unit configured to obtain a temperature field default duty cycle, and to determine a duty cycle average value based on the temperature field default duty cycle and the heating tube power loss rate; wherein a calculation formula of a power P1 of the heating tube after loss is as follows: wherein P represents the heating tube power; and P represents the heating tube power loss rate. Suppose that the temperature field default duty cycle is Z, and a duty cycle output by the heating tube power loss is Z1, an expression for dynamically balancing a power demand of the temperature field is as follows: A calculation formula of the duty cycle output by the heating tube power loss after dynamic adjustment of the temperature field is as follows: Wherein, U represents a heating tube voltage, I1 represents an actual current value, and I represents a theoretical current value; A calculation formula of the duty cycle average value is as follows: Wherein, n is a number of duty cycle output stages; An adjustment unit configured to use the duty cycle average value as a temperature field adjustment duty cycle, and to perform dynamic adjustment on the temperature field using the temperature field adjustment duty cycle.

7. A computer device, comprising: The device includes: A memory and a processor, which are communicatively connected, the memory stores computer instructions, and the processor executes the computer instructions to perform the temperature field dynamic adjustment method for selective laser sintering according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium has stored thereon computer instructions for causing a computer to execute the method for dynamic adjustment of temperature field for selective laser sintering according to any one of claims 1 to 5.

9. A computer program product, characterised in that, The computer readable storage medium has stored thereon computer instructions for causing a computer to execute the method for dynamic adjustment of temperature field for selective laser sintering according to any one of claims 1 to 5.

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