TITLE OF THE INVENTION:

PARALLEL AXIS WITH PLATE PRINTER (P.A.P PRINTER)

TECHNICAL FIELD OF INVENTION:

[0001], Aerospace, architecture, auto industry, industrial parts, military equipment, medical equipment, bioprinting, art, printing computational phantom, and physical phantom casting.

BACKGROUND ART OF THE INVENTION:

[0002], Since 1980 3D printing technology has been employed in a wide range of science and academic fields as an important, easily-implementable process for producing parts and tools from the design stage to manufacturing. Quality of parts manufactured in this method varies depending on manufacturing techniques and ultimate quality and precision in terms of the size of the parts produced.

[0003], The techniques used for manufacturing parts and components through 3D printing include photopolymerization (SLA, DLP, and CLIP) where a (photosensitive) photopolymer resin is exposed to light with a certain wavelength that solidifies the polymer through a chemical reaction. While the technique produces parts having a good, soft surface with highly- detailed fast modeling, the parts manufactured by this technique are very fragile although the UV radiation plays a role in reinforcing them to a certain extent. Therefore, the technique is limited to gold and jewelry industry and plastic injection molding in medical and dental applications.

[0004], One technique used in making 3D printed components is binder jet or powder bed and inkjet printing (SLS, SLM, DMLS, EBM, Jetting material, and poly jet). Although the technique involves a layer-by-layer production of the final component by adding the different parts with no requirement for support leading to relatively strong components manufactured, the problem with this technique is coarse surfaces, internal porosity, bending, and contractions during the manufacturing process. The jet material techniques (MJ, NPJ, and DOD), which are very similar to the technique note above and have found applications in rapidly modeling soft and smooth components through combining different materials, enable production of a wide range of parts of various types of materials, but the parts produced by this technique still have the problem of fragility even after being exposed to UV light, in addition to their very high cost of production. [0005], Directed energy deposition (DED) technique which usually involves metal powders, often finds applications in repairing surfaces or adding additional materials to metal surfaces to prevent or cover cracks. The technique is very similar to industrial coating; however, it is not a very good candidate given that it requires supports for the structures used in this technique.

[0006], The printing technique utilized in the present invention is known as fused deposition modeling (FDM) also referred to as fused filament fabrication (FFF) in a number of sources. This involves the fusing of the materials applied in this technique using thermoplastic materials. Filament rolls are fed from a large coil (used as consumables) measuring 1.75 mm or 3 mm in diameter as the commonly available standard size.

[0007], In this technique, printing resolution directly depends on nozzle size and the precision of extruder movements i.e. the stepper motor step bit. In addition, given the smaller laser width for 3d SFA printing compared to FDM, the technique obviously has a greater resolution and precision.

[0008], In terms of manufacturing technology and mechanical structure, currently available FDM 3D printers can be classified into three mechanical models depending on the manufacturer’s brand:

( 1 ) Prusa type

(2) HyperCube Type

(3) Diy Type

Each mechanical structure has its own advantages and disadvantages in FDM printing.

[0009], Prusa Type: In this mechanical model, the heat bed plate is mounted on a (Y-axis) chassis while the Z-axis is installed and fixed on a frame and the X-axis moves up and down along the Z-axis. The structure is the cheapest to manufacture but the bed vibration during back and forth movements along the Y-axis changes the heat bed level. Furthermore, the vibrations at high-speed printing lower printing quality and, thus, printing speed must be lowered in order to achieve a higher printing quality.

[00010], Hypercube Type: In this mechanical model, the heated bed surface is mounted on a (Z- axis) chassis and led vertically downward along the Z-axis during printing job while the X-axis and the Y -axis form the CoreXY above the cube-like chassis of the printer and the print head moves back and forth on the X-axis and the Y-axis to produce the printing output. While the fact that these two axes are located above the chassis results in a minimized vibration during printing, making it possible to achieve higher printing speeds, the problem is that the bed surface is pushed out of level when the components are removed once the printing job is finished. Although position sensors can be used in this model, for larger printers with vertical movement of printing surface the heavy weight creates vibration problems, leading to a non-smooth surface and making it more difficult to adjust the level of heat bed chassis along the Z-axis. Hypercube is one of the most well-known and popular mechanical structures used in commercial printers.

[00011], Diy Type: This mechanical structure, where the heat bed is fixed and embedded on the floor of the chassis and during printing the X-axis and the Y -axis are directed upward along the Z-axis, has been designed to address the problem of heat bed vibrations in large printers with hyper structures. However, the X-axis and the Y-axis create some vibrations during the operation of stepper motors, leading to the appearance of lines on the print surface. The moving frame on the X-axis and the Y-axis needs re-adjustment during initial installation or successive printing.

