阅读说明：本技术 一种金属材料加工系统 (Metal material processing system ) 是由 王怀志 于 2021-09-29 设计创作，主要内容包括：本发明涉及一种金属材料加工系统,包括机身、挤出机构、送料机构、传动机构以及控制系统,送料机构包括一个主动轮、两个从动轮、加热块、轮轴安装板,送料机构提供驱动力将金属材料牵引进喉管,两个从动轮的中心距可调；传动机构包括X轴传动机构、Y轴传动机构、Z轴传动机构以及调平结构；控制系统包括主控制器、步进电机驱动模块、温度控制模块、串口通信模块、数据存储模块,主控制器控制温度控制模块,对加热块进行加热,并对喷头温度进行采集反馈,使用温度控制算法对喷头温度进行控制,保证喷头的温度要能熔融金属材料,并处于恒温状态；主控制器控制电机驱动模块驱动送料机构的步进电机、X轴步进电机、Y轴步进电机、Z轴步进电机,使用直线曲线控制算法对步进电机进行控制。(The invention relates to a metal material processing system, which comprises a machine body, an extrusion mechanism, a feeding mechanism, a transmission mechanism and a control system, wherein the feeding mechanism comprises a driving wheel, two driven wheels, a heating block and a wheel axle mounting plate; the transmission mechanism comprises an X-axis transmission mechanism, a Y-axis transmission mechanism, a Z-axis transmission mechanism and a leveling structure; the control system comprises a main controller, a stepping motor driving module, a temperature control module, a serial port communication module and a data storage module, wherein the main controller controls the temperature control module, heats the heating block, collects and feeds back the temperature of the spray head, controls the temperature of the spray head by using a temperature control algorithm, and ensures that the temperature of the spray head can melt metal materials and is in a constant temperature state; the main controller controls the motor driving module to drive the stepping motor, the X-axis stepping motor, the Y-axis stepping motor and the Z-axis stepping motor of the feeding mechanism, and the stepping motor is controlled by using a linear curve control algorithm.)

1. A metal material processing system, which comprises a machine body, an extrusion mechanism, a feeding mechanism, a transmission mechanism and a control system,

the machine body supports the extrusion mechanism, the feeding mechanism and the transmission mechanism, the machine body comprises a base, a guide rail, a bearing seat, a support frame, a base, a Z-axis mounting plate and an XY-axis mounting plate, and is formed by combining modules, and the modules are connected with each other in a welding mode through rivets;

the extrusion mechanism comprises a spray head, a throat pipe and a heat dissipation device, the spray head and the throat pipe form a piston cylinder, a metal material is used as a piston, a stepping motor provides power, and the metal material is fed towards the spray head under the traction of the power;

the feeding mechanism comprises a driving wheel, two driven wheels, a heating block and a wheel shaft mounting plate, the feeding mechanism provides driving force to draw the metal material into the throat pipe, the extrusion nozzle mechanism heats the metal material and extrudes the metal material out of the nozzle, the heat dissipation device cools the whole extrusion process, the metal material is conducted between the two driven wheels and enters the heating block in the conduction process, and the rotation of the driving wheel drives one of the driven wheels to rotate; the center distance of the two driven wheels is adjustable, the driving wheel driven by the motor and one driven wheel directly contacted with the driving wheel are assembled on the wheel shaft mounting plate, relative movement does not exist, and the relative position of the wheel shaft mounting plate and the machine body in the horizontal direction is adjustable; the other driven wheel is fixed on the machine body, and the horizontal relative position between the other driven wheel and the machine body is not adjustable; the center distance between the two driven wheels is adjusted by adjusting the positions of the wheel axle mounting plate and the machine body, so that the extrusion degree of the metal material is adjusted; the feeding mechanism is bilaterally symmetrical, and an inlet of the feeding mechanism is provided with an inverted cone-shaped opening with a wide upper part and a narrow lower part; each driven wheel comprises a shaft-shaped core made of a metal material and a rubber material coated in the middle, the conductive metal material is in contact with the rubber material, and an arc-shaped groove is formed in the rubber part of the roller in contact with the metal material;

the transmission mechanism comprises an X-axis transmission mechanism, a Y-axis transmission mechanism, a Z-axis transmission mechanism and a leveling structure;

the control system comprises a main controller, a stepping motor driving module, a temperature control module, a serial communication module and a data storage module, wherein the stepping motor driving module, the temperature control module, the serial communication module and the data storage module are connected with the main controller; the main controller controls the motor driving module to drive the stepping motor, the X-axis stepping motor, the Y-axis stepping motor and the Z-axis stepping motor of the feeding mechanism, and the stepping motor is controlled by using a linear curve control algorithm.

