COMBINED THERMOFORMING AND ADDITIVE MANUFACTURING DEVICE

A single-station additive manufacturing and thermoforming machine includes a heated bed forming a perforated print surface, a print head pivotable between a stowed position and a range of printing locations relative to the heated bed, and a thermoforming subassembly. The thermoforming subassembly is vertically movable relative to the heated bed to position a thermoforming sheet at a raised location to be heated to a plastic state, and a lowered position for vacuum forming over one or more printed parts upon the heated bed. The disclosure provides a fluid process between additive manufacturing and thermoforming where no interaction is needed from an operator in between additive manufacturing process stopping and thermoforming starting. The device can be easily increased in size to allow for larger parts to be manufactured and formed, while also providing a print bed that allows for air topass through for vacuum thermoforming, while also being heated.

TECHNICAL FIELD

The present disclosure relates generally to the fields of additive manufacturing and thermoforming, and more particularly to producing a part via single-station additive manufacturing and thermoforming.

BACKGROUND

The design and capabilities of manufacturing machines, specifically additive manufacturing or “3D printing,” are increasingly becoming a viable way to make parts for both prototypes and consumer grade products. Often the workflow for additive manufacturing includes other processes like thermoforming. In a workflow where an additive manufacturing machine and thermoform are both used there is typically a touch point or stage where the part created on the additive manufacturing device needs to be transferred to the thermoforming device, located for processing, or otherwise manipulated between stages. Such touch points add time and complexity to the overall process.

SUMMARY

In one aspect, the present disclosure provides a combined thermoforming and additive manufacturing device in a single station dispensing with the need for outside intervention by personnel between the creation of a base portion of a part and a succeeding thermoforming process. Such a strategy offers benefits of faster prototyping and potential for enhanced automation in assembly line fashion.

According to one implementation, a machine capable of additive manufacturing and thermoforming can create parts made of various materials which can then be quickly thermoformed resulting in a negative mold or shell which can be used in various manufacturing and design applications. The device is able to complete both additive manufacturing processes and thermoforming processes without requiring movement of the part to a different station or intervention by a user, created via the additive manufacturing process, before it is thermoformed.

Corresponding reference characters are used, at least at times, to indicate corresponding parts throughout the views.

DETAILED DESCRIPTION

The present disclosure provides the design for a combined thermoforming and additive manufacturing device in a single all-encompassing device which doesn't require outside intervention from an individual in between the creation of a part, via the additive manufacturing method, and the succeeding thermoforming of the part just created. Such a machine offers benefits of faster prototyping and potential for automation in assembly line fashion.

Referring to the drawings generally, but focusing first onFIG. 1, the machine60is shown.FIG. 1shows the components of the machine60when viewed from a right side. Additionally, several components cannot be seen inFIG. 1, as they are covered by the other components. Machine60may include a user interface1, thermoform structural supports16aand16b,trolley belt attachments23aand23b,trolley belts13aand13b,trolley steppers11aand11b,trolley stepper holders20aand20b,trolley pulleys14a,14b,14c,and14d,heating element array10, heating element base19, thermoplastic holder50, thermoplastic holder clamps27a,27b,27c,and27d,vertical trolleybeams17aand17b,trolley slides24a,24b,24c,and24d,z-axis stepper7, z-axis strut21, extruder stepper6, hot end15, vacuum print bed9, electronics enclosure4, lower trolley pulley supports26aand26b,vacuum hose3, base plate,18, pivot stepper8, pivot stepper holder29, and driving pinion gear28, x-axis stepper5, vacuum2, and z-axis stepper support32. The terms x, y, z, and other directional indicators are used herein for purposes of convenience and do not require specific orientations in space of any given element, process, or attribute.

The additive manufacturing portion of machine60may include a type of fuse deposition modeling system. While this is not the only type of additive manufacturing system that could be used in machine50, it provides a simpler method which also displays the intricacies of the machine more easily. One function in fuse deposition modeling (FDM) additive manufacturing systems is the use of a thermoplastic filament to create a part. A circular profile filament may be pushed into hot end15using extruder stepper6. Usually two pinon gears, one attached to an extruder stepper, like part6, mesh with the filament between the two gears and control the filament feed rate into the hot end.

Hot end15is held at a specific temperature via known electronic heating methods which liquifies and compresses the filament into a much smaller orifice that then exits the hot end, laying down a partially elastic, still hot filament which can be continuously positioned in the x and y plane to create the forms needed to manufacture a part.

Heating element array10is positioned above thermoplastic holder50and onto heating element base19. By mounting heating element array10on heating element baseplate19, a static position for heating element array10is provided atop of thermoform structural supports16a,16b,16c,and16d,so that when the thermoplastic holder50is in an upward position, the respective thermoplastic material, held by thermoplastic holder50, can be heated to the necessary temperature to enter a plastic state.

