TW201739599A - A mechatronic movement system for a rapid-prototyping machine - Google Patents

Abstract

A mechatronic movement system for three-dimensional printing means of a rapid-prototyping machine, such as a 3D printer, of the type provided with at least one microprocessor electronic management board, in which the movement of the printing means of the 3D printer along the axes X and Y of the horizontal plane is obtained exclusively with geared kinematic chains.

Description

Electromechanical mobile system for fast plotters

The present invention relates to a portion of a fast plotter, commonly referred to as a "3D (dimensional) printer".

3D printing can take into account the natural evolution of 2D printing and presenting this major advantage in being able to provide a true rework of the 3D model that has been built with one of the current 3D model programs. Through this technique, three-dimensional objects are created by deposition of a continuous layer of material.

Basically, it can be said that the 3D printer uses the archive of the three-dimensional model of the object and "disassembles down" to define a portion of the series in the cross-sectional view of the object. In other words, these parts are the "slices" of the objects to be created, which are printed on top of each other to create a layer of the 3D object.

There are different 3D-printing techniques, and the main differences in this technique focus on the way in which the material layer is printed. Some methods use a material that is melted or softened to produce a layer of the material, such as Selective Layer Sintering (SLS) and fused deposition. Fused Deposition Modelling, on the other hand, deposits a hardened liquid material using various techniques. In this example of a lamination system, there are thin layers cut according to the shape and joined together.

Any 3D printing technique has advantages and disadvantages, the main factors being considered are the speed, the cost of the printed prototype, the cost of the 3D printer, the choice of the material, the color available, and the like.

Without considering the various 3D printing techniques and methods, it should be noted that for all current 3D printers, the general problem is to focus on the movement of the device that must be printed.

Almost all currently known 3D printers use Cartesian movement governed by a kinematic chain of general belts, pulleys and belt tensioners driven by stepper motors.

Therefore, the final gear ratio driven by the configuration may not be fixed with time considering the elasticity of the belt, and the final gear ratio cannot always guarantee the homogeneity of movement and transmission along the motion chain. In a belt type kinematic chain, regardless of the toothed or non-toothed belt, the gear ratio must always be taken into account between the value of the force applied by the drive pulley and the value of the force to which the driven pulley is subjected. The difference (commonly referred to as "DELTA"), the difference between the aforementioned values is determined by the movement of the movement through the second component (pulley, belt tensioner, belt, etc.).

Belt transmission cannot be considered completely as in the case of a geared kinematic chain, which is that at present the possible slippage of the belt itself and/or the fall of the structure cannot be ruled out over time, especially as The latter consists of rubber or materials that are easy to wear.

It may happen that, for example, for the initial movement of the drive pulley, the driven pulley does not instantaneously correspond to the resulting movement, and this is because the belt tensioner may be elastic due to the presence of the belt tensioner. And/or this is due to the inherent elasticity of the belt connecting the two pulleys.

In the gear ratio of a geared kinematic chain (for example, a rack and pinion, a gear, a ball screw having a main shaft), the aforementioned difference (DELTA) is almost zero, and the gear type kinematic chain is far more accurate and accurate. This initial accuracy is maintained over time.

In accordance with the unique characteristics of the present invention, it is envisaged that the movement of the 3D printer is obtained using only a gear type kinematic chain, which is preferably composed of components having helical teeth.

A second unique feature of the present invention resides in the fact that the rack of movement of the printing device for at least one of the two axes along the horizontal plane XY does not move and is relative to the load bearing structure It is referred to as a "chassis" and is fixed so that the member carries more weight, that is, the rack is still stationary, and the gear carrying less weight moves along the rack for a substantial reduction. The inertial mass to be displaced. Beneficially, it can be pointed out that moving a small inertial mass results in considerable benefits, meaning: - applying less force to overcome the initial friction; - increasing the likelihood of this speed, according to the 3D printing technique a short time for the obvious advantages of the production of the product; - a reduction in the necessary torque for the motor to overcome the initial friction, and a reduction in the acceleration/deceleration for the movement of the print head, consequent savings in power and energy, and in terms of cost Savings.

As has been suggested, in a preferred embodiment of the invention, the use of gears and racks with helical teeth is contemplated. This spiral solution places considerable limitations on the friction and noise of typical gears with straight teeth.

The result of this solution is that the gear ratio can be accurate and accurate while avoiding or at least significantly reducing the problems of friction, jamming and noise during displacement.

