Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
  • H02K41/02—Linear motors; Sectional motors
  • H02K41/035—DC motors; Unipolar motors
  • H02K41/0352—Unipolar motors
  • H02K41/0354—Lorentz force motors, e.g. voice coil motors
  • H02K41/0356—Lorentz force motors, e.g. voice coil motors moving along a straight path
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
  • H02K2201/18—Machines moving with multiple degrees of freedom

Definitions

• the invention is directed to a process and apparatus to manufacture a three- dimensional object by
• Subtractive manufacturing or machining is any of various processes of turning, drilling and milling in which material comprising object sometimes referred to as raw material is cut into a desired final shape and size by a controlled material-removal process.
• a mechanical arm is used to either remove the material from a raw object or to control the object interaction with the fixed mechanical tool.
• controlled material removal are today collectively known as subtractive manufacturing, in distinction from processes of controlled material addition, such as 3D printing, which are known as additive manufacturing.
• the mechanical arm is used to either control the position of the printer head that deposits material onto the collection table or to control the position of the collection table in respect to the fixed printer head.
• the mechanical arm is controlling the dynamic component to provide correct positioning.
• the present invention aims at providing a process and an apparatus, which does not have the above mentioned disadvantages. Summary of the invention
• a 3-D printer comprising a material printer head for laying down successive layers of material, a support for a three dimensional object to be printed by the 3-D printer and an array of electromagnets positioned in an horizontal plane, the array of electromagnets is positioned above and/or below the material printer head and support for the three dimensional object and the array of electromagnets may, when in use, create a dynamic electromagnetic field which can change the position of either the material printer head or the support of the three dimensional object to be printed.
• a subtractive manufacturing apparatus comprising a platform for attaching a starting object, one or more machining tools and an array of electromagnets positioned in an horizontal plane, the array of electromagnets is positioned above and/or below the platform and machining tools and the array of electromagnets may, when in use, create a dynamic electromagnetic field which can change the position of either the platform with the starting object or the machining tool or tools.
• Applicant found that by substituting the mechanical arm suitable for either subtractive or additive manufacturing by an array of electromagnets which position the dynamic component by means of a dynamic magnetic field it is possible to achieve a more accurate positioning.
• the effect of gravity is compensated by a dynamic electromagnetic field, providing levitation of the dynamic component and thus a friction-less positioning. Further, because of the absence of friction during positioning and the absence of moving components virtually no wear of the systems occurs, thereby reducing or making obsolete maintenance.
• the described process and apparatuses can operate on greater distances under zero gravity conditions .
• Figure 1 shows a 3-D printer according to the invention, not to scale.
• Figure 2 shows a printer head for additive manufacturing setup.
• Figure 3 shows a top view of an horizontal array of electromagnets
• Figure 4 shows a side, cross-sectional view of the setup of the electromagnets and dynamic component.
• Figure 5 shows a side, cross-sectional view of the setup of the electromagnets and a dynamic component
• Figure 6 shows a model of magnetic interactions between two electromagnets.
• Figure 7 shows the relation of force of interaction of small neodymium magnet and electromagnet with distance between them.
• Figure 8 shows a subtractive manufacturing apparatus according to the invention.
• the dynamic electromagnetic field is generated by an array of electromagnets positioned in an horizontal plane, the array of electromagnets is positioned above and/or below the dynamic component and wherein the positioning is performed by independently controlling more than one of the electromagnets of the array thereby controlling electromagnetic field in both (i) and (ii).
• the material comprising object may be positioned as the dynamic component relative to the one or more machining tools or the one or more machining tools may as the dynamic component be positioned relative to the material comprising object.
• the printer head as the dynamic component may be positioned relative to the three-dimensional object being manufactured or the three-dimensional object to be manufactured as the dynamic component may be positioned relative to the printer head.
• the horizontal change of position of the dynamic component may be performed by increasing field intensity (generating torque) and therefore the attraction of the dynamic component to the a first set of electromagnets positioned in the direction of the desired motion in the array of electromagnets and decreasing field intensity in the second set of electromagnets positioned in the direction opposite to the motion.
• the vertical change of position of the dynamic component may be performed by increasing or decreasing the magnetic field intensity of one or more electromagnets in the vicinity of the dynamic component.
• Magnetic levitation of the dynamic component may be achieved by constantly adjusting the intensity of a magnetic field produced by electromagnet array using a feedback control loop.
• Z-axis stability, levitation height, or vertical position is achieved by adjusting the field intensity generated by the electromagnets to compensate for the gravity of the earth, correlating the current position coordinate with the required intensity to adjust to the desired position.
