Thermoforming multiple aligners in parallel

Abstract

Embodiments relate to thermoforming multiple aligners simultaneously. In one embodiment, an aligner manufacturing system includes a plate, a heating section, and a thermoforming chamber. The plate is configured to secure a first mold of a first dental arch and a second mold of a second dental arch. The heating section is configured to heat a sheet of plastic to generate a heated sheet. The thermoforming chamber is configured to simultaneously thermoform the heated sheet over the first mold of the first dental arch and the second mold of the second dental arch to form a first aligner shaped to fit the first dental arch and a second aligner shaped to fit the second dental arch.

What is claimed is: 
     
         1 . An aligner manufacturing system comprising:
 a plate configured to secure a first mold of a first dental arch and a second mold of a second dental arch;   a heating section configured to heat a sheet of plastic to generate a heated sheet; and   a thermoforming chamber configured to simultaneously thermoform the heated sheet over the first mold of the first dental arch and the second mold of the second dental arch to form a first aligner shaped to fit the first dental arch and a second aligner shaped to fit the second dental arch.   
     
     
         2 . The aligner manufacturing system of  claim 1 , wherein the plate is to secure each of the first mold and the second mold via:
 a corresponding pin to secure a corresponding mold in an x-direction and a y-direction;   a corresponding locking mechanism to secure the corresponding mold in a z-direction; and   a corresponding keyway to maintain orientation of the corresponding mold.   
     
     
         3 . The aligner manufacturing system of  claim 1 , wherein the plate is to secure each of the first mold and the second mold in a predetermined position, a predetermined orientation, and predetermined distances from inner walls of the thermoforming chamber. 
     
     
         4 . The aligner manufacturing system of  claim 1  further comprising:
 a pallet comprising a plurality of holding pins to pierce the sheet of plastic to secure the sheet of plastic to the pallet during heating via the heating section and thermoforming via the thermoforming chamber. 
 
     
     
         5 . The aligner manufacturing system of  claim 4 , wherein the plurality of holding pins comprises a corresponding holding pin at each corner of the sheet of plastic. 
     
     
         6 . The aligner manufacturing system of  claim 1 , wherein the heating section comprises:
 a mask to surround the sheet of plastic during heating of the sheet of plastic to minimize heat transfer from the heating section to other sheets of plastic.   
     
     
         7 . The aligner manufacturing system of  claim 6 , wherein the mask is heat resistant up to about 500 degrees Fahrenheit, is an insulator, and does not adhere to the heated sheet. 
     
     
         8 . The aligner manufacturing system of  claim 6 , wherein the mask comprises polytetrafluoroethylene (PTFE). 
     
     
         9 . The aligner manufacturing system of  claim 1 , wherein the heating section comprises a ceramic heater, a convection oven, or an infrared heater. 
     
     
         10 . The aligner manufacturing system of  claim 1 , wherein:
 a maximum profile of each of the first mold and the second mold has a maximum length and a maximum width; and   the sheet of plastic has a first length that is about twice the maximum length and a first width that is about 1.4 times the maximum width.   
     
     
         11 . The aligner manufacturing system of  claim 10 , wherein:
 a distance from an inner wall of the thermoforming chamber that surrounds the first mold and the second mold to a perimeter edge of the sheet of plastic is at least 1.8% of the first length or at least 3.1% of the first width to avoid air leakage during thermoforming via the thermoforming chamber.   
     
     
         12 . The aligner manufacturing system of  claim 10 , wherein:
 a minimum distance from an inner wall of the thermoforming chamber to the maximum profile is about 4.2-4.5% of the first length or about 7-7.2% of the first width to maintain thickness of the first aligner and the second aligner.   
     
     
         13 . The aligner manufacturing system of  claim 10 , wherein:
 each of the first mold and the second mold is at about a 25-degree to a 40-degree angle from a first edge of the sheet of plastic that has the first length.   
     
     
         14 . The aligner manufacturing system of  claim 10 , wherein:
 a distance between a first line tangent to molar sections of the maximum profile corresponding to the first mold and a second line tangent to molar sections of the maximum profile corresponding to the second mold is about 3-4% of the first length or 5-6% of the first width to avoid forming defects.   
     