2. A metallic material processing system as set forth in claim 1, wherein: the X-axis transmission component comprises an X-axis stepping motor, an X-axis motor base, an X-axis driven wheel base, an X-axis synchronous belt, a pressing block, a sliding base, an X-axis driving wheel, an X-axis driven wheel and an X-axis double-rod guide rail, wherein one end of the X-axis double-rod guide rail is fixedly connected with the X-axis motor base, the X-axis motor base is provided with the stepping motor, an X-axis driving wheel is arranged on an output shaft of the stepping motor, the sliding base is slidably connected with the X-axis double-rod guide rail, the other end of the X-axis double-rod guide rail is fixedly connected with the X-axis driven wheel base, the X-axis driven wheel base is rotatably connected with the X-axis driven wheel through a short shaft, the X-axis synchronous belt is sleeved on the X-axis driving wheel and the X-axis driven wheel, the sliding base is fixedly connected with the X-axis synchronous belt through the pressing block, a nozzle is arranged on the sliding base, and the X-axis stepping motor rotates to realize X-axis linear motion of the nozzle;

the Y-axis transmission mechanism comprises a square mounting plate, a transmission shaft, a Y-axis driving wheel, three Y-axis synchronous wheels, two Y-axis guide rails, two Y-axis synchronous belts and a Y-axis stepping motor, the Y-axis driving wheel and the three Y-axis synchronous wheels are mounted at four corners of the mounting plate, a first Y-axis synchronous belt is sleeved on the Y-axis driving wheel and the first Y-axis synchronous wheel, a first Y-axis synchronous belt is sleeved on a second Y-axis synchronous wheel and a third Y-axis synchronous wheel, the two Y-axis guide rails are mounted on two sides of the mounting plate in parallel, the first Y-axis synchronous wheel and the second Y-axis synchronous wheel are fixedly connected through the transmission shaft, an X-axis transmission member and an X-axis driven wheel seat are respectively and slidably connected on the two Y-axis guide rails, the X-axis transmission member and the X-axis driven wheel seat are respectively and fixedly connected with the two Y-axis synchronous belts through pressing blocks, and an output shaft of the Y-axis stepping motor is actively and fixedly connected with the Y-axis, the Y-axis stepping motor rotates to drive the two Y-axis synchronous belts to move synchronously, and the X-axis transmission mechanism moves linearly along the Y axis;

the Z-axis transmission mechanism comprises a Z-axis stepping motor, a lead screw, a bearing, a nut, a supporting plate, two Z-axis guide rails and a bracket, wherein an output shaft of the Z-axis stepping motor is connected with the lead screw, two ends of the lead screw are rotatably connected with the machine body through the bearing, the nut is movably connected with the lead screw through threads, two ends of the nut are slidably connected with the two Z-axis guide rails, the supporting plate is fixedly connected with the nut, the mounting plate is connected with the supporting plate through a leveling structure, and the Z-axis stepping motor rotates to drive the Z axis of the mounting plate to move linearly;

the leveling structure comprises a knob, cross beams, springs and bolts, the leveling structure is respectively arranged at four corners of the mounting plate, the four corners of the supporting plate are provided with four extending cross beams, the bolts are fixed with the cross beams and matched with the threads of the knob after penetrating through holes of the supporting plate, the springs are sleeved on the bolts of the knob and abutted between the cross beams and the supporting plate, and the bolts are rotated to adjust the length of the bolts, so that the flatness of the mounting plate is checked.

