# US 10,766,178 B2 · Screw for injection molding machine, injection molding machine, and injection molding method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,766,178 B2 - Document ID: US10766178B2 - Status: Granted - Kind: B2 - Application number: 15/541,281 - Filed: 2015-01-15 - Published: 2017-12-14 - Granted: 2020-09-08 - Earliest claimed: 2015-01-15 - Assignees: U-Mhi Platech Co., Ltd.; Mitsubishi Heavy Industries, Ltd. - Applicants: U-Mhi Platech Co., Ltd.; Mitsubishi Heavy Industries, Ltd. - Inventors: Munehiro Nobuta; Naoki Toda; Toshihiko Kariya; Takeshi Yamaguchi; Kiyoshi Kinoshita - Web page: https://patentgrep.com/patent/US10766178B2 ## CPC - B29C 45/50: Axially movable screw - B29B 7/14: with screw or helix - B29B 7/24: for feeding - B29B 7/421: {with screw and additionally other mixing elements on the same shaft, e.g. paddles, discs, bearings, rotor blades of the Banbury type} - B29B 7/60: for feeding, e.g. end guides for the incoming material {(B29B7/7615 takes precedence; feeding predetermined amounts for mixing in general B01F35/714)} - B29B 7/90: Fillers or reinforcements {, e.g. fibres} - B29C 45/0005: {using fibre reinforcements} - B29C 45/03: Injection moulding apparatus (transfer moulding B29C45/02) - B29C 45/60: Screws - B29K 2101/12: Thermoplastic materials - B29K 2105/06: containing reinforcements, fillers or inserts - B29K 2105/12: of short lengths, e.g. chopped filaments, staple fibres or bristles - 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) - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS ## Abstract Provided is a screw that is for use in an injection molding machine and that makes it possible to benefit from the kneading effect of a multi-start screw while minimizing the received friction resistance. The screw for an injection molding machine is provided with a first stage 20 on the upstream side and a second stage 30 on the downstream side. The screw for an injection molding machine is characterized in that: the first stage 20 is provided with a compression section 22 comprising a main scraper 25 and an auxiliary scraper 26 having a smaller outer diameter than the main scraper 25; and the second stage 30 is provided with a multi-start screw section 31, said multi-start screw section being provided on the upstream side and comprising a plurality of scrapers, and a fin kneading section 32 provided downstream from the multi-start screw section. ## Claims ### Claim 1 An injection molding machine comprising: a cylinder that is provided with an injection nozzle; and a screw that is provided inside the cylinder so as to be able to rotate around a rotating axis and to be able to advance and retreat along the rotating axis, wherein the injection molding machine performs injection molding of a fiber reinforcing resin, and wherein the screw includes: a first stage that is provided on an upstream side; and a second stage that is provided on a downstream side of the first stage, wherein the first stage includes a feed zone, a compression zone, and a metering zone in order from the upstream side, the compression zone being provided with a main flight and an auxiliary flight having an outer diameter smaller than the outer diameter of the main flight, wherein the second stage includes a multi-start screw portion which is provided on an upstream side and has a plurality of flights, and a kneading portion which is provided on a downstream side of the multi-start screw portion and has a fin, and when a diameter of an apex portion of the main flight is D, a length of the screw, in which the multi-start screw portion is provided, in a rotating axis direction ranges from 2 D to 5 D. ### Claim 2 (depends on 1) The injection molding machine according to claim 1, wherein a feed port through which a reinforcing fiber is able to be fed into the cylinder together with a resin raw material is provided on an upstream side of the cylinder. ### Claim 3 (depends on 1) The injection molding machine according to claim 1, wherein the number of the flights in the multi-start screw portion ranges from 6 to 10, and wherein the number of times of winding of each of the flights in the multi-start screw portion ranges from 1 to 2. ### Claim 4 (depends on 1) The injection molding machine according to claim 1, wherein a groove depth of the multi-start screw portion is a groove depth equal to or deeper than the groove depth of a downstream side terminal end portion of the first stage. ### Claim 5 (depends on 1) The injection molding machine according to claim 1, wherein the kneading portion includes a plurality of fin groups which are disposed with gaps in the rotating axis direction and each of which has a plurality of plate-like fins provided with gaps in a circumferential direction, and wherein when the diameter of the apex portion of the main flight is D, the length of each fin in the rotating axis direction ranges from 0.05 D to 0.2 D, the gap between the fins adjacent to each other in the rotating axis direction ranges from 0.1 D to 0.2 D, and the number of lines of the fin groups ranges from 5 to 10. ### Claim 6 (depends on 1) The injection molding machine according to claim 1, wherein when the diameter of the apex portion of the main flight is D, D is equal to or greater than 90 mm. ### Claim 7 (depends on 1) The injection molding machine according to claim 1, wherein a groove depth of the multi-start screw portion is a groove depth such that a total sum of cross-sectional areas of the grooves of the multi-start screw portion is equal to or greater than a cross-sectional area of the groove of the metering which is a downstream side terminal end portion of the first stage.