KR20170098088A - 3d printer with loadcell - Google Patents

Abstract

The purpose of the present invention is to provide a three-dimensional printer which is capable of seeing an amount of loaded raw material in advance before manufacturing an article by operating the three-dimensional printer, and which is capable of seeing whether the amount of the loaded raw material is sufficient or not compared with the mass of the article to be manufactured. The three-dimensional printer of the present invention comprises: a raw material loading unit which is mounted on a load cell to see the amount of the raw material; a load cell which senses the weight of the raw material; and a display panel on which the weight of the raw material sensed by the load cell is displayed. Further, the three-dimensional printer of the present invention comprises: a nozzle which is integrally assembled to an extruder, and which is improved such that an end portion of the nozzle is detachably constructed when it is necessary to replace the nozzle; and a nozzle unit module to which the nozzle end portion, a heater unit surrounding the nozzle end portion, and a temperature sensor are assembled all together, and which is entirely detachably constructed such that the nozzle unit module can be assembled and disassembled.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a 3D printer having a load cell,

The present invention relates to a 3D printer, and more particularly, to a 3D printer having an improved configuration for ease of use.

3D printers are technologies that make 3D shapes using materials such as plastics, metals, and powders based on designs designed with CAD programs. Stack materials to make products. A home 3D printer mainly uses extrusion lamination molding (FDM). It was developed by Stratasys Inc. in Minneapolis. When the first 3D printer technology was developed, it was expected to be difficult to commercialize, but the expiration of the patent right led to the creation of a 3D printer manufacturer. Since then, 3D printer technology has improved, simplified, and delivered to the public at lower prices. The FDM method has expired in 2014, and the SLS method has expired in 2015.

In the case of 3D printing method, machining is possible in a smaller space than NC machining technology, and it is possible to process complex shapes without using a fixing device for fixing the workpiece. In the case of NC, it is a method to make a product by cutting from raw material, but in the case of 3D printer, a method of stacking products using raw materials is used. Although there are many advantages over NC in many fields, the lack of a feedback system for the lack of raw materials during 3D printer processing is a problem due to a technological development state which is insufficient. Extruder parts continue to output, lack of material, and 3D printer stops working when the 3D printer is not recognized by the lack of raw materials and there is no material. If the 3D printer is not recognized, it can not be stacked and processed in the air. If the 3D printer is stopped, there is a residual, which may result in an abnormal processing surface. Therefore, it is necessary to check the amount of raw materials such as filaments in real time before starting printing.

Meanwhile, the FDM (Fused Deposition Modeling) method of the present invention is a method in which a filament, which is a thermoplastic material, is melted by heat and then extruded through a nozzle to laminate the materials. In this case, although the filaments occasionally occlude in the nozzle, in order to separate the extruder part for repairing the nozzle, the operator must disassemble and reassemble by using the tool in an inconvenient manner. In this respect, there may be problems in maintenance and repair of 3D printers.

Accordingly, it is an object of the present invention to provide a 3D printer capable of recognizing the amount of a pre-loaded raw material before manufacturing an article by operating a 3D printer and knowing whether the amount of the raw material to be loaded is sufficient I would like to.

Another object of the present invention is to provide a detachable nozzle unit integrated with an extruder for easy replacement of the nozzle.

According to the present invention, a raw material loading unit of a 3D printer is mounted on a load cell so that the amount of the raw material can be known, and the weight of the raw material detected by the load cell is displayed on the display panel.

In addition, when it is necessary to replace the nozzles, the nozzles integrally assembled into the extruder are improved so that the nozzle end portion is detachable, and the entire nozzle unit module in which the nozzle end portion, the heater portion surrounding the nozzle portion, So that it can be disassembled and assembled.

According to the present invention, since the display panel that displays the weight of the raw material portion of the 3D printer in real time can be determined in advance, it is possible to determine in advance whether the amount of the material to be manufactured is sufficient with respect to the mass of the article to be manufactured, Can be reduced.