3. A metallic material processing system as set forth in claim 2, wherein: the Z-axis transmission mechanism is a screw nut mechanism, and the length of a screw is the sum of the maximum stroke, the length of a nut, the safety distance and the reserved amount of the shaft end; calculating the shaft diameter of the lead screw as follows:

wherein d is the shaft diameter of the screw, n is the allowable rotating speed, f is the support coefficient, and L is the installation distance;

the service life of the screw is calculated as follows:

F_avethe average load of the lead screw; f_iAt a rotation speed n_iWorking time t of_iThe inner lead screw bears the load after the load,

N_avein order to obtain an average rotational speed,

L_tfor the life of the screw, Ca is the stress factor, f_wIs the load factor;

calculating the checking stress delta of the screw:

the axial stress of the lead screw is reduced,

σ is the axial stress; f_maxIn order to be the maximum load,

calculating the radial stress of the lead screw,

tau is radial stress, J is moment of inertia, T is material torque,

4. a metallic material processing system as set forth in claim 1, wherein: the temperature control algorithm specifically comprises the following steps:

step 1, initializing a system;

step 2, the temperature control module heats the heating block, and the temperature of the spray head is acquired through the temperature sensor;

step 3, constructing a control model, and forming a control quantity by linearly combining the proportion, derivation and accumulation of errors according to the errors between the target set value and the measured value, so that the errors between the target temperature value and the actual temperature value responding to the temperature control module are reduced as much as possible, thereby accurately controlling the heating temperature, wherein the control model is as follows:

ec(KT)＝e(KT)-e((K-1)T)

in the formula: k is a sequence of sample points, T is the sample period, e (KT) represents the deviation of the measured value from the target value; ec (kt) represents the rate of change of deviation; u (KT) represents a control amount of the system; k_PIs a ratio coefficient; t is_IIs the cumulative time constant; t is_DIs the derivative time constant; k_IIs an accumulated coefficient; k_DIs the derivative coefficient;

the electric heating system is in an open-loop state, a step signal is given to the system, the system is tested once every sampling period T, the collected data of the temperature changing along with the time is obtained, the response curve of the controlled object is obtained,

and calculating the response function of the controlled object according to the response curve, wherein the response function G (S) is as follows:

in the formula: k_ZIs the static gain; t is_CIs the gain time constant; τ is the lag time.

T_C＝1.5(t_0.632-t_0.28)，

Wherein, Δ C is the output response value of the system; Δ M is the phase input of the system; t is t_0.632The time required to rise to 0.632 Δ C; t is t_0.28The time required to rise to 0.28 deltac,

according to the type of the controller, T is obtained_I＝2.2τ，T_D＝0.5τ，Thereby obtaining a control model;

step 4, deviation correction, namely obtaining a sampling point sequence K by adopting the temperature according to a sampling period T, calculating the deviation e (KT) of the measured value of each sampling point and the target value, calculating deviation change ec (KT) according to the deviation e (KT) of the measured value and the target value of the previous time, quantizing e (KT) and ec (KT), and converting e (KT) and ec (KT) to a domain interval to be represented as: e 3,3]，ec[-3,3]Constructing quantized subsets of e (kt) and ec (kt) with 7 dimensions: { NL, NM, NS, Z, PS, PM, PL }, which respectively represent negative large, negative middle, negative small, zero, positive small, positive middle, positive large, and the ratio coefficient K is obtained by a rule table_PThe cumulative coefficient K_ICoefficient of derivation K_DCorresponding proportion coefficient correction quantity delta K_PCumulative coefficient correction amount Δ K_IDerivative coefficient correction amount delta K_DIs quantized by Δ K_P、ΔK_IAnd Δ K_DThe transformation to discourse domain interval is represented as: Δ K_P[-3,3]、ΔK_I[-0.03,0.03]And Δ K_D[-5,5]Respectively obtaining delta K according to the quantization control rule table_P、ΔK_IAnd Δ K_DAmount of (2)And quantizing the subset, wherein the quantization control rule table is as follows:

ΔK_Ptable of quantization control rules

ΔK_ITable of quantization control rules

ΔK_DTable of quantization control rules

According to Δ K_P、ΔK_IAnd Δ K_DThe numerical value and the quantization rule on the discourse domain interval corresponding to the quantization subset are compared with the K calculated in the step 3_P、K_I、K_DCarrying out quantitative reasoning and correction;

step 5, according to the control model of the step 3 and the corrected K of the step 4_P、K_I、K_DAnd calculating a system control quantity U (KT), controlling the electric heating system to heat, finishing temperature control if e (KT) is less than 1, and returning to the step 2 if the e (KT) is not less than 1.

