SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a simple structure is reasonable, excellent performance, plastify of high quality, high efficiency, commonality are strong, the energy consumption is low and safe and reliable's plastic injection molding machine and injection screw to overcome the weak point among the prior art.
An injection screw designed for this purpose, comprising a threaded portion and a mixing element connected to each other, the threaded portion being provided with an external thread, characterized in that: the threaded part is sequentially provided with a feeding section, a compression section and a wave homogenization section along the spiral direction of the external thread; the wave homogenizing section is provided with at least six waves, each wave is composed of a first wave band and a second wave band with a phase difference of 180 degrees, and the first wave band and/or the second wave band are eccentrically arranged and respectively composed of wave troughs and wave crests uniformly distributed along the circumference of the screw.
The center of the first waveband deviates from the center of the injection screw and the eccentricity is S1, the center of the second waveband deviates from the center of the injection screw and the eccentricity is S2, the eccentricity direction of the first waveband is opposite to the eccentricity direction of the second waveband, and the eccentricity S1 is the same as the eccentricity S2 and is 0.06d-0.03 d; wherein d is the outer diameter of the injection screw.
The feeding section has a certain length L1, and the length L1 is larger than 8 d.
The compression section has a length L2, the length L2 is greater than 3d-5 d.
The compression ratio of the compression section is less than 1.8; wherein, the compression ratio is the ratio of the depth of the screw groove at the feeding section to the depth of the screw groove at the end of the compression section.
The wave homogenizing section has a length L3, L3 being greater than 7 d.
The mixing elements have a length L4 and are formed of interconnected screw flight portions and mixing element portions.
The sum of the lengths L1, L2, L3 and L4 is at least greater than 22 d.
And a plurality of single-thread screw edges are also arranged on the feeding section, the compression section and the wave homogenizing section.
A plastic injection molding machine is characterized by comprising the injection screw; the plastic injection molding machine at least comprises a melt adhesive cylinder and a blanking hopper, wherein the injection screw is rotatably arranged in the melt adhesive cylinder, and the blanking hopper is positioned above the feeding section and communicated with the melt adhesive cylinder; the wave crests and the inner wall of the melt adhesive cylinder form a certain distance H4, and the wave troughs and the inner wall of the melt adhesive cylinder form a certain distance H5.
The utility model discloses an improvement of above-mentioned structure, based on equal-volume rheological reverse eccentric wave single thread screw rod and tensile deformation strengthening method, not only solved effectively and promoted injection screw rod plastics homogeneity problem in the plastify process, can also avoided effectively that injection screw rod strong shearing leads to plastics to decompose and the molecular chain splits, makes the problem that the plastics performance changes to protect the plastics performance as far as possible, in order to realize injection screw rod in plastify quality, quick high efficiency, commonality and energy consumption four aspects reach the complementary effect of performance; meanwhile, the screw rod injection molding machine can be widely applied to various general reciprocating screw rod plastic injection molding machines to process various shear-sensitive high polymer materials or high polymer materials and inorganic fillers.
In summary, the device has the characteristics of simple and reasonable structure, excellent performance, good plasticizing quality, rapidness, high efficiency, strong universality, low energy consumption, safety, reliability and the like, and is strong in practicability.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and examples.
Referring to fig. 1 and 2, the injection screw comprises a thread part and a mixing element 1 which are connected with each other, wherein the thread part is provided with external threads, and the thread part is sequentially provided with a feeding section, a compression section and a wave homogenization section along the spiral direction of the external threads; the wave homogenizing section is provided with at least six waves, each wave is respectively composed of a first wave band A and a second wave band B with a phase difference of 180 degrees, and the first wave band A and/or the second wave band B are eccentrically arranged and respectively composed of wave troughs 3 and 6 and wave crests 4 and 5 which are uniformly distributed along the circumference of the screw.
Further, the center 10 of the first band a is deviated from the center 9 of the injection screw and its eccentricity is S1, the center 8 of the second band B is deviated from the center 9 of the injection screw and its eccentricity is S2, the eccentricity direction of the first band a is opposite to the eccentricity direction of the second band B, and the eccentricity S1 is the same as the eccentricity S2 and is 0.06d-0.03 d; wherein d is the outer diameter of the injection screw.
Further, the feeding section has a certain length L1, and the length L1 is larger than 8 d.
Further, the compression section has a length L2, and the length L2 is greater than 3d-5 d.
Further, the compression ratio of the compression section is less than 1.8; wherein the compression ratio is the ratio of the depth of the feed section screw groove 11 to the depth of the screw groove 7 at the end of the compression section.
Further, the wave homogenizing section has a length L3, L3 being greater than 7 d.
Further, the mixing element 1 is intended for increased mixing and plasticization, has a certain length L4 and is composed of a screw flight portion and a mixing element portion connected to each other. Wherein, mixing component 1's length L4 and structure can be customized according to the product demand, and the structure is not only limited to the structure is looked at to the drawing, except that the structure of screw thread section part, other totalities all regard as mixing component, and the suggestion collocation result of use is better.
Further, the sum of the length L1, the length L2, the length L3, and the length L4 is at least greater than 22 d.
Furthermore, a plurality of single-thread screw edges 2 are arranged on the feeding section, the compressing section and the wave homogenizing section.
