# US 2023/0053973 A1 · Resin level detection in additive manufacturing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0053973 A1 - Document ID: US20230053973A1 - Status: Published application - Kind: A1 - Application number: 17/428,786 - Filed: 2020-02-25 - Published: 2023-02-23 - Earliest claimed: 2019-02-26 - Assignees: Carbon, Inc. - Inventors: Ronald A. Truong; Steven R. Katzman - Web page: https://patentgrep.com/patent/US20230053973A1 ## CPC - B29C 64/129: characterised by the energy source therefor, e.g. by global irradiation combined with a mask - B29C 64/386: Data acquisition or data processing for additive manufacturing - B29C 64/245: Platforms or substrates (support structures intended to be sacrificed after manufacture B29C64/40) - B29C 64/307: Handling of material to be used in additive manufacturing - B29C 64/393: for controlling or regulating additive manufacturing processes - B33Y 50/02: for controlling or regulating additive manufacturing processes - B33Y 10/00: Processes of additive manufacturing - B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor - B33Y 50/00: Data acquisition or data processing for additive manufacturing - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING ## Abstract In some embodiments, a method of determining the fill level of a resin pool in a bottom-up additive manufacturing apparatus includes the steps of: (a) providing an additive manufacturing apparatus including a build platform and a light transmissive window (12), the build platform (15) and the window (12) defining a build region therebetween, with the window (12) carrying a resin pool, the pool having a resin top surface portion; (b) advancing the build platform (15) and the window (12) towards one another until the build platform (15) contacts the resin top surface portion; (c) detecting the impact of the build platform (15) with the resin top surface portion; and (d) determining the fill level of the resin pool from the detected impact. ## Claims ### Claim 1 A method of determining the fill level of a resin pool in a bottom-up additive manufacturing apparatus, comprising the steps of: (a) providing an additive manufacturing apparatus including a build platform and a light transmissive window, said build platform and said window defining a build region there between, with said window carrying a resin pool, said pool having a resin top surface portion; (b) advancing said build platform and said window towards one another until said build platform contacts said resin top surface portion; (c) detecting the impact of said build platform with said resin top surface portion; and (d) determining the fill level of said resin pool from said detected impact. ### Claim 2 (depends on 1) The method of claim 1, further comprising: producing an object on said build platform from said resin with said apparatus when (i) said fill level is above a minimum fill level and/or (ii) below a maximum fill level. ### Claim 3 (depends on 1) The method of claim 1, further comprising: halting production of objects on said build platform from said resin with said apparatus, and/or generating an alarm signal, when (i) said fill level is below a minimum fill level and/or (ii) above a maximum fill level. ### Claim 4 (depends on 1) The method of claim 1, said apparatus further comprising a resin dispenser, said method further comprising the step of: dispensing additional resin into said pool when said fill level is below a minimum fill level. ### Claim 5 (depends on 1) The method of claim 1, wherein said apparatus includes a force sensor operatively associated with said build platform and/or said light transmissive window, and said detecting step is carried out by detecting force exerted on said force sensor. ### Claim 6 (depends on 1) The method of claim 1, wherein said window is stationary in the lateral (X, Y) dimensions. ### Claim 7 (depends on 1) The method of claim 1, further comprising: initiating production of an object on said build platform from said resin by additive manufacturing; and detecting a collision impact between said carrier platform and a fallen object on said window, or a collision impact between a dangling object on said carrier platform and said window. ### Claim 8 (depends on 7) The method of claim 7, further comprising halting said production and/or generating an alarm signal when said collision impact is greater than said detected impact of said build platform with said resin top surface portion or a predetermined expected impact of said build platform with said resin top surface portion. ### Claim 9 (depends on 1) The method of claim 1, wherein said step of detecting an impact of said build platform with said resin top surface portion, and said step of detecting a collision impact when present, are carried out with a force sensor operatively associated with said carrier platform and/or said window. ### Claim 10 (depends on 9) The method of claim 9, wherein said force sensor comprises a strain gauge. ### Claim 11 An apparatus useful for making a three-dimensional object from a polymerizable resin, comprising: (a) a build platform on which a three-dimensional object can be made; (b) a light transmissive window having a build surface operatively associated with said build platform, said build platform and said build surface defining a build region therebetween, said window configured to support a resin pool thereon; (c) an elevator assembly operatively associated with said build platform and/or said window, said elevator assembly configured for advancing said build platform and said window member away from one another to draw said polymerizable liquid into said build region; (d) a light engine operatively associated with said window and positioned to irradiate said build region with light to form a growing three-dimensional object from said resin; (e) a force sensor operatively associated with said platform and/or said window and configured to detect an impact of said build platform with a top surface portion of said resin pool; and (f) controller operatively associated with said carrier platform, said light engine, and said force sensor, said controller configured to determine a resin pool fill level from a detected impact of said carrier platform with a resin pool top surface portion. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein said window is stationary in the lateral (X, Y) dimensions. ### Claim 13 (depends on 11) The apparatus of claim 11, further comprising: (g) a resin dispenser operatively associated with said controller. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein said light engine comprises a light source in combination with a patterning array. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein said force sensor comprises a strain gauge. ### Claim 16 (depends on 11) The apparatus of claims 11, wherein said controller is configured to carry out a method comprising: (a) providing an additive manufacturing apparatus including a build platform and a light transmissive window, said build platform and said window defining a build region there between, with said window carrying a resin pool, said pool having a resin top surface portion; (b) advancing said build platform and said window towards one another until said build platform contacts said resin top surface portion; (c) detecting the impact of said build platform with said resin top surface portion; and (d) determining the fill level of said resin pool from said detected impact.