5. The metal material processing system according to claim 1, wherein the linear curve control algorithm is specifically:

when the time T is more than 0 and less than or equal to T_AThe acceleration phase of (1), the acceleration phase using linear acceleration,

alpha is the acceleration of the stepping motor, theta_iFor the angle, t, which has been rotated after the i-th pulse has been sent_iFor the ith pulse transmission time, T_AFor the acceleration period, δ is the step angle, i ═ 1,2,3_A，n_AIn order to speed up the number of steps of the segment, for the angle of rotation of the acceleration section

The ith pulse period T of the acceleration section_iComprises the following steps:

when time T is at T_A＜t≤T_A+T_BIn the constant-speed stage of the process,

t_ifor the ith pulse transmission time, T_BFor a constant time period, i ═ n_A+1,n_A+2,n_A+3,...,n_A+n_B，n_BIn order to realize the step number of the uniform-speed section,

the ith pulse period of the constant velocity segment

When time T is at T_A+T_BIn the deceleration stage when T is less than or equal to T, curve deceleration is adopted,

i pulse period T of deceleration section_iComprises the following steps:

wherein, T_CFor the deceleration period, i ═ n_A+n_B+1,n_A+n_B+2,n_A+n_B+3,...,n_A+n_B+n_C，n_CIn order to reduce the number of steps of the speed reduction section,

t is the total control period, T is T ═ T_A+T_B+T_C；

The control voltage of the stepping motor is as follows:

wherein, U_A、U_BControl voltages applied to the two phase windings of the stepping motor A, B; r_A、R_BA, B resistances of the two-phase windings, respectively; i is_A、I_BA, B currents on two-phase stator windings respectively; l is₀The average component of the self-inductance of the motor stator winding is obtained; l is₁Is the fundamental component of the self-inductance of the stator winding; k₀Is the back electromotive force coefficient of the stepping motor; ω is the mechanical angular velocity of the motor rotor.

Technical Field

The present application relates to a processing system, and more particularly to a metal material processing system.

Background

The traditional material removing machine tool is used for removing unnecessary parts in materials by processes of turning, cutting, milling, grinding and the like, but the problem that a machining tool cannot extend into or reach enough exists, products with any complex shapes cannot be machined, and the removed materials are wasted. In contrast, additive materials are a manufacturing technique that eliminates the need for conventional tools, fixtures and tooling to create objects of any shape. The design model in the computer is automatically, quickly, directly and accurately converted into a solid part, so that the processing period is effectively reduced, the product quality is improved, the material cost is greatly reduced, and the manufacturing cost is reduced by about 50%.

The existing metal material has the defects of non-adjustable strength, limited plane of a processing system, inaccurate and invariable temperature adjustment, lack of accurate control of a stepping motor and non-timeliness.

Disclosure of Invention

In order to solve the problems of the prior art, the invention provides a metal material processing system. The intensity adjustment of the metal material, the feeding of the metal material in three directions, the quick and accurate response of the stepping motor and the accurate and stable control of the heating temperature are realized.

The technical scheme of the invention is as follows: a metal material processing system, which comprises a machine body, an extrusion mechanism, a feeding mechanism, a transmission mechanism and a control system,

the machine body supports the extrusion mechanism, the feeding mechanism and the transmission mechanism, the machine body comprises a base, a guide rail, a bearing seat, a support frame, a base, a Z-axis mounting plate and an XY-axis mounting plate, and is formed by combining modules, and the modules are connected with each other in a welding mode through rivets;

the extrusion mechanism comprises a spray head, a throat pipe and a heat dissipation device, the spray head and the throat pipe form a piston cylinder, a metal material is used as a piston, a stepping motor provides power, and the metal material is fed towards the spray head under the traction of the power;