SUMMARY OF THE INVENTION:

TECHNICAL PROBLEM AND SOLUTION TO PROBLEM:

[00012], The device covered by this patent application improves large-scale 3D printing in terms of speed and accuracy through a number of changes in the mechanical and electrical systems as well as the conventional (Cartesian) 3D printing mechanism.

[00013], To solve the problem of heat bed vibration in the mechanical system of the current printers, the heat bed has been designed as a fixed, non-moving surface.

[00014], To solve the problems related to replacing the X-axis stepper motors without needing to disassemble other components, an easy disassembling mechanism has been provided in the form of portable motors that enables troubleshooting and facilitates settings on stepper motors. A fixing bracket has been incorporated at the lower section, in addition to the screwing mechanism for the connecting plate, that enables re-fixing the stepper motors after re assembly.

[00015], To resolve the step-our problem at high speeds, a double stepper motor system has been included to enhance speed and accuracy.

[00016], To solve the vibration problem of moving heat beds in conventional FDM 3D printer with Cartesian motion and the requirement for leveling adjustment spring which lowers the final quality of printed part layers, here a fixed heat bed system has been used to overcome this problem. [00017], To enhance versatility, as the printing bed is fixed and the heat bed can move, the bed can be easily converted to a CNC bed for machining. The head system has been designed in a way that enables installation of laser head modules and extruder head on the printer and CNC rotary table on the head bracket mount.

[00018], To reduce belt vibration and overcome loosen belt problem during operation along the X- axis, the X-axis motion system is equipped with two belt tensioners perpendicular to the direction of stepper motor belts. This improves stability of the belts during bracket motions along the X-axis and enables resolving any problem in the belt tensioning system by using only one of the tensioners (In contrast, conventional printers only have one belt tensioner and the whole printing process may stop if this one tensioner is out of service).

[00019], To resolve the problem of the physical maintenance of the cable chain in large printers, a wiring separation system has been included to minimize the impact of the physical presence of the cable chain.

[00020], Since large printer need proper control of chassis weight and mechanical tensions in moving chassis (particularly at high printing speeds), to overcome the problem of the motion system with a fixed bed, a carriage assembly (moving frame) has been designed along the Y - axis which is directed and controlled by a rail and a linear ball bearing while the motions along the X-axis and the Z-axis coincide the moving frame. Therefore, the weight of the chassis has a minimized impact on the motion of the moving parts in large printing systems.

[00021], To enhance coordination and uniformity in Z-axis and prevent shaft deviations during movements of lead screws, four round-bottom ball bearings were used to fix this part.

[00022], Four vertical axes are incorporated into the frame (chassis) structure to control and minimize vibrations in the moving parts along the X-axis. Two-time pulleys and belts connected to the Z-axis lead screws enable simultaneous motion of the Z-axis lead screws.

[00023], To prevent backlash in the X-axis moving parts along the Z-axis long linear ball bearings have been embedded in the lifting bracket system on the Z-axis.

[00024], To enhance coordination and uniformity in motion along the Y-axis, two long lead screws are used as optional parts and two or four stepper motors are used to resolve the step-out error in the stepper motors (the same mechanism is employed along the Y-axis).

[00025], For easier access to the Z-axis stepper motor, two brackets have been embedded in the carriage assembly at the lower part of the moving chassis. Given its location below the chassis equilibrium point, it will enhance the mechanical balance of the moving chassis while the bracket on the Z-axis stepper motor enables tensioning of the stepper motor belt.

[00026], To control Z-axis stepper motor power in case of malfunction of the Z-axis position sensor which damages the heat bed, the Z-axis stepper motor is indirectly connected to the Z-axis lead screw through a belt and pulley assembly.

[00027], To couple the path of the cables to the chassis Z-axis carrying movable brackets are equipped with a support to hold the cable chain.

[00028], For better access to screw/unscrew the Z-axis lead screw nut, the X-axis mounting bracket moving along the Z-axis is embedded with a slot making it easy to access the retaining nut at its back.

[00029], To fix the X-axis shaft and solve the problem of back and forth (reciprocating) movements of the shafts, a number of bolts and nuts have been provided on the body of the X-axis mounting bracket moving along the Z-axis.

[00030], A number of handles have been installed on the chassis corners for easier handling of the printer while the metal brackets at the bottom make it possible to screw and fix the printer onto a lower surface or a wall.

[00031], To resolve the problem of adjusting the Z-axis position sensor (endstop), it has been embedded in the X-axis mounting bracket moving along the Z-axis in a way that its height can be easily adjusted through an outer edge mounted on the shafts.

[00032], To resolve the problem of adjusting the position along the Z-axis, two-position sensors can be used: a fixed sensor installed on the X-axis mounting bracket moving along the Z-axis and an automatic leveling sensor installed on the X-axis bracket to resolve the adjustment problem for bed surface in long, successive printing.