The solution according to the invention provides the accuracy of the positioning on the axis XY of the horizontal plane, with consequent advantages in the operation and accuracy of the object obtained by 3D printing, The advantages cannot be achieved by using the general movement controlled by the belt.

It is therefore apparent that the present invention achieves a competitive advantage over currently known 3D printers.

As will be more clearly emerged below, for example using two racks with helical teeth and corresponding gears on the shaft Y with a helical rack and gears on the shaft X, it is possible to greatly reduce the possibility during operation Produced backlash. The gradual and smooth meshing of typical helical teeth in fact makes it possible to use a less powerful motor, thus delivering less force. Furthermore, the option of directly securing the rack to the chassis has a feature for releasing the vibration on the chassis itself and not in the three-dimensional workpiece The strategic importance of printing on the machined surface.

The detailed description of the present invention is set forth with reference to the appended claims,

1‧‧‧Slide gantry

2‧‧‧rail

3‧‧‧Slide gantry

4‧‧‧ rails

MX‧‧ motor

MY‧‧ motor

MZ‧‧‧ motor

CX‧‧‧ rack

CY‧‧‧ rack

In the drawings: Fig. 1 is a front view schematically showing the device for moving along the three-axis XYZ; Fig. 2 is an isometric view corresponding to the previous view, the isometric view also showing the 3D a platform on which the article is built; FIG. 3 is a front view of a non-limiting example of a 3D printer in which the moving member is mounted in accordance with the present invention; and FIG. 4 corresponds to the previous view View the floor plan.

According to the invention, the movement along the axis X is controlled by a rack and a corresponding gear (having at least one motor), for which the two racks are provided with individual motors having each of the matings themselves. Gears. The motors are connected in series to ensure consistent motion. In addition, an accurate correction of the motor, the current, the voltage, and the phase of the microstep has been achieved.

A solution with a double rack-gear and a two-motor series is now described with reference to the axis Y, since the weight along the axis Y is much heavier along the axis X, for the weighting and for guaranteeing The consistency of motion along this axis Y has become necessary.

In fact, the weight on the axis Y is the weight of the member for displacement along the axis X: the motor MX, the rack CX, the sliding gantry 3, the guide rail 4, a printing member of a known type, Such as an extruder.

In this way, the maximum accuracy of positioning is guaranteed.

As shown in the figure, the two motors MY are fixed to the individual sliding gantry 1 sliding on the guide rail 2 arranged according to the axis Y and parallel to the rack CY, and the corresponding gear - fitted to the shaft of the motor MY - always engaged on the rack CY.

The sliding carriage CY is firmly connected together via two transverse rails 4 arranged according to the axis X, which are parallel to each other and perpendicular to the aforementioned guide rail 2. Moving along the lateral rail 4 as a third sliding gantry 3, the third sliding gantry 3 is fixed relative to the motor MX, and is fitted to the shaft X as a gear that always meshes with the corresponding rack CX, the tooth The strip CX is also set to be perpendicular to the guide rail 2.

In the example of the described embodiment, the above-described sliding carriage 3 also supports the printing member 3D, which is constituted, for example, by an extruder.

As already mentioned, according to the invention, the guide rail 2 is configured in accordance with the axis Y and the guide rail 4 is configured in accordance with the axis X of the mobile system as described.

In view of the fact that the fact that the gear of the motor always meshes with the individual rack and the fact that it has a helical tooth profile substantially reduces the motion and noise of the moving chain, while providing the three-dimensional object The high degree of accuracy of the movement applied during the production of the piece and the precise control of the displacement.

As with the use of two motors MY for the movement of the sliding carriage 1 along the guide rail 2 parallel to the axis Y, the single motor MY can be fixed relative to one of the sliding carriages 1 and can be provided It is contemplated that the connection of the motor-driven sliding gantry to the structure of the other sliding gantry 1 for the shaft Y is significantly enhanced, but this will necessarily result in an undesired weight or cost from the use of the rigid material. Increasingly, the rigid material is lighter but costly.

One of them will be able to use a single motor for possible replacement of each shaft, especially for the shaft Y, it is also possible to mount the gear on the sliding carriage 1 without the motor MY, it is envisaged that the movement of the gear is connected to the provision of a motor The gear of the sliding gantry 1 of MY is via a gear type kinematic chain, such as a system of bevel gears cooperating with a drive shaft, the drive shaft being movably coupled to the gears of one of the sliding gantry 1 The rotation has an equal rotation corresponding to the gear on the other sliding carriage 1.