Once the respective thermoplastic sheet held in the thermoplastic holder50has reached a desired plastic state via the heating element array10, it utilizes the dynamic trolley system running the height of the machine and including trolley steppers Ila and11b,trolley stepper holders20aand20b,trolley pulleys14a,14b,14c,and14d,trolley belts13and13b,trolley pulley supports26aand26b,and linear slides24a,24b,24c,and24d.This system pairs with the actual trolley, consisting of trolley belt attachments23aand23b,linear slides24a,24b,24c,and24d,horizontal trolley beams25aand25b,vertical trolley beams17aand17b,thermoplastic holder clamps27a,27b,27c,and27d,and thermoplastic holder50, which moves parallel to thermoplastic structural supports16a,16b,16c,and16dvia the linear slides24a,24b,24c,24dwhich wrap the circumference of the thermoplastic structural supports. The driving force which dictates the position of the trolley relative the base plate are the actual trolley steppers11aand11bwhich are held in a static position by trolley stepper holders20aand20b.Trolley pulleys14aand14bare mounted on the rotor of the two steppers and have mirror trolley pulleys14cand14dwhich are driven by trolley belts13aand13b,and secured by trolley pulley supports26aand26b.

Trolley belt attachments23aand23bprovide the mechanical engagement for the trolley system to connect with the belt system. If the system is viewed from the front, similar toFIG. 2, the trolley steppers11aand11bturning counter clockwise would result in the trolley sub assembly moving down, whereas a counterclockwise turn would bring the system up and closer to the heating element baseplate19. This described movement of the trolley is responsible for moving the trolley from the position closest to the heating element array10down onto vacuum print bed9, and a major function of the vacuum thermoforming aspect of the machine. It should further be appreciated that various alternatives to the presently described strategies for actuating the various parts and performing the various functions of the present disclosure might be employed. For instance, rather than a belt drive a ball screw actuator, a linear rail system including a leadscrew, a pneumatic actuator, or still others might be used. The present disclosure is applicable without regard to the specific type of actuator used to position a sheet tray, or to perform any of the other motions of the device.

As mentioned, the trolley sub assembly acts to bring the thermoplastic material down onto the additively manufactured part. However, it is common in thermoforming to include a vacuum feature as to remove the air more efficiently from the recently manufactured part so the thermoplastic material can be more tightly drawn to the part. This process is usually facilitated by a perforated surface the manufactured part sits on. The perforated surface allows for an array of inlets for the air to be sucked out to provide the improved seal around the part while thermoforming. This device includes a similar body which acts as both the additive manufacturing surface, as well as the vacuum bed9. In another implementation, positive pressure is used to apply thermoforming material to a part. In contrast to removing air such as through perforations in a vacuum bed, in a positive pressure strategy air is forced onto a heated thermoforming sheet which is responsively urged down into contact with parts to be encased or otherwise coupled with the thermoforming sheet. The present disclosure contemplates any use of positive pressure or negative pressure to cause a thermoforming sheet to be attached to one or more parts. Applications where thermoforming is achieved without the assistance of air pressure at all are nevertheless also within the scope of the present disclosure.

Parts27a,27b,27c,and27dact as a static clamp which secures thermoplastic holder50. Thermoplastic holder50needs to be able to be removed easily from machine60so that the respective thermoformed sheets, which have gone through the vacuum forming process, can be replaced with new ones and the machine prepared for another working cycle. The thermoplastic holder clamps act as a way to control the amount of pressure and physical engagement with thermoplastic holder50so this removal process can take place while maintaining enough pressure so when the trolley sub assembly is in its bottom position, thermoplastic holder50will not move and otherwise compromise the manufacturing process. As an alternative to mechanical clamps magnetic retention or still another mechanism, such as snap-in engagement, thumb levers, or still another strategy may be used.

User interface1is most clearly seen in this view. The user interface serves as an electronic screen that allows the user to access settings and maintenance of machine60. A variety of programmable functions can be accessed from this component and allows users to change features to make better final results and match their use cases without having to load full new software onto the machine.

The design of this machine is such that machine60's manufacturing build volume can be expanded without major design features. As noted, thermoform structural supports16a,16b,16c,and16d,and z-axis strut21. These supports/struts are part of what may physically limit both the additive manufacturing build height and the respective thermoforming to go around a taller part. These parts are kept at a simple geometry so the parts could be extruded or shortened to a different length to make a different size machine to match a user's needs.

Heating element array10, is most clearly seen from this view. Positioning the heating element array10atop of the machine allows thermoplastic holder50to be far above the print surface, such that the thermoplastic sheet that thermoplastic holder50will contain can be heated to the necessary temperature without affecting other parts that may otherwise be affected by high levels of heat like z-axis stepper7or vacuum2. Once thermoplastic tray50and its respective thermoplastic sheet reaches the chosen temperature of the operator, they slide down thermoform structural supports16a,16b,16c,and16dvia trolley steppers11aand11b.Heating element array10is controlled via electronics within electronic enclosure4and can be controlled via LCD display10. The present disclosure is not limited with regard to the manner by which a user interacts with the machine. A touchscreen, a graphical user interface (GUI), a keypad, voice recognition commands, and other known user interface strategies are within the scope of the present disclosure.