[00033], To facilitate bed movement under the heat bed, there are a number of aluminum panels that can be easily slid open and, if the heated plate and heat bed insulators are removed, can be used as a fixed bed for CNC and laser cutting. In addition, screws and springs can be used to adjust the heat bed height, transforming it into an elastic assembly to prevent breaking in the heat bed glass in cases where a problem occurs in the Z-axis location sensor.

[00034], Employing three-time pulleys (two of them being fixed pulleys) on the X-axis stepper motor brackets not only helps in adjusting belt tension which plays an essential role in controlling the X-axis bracket but also prevents belt deviation and dislocation during operation. [00035], The head bed hot plate in large printers often consists of a large heater that is responsible for heating the bed surface during printing. These are usually expensive and may render the heat bed almost useless if a problem occurs during current consumption. Therefore, a combination of several small heat beds is used to cover the printer’s main hot plate and thermally conductive adhesives are added to properly transfer heat to the main plate. In this case, a damaged or non-functioning small heat bed can be easily replaced.

[00036], As large printers require high current consumptions on the heat bed surface which is mainly heated by a high electrical current, the heating process for a large heat bed is controlled using a solid-state relay placed directly in-line with a higher- voltage power supply (mains electricity, single-phase, 110/220V). Since the mains electricity may cause electric shock during power failure or short circuits, in the invented system this source of a power supply is replaced with a set power supplies (34/36V-20/30A) arranged in series and parallel in combination with MOSFET relays.

[00037], To address the problem of current consumption and electrical noise in all parts of the power supply, the different parts of the system are designed to meet their current requirements independent of the industrial power supply. Furthermore, a damage to any of these parts will not cause a damage to other parts (A 12V, 15A power supply supports the control system, a 24V/12V, 30A power supplies the stepper motors and their drivers, a 12V/5A power supplies the fan, the sensors, and other connected components, and 24V/36V, 20A/30A power supplies support the heat beds and the FET relays.

[00038], To solve the power outage problem, the device is designed to be UPS -compatible and work during an outage by a connection to a UPS. In addition, outage sensors and relays can be used to temporarily stop the printing task and resume it once the power is back.

[00039], To solve the filament (consumables) run-out problem, the position sensor can help detecting when the printer runs out of filament during printing.

[00040], To overcome the problem of cold heat bed, the closed-loop PID controller has been modified in the integral and derivative sections.

[00041], A Wi-Fi module can be incorporated to easily control and direct the printing process on a computer or using a mobile application.

[00042], A metal enclosure can be used to keep the temperature inside the printer chassis constant and also provide a space for keeping and guiding filament rolls, UPS, and other components of the electrical control system. BENEFITS OF THE INVENTION:

[00043], FDM is more suitable for fast modeling compared to the expensive and time-consuming traditional molding.

[00044], FDM is the best option if you care about your model’s strength and durability.

[00045], FDM is the best solution for low-cost 3D printing of models.

[00046], FDM is the best option for the assessment of parts and components prior to mass production.

[00047], FDM is the best option for achieving a detailed design with smooth surfaces. Given that this is a 32-bit device, it offers a relatively smooth and acceptable surface.

[00048], The invented technique offers the highest quality for large parts and components when small sizes are not much important and larger sizes are sought. For example, for large printing options ( e.g . architecture models), it provides the best output available.

[00049], Given its mechanical structure, produces the highest-quality large-size parts and components using FDM technique.

[00050], Versatile print heads can be used to print different parts of various kinds using this printing technique.

[00051], The automatically fixed position sensor in the device can be utilized in successive printing tasks without much requirement for repeated level adjustment.

[00052], UPS capability enables operation during power cuts.

[00053], The power failure sensor enables shutting down the device once the printing job is over.

[00054], The mainboard can be connected through a USB socket for directly printing from a computer or from an SD card by connecting it to the device.

[00055], The X-axis bracket can be used to mount a print head for 3D printing, laser head for engraving and laser cutting, and CNC head for drilling (since the device bed is fixed and the heat bed can be removed). [00056], Since the basic design features lead screws along the Z- and the Y-axis, the highest accuracy is achieved in printing using FDM technique.

[00057], All stepper motors are mounted are brackets and can be easily removed or replaced without removing/disassembling other parts or components of the device (this feature has not been included in any printer made before).

[00058], All shafts and lead screws axes are fixed and secured using nuts and round-bottom ball bearings to prevent vibrations. In addition, all parallel lead screw axes are connected through time pulleys and belts to enable simultaneous motions. Therefore, the Z-axis and the Y-axis have the best simultaneous motion at both ends while the X-axis, with the most considerable back and forth movements, is connected to dual stepper motors.

[00059], The Z-axis stepper motors are indirectly connected to the main lead screw axis.

[00060], All axes use one or more steps in back and forth motions (reciprocations) to minimize step- out errors in the stepper motors.

