Contact resistance thermal printing head

Abstract

The utility model provides a contact resistance thermal printing head, and belongs to the technical field of additive manufacturing. A pressure sensor is arranged at the upper end of the printing head, a copper electrode compresses a spring in the printing process, the spring transmits pressure to the pressure sensor, the pressure sensor transmits pressure information to a controller, the controller outputs a control signal to a pressure motor, and the pressure motor pushes a sliding block to move, so that the compression amount of the spring is changed; the spring pushes the copper electrode of the printing head to be directly pressed on the metal raw material, and stable pressure control in the printing process is achieved. A copper electrode tip in the printing head is connected with an alternating power supply, the alternating power supply is connected with the printing head, the metal raw material and the substrate through wires to form a closed loop, and contact resistance thermal printing is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of metal additive manufacturing, and in particular relates to a contact resistance thermal print head. Background Art

[0002] Additive manufacturing (AM) technology is a technology that manufactures physical parts based on CAD / CAM design by layer-by-layer accumulation. Compared with traditional subtractive manufacturing (cutting) technology, it is a material accumulation manufacturing method. Additive manufacturing technology, commonly known as 3D printing technology, is an advanced manufacturing technology that has developed rapidly in the past 30 years. Its advantage lies in the rapid and free manufacturing of three-dimensional structures. It is widely used in new product development and single-piece small-batch manufacturing. Among them, metal direct forming is a difficult and hot technology in additive manufacturing technology.

[0003] At present, the most common types of metal materials in metal additive manufacturing are mainly metal powders and metal raw materials. The molding accuracy of powder-based additive manufacturing technology is relatively high, and its development is relatively fast, but its material utilization rate is very low (the material utilization rate is only 20% to 30%), the price of metal powder is relatively expensive, and the powder particles have certain hazards to the environment and operators. The heat sources used in powder-based additive manufacturing technology are mainly lasers and electron beams. Depending on the heat source, the common ones are wire and laser additive manufacturing (WLAM), electron beam freeform fabrication (EBF3) and arc delivery additive manufacturing (WAAM). The material utilization rate of delivery additive manufacturing is close to 100%, the cost of metal raw materials is low, and the molding process is safer. Laser as a heat source is the most popular research method, but its energy utilization rate is very low (2% to 5%); the energy utilization rate of electron beam is also low (15% to 20%), and lasers and electron guns are expensive; the energy utilization rate of arc process is as high as 70%, but arc equipment is often large, accompanied by a lot of noise and arc light pollution. Because the arc is difficult to accurately control, the surface of the molded parts is uneven, and the molding accuracy is also poor. It cannot be used directly and must be processed by subtractive equipment. The molding process is complicated. Direct high-energy beam additive manufacturing equipment is expensive, complex, large in size, and radiates pollution. However, the existing Joule thermal printing technology uses the Joule heat generated by the print head to conduct to the wire to melt the wire. This method relies on heat conduction to cause part of the energy to be lost, has low energy utilization, and can only print low-melting-point metals. Another method is to directly energize the filament. The print head conducts the current to the filament and relies on the filament's own resistance heat to melt the filament for printing. All the heat is concentrated on the filament itself, so this method has high energy utilization rate. However, the pressure cannot be controlled during printing, resulting in poor contact between the filament and the substrate. The resistance heat is difficult to control, so the morphology of the filament cannot be controlled. Utility Model Content

[0004] The utility model aims to overcome the above-mentioned shortcomings of the prior art and provide a contact resistance thermal print head to solve the problems of low energy utilization rate of the Joule thermal print head or difficulty in controlling pressure during printing in the prior art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A contact resistance thermal print head comprises a motor bracket, a pressure control motor is mounted on the motor bracket, a lead screw of the pressure control motor passes through the motor bracket, and the lead screw is connected to a slider;

[0007] The lower end of the slider is connected to a pressure sensor, the lower end of the pressure sensor is connected to a spring guide rod, the spring guide rod is connected to a spring, and the spring is inserted into the hole at the upper end of the copper electrode head;

[0008] The copper electrode head is connected to an alternating power source.

[0009] The further improvement of the utility model is:

[0010] Preferably, the motor bracket is connected to the frame of the additive printing device through a motor head guide sleeve.

[0011] Preferably, the pressure sensor, the spring guide rod, the spring and the copper electrode head are all arranged in the electrode head guide sleeve.