the feeding mechanism comprises a driving wheel, two driven wheels, a heating block and a wheel shaft mounting plate, the feeding mechanism provides driving force to draw the metal material into the throat pipe, the extrusion nozzle mechanism heats the metal material and extrudes the metal material out of the nozzle, the heat dissipation device cools the whole extrusion process, the metal material is conducted between the two driven wheels and enters the heating block in the conduction process, and the rotation of the driving wheel drives one of the driven wheels to rotate; the center distance of the two driven wheels is adjustable, the driving wheel driven by the motor and one driven wheel directly contacted with the driving wheel are assembled on the wheel shaft mounting plate, relative movement does not exist, and the relative position of the wheel shaft mounting plate and the machine body in the horizontal direction is adjustable; the other driven wheel is fixed on the machine body, and the horizontal relative position between the other driven wheel and the machine body is not adjustable; the center distance between the two driven wheels is adjusted by adjusting the positions of the wheel axle mounting plate and the machine body, so that the extrusion degree of the metal material is adjusted; the feeding mechanism is bilaterally symmetrical, and an inlet of the feeding mechanism is provided with an inverted cone-shaped opening with a wide upper part and a narrow lower part; each driven wheel comprises a shaft-shaped core made of a metal material and a rubber material coated in the middle, the conductive metal material is in contact with the rubber material, and an arc-shaped groove is formed in the rubber part of the roller in contact with the metal material;

the transmission mechanism comprises an X-axis transmission mechanism, a Y-axis transmission mechanism, a Z-axis transmission mechanism and a leveling structure;

the control system comprises a main controller, a stepping motor driving module, a temperature control module, a serial communication module and a data storage module, wherein the stepping motor driving module, the temperature control module, the serial communication module and the data storage module are connected with the main controller; the main controller controls the motor driving module to drive the stepping motor, the X-axis stepping motor, the Y-axis stepping motor and the Z-axis stepping motor of the feeding mechanism, and the stepping motor is controlled by using a linear curve control algorithm.

The invention has the beneficial effects that:

(1) the feeding seat with the ball screw is used for realizing stable transverse feeding, and the bearing table with the matching of the balls and the linear guide rail is used for realizing high positioning precision and high repetition precision;

(2) the precise control of the stepping motor is effectively realized through a linear curve control algorithm, and the waste on efficiency and the inaccuracy of precision caused by repeated modification of manual setting are reduced;

(3) the temperature control algorithm is used for realizing feedback control on the temperature, so that the temperature is kept at a preset constant temperature and is accurately adjusted;

(4) the three-shaft transmission mechanism realizes the feeding of metal materials in three directions, and the feeding is accurate.

Drawings

FIG. 1 is a block diagram of a metallic material processing system of the present invention;

FIG. 2 is a schematic view of the feed mechanism of the present invention;

FIG. 3 is a flow chart of temperature control according to the present invention;

Detailed Description

The invention is further described with reference to the following figures and examples.

Embodiments of the invention are illustrated with reference to fig. 1-3.

A metal material processing system, which comprises a machine body, an extrusion mechanism, a feeding mechanism, a transmission mechanism and a control system,

the machine body supports the extrusion mechanism, the feeding mechanism and the transmission mechanism, the machine body comprises a base, a guide rail, a bearing seat, a support frame, a base, a Z-axis mounting plate and an XY-axis mounting plate, a module combination mode is adopted for forming, and the modules are connected with one another in a welding mode through rivets.

The extrusion mechanism comprises a spray head, a throat pipe and a heat dissipation device,

the diameter of a nozzle of the nozzle is 0.4mm, the nozzle is made of stainless steel materials, the diameter of the nozzle is designed to be 0.2mm, the nozzle and a throat pipe form a piston cylinder, metal materials serve as a piston, a stepping motor provides power, and the metal materials are fed towards the direction of the nozzle under the traction of the power.