[00061], Different parts are supplied through independent power supplies, enabling an operation independent of failure or malfunction in other parts.

[00062], The heat bed is supplied using a 24V/36V power supply which, given the large dimensions of the printer, is safer than the public 110V/220V power supply.

[00063], The large heat bed surface consists of a number of smaller, separate beds. A defected heat bed can be easily replaced in case of failure as a result of over-current.

[00064], The stepper motor drivers are connected to the stepper motors in a modular fashion.

BRIEF DESCRIPTION OF DRAWINGS:

[00065], Figure 1 illustrates the overall structure and mechanical working of the device. Figure 2 shows the overall view of the device from different angles. Figure 3 depicts a view of the device’s moving mechanical parts which include the moving chassis and the supporting axes. Figure 4 shows the Z-axis moving bracket and the X-axis mounting bracket for stepper motors in two different views. Figure 5 shows different parts of the X-axis moving bracket and how they are assembled and mounted. Figure 6 depicts the assembled set of the Z-axis moving bracket and the X-axis mounting bracket for the stepper motors. Figure 7 depicts different views of each moving bracket of the Z-axis and the X-axis mounting bracket for the stepper motors. Figure 8 presents an overall diagram of the major parts and components of the device and how they are connected to each other.

[00066], 1 Heated bed, 2 supporting profile, 3 metal panel beneath the heated bed, 4 support clamp for time pulley base, 5 support clamp for time pulley , 6 linear ball bearing at the bottom of the moving chassis, 7 Z-axis stepper motor mounting bracket, 8 round bottom ball bearing for supporting lead screw, 9 Z-axis lead screw, 10 supported guiding shaft beneath the moving chassis, 11 metal bracket holding the industrial profile, 12 shaft support, 13 cable chain for the Z-axis moving chassis, 14 X-axis stepper motor mounting bracket, 15 X-axis stepper motor, 16 support shaft for the upper part of the moving chassis, 17 Y-axis stepper motor, 18 shaft support, 19 X-axis horizontal cable chain, 20 linear ball bearing in moving chassis, 21 round-bottom ball bearing above the lead screw, 22 Chassis support, 23 X-axis mounting bracket and belt tensioner, 24 X-axis moving bracket, 25 Z-axis shaft, 26 industrial profile for chassis, 27 shaft support, 28 stepper motor pulley, 29 stepper motor bracket, 30 stepper motor extruder, 31 heated bed insulator, 32 extruder fan, 33 linear ball bearing, 34 X-axis support, 35 inner section of belt tensioner and support, 36 Z-axis moving and supporting part, 37 support edge for Z-axis cable protector, 38 Z-axis endstop support, 39 belt guide, 40 automatic position sensor, 41 filament guide, 42 belt tension adjustment knob, 43 lead screw installation spot, 44 linear ball bearing mounting slot, 45 space for time pulley inside the belt retainer, 46 retaining nut for inner fixed time pulleys, 47 retaining nut for cable protector, 48 retaining pin for X-axis cable protector, 49 retaining nut for X-axis stepper motor bracket on the Z-axis lifting assembly, 50 bolt for endstop retaining nut to be placed here, 51 retaining nut for X-axis metal bracket, 52 X-axis endstop holder, 53 extruder heat sink and cooling fan, 54 extruder metal bracket, 55 stepper motor time pulley, 56 mounting slot for bolt on X-axis stepper motor bracket, 57 belt-guiding time pulley, 58 inner screw for fixing time pulley, 59 mounting slot for X-axis cable chain, 60 retaining nut for X-axis stepper motor, 61 interior span of the lead screw bolt support, 62 mounting slot for lead screw bolt, 63 space for X-axis shaft, 65 lower edge of X-axis mounting bracket, 66 retaining nut for X-axis bracket from below, 67 slot for passage of lead screw, 68 electronic board cooling fan, 69 12V power supply, 70 24V power supply, 71 stepper motor driver, 72 FET relay, 73 LCD touch screen, 74 graphic LCD display, 75 Wi-Li module, 76 USB cable and socket, 77 computer, 78 UPS, 79 ramp board, 80 MKS board. DESCRIPTION OF EMBODIMENTS:

[00067], The USB socket can be used to establish a connection between a computer and the control board for computer-aided 3D printing. When the printer is turned on, regardless of the print head position, if the heat bed is ready to start a printing a task, the command“Home” can be used in the program to direct the print head to an initial default position. The Z-axis position sensor will automatically detect the position of the bed and will be located at the default position. The command“ABS Preheat” prompts the start of the warming up process for the heat bed and the head. Once a predefined temperature is reached, a filament can be fed into the extruder input and guided to the nozzle output to make the device ready for printing. Now, the printing task will start by choosing a file from an SD card or a computer connected to the device.