• the dynamic component may be tilted, i.e. subjected to a pitch, roll and/or yaw movement, by controlling the magnetic field intensity of one or more of the
• electromagnets in the vicinity of the dynamic component.
• the dynamic electromagnetic field is suitably generated by an array of electromagnets positioned in a first horizontal plane.
• the array of electromagnets is suitably in a hexagonal lattice arrangement.
• a base electromagnet may be positioned in a second horizontal plane adjacent to the first horizontal plane.
• Such a base electromagnet is an optional component.
• base electromagnet When included in the apparatus or process, base electromagnet will provide an homogeneous field intensity partially compensating gravity at the position of the dynamic component. Compensating earths' gravity results in either extention of the operational distance of the dynamic component or support of additional weight on the dynamic component.
• Such a base electromagnet is therefore suitably used when the array of electromagnets is positioned below or above the dynamic component in the process or apparatus.
• the electromagnets and the optional base electromagnets may be any known electromagnet, for example a superconducting electromagnet, a standard coil electromagnet or a so-called Bitter electromagnet as described by (Kato, Crouch, & Sar, 2005).
• the position of the dynamic component is detected resulting in a set of position data.
• the process will suitably make use of a feedback control system that adjusts the dynamic electromagnetic field by changing the magnetic field intensity of one or more electromagnets in the vicinity of the dynamic component in order to change the position of the dynamic component to a desired position using the set of position data as input.
• the position of the dynamic component is suitably detected using one or a combination of the following position detection sensors: a triangulation laser scanner with charge-coupled position sensitive device (CCD/PSD), a Hall Effect sensor, an accelerometer, a gyroscope and/or a camera or other position detection technologies.
• the dynamic component In order to interact with a horizontal array of electromagnets the dynamic component must comprise one or more parts magnetic in nature. Such parts can be, however not limited to, permanent magnets, electromagnets, paramagnetic materials, diamagnetic materials, ferromagnetic materials and other materials with a magnetic permeability that allows force interactions with an array of electromagnets.
• the magnetic field produced by these parts allows the dynamic component to be positioned by the electromagnetic field.
• the electromagnets as present in the array can comprise a core of ferromagnetic material, such as iron.
• a core results in increasing field intensity produced by the electromagnets and may achieve reduced power consumption by providing an attraction force with the dynamic component.
• the additional attraction may compensate all or part of the gravity affecting the dynamic component. This is advantageous because then a lower magnetic field intensity and therefore lower power consumption is required for positioning of the dynamic component at the point where the gravity is compensated by the attraction to the
• the invention is therefore also directed to a process or apparatus wherein the array of electromagnets having a metal core is positioned above the dynamic component and wherein the dynamic component comprises a magnetic part or parts as described above.
• the three-dimensional object is formed by means of subtractive manufacturing of the starting object to the desired final shape and size by a controlled material-removal process using one or more machining tools and wherein the dynamic component is positioned by a dynamic electromagnetic field.
• machining tools are an electric drill for CNC (Computer Numerical Control) operation or an electric saw for cutting.
• the dynamic component is the material comprising object or sometimes referred to as raw material to be manufactured it can also be subjected to lathes, a material removal by high speed rotation of the raw material in contact with the indexable tools.
• the dynamic component suitably is of a material which is negligibly affected by magnetic fields.
• Such material may be metal and metal alloys such as aluminium, titanium and alloys thereof, organic and inorganic polymeric materials such as plastics material.
• the invention is also directed to a subtractive manufacturing apparatus as described above.
• a subtractive manufacturing apparatus also comprises a position detection sensor control system for detecting and controlling the position of the platform or the machining tool or machining tools and a feedback control system which in use compares the detected position data to a desired position, and adjusts the position of the platform or machining tool or machining tools by changing the magnetic field intensity of one or more electromagnets in the vicinity of the platform or machining tool or machining tools.
• the position detection sensor may be one or a combination of the following position detection sensors: a triangulation laser scanner with charge-coupled position sensitive device (CCD/PSD), a Hall Effect sensor, an accelerometer, a gyroscope and/or a camera or any combination of these sensors.
• CCD/PSD charge-coupled position sensitive device
• Hall Effect sensor an accelerometer
• accelerometer a gyroscope and/or a camera or any combination of these sensors.
• the array of electromagnets may be positioned in a first horizontal plane and a single base magnet in a second horizontal plane adjacent to the first horizontal plane as described above.
• the electromagnets may also have a metal core as described above.
• the apparatus has the array of magnets positioned above the platform and machining tools and wherein the platform or machining tools which can change position is provided with one or more magnetic parts.