[0012] Preferably, the electrode head guide sleeve is provided with a stepped hole, including an upper through hole and a lower through hole of the same axis, and the diameter of the upper through hole is larger than that of the lower through hole;

[0013] The pressure sensor and the spring guide rod are installed in the upper through hole, and the copper electrode head is installed in the lower through hole.

[0014] Preferably, the copper electrode head and the lower through hole are clearance-fitted.

[0015] Preferably, the copper electrode head is provided with a positioning groove along the length direction, and the electrode head guide sleeve is provided with a positioning pin, which is inserted into the positioning groove.

[0016] Preferably, the electrode head guide sleeve is connected to an alternating power source.

[0017] Preferably, the spring guide rod is divided into a coaxial connecting plate and a guide rod portion, and the diameter of the connecting plate is larger than the diameter of the guide rod portion;

[0018] The connecting plate is connected to the pressure sensor, and the spring is sleeved on the guide rod part.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] The utility model proposes a contact resistance thermal print head, which has a completely different structure from the traditional Joule thermal print head. During the printing process, the copper electrode of the print head is directly pressed on the metal raw material, and the copper electrode head in the print head is connected to an alternating power supply, which is connected to the print head, the metal raw material and the substrate through a wire to form a closed loop. A pressure sensor is provided at the upper end of the print head. During the printing process, the copper electrode compresses the spring, and the spring transmits the pressure to the pressure sensor. The pressure sensor transmits the pressure information to the controller, and the controller outputs a control signal to the pressure motor. The pressure motor pushes the slider to move, thereby changing the compression amount of the spring, and realizing stable control of the pressure during the printing process, so that the contact between the wires is good during the printing process, thereby ensuring the stability of the printing process, solving the problem that the existing Joule thermal print head pressure cannot be controlled, resulting in an uncontrollable printing process, and the print head transmits the current to the wire, relying on the wire itself to generate resistance heat for printing, and the heat is all concentrated on the wire itself, with high energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an exploded structural diagram of the contact resistance thermal print head of the utility model;

[0022] Figure 2 It is a schematic diagram of the three-dimensional structure of the contact resistance thermal print head of the utility model;

[0023] Figure 3 It is a top view and cross-sectional schematic diagram of the three-dimensional structure of the contact resistance thermal print head of the utility model;

[0024] Figure 4 It is a cross-sectional view of the contact resistance thermal print head of the utility model;

[0025] Among them: 1. Electrode head guide sleeve; 2. Pressure control motor; 3. Slider; 4. Motor bracket; 5. Pressure sensor; 6. Spring guide rod; 7. Spring; 8. Copper electrode head; 9. Positioning pin; 101. Upper through hole; 102. Lower through hole; 103. Connecting part; 104. Fixed part; 10. Frame; 11. Metal raw material; 12. Base plate; 601. Connecting plate; 602. Guide rod part. DETAILED DESCRIPTION

[0026] The utility model is further described in detail below with reference to the accompanying drawings:

[0027] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0028] The utility model discloses a contact resistance thermal print head, comprising an electrode head guide sleeve 1, a pressure control motor 2, a slide block 3, a motor bracket 4, a pressure sensor 5, a spring guide rod 6, a spring 7, a copper electrode head 8 and a positioning pin 9.

[0029] See also Figure 1 The entire print head is provided with a motor bracket 4 for fixing the motor. The pressure control motor 2 is arranged on the motor bracket 4 and connected by screws. The power output end of the pressure control motor 2 is a lead screw, and a slider 3 is installed on the lead screw. The lead screw of the pressure control motor 2 passes through the motor bracket 4, and the slider 3 cooperates with the lead screw of the pressure control motor 2, and can drive the slider 3 to move up and down smoothly when the pressure control motor 2 rotates.

[0030] The pressure sensor 5 is installed at the lower end of the slider 3, and the spring guide rod 6 is connected to the lower end of the pressure sensor 5 by screws. The spring guide rod 6 is divided into a connecting plate 601 and a guide rod part 602 which are integrally connected and coaxial. The diameter of the guide rod part 602 is smaller than the diameter of the connecting plate 601; the upper part is connected to the pressure sensor 5 by screws, and the spring 7 is sleeved on the guide rod part 602 of the spring guide rod 6.

[0031] The pressure sensor 5 and the spring guide rod 6 are both arranged at the upper part of the step hole, so that they can move up and down under the drive of the slider 3, and the slider 3 can also extend into the upper part of the step hole.