The movement of the various motors is configured in a manner known in the art of microprocessor electronics that is capable of processing the data contained within the 3D graphics file.

The present invention has been described and illustrated by the preferred embodiments of the present invention, but it will be apparent to those skilled in the art that the functional and/or technically equivalent modifications and/or substitutions may be Therefore, it violates the scope of protection of patent rights in this industry.

1‧‧‧Slide gantry

2‧‧‧rail

3‧‧‧Slide gantry

4‧‧‧ rails

MX‧‧ motor

MY‧‧ motor

MZ‧‧‧ motor

CX‧‧‧ rack

CY‧‧‧ rack

Claims (11)

An electromechanical moving system for a three-dimensional printing member of a fast plotter, such as, for example, a 3D printer, having at least one type of microprocessor electronic circuit board having the feature that the printing member is only in a horizontal plane XY The middle movement and the movement of the printing member along the horizontal plane along the horizontal plane X and Y of the 3D printer are obtained only via a gear type kinematic chain having gears and teeth having helical teeth Strip (CX, CY) for reducing the motion, vibration, friction and noise normally present in a spur gear; wherein the rack along the axis X or other teeth along the axis Y of the horizontal plane The strip is directly attached to the chassis of the system itself, and the support surface of the three-dimensional object is moved along the vertical axis Z via at least one ball screw driven by a motor (MZ). A moving system according to claim 1, wherein the member for moving along the axis X comprises a rack (CX) having a gear that is always engaged thereon and mounted by the The motor (MX) controlled by the electronic management circuit board; wherein the motor (MX) is fixed relative to the sliding carriage (3) on at least one of the specially provided rails (4) For movement, the set of guides is based on the axis X and parallel to the rack (CX). A moving system according to claim 1 or 2, characterized in that the member for moving along the axis Y comprises at least one rack (CY), the at least one rack (CY) always Separate gears with the motor (MY) mounted on the corresponding electronic control board The motor (MY) is fixed relative to the sliding gantry (1), and the sliding gantry (1) moves on at least one specially provided set of rails (2) according to the axis Y and parallel On the rack (CY). A moving system according to any one of claims 1 to 3, characterized in that the member for moving along the axis Y comprises two motors (MY), one for each slide table Rack (2), wherein the motors are connected in series to ensure consistency of motion. A mobile system according to any one of claims 1 to 4, characterized in that for each of the motors (MX, MY), accurate correction of phase, current, voltage and microstepping has been performed. A mobile system according to claim 4, characterized in that the two sliding carriages (CY) are firmly connected together via two lateral rails (4) arranged according to the shaft (X), The transverse rails (4) are parallel to each other and perpendicular to the aforementioned rails (2). The mobile system according to any one of claims 1 to 6, characterized in that the third sliding carriage (3) fixed relative to the motor (MX) is moved on the lateral rail (4). Mounted on the shaft of the motor (MX) is a gear that always meshes with the corresponding rack (CX), and the rack (CX) is also set perpendicular to the rail (2). The mobile system of claim 5 or 7, wherein the sliding carriage (3) also supports a 3D printing member, such as an extruder. A mobile system according to any one of claims 1 to 8, characterized in that each of the gear-type kinematic chains is envisaged to have The use of helical gears and racks made of metal materials. A mobile system as claimed in claim 4, characterized in that a single motor (MY) is provided as an alternative to the use of two motors (MY) for paralleling the axis Y a guide rail (2) moves the sliding carriage (1), the single motor (MY) is fixed relative to one of the sliding carriages (1), and the solid structure of the motor-driven sliding carriage is connected to Another sliding carriage (1) that moves with the shaft (Y). The mobile system of claim 4, characterized in that it provides a single motor (MY) fixed relative to one of the sliding carriages (1) as an alternative to the use of two motors (MY) The two motors are used to move the sliding carriage (1) along the guide rail (2) parallel to the axis Y, while there is no motor on the other sliding carriage (1), the gears are provided for movement a geared kinematic chain coupled to the gear of the sliding carriage (1) having a motor (MY), such as, for example, a bevel gear system cooperating with a drive shaft for one of the sliding carriages (1) The rotation of the gear will connect the two gears in a manner corresponding to the equal rotation of the gears on the other sliding carriage (1).