Compared with the prior art, the method has the following advantages:
first, the strengthening effect of the constant volume rheological reverse waveband groove: when the single screw rotates, materials filled in the reverse wave band grooves can freely slide to the positions of the wave troughs 3 and 6 from the positions of the wave crests 4 and 5, the wave crests 4 and 5 and the wave troughs 3 and 6 are periodically changed, the materials build pressure at the positions of the wave crests 4 and 5, the pressure is released at the positions of the wave troughs 3 and 6, two alternate positions are arranged in one screw groove and can be alternated mutually, the materials are fused to the maximum extent, the pressure built by the wave crests 4 and 5 can be released to the wave troughs 3 and 6 of the same wave band, and the wave troughs 3 and 6 of the other wave band of the same screw groove can also be released, so that strong shearing cannot occur, and the two wave bands of the same screw groove, namely the first wave band A and the second wave band B are 180-degree phase difference and periodically change.
Secondly, a constant volume rheological screw:
1) non-compressive isovolumetric rheology: the volumes of adjacent screw grooves are kept basically consistent or similar, so that the melt pressure of each screw groove can also be kept basically consistent, and the phenomenon that the melt pressure is suddenly changed to cause strong shearing of the material is avoided, so that the material performance is changed;
2) low shear isobaric rheology: through the depth-thickness change of a local groove in the groove, the transverse flow and the overturning mixing in the melt groove are realized, the laminar flow is broken, the high shear is avoided, the extensional rheological effect is caused, and the materials are fully fused; meanwhile, heat conduction melting is enhanced, strong shearing is inhibited, and material plasticizing is accelerated;
3) according to the principle of low-shear isobaric rheology, the pressure of a melt in a spiral groove is automatically adjusted through internal volume change, local high shear cannot occur, the plasticizing process is smooth, heat energy and mechanical energy provided by a machine are utilized to the maximum extent, and the purpose of reducing energy consumption is achieved;
4) the combination of no compression isovolumetric rheology and low shear isovolumetric rheology enlarges the application range of the injection screw, and particularly, the original characteristics of inorganic matters are well protected when the high molecular resin and the inorganic filler are added.
Thirdly, the screw is arranged in a single-thread screw groove, two wave bands with 180-degree phase difference are added, namely a first wave band A and a second wave band B, the eccentricity S1 and S2 of the first wave band A and the second wave band B are the same, the eccentricity directions are opposite, the screw grooves are distributed periodically in adjacent screw grooves, the larger the eccentricity S1 and S2 are, the larger the power consumption is, the smaller the eccentricity S1 and S2 are, the insufficient plasticizing quality is, and the screw effect of the structure cannot be achieved, so that the suggested eccentricity S1 and S2 are both 0.06d-0.03 d; when the single screw rotates, the volume in one screw groove is unchanged, but in one wave band groove, the materials are periodically changed from large to small and then from small to large by a phase difference of 180 degrees, the other wave band groove has the same principle, and meanwhile, in one screw groove, the materials in the two wave band grooves can be mutually blended, so that energy and pressure complementation is realized, and the tensile deformation of the materials in the plasticizing conveying process is strengthened.
The injection screw has the characteristics, so the injection screw can be defined in the range of processing high polymer resin, and the injection screw can be suitable for all high-value resins and additives thereof, including inorganic fillers.
The injection screw with the structure is applied to a high polymer plastic injection molding machine, the plastic injection molding machine at least comprises a melt adhesive cylinder 12 and a blanking hopper 13, wherein the injection screw is rotatably arranged in the melt adhesive cylinder 12, and the blanking hopper 13 is positioned above a feeding section and is communicated with the melt adhesive cylinder 12; the wave crests 4 and 5 form a certain distance H4 with the inner wall of the melt glue cylinder 12, and the wave troughs 3 and 6 form a certain distance H5 with the inner wall of the melt glue cylinder 12.
The working principle is as follows:
the material enters the feeding section area from the feeding section 13, the material is conveyed to the compression section area from the feeding section, the material is in a high-elasticity state in the compression section area, the material is in a semi-molten state and is properly compressed to promote the plasticization of the material, a small amount of plasticized material enters the wave homogenizing section area, the material is fully plasticized in the area, the material can be pushed forwards along the first wave band A in a burst mode or can be pushed forwards along the second wave band B in a burst mode, meanwhile, when the pressure at the wave crest 4 of the second wave band B reaches a certain degree, the pressure can be released to the wave trough 3 of the first wave band A or the wave trough 6 of the second wave band B, the same condition can be realized at the wave crest 5 of the first wave band A, the pressure can be released to the wave trough 3 of the first wave band A or the wave trough 6 of the second wave band B, so that the material can be kneaded to the maximum extent in the screw groove, the material is uniform, and the pressure of the melt, after several cycles, the material is fully plasticized.
The screw has wave crests 4 and 5, so that the contact chance of materials and the inner wall of the melt glue cylinder 12 is increased, and the heat energy of the heating ring outside the melt glue cylinder 12 can be fully utilized, so that the injection screw groove depth of the structure can be 20-40% deeper than that of the traditional injection screw groove, the efficiency can be effectively improved, and the energy consumption is reduced.
The shear rate of the injection screw of the structure is obviously reduced compared with that of the injection screw of the traditional structure (the screw rotating speed is 60rpm, the material PS, and the viscosity η is 200 Pa.s).
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are intended to illustrate the principles of the invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention, and the scope of the invention is to be protected. The scope of the invention is defined by the appended claims and equivalents thereof.
Also, the drawings are for illustrative purposes only and are presented as schematic illustrations only, not as physical illustrations, and are not to be construed as limiting the present patent; for a better understanding of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
Moreover, like or similar reference numerals in the drawings of the embodiments of the present invention correspond to like or similar parts; in the description of the present invention, it should be understood that, if there are any terms such as "upper", "lower", "left", "right", "vertical", "horizontal", "longitudinal", "top", "bottom", "inner", "outer", etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, the description is for convenience and simplicity, and it is not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, the terms describing the positional relationships in the drawings are used for illustrative purposes only and are not to be construed as limiting the present patent.