The feeding mechanism comprises a driving wheel (driven by a stepping motor), two driven wheels (driven by no motor), a heating block and a wheel shaft mounting plate, the feeding mechanism provides driving force to draw the metal material into the throat pipe, the extrusion nozzle mechanism heats the metal material and extrudes the nozzle, the heat dissipation device cools the whole extrusion process, the metal material is conducted between the two driven wheels and enters the heating block in the conduction process, and the driving wheel rotates to drive one driven wheel to rotate;

the center distance of the two driven wheels is adjustable, the driving wheel driven by the motor and one driven wheel directly contacted with the driving wheel are assembled on the wheel shaft mounting plate, relative movement does not exist, and the relative position of the wheel shaft mounting plate and the machine body in the horizontal direction is adjustable; the other driven wheel is fixed on the machine body, and the horizontal relative position between the other driven wheel and the machine body is not adjustable; the center distance between the two driven wheels is adjusted by adjusting the positions of the wheel axle mounting plate and the machine body, so that the extrusion degree of the metal material is adjusted.

The advantage of this design is that if the metal material conduction effect is found to be poor, it is only necessary to adjust the roller spacing, rather than directly scrapping the feeding mechanism and replacing it with new one.

The feeding mechanism is symmetrical left and right, an inverted cone-shaped opening with a wide upper part and a narrow lower part is arranged at the inlet of the mechanism,

each driven wheel comprises a shaft-shaped core made of a metal material and a rubber material coated in the middle, the conductive metal material is in contact with the rubber material, and an arc-shaped groove is formed in the rubber part of the roller in contact with the metal material.

The feeding mechanism has reasonable structural design, improves the conduction effect and efficiency, avoids blockage and avoids the weakening of strength due to overlarge deformation of metal materials.

The transmission mechanism comprises an X-axis transmission mechanism, a Y-axis transmission mechanism, a Z-axis transmission mechanism and a leveling structure, wherein the X-axis transmission component comprises an X-axis stepping motor, an X-axis motor base, an X-axis driven wheel base, an X-axis synchronous belt, a pressing block, a sliding base, an X-axis driving wheel, an X-axis driven wheel and an X-axis double-rod guide rail, one end of the X-axis double-rod guide rail is fixedly connected with the X-axis motor base, the X-axis motor base is provided with the stepping motor, an X-axis driving wheel is arranged on an output shaft of the stepping motor, the sliding base is slidably connected with the X-axis double-rod guide rail, the other end of the X-axis double-rod guide rail is fixedly connected with the X-axis driven wheel base, the X-axis driven wheel base is rotatably connected with the X-axis driven wheel through a short shaft, the X-axis synchronous belt is sleeved on the X-axis driving wheel and the X-axis driven wheel, the sliding base is fixedly connected with the X-axis synchronous belt through the pressing block, and a nozzle is arranged on the sliding base, the X-axis stepping motor rotates to realize the X-axis linear motion of the nozzle;

the Y-axis transmission mechanism comprises a square mounting plate, a transmission shaft, a Y-axis driving wheel, three Y-axis synchronous wheels, two Y-axis guide rails, two Y-axis synchronous belts and a Y-axis stepping motor, the Y-axis driving wheel and the three Y-axis synchronous wheels are mounted at four corners of the mounting plate, a first Y-axis synchronous belt is sleeved on the Y-axis driving wheel and the first Y-axis synchronous wheel, a first Y-axis synchronous belt is sleeved on a second Y-axis synchronous wheel and a third Y-axis synchronous wheel, the two Y-axis guide rails are mounted on two sides of the mounting plate in parallel, the first Y-axis synchronous wheel and the second Y-axis synchronous wheel are fixedly connected through the transmission shaft, an X-axis transmission member and an X-axis driven wheel seat are respectively and slidably connected on the two Y-axis guide rails, the X-axis transmission member and the X-axis driven wheel seat are respectively and fixedly connected with the two Y-axis synchronous belts through pressing blocks, and an output shaft of the Y-axis stepping motor is actively and fixedly connected with the Y-axis, the Y-axis stepping motor rotates to drive the two Y-axis synchronous belts to move synchronously, and the X-axis transmission mechanism moves linearly along the Y axis;