[0032] See also Figure 2 , Figure 3 and Figure 4The electrode head guide sleeve 1 is fixed to the frame 10 by screws. The electrode head guide sleeve 1 includes a connecting portion 103 and a fixing portion 104 which are connected in one piece. The fixing portion 104 is in the middle of the connecting portion 103. Both sides of the connecting portion 103 are fixedly connected to the frame 10 of the additive printing device by screws respectively. The motor bracket 4 is at the upper part of the fixing portion 104. The motor bracket 4 is fixed to the fixing portion 104 by screws. The fixing portion 104 is vertically provided with a platform for placing the copper electrode head 8 and related components. Step hole, the step hole includes a coaxial upper through hole 101 and a lower through hole 102, the diameter of the upper through hole 101 is larger than that of the lower through hole 102; the pressure sensor 5 and the spring guide rod 6 are installed in the upper through hole 101, and the copper electrode head 8 is installed in the lower through hole 102; the diameter of the upper through hole 101 enables the pressure sensor 5 and the spring guide rod 6 to move up and down therein, and the copper electrode head 8 and the lower through hole 102 are clearance fit, so that the lower through hole 102 can provide a certain supporting force for the copper electrode head 8.

[0033] In some embodiments of the present invention, the copper electrode tip 8 is provided with a positioning groove along the length direction, and the electrode tip guide sleeve 1 is provided with a positioning pin 9, which is inserted into the positioning groove so that the copper electrode tip 8 will not deviate from the axis when moving along the length direction of the lower through hole 102, and the cooperation of the positioning pin 9 and the positioning groove can limit the extreme position of the upward and downward movement of the copper electrode tip 8, so that the copper electrode tip 8 will not slip out of the electrode tip guide sleeve 1.

[0034] A hole is provided at the top of the copper electrode head 8, the lower end of the spring 7 is installed in the hole at the top of the copper electrode head 8, and the upper end is sleeved on the spring guide rod 6, so that the spring 7 can be compressed in the vertical direction.

[0035] During the printing process, the copper electrode head 6 presses the metal raw material 11 onto the substrate 12, and the external alternating power source transmits the power to the copper electrode head 8 through the electrode head guide sleeve 1, and the copper electrode head 8 performs printing.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A contact resistance thermal print head, characterized in that: It comprises a motor bracket (4), a pressure control motor (2) is mounted on the motor bracket (4), a lead screw of the pressure control motor (2) passes through the motor bracket (4), and the lead screw is connected to a slider (3); The lower end of the slider (3) is connected to a pressure sensor (5), the lower end of the pressure sensor (5) is connected to a spring guide rod (6), the spring guide rod (6) is connected to a spring (7), and the spring (7) is inserted into a hole at the upper end of the copper electrode head (8); The copper electrode head (8) is connected to an alternating current power source.

2. A contact resistance thermal print head according to claim 1, characterized in that: The motor bracket (4) is connected to a frame (10) of the additive printing device via an electrode head guide sleeve (1).

3. A contact resistance thermal print head according to claim 2, characterized in that: The pressure sensor (5), the spring guide rod (6), the spring (7) and the copper electrode head (8) are all arranged in the electrode head guide sleeve (1).

4. A contact resistance thermal print head according to claim 3, characterized in that: The electrode head guide sleeve (1) is provided with a stepped hole, comprising an upper through hole (101) and a lower through hole (102) which are coaxial, and the diameter of the upper through hole (101) is larger than that of the lower through hole (102); The pressure sensor (5) and the spring guide rod (6) are installed in the upper through hole (101), and the copper electrode head (8) is installed in the lower through hole (102).

5. A contact resistance thermal print head according to claim 4, characterized in that: The copper electrode head (8) and the lower through hole (102) are clearance-fitted.

6. A contact resistance thermal print head according to claim 2, characterized in that: The copper electrode head (8) is provided with a positioning groove along the length direction, and the electrode head guide sleeve (1) is provided with a positioning pin (9), which is inserted into the positioning groove.

7. A contact resistance thermal print head according to claim 2, characterized in that: The electrode head guide sleeve (1) is connected to an alternating power source.

8. The contact resistance thermal print head according to any one of claims 1 to 7, characterized in that: The spring guide rod (6) is divided into a coaxial connecting plate (601) and a guide rod portion (602), and the diameter of the connecting plate (601) is larger than the diameter of the guide rod portion (602); The connecting plate (601) is connected to the pressure sensor (5), and the spring (7) is sleeved on the guide rod part (602).

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