• the invention is also directed to the use of the subtractive manufacturing apparatus here described in a process as here described.
• the manufacturing of the three-dimensional object is performed by addition of material using a printer head to form the three-dimensional object and wherein the dynamic component is positioned by a dynamic electromagnetic field to obtain the three-dimensional object and wherein either the printer head or the object is positioned by the dynamic electromagnetic field.
• the printer head deposits successive layers of extrudable or wire based materials.
• the materials are suitably negligibly affected by magnetic fields and may comprise metals and metal alloys and organic and inorganic polymeric materials. Examples of metals are aluminium, titanium and alloys thereof. Examples of organic and inorganic polymeric materials are plastic and ceramics material.
• the invention is also directed to a computer implemented method for position and control of the platform or the machining tool or machining tools of the above apparatus, wherein a programmed computer controls the position of the dynamic component.
• the invention is also directed to the software when used in a computer on a computer readable storage.
• the invention is also directed to a 3-D printer as described above.
• the printer head preferably comprises one or more magnetic parts as described above if the printer head is the dynamic component.
• the magnets employed by the printer head may for example be permanent or, in case the printer head has an additional current source, electromagnets.
• Product construction can be achieved through additive processes. Several technologies can be employed, among others, extrusion printing, for example fused deposition modelling. In the extrusion 3D printing, the material, polymer, metal or other, is melted inside a fixed injector system that may be located above the levitated printer head.
• the 3-D printer also suitably comprises a position detection sensor control system for detecting and controlling the printer head or the support and a control feedback system which, in use, compares the detected position data to a desired position, and adjusts the position of the material printer head or support by changing the magnetic field intensity of one or more electromagnets in the vicinity of the printer head or support.
• the position detection sensor is suitably one or a combination of the following position detection sensors: triangulation laser scanner with charge-coupled position sensitive device (CCD/PSD), a Hall Effect sensor, an accelerometer, a gyroscope and/or a camera.
• the array of electromagnets of the 3-D printer may be positioned in a first horizontal plane and a single base electromagnet in a second horizontal plane adjacent to the first horizontal plane as described above.
• the electromagnets may also have a metal core as described above.
• the apparatus has the array of magnets positioned above the material printer head and support for the three dimensional object and wherein position change is provided by interacting with a magnetic part of the dynamic component.
• the invention is also directed to the use of the 3-D printer here described in a process as here described.
• the invention is also directed to a computer implemented method for position and control of the printer head or the support of the 3-D printer described above, wherein a programmed computer controls the printer head position or support position and the control feedback system.
• the invention is also directed to the software when used in a computer on a computer readable storage.
• Figure 1 shows schematics of a 3-D printer according to the invention.
• a printer head 3 is positioned by the means of a magnetic field generated by two types of electromagnets, depicted as an array of electromagnets 1 and top base electromagnet 2. Due to dynamic sensor control system the printer head 3 is steadily levitated or its position is manipulated with at least three degrees of freedom to even 6 degrees of freedom (referring to pitch roll and yaw) by the means of electromagnetic field generated by the electromagnets above.
• Each cylinder represents an independently controllable electromagnet.
• the array of electromagnets shown is positioned in one plane, however the actual number of electromagnets and geometry may be different from shown. In figure 1, the position of printer head 3 is controlled by the
• the material delivery mechanism 5 is located either directly on the printer head or separately with a flexible connection, as also shown on figure 1.
• a position detection system 4 is shown connected with sensor control system.
• the human figure is provided solely as a visual reference, as the device is not scale dependent.
• the suspended and movable printer head provides the delivery mechanism for the material to be extruded to achieve the final product geometry.
• the upside-down setup where the printer head is hovering above the magnet is also viable by employing the same electromagnetic control principle.
• the printer head may function as a hovering collection table with fixed material delivery system.
• Figure 2 shows a schematic representation of the printer head 3 and material delivery system 5 with printed components 4 located below the printer head.
• the printer head has three permanent magnetic parts 9 that are responsible for the interaction with the array above the platform.
• Figure 3 shows a top view of an array of electromagnets 1 and 2 (contour outlined) for positioning of the printer head 3 (contour and magnetic parts outlined).
• the levitating printer head contains three magnetic parts, represented with bold stroke line within 3.
• Each circle in the array 1 represents independently controllable electromagnet, wherein the darker coloured electromagnets represents active magnets used to position printer head 3 and the lighter coloured electromagnets are inactive electromagnets.