In addition, when the nozzle is to be replaced, the nozzle portion is modularized, which makes it very convenient to replace the cartridge with a job of a degree of cartridge replacement.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram and a three-dimensional perspective view of a configuration of a 3D printer of FDM (Fused Deposition Modeling) system.
FIG. 2 is a photograph of a cross-sectional configuration showing application of a load cell to a raw material supply portion of a three-dimensional printer according to the present invention, and a photograph taken in actual implementation.
FIG. 3 is a flowchart showing the operations performed in FIG. 2 in order.
FIG. 4 is a perspective view showing components for applying a load cell to a raw material supply unit as shown in FIG. 2. FIG.
FIG. 5 is a perspective view of a photograph and parts showing a nozzle made in a cartridge and detachable according to the present invention. FIG.
FIG. 6 is a photograph of the operation of a 3D printer made by attaching a nozzle to a cartridge according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows a configuration of a 3D printer using a filament as a raw material. A filament is used as a raw material for printing and manufacturing an object. The filament is passed through an extruder to supply it to a nozzle, a heater is attached to a nozzle, and melted and then printed in a desired shape to produce an article. FDM is an abbreviation of Fused Deposition Modeling. It is a method to melt the filament-type thermoplastic material in the nozzle and push the melted material in the necessary part to make the desired shape, and to stack it from the bottom to make 3D printing. The size and detail of the layer is determined by the speed and force that the melt is pushed out of the nozzle. In order to melt the material with the nozzle, it is necessary to raise the temperature of the nozzle hot, and the filament after the process becomes hardened at the room temperature. Features include strong strength, strength against humidity, and excellent durability. On the other hand, the disadvantage is that the surface is rough and the production speed is slow compared to other methods. In order to be applied in the industrial field, a lot of development is required. Currently, it is mainly used for personal use and home use using open source.

As described above, the present invention aims at improving the fact that, when an article is manufactured using a three-dimensional printer, the amount of the raw material of the raw material supply portion remains unknown. Accordingly, a configuration is provided in which information on the weight of the raw material is displayed so that the user can check the remaining amount of the raw material before printing and determine whether or not printing is possible. To this end, a load cell capable of measuring the weight of a raw material such as a filament is disposed under the filament rest, and the weight information of the filament measured in the load cell is displayed on a display device such as a liquid crystal device. A schematic configuration thereof is shown in FIG. 2 by photographing a cross-sectional view and an actual implemented state.

Since the load cell measures the weight by the fine strain, the load cell (first plate) for holding the filament is placed on the load cell, and the load cell is connected to a predetermined point of the load cell. In order to receive this deformation force, a load cell support (second plate) is connected which is connected to the load cell at a point different from the cradle connection portion. Fig. 4 is a perspective view showing the shape of a supporting base on which both ends of the core wound around the filament can be supported, and a supporting base and supports for supporting the load cells and the load cells at different points in the up and down directions.

The weight of the filament measured by the load cell must be greater than the weight of the article to be produced by the user, and the weight of the filament requires accuracy. Accordingly, in order to minimize the weight error, the present invention provides five times of weight measurement and displays an error range on the display so that the user can determine whether or not to print based on the error.

In addition, if not only the weight of the filament but also the length of the filament is indicated, the weight of the filament is converted into the length and displayed so that it can be more helpful in determining whether or not the article is manufactured. The method of converting weight to length will be described later.

The detailed configuration of the filament weight measurement is shown in the flow chart of Fig.

The weighing starts when weighing menu is selected from the LCD screen selection menu. At the next run, all measurements are reset. When the measurement starts, the load cell receives the weight analog signal. Then, the analog signal is amplified through a pressure amplifier Hx711. Next, the analog signal is converted into a digital signal through the main board. The weight sensor transmits the weight value in real time. Here, the average of the five digital signals accumulated in the calculation module of the main board is obtained. The offset value is set on the main board based on the weight of the intermediate holder of each filament. The weight value is determined by taking the offset value into account for the average weight. The determined weight value is converted to a length by [Equation 1]. LCD screen coding shows the weight and length of the remaining filaments. The display panel is an LCD in this embodiment, but an OLED panel may be used.

The characteristics of the weight sensor LCD design are as follows.

First, provide immediate information value. However, it is possible to calculate the weight value only before the 3D printer is activated.

Second, we set the font size and position that are easy to read and easy to read.

Third, it shows tolerance range.

The weight measurement by the load cell will be described in more detail as follows.

 Generally, a load cell is a generic term of a force transducer in which an electric output is generated in proportion to a load when a load is applied. The strain cell is a strain gage type load cell employed in the present invention.

Strain refers to the amount of deformation that occurs when an elastic body is pulled or pushed, where the amount of strain is called the strain, and the strain gauge is used to measure the amount of deformation. By using these characteristics, it is the principle of the load cell to convert the strain to the load and measure it. In order to detect such a minute change, a circuit called an electric bridge circuit is used.

The actual 3D modeling slicer provides the cumulative length used through the E-value of the G-Code. The cumulative length is the value excluding the length to remove the impurities when the printer is started for the first time. The length is in cm. The filament is difficult to get the correct length because of the curled shape and the hard material. Therefore, the load is measured through the load cell, and the electrical load is converted into weight by Arduino sketch coding, and the weight is converted into the length by the length conversion equation.

The formula for converting weight to length is shown in [Equation 1].