the Z-axis transmission mechanism comprises a Z-axis stepping motor, a lead screw, a bearing, a nut, a supporting plate, two Z-axis guide rails and a bracket, wherein an output shaft of the Z-axis stepping motor is connected with the lead screw, two ends of the lead screw are rotatably connected with the machine body through the bearing, the nut is movably connected with the lead screw through threads, two ends of the nut are slidably connected with the two Z-axis guide rails, the supporting plate is fixedly connected with the nut, the mounting plate is connected with the supporting plate through a leveling structure, and the Z-axis stepping motor rotates to drive the Z axis of the mounting plate to move linearly;

the leveling structure comprises a knob, cross beams, springs and bolts, the leveling structure is respectively arranged at four corners of the mounting plate, the four corners of the supporting plate are provided with four extending cross beams, the bolts are fixed with the cross beams and matched with the threads of the knob after penetrating through holes of the supporting plate, the springs are sleeved on the bolts of the knob and are abutted between the cross beams and the supporting plate, and the length of the bolts is adjusted by rotating the knob so as to check the flatness of the mounting plate;

the mounting plate plays a role in supporting materials, so that the requirement on flatness is high, and the leveling structure of the mounting plate is designed on the basis of the Z-axis transmission structure, so that the working platform can achieve good flatness through the method.

The Z-axis transmission mechanism is a lead screw and nut mechanism,

the length of the screw rod is the sum of the maximum stroke, the length of the screw cap, the safety distance and the reserved amount of the shaft end;

calculating the shaft diameter of the lead screw as follows:

wherein d is the shaft diameter of the screw, n is the allowable rotating speed, f is the support coefficient, and L is the installation distance;

the service life of the screw is calculated as follows:

F_avethe average load of the lead screw; f_iAt a rotation speed n_iWorking time t of_iThe inner lead screw bears the load after the load,

N_avein order to obtain an average rotational speed,

L_tfor the life of the screw, Ca is the stress factor，f_wIs the load factor;

calculating the checking stress delta of the screw:

axial stress of lead screw

σ is the axial stress; f_maxIn order to be the maximum load,

calculating the radial stress of the lead screw,

τ is radial stress, J is moment of inertia, and T is material torque

The control system comprises a main controller, a stepping motor driving module, a temperature control module, a serial port communication module and a data storage module, wherein the stepping motor driving module, the temperature control module, the serial port communication module and the data storage module are connected with the main controller, the main controller controls the temperature control module to heat a heating block and collect and feed back the temperature of the spray head, the temperature of the spray head is controlled by using a temperature control algorithm, and the temperature of the spray head is ensured to be capable of melting metal materials and to be in a constant temperature state. The main controller controls the motor driving module to drive a stepping motor, an X-axis stepping motor, a Y-axis stepping motor and a Z-axis stepping motor of the feeding mechanism, and the stepping motor is controlled by using a linear curve control algorithm;

the temperature control algorithm specifically comprises the following steps:

step 1, initializing a system;

step 2, the temperature control module heats the heating block, and the temperature of the spray head is acquired through the temperature sensor;

step 3, constructing a control model, and forming a control quantity by linearly combining the proportion, derivation and accumulation of errors according to the errors between the target set value and the measured value, so that the errors between the target temperature value and the actual temperature value responding to the temperature control module are reduced as much as possible, thereby accurately controlling the heating temperature, wherein the control model is as follows:

ec(KT)＝e(KT)-e((K-1)T)

in the formula: k is a sequence of sample points, T is the sample period, e (KT) represents the deviation of the measured value from the target value; ec (kt) represents the rate of change of deviation; u (KT) represents a control amount of the system; k_PIs a ratio coefficient; t is_IIs the cumulative time constant; t is_DIs the derivative time constant; k_IIs an accumulated coefficient; k_DIs the derivative coefficient;

the electric heating system is in an open-loop state, a step signal is given to the system, the system is tested once every sampling period T, the collected data of the temperature changing along with the time is obtained, the response curve of the controlled object is obtained,

and calculating the response function of the controlled object according to the response curve, wherein the response function G (S) is as follows:

in the formula: k_ZIs the static gain; t is_CIs the gain time constant; τ is the lag time.