     
         15 . The aligner manufacturing system of  claim 10 , wherein:
 a distance between a first molar section of a first maximum profile and a second molar section of a second maximum profile is about 9-10% of the first length or 16-17% of the first width to avoid forming defects.   
     
     
         16 . The aligner manufacturing system of  claim 1 , wherein the sheet of plastic is sized to fit only the first mold and the second mold. 
     
     
         17 . The aligner manufacturing system of  claim 1 , wherein the first aligner and the second aligner each comprise:
 at least two outer layers, wherein each of the at least two outer layers comprises a thermoplastic polymer; and   a middle layer comprising a polyurethane elastomer.   
     
     
         18 . The aligner manufacturing system of  claim 17 , wherein the thermoplastic polymer has a flexural modulus of from about 1,000 MPa to 2,500 MPa and a glass transition temperature and/or melting point of from about 80° C. to about 180° C. 
     
     
         19 . The aligner manufacturing system of  claim 17 , wherein the polyurethane elastomer has a flexural modulus of from about 50 MPa to 500 MPa and one or more of a glass transition temperature and/or melting point of from about 90° C. to about 220° C. 
     
     
         20 . The aligner manufacturing system of  claim 17 , wherein each of the first aligner and the second aligner has a combined thickness of the at least two outer layers and the middle layer from 250 microns to 2,000 microns and a flexural modulus of from 500 MPa to 1,500 MPa. 
     
     
         21 . The aligner manufacturing system of  claim 1 , wherein the first aligner and the second aligner each comprise:
 a hard inner polymer layer comprising a co-polyester and having a hard polymer layer elastic modulus; and   a first soft outer polymer layer and a second soft outer polymer layer each comprising a thermoplastic polyurethane elastomer and each having a soft polymer elastic modulus less than the hard polymer layer elastic modulus.   
     
     
         22 . The aligner manufacturing system of  claim 20 , wherein the first soft outer polymer layer and the second soft outer polymer layer each have a flexural modulus of greater than about 35,000 psi, a hardness of about 60A to about 85D, and a thickness in a range from 25 microns to 100 microns. 
     
     
         23 . The aligner manufacturing system of  claim 20 , wherein the hard inner polymer layer comprises a blend of polymeric materials including the co-polyester and one or more of: a polyester, a thermoplastic polyurethane, a polypropylene, a polyethylene, a polypropylene and polyethylene copolymer, an acrylic, a polyetheretherketone, a polyamide, a polyethylene terephthalate, a polybutylene terephthalate, a polyetherimide, a polyethersulfone, a polytrimethylene terephthalate, or a combination thereof. 
     
     
         24 . A method comprising:
 securing a first mold of a first dental arch and a second mold of a second dental arch to a plate;   heating a sheet of plastic to generate a heated sheet; and   simultaneously thermoforming the heated sheet over the first mold of the first dental arch and the second mold of the second dental arch to form a first aligner shaped to fit the first dental arch and a second aligner shaped to fit the second dental arch.   
     
     
         25 . The method of  claim 24  further comprising:
 determining whether a size of a third mold of a third dental arch is below a threshold size; 
 responsive to determining the size is below the threshold size, thermoforming a third aligner shaped to fit the third dental arch simultaneously with another aligner; and 
 responsive to determining the size is above the threshold size, thermoforming the third aligner by itself. 
 
     
     
         26 . The method of  claim 24  further comprising:
 piercing, using a plurality of holding pins of a pallet, the sheet of plastic to secure the sheet of plastic to the pallet during the heating and the thermoforming. 
 
     
     
         27 . The method of  claim 24  further comprising:
 surrounding the sheet of plastic with a mask during the heating of the sheet of plastic to minimize heat transfer to other sheets of plastic. 
 