[Equation 1]

The density of the corresponding PLA filament is required in the weight value. Obtain the width of the cross-sectional area through the cross-sectional diameter. By multiplying the density by the area of the cross-sectional area and dividing the weight, the length can be known. Diameter and density are already defined.

In the above description, the filament type raw material has been described by way of example, but it is also possible to display the remaining amount of raw material by applying the load cell to other types of raw materials.

Next, the inventors of the present invention fabricated each part of the 3D printer through 3D printing in order to improve the ease of repair of the user. In particular, we have fabricated a modularized nozzle structure that is easy to attach and detach to prepare for repairs of nozzle failure.

In other words, conventionally, the roots of the nozzles start from the raw material supply portion and are sandwiched by the extruder. When the nozzle and the heater come near the end of the nozzle, the heater and the sensor are assembled integrally with the main body. And reassembly is very difficult. Especially, since the nozzles are arranged downward, in order to disassemble the nozzle, it is very inconvenient for a person to push his / her head and look up above the 3D printer.

Therefore, the inventors of the present invention constructed a detachable type that can easily assemble / disassemble the nozzle unit in a cartridge type manner at a portion where the heater is coupled after passing through the extruder. The nozzle and the extruder and the heater and temperature sensor coupled to the nozzle were fabricated as one module (called the "nozzle module"), the module was assembled to the extruder support, and the extruder support was forced into the extruder holder. To this end, as shown in FIG. 5, the extruder support and the extruder support itself, which fit the nozzle module in an interference fit manner, are assembled to the extruder stand. The extruder stand can move the nozzle so that a shaft for moving the nozzle module in the X-Y direction is penetrated and printed and produced in a three-dimensional shape.

In other words, the existing nozzle, the heater and the sensor are assembled in the same manner, they are modularized into a single cartridge and inserted into an extruder support having a mounting part capable of fixing them stably, Respectively. The extruder support itself is inseparably assembled to the extruder stand, and the extruder stand has openings for the nozzles which are aligned when assembled with the extruder stand. The extruder stand is provided with a tunnel-shaped shaft penetration portion at its both ends so that the shaft can be penetrated.

FIG. 6 is a photograph showing that the assembled nozzle module implemented by the present inventors is connected to a raw material supply unit in a state where the cartridge is packed and modularized.

In the above, all members required for assembly were directly manufactured through 3D printing. The production process will be described as follows. However, parts can be ordered and purchased.

A 3D modeling program is a program that creates a 3D shape. The drawing of the printer is created using a 3D modeling program. In order to output to 3D printer, STL extension should be saved. In the present invention, a CATIA program is used.

Slicer program is a program that converts STL file created by 3D modeling program to G-code. The slicer can set the path, speed, extrusion amount, stacking height, etc. for stacking materials to output the model. The quality of the output varies depending on the performance and setting values of the slicer program. Programs include CURA, Slic3r, and Kisslicer. The present inventors used CURA.

The mainboard chosen by the present inventors is Arduino, which uses a ramps 1.4 expansion board. An open source program that supports rams 1.4 is Marlin firmware. You can compile G-Code using open source of Marlin firmware. In addition, a method of controlling a stepping motor, a temperature sensor control, a cooler, and the like is provided. Changing the open source of Marlin firmware uses the Arduino Sketch program.

Thus, a 3D printer providing convenience to the user can be provided.

It is to be understood that the invention is not limited to the disclosed embodiment, but is capable of many modifications and variations within the scope of the appended claims. It is self-evident.

Claims (6)

A raw material loading section of a 3D printer;
A load cell mounting the raw material loading unit and measuring the weight;
A calculation module for calculating the weight of the raw material from the weight of the raw material distribution portion measured by the load cell; And
And a display for displaying the weight of the raw material in numerical values. The 3D printer according to claim 1, wherein the calculation module collects a plurality of weight measurement values of the material stacking portion by the load cell, calculates an error, and displays the error range together with the average weight of the material on the display. [2] The 3D printer according to claim 1, wherein the calculation module converts the weight of the raw material into the length of the filament, and displays the weight on the display together with the average weight of the raw material. The method according to claim 1,
A nozzle module unit connected to the raw material supply unit;
An extruder support to which the nozzle module is assembled; And
Further comprising: an extruder stand on which the extruder supports are assembled,
The nozzle module part being detachably assembled to the extruder support,
Wherein the extruder stand is coupled to a drive shaft including a penetration portion through which a drive shaft for moving the nozzle module portion moves to produce a three-dimensional shaped article. 5. The 3D printer according to claim 4, wherein the nozzle module section includes a nozzle, a heater, and a temperature sensor. 5. The 3D printer according to claim 4, wherein the extruder support and the extruder stand each have openings through which the nozzles can be exposed, and each of the openings is aligned with each other when assembled.

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