Wherein, Δ C is the output response value of the system; Δ M is the phase input of the system; t is t_0.632The time required to rise to 0.632 Δ C; t is t_0.28The time required to rise to 0.28 deltac,

according to the type of the controller, T is obtained_I＝2.2τ，T_D＝0.5τ，Thereby obtaining a control model; step 4, deviation correction, namely obtaining a sampling point sequence K by adopting the temperature according to a sampling period T, calculating the deviation e (KT) of the measured value of each sampling point and the target value, calculating deviation change ec (KT) according to the deviation e (KT) of the measured value and the target value of the previous time, quantizing e (KT) and ec (KT), and converting e (KT) and ec (KT) to a domain interval to be represented as: e 3,3]，ec[-3,3]Constructing quantized subsets of e (kt) and ec (kt) with 7 dimensions: { NL, NM, NS, Z, PS, PM, PL }, which respectively represent negative large, negative middle, negative small, zero, positive small, positive middle, positive large, and the ratio coefficient K is obtained by a rule table_PThe cumulative coefficient K_ICoefficient of derivation K_DCorresponding proportion coefficient correction quantity delta K_PCumulative coefficient correction amount Δ K_IDerivative coefficient correction amount delta K_DIs quantized by Δ K_P、ΔK_IAnd Δ K_DThe transformation to discourse domain interval is represented as: Δ K_P[-3,3]、ΔK_I[-0.03,0.03]And Δ K_D[-5,5]Respectively obtaining delta K according to the quantization control rule table_P、ΔK_IAnd Δ K_DWherein the quantization control rule table is as follows:

TABLE 1. DELTA.K_PTable of quantization control rules

TABLE 2. DELTA.K_ITable of quantization control rules

TABLE 3. DELTA.K_DTable of quantization control rules

According to Δ K_P、ΔK_IAnd Δ K_DThe numerical value and the quantization rule on the discourse domain interval corresponding to the quantization subset are compared with the K calculated in the step 3_P、K_I、K_DCarrying out quantitative reasoning and correction;

step 5, according to the control model of the step 3 and the corrected K of the step 4_P、K_I、K_DAnd calculating a system control quantity U (KT), controlling the electric heating system to heat, finishing temperature control if | e (KT) | is less than 1, and returning to the step 2 if the | e (KT) | is not more than 1.

The linear curve control algorithm specifically comprises the following steps:

when the time T is more than 0 and less than or equal to T_AThe acceleration phase of (1), the acceleration phase using linear acceleration,

alpha is the acceleration of the stepping motor, theta_iFor the angle, t, which has been rotated after the i-th pulse has been sent_iFor the ith pulse transmission time, T_AFor the acceleration period, δ is the step angle, i ═ 1,2,3_A，n_AIn order to speed up the number of steps of the segment,

for the angle of rotation of the acceleration section

The ith pulse period T of the acceleration section_iComprises the following steps:

when time T is at T_A＜t≤T_A+T_BAt a constant speed stage，

t_iFor the ith pulse transmission time, T_BFor a constant time period, i ═ n_A+1，n_A+2，n_A+3，...，n_A+n_B，n_BIn order to realize the step number of the uniform-speed section,

the ith pulse period of the constant velocity segment

When time T is at T_A+T_BIn the deceleration stage when T is less than or equal to T, curve deceleration is adopted,

i pulse period T of deceleration section_iComprises the following steps:

wherein, T_CFor the deceleration period, i ═ n_A+n_B+1，n_A+n_B+2，n_A+n_B+3，...，n_A+n_B+n_C，n_CIn order to reduce the number of steps of the speed reduction section,

t is the total control period, T is T ═ T_A+T_B+T_C；

The control voltage of the stepping motor is as follows:

wherein, U_A、U_BControl voltages applied to the two phase windings of the stepping motor A, B; r_A、R_BA, B resistances of the two-phase windings, respectively; i is_A、I_BA, B currents on two-phase stator windings respectively; l is₀The average component of the self-inductance of the motor stator winding is obtained; l is₁For stator windingA fundamental component of inductance; k₀Is the back electromotive force coefficient of the stepping motor; ω is the mechanical angular velocity of the motor rotor.

The above-described embodiment merely represents one embodiment of the present invention, but is not to be construed as limiting the scope of the present 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.