• the array 1 of circular electromagnets is arranged in a hexagonal lattice arrangement.
• the array of electromagnets 1 may be as shown are in tight arrangement that provides high field intensity. Two requirements are suitably met in order to sustain the levitation of the printer head.
• the sensor control system must be able to independently control the intensity of the magnetic field generated by the array of electromagnets 1 and optionally base magnet 2.
• the sensor control system is able to independently control the field intensity generated by each of the electromagnets.
• Only the electromagnets in the direct vicinity of the magnetic parts of printer head 3 are required to be activated as shown in Figure 3.
• Independently controlled electromagnets maintain both: the horizontal position X / Y, height Z and the pitch, roll and yaw, between printer head and the magnet array 1 of the printer head 3.
• Position detection and sensor control system 4 can employ one or a combination of the following position detection sensors: triangulation laser scanner with charge-coupled position sensitive device (CCD/PSD) Sensor, Hall Effect sensor, accelerometer, gyroscope or optical camera. Once the position of the printer head is obtained, adjustment / movement is achieved via activation of electromagnets in the printer head vicinity.
• CCD/PSD charge-coupled position sensitive device
• Figure 4 illustrates pitch / row control.
• Figure 4 shows a side, cross-sectional view of the setup of the electromagnets for positioning of the printer head 3 by the means of the magnetic field generated by electromagnets 1 (A-F) and base electromagnet 2.
• Each rectangle in 1 represents independently controllable electromagnet positioned in an array, of which only few are shown.
• the printer head 3 is provided with (visualized) two magnetic parts whose force interactions are shown with arrows.
• Figure 4 shall be used to illustrate how the electromagnets influence the positioning of the printer head by interacting with magnetic parts.
• Figure 4 illustrates a case where the printer head is adjusted until it reaches the horizontal position, which can be achieved by generating torque through the following algorithm:
• Figure 5 illustrates the X-Y control or horizontal movement of the dynamic component.
• Figure 5 shall be used to illustrate how the electromagnets influence the positioning of the printer head and shows a side, cross-sectional view of the setup of the electromagnets for positioning of the printer head 3 as in Figure 4.
• the printer head 3 in Figure 5 may be provided with a horizontal movement, which can be achieved by the following algorithm:
• a) Detect the position of the printer head by the means of position detection system. b) Select the set of electromagnets (A, B, D, E) located below the magnetic parts on the direction of the printer head motion and set of electromagnets (C, F) on the opposite direction.
• printer head height (Z-axis control) is controlled by increasing field intensity of all the magnets in the vicinity of printer heads' magnets and/or by employing an optional base electromagnet.
• Figure 6 is used to illustrate the field interactions. The theory of the amount of force that can achieve by interaction of magnets is described in some detail below. Below is the estimation of the force exerting by a coil on a small neodymium magnet with geometrical characteristics described in Figure 6.
• Figure 6 shows a model of magnetic interactions between small cylindrical neodymium magnet (left) of diameter 5 mm and 15 mm length and an electromagnet with a diameter of one meter and height of 50 cm.
• the force i nteracting between two magnets is estimated using Gilbert Model. While physically inexact on short proximity to the magnet, the Gilbert model is well suited for description of interactions between two magnets on a distance, as required by the setup.
• Gilbert model is a simplification of Ampere model that most commonly used to estimate macro- interactions.
• F magnitude of force (newton)
• qr ml and q m2 are the magnitudes of magnetic poles (ampere-meter)
• ⁇ is the permeability of the intervening medium (tesla meter per ampere)
• d is the separation (SI unit: meter).
• B Q is a magnetic field at the end of the coil
• A is an area of the interacting surface of the magnet or wire loop area in case of the coil
• L is the length of the magnet or coil
• R the radius of the magnet
• F ns is a force exert by the north pole of the printer head to the south pole of the gradient magnet
• F nn is the force exert by interaction of north pole of a printer head with north printer head of a coil and so on.
• Support material SI contains the matlab routine employed for the calculus of Figure 7.
• Figure 8 shows a subtractive apparatus where the platform is controlled via magnetic fields generated by an array of electromagnets 1. Also shown is a base electromagnet 2. The object 11 to be machined 3 is positioned (levitating) by the means of a magnetic field generated by electromagnets 1 and 2. Object 11 is attached to a platform 7 provided with three permanent magnets 10. A sensor-control positioning system 4 is shown. Also shown are subtractive manufacturing tools 12, from left to right: Electric drill for CNC operation, electric saw for cutting and a turning component. Turning component may be used to machine a quickly rotating moving object 11. References

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Electromagnetism (AREA)
• Power Engineering (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=51417549

Family Applications (1)

Country Status (2)

Families Citing this family (3)

Family Cites Families (3)

• 2014
  • 2014-05-21 WO PCT/NL2014/050320 patent/WO2014189371A2/en active Application Filing
  • 2014-05-21 EP EP14755928.0A patent/EP3000126A2/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events