The movement of the vacuum print bed9in the y-axis can be further understand from inFIG. 4. Vacuum print bed9is attached to the printer sub assembly via linear bearings38a,38b,and38c,which slide parallel to linear rods37aand37b.Y-axis stepper41powers this movement and translates its rotational movement into linear movement via y-axis belt attachment44which attaches the vacuum print bed9to the belt attached to y-axis belt attachment44.

Amongst the structures running in the y direction is also y-axis structural supports39aand39b.These components not only serve to give structural support during y-axis movement by vacuum print bed9, but also are the limiting factor in total distance the vacuum print bed9can move, along with y-axis linear rods37aand37b.If these components were made longer, the machine's movement can become greater and therefore make for an increasingly larger machine with ease.

Z-axis stepper6moves parts33,15,34, and more along the z-axis. Unlike the Y-axis and x-axis which move via stepper motors with belts, z-axis stepper moves the arm with hot end15via a lead screw which is within stepper6itself. The threads on the lead screw, which is part of stepper6, rotate and mesh with matching threads on the arm with hot end15and move along the z-axis. While the machine is printing a part this z-axis system remains stationary. However, once printing has finished the arm with hot end15pivots away from the print bed in a counterclockwise direction. By pivoting said arm, space is then made for thermoplastic holder50and the sub assembly that moves it, to slide directly down, as discussed earlier, and slide down over vacuum print bed9without any contact of other parts.

Following thermoplastic holder50sliding over vacuum print bed9, vacuum2is turned on and removes air from within vacuum print bed9. Since this happens while thermoplastic holder50is down an airtight seal is created removing air from around the recently printed part and thermoplastic within thermoplastic holder50, pulling the hot thermoplastic sheet tightly across the additively manufactured part. The array of holes on vacuum print bed9provide a way for the air between the top surface of print bed9and thermoplastic sheet in thermoplastic holder9to be evacuated quickly and efficiently. It will be recalled that as an alternative to removal of air with a vacuum positive air pressure could be used.

FIG. 6displays detailed views A and B. Where detailed view B shows a clearer view of parts at the end of the x-axis assembly and detailed view shows a cleared view of gears involved in the pivoting function of the machine. Detailed view A displays vacuum2, vacuum hose3, electronics enclosure4, pivot stepper8, driving pinion gear28, driven pinion gear40, z-axis strut21, lead screw31, z-axis linear rod28a,and z-axis strut21. Detailed view B displays x-axis linear rods33and34, x-axis belt30, and x axis pulley support51.

Detailed view A shows how the pivot action discussed earlier occurs. Once again a stepper motor is used where two pinion gears mate with one another. One on the z-axis strut21, referred to as driven pinion gear40, the other attached to pivot stepper8, and referred to as driving pinion gear28. As driving pinion gear turns clockwise with pivot stepper8, driven pinion gear40meshes with it and turns the assembly its attached to, therefore rotating the z-axis away from the print bed. In another implementation a pivot stepper or other suitable motor in any arrangement and/or using any number of gears, including no gears, could be used to directly drive the assembly.

Detailed view B gives a clearer differentiation between parts on the x-axis. Similar to the movement in the y-axis a stepper motor, belt, and linear rods are used. Linear rods33and34are the bodies which hot end15slides along while, x-axis belt30provides the physical movement as it is looped around x-axis stepper6. Part51acts as a housing for the end of linear rods33and34as well as a place for x-axis belt30to make a rotation around.

INDUSTRIAL APPLICABILITY

Referring to the drawings generally, now focusing on FIG.7-10, there shown stages in making one or more parts116using a machine100according to the present disclosure. The machine100may be similar or identical to other machines discussed herein, and includes a print head110that can be pivoted about a vertical axis above a heated bed112. Heated bed112includes a print surface126that is perforated, and may be supported upon a support stand or the like114. Machine100includes similar or identical components to those discussed elsewhere herein supported upon and vertically above a base108. A carriage120is operable to move a tray118vertically between a heating array122and heated bed112to position thermoplastic material or sheets supported in tray118over parts116for thermoforming.

InFIG. 7, machine100is depicted as it might appear where parts116have been printed using print head110. In the illustrated embodiment, parts116include arches as might be used to create molds for straightening or otherwise adjusting teeth in a human individual. Parts116can be used as a negative image of molds to be used for production of alignment devices that form an end user product. Principles discussed herein connection with producing parts116are applicable without regard to the specific type of part being made.

AtFIG. 8, print head110has been pivoted out of the way in preparation for thermoforming. Heated bed112has been heated and heating array122is heated to increase a temperature of a thermoplastic sheet loaded in tray118by way of radiant heat124depicted inFIG. 9. When the thermoplastic sheet has been heated to a desired temperature, carriage120is operated to lower tray118and position the thermoplastic sheet upon parts116.FIG. 10approximately depicts this stage in the procedure. Vacuum can then be applied to draw air through perforations in print surface126and the sheet suctioned down onto parts116for removal of air and completion of the process. Carriage120can then be operated in reverse to raise tray118for loading of a new thermoplastic sheet and printing of a new part or parts.