     
     
         28 . A method comprising:
 determining a first size of a first mold of a first dental arch and a second size of a second mold of a second dental arch;   selecting a first plate, a first sheet of plastic, and a first pallet based on at least one of the first size or the second size;   causing the first mold and the second mold to be secured to the first plate;   causing the first sheet of plastic to be heated to generate a first heated sheet; and   causing the first heated sheet to be simultaneously thermoformed over the first mold of the first dental arch and the second mold of the second dental arch to form a first aligner shaped to fit the first dental arch and a second aligner shaped to fit the second dental arch.   
     
     
         29 . The method of  claim 28  further comprising:
 determining a third size of a third mold of a third dental arch and a fourth size of a fourth mold of a fourth dental arch; 
 selecting a second plate, a second sheet of plastic, and a second pallet based on at least one of the third size or the fourth size, wherein the second plate has a different size than the first plate, the second sheet of plastic has a different size than the first sheet of plastic, and the second pallet has a different size than the first pallet; and 
 causing, using the second plate, the second sheet of plastic, and the second pallet, a third aligner and a fourth aligner to be formed. 
 
     
     
         30 . The method of  claim 28  further comprising laterally moving, via a conveyor system, the first plate to a loading station to receive the first sheet of plastic, to a heating station to heat the first sheet of plastic, and to a thermoforming station to thermoform the first heated sheet. 
     
     
         31 . The method of  claim 28  further comprising rotationally moving, via a dial system, the first plate to a loading station to receive the first sheet of plastic, to a heating station to heat the first sheet of plastic, and to a thermoforming station to thermoform the first heated sheet. 
     
     
         32 . A heat mask comprising:
 an upper surface configured to couple with a heater of an aligner manufacturing system   a lower surface configured to be disposed on a sheet of plastic, wherein the sheet of plastic is to be disposed between a pallet and the lower surface of the heat mask, wherein the heat mask is to minimize heat transfer from the heater to other sheets of plastic; and   a plurality of inner sidewalls forming recesses, wherein a first portion of the sheet of plastic that is disposed on the pallet is exposed by the recesses to the heat transfer from the heater, and wherein the heat mask is to minimize the heat transfer from the heater to a second portion of the sheet of plastic that is disposed on the pallet and is covered by heat mask.   
     
     
         33 . The heat mask of  claim 32 , wherein the recesses are substantially uniformly formed along the plurality of inner sidewalls to provide the heat transfer from the heater to the first portion of the sheet of plastic to seal the sheet of plastic to the pallet for thermoforming of the sheet of plastic over a first mold of a first dental arch and a second mold of a second dental arch to form a first aligner shaped to fit the first dental arch and a second aligner shaped to fit the second dental arch. 
     
     
         34 . A pallet of an aligner manufacturing system, the pallet comprising:
 an upper surface configured to receive a sheet of plastic to be heated and to be thermoformed over a first mold of a first dental arch and a second mold of a second dental arch to form a first aligner shaped to fit the first dental arch and a second aligner shaped to fit the second dental arch;   a plurality of inner sidewalls sized and shaped to receive a plate securing the first mold and the second mold for thermoforming of the sheet of plastic;   a plurality of holding pins disposed on the upper surface, wherein the plurality of holding pins are configured to pierce the sheet of plastic to secure the sheet of plastic during heating and the thermoforming.   
     
     
         35 . The pallet of  claim 34 , wherein the plurality of inner sidewalls form a first inner corner of the pallet, a second inner corner of the pallet, a third inner corner of the pallet, and a fourth inner corner of the pallet, wherein the plurality of holding pins comprise:
 a first holding pin located on the upper surface proximate the first inner corner;   a second holding pin located on the upper surface proximate the second inner corner;   a third holding pin located on the upper surface proximate the third inner corner; and   a fourth holding pin located on the upper surface proximate the fourth inner corner.   
     
     
         36 . The pallet of  claim 35 , wherein the plurality of holding pins further comprise:
 a fifth holding pin located on the upper surface between the first holding pin and the second holding pin;   a sixth holding pin located on the upper surface between the second holding pin and the third holding pin;   a seventh holding pin located on the upper surface between the third holding pin and the fourth holding pin; and   an eighth holding pin located on the upper surface between the fourth holding pin and the first holding pin.