CN2126516Y

CN2126516Y - High effective injection screw stem without scales

Info

Publication number: CN2126516Y
Application number: CN 92228487
Authority: CN
Inventors: 王兴天; 杨于光
Original assignee: BEIJING COLLEGE OF CHEMICAL TECHNOLOGY
Current assignee: BEIJING COLLEGE OF CHEMICAL TECHNOLOGY; Beijing University of Chemical Technology
Priority date: 1992-07-25
Filing date: 1992-07-25
Publication date: 1993-01-06
Anticipated expiration: 2002-07-25

Abstract

The utility model relates to a high effective injection threaded rod without scales. The front end of a threaded rod main body composed of only two segments of threaded rods is connected with a screw threaded rod head having a non-return ring. One segment L of the threaded rod main body is divided into a conveying segment L2 with a deeper flute spiral and a plasticizing segment L2 changed into a deep flute spiral, L=(18-20) D, L1 =(9-10) D, L2 =(9-10) D. The depth h1 of the deep flute spiral is equal to (0.14-0.16) D and the compression ratio epsilon is equal to h1 /h2 =2.1-2.3. Owing to that the structure and the design parameter change, the effective plasticizing length of the first and the second segments is increased relatively, and the temperature history of material is increased. Thus, the material can be fully propelled forwards and the metering segment of a shallow flute spiral is cancelled, which effectively reduces the shearing heat and prevents some materials from being heat-decomposed.

Description

High effective injection screw stem without scales

The utility model relates to a kind of plastic processing machinery, particularly a kind of efficient injection screw of no metering section that is applied on the plastic-injection moulding machine.

Injection screw is the critical component of injection (mo(u)lding) machine, and the correctness that its structural design and optimization of geometric parameters are selected directly has influence on the quality quality of injection molded article and the height of output, and is related to the accommodation of injector to different material.The basic structure of present conventional injection screw as shown in Figure 1, this screw rod is made of screw rod main part 1 and screw head 2, the main part of screw rod 1 is divided into feeding section L again ₁, compression section L ₂With metering section L ₃, three sections sums are generally 18D, and wherein D is the screw rod external diameter, and three sections sums are called L.It each section segment length distributes is: L ₁=8D, L ₂=6D, L ₃=4D, the pitch t=D of screw rod, bosom screw channel groove depth is h ₁=0.12D, compression ratio h ₁/ h ₃=2.5.h ₃Be the most shallow place of screw rod screw channel groove depth.The conveying of the conventional screw of this old syllogic and plasticizing mechanism mainly are to be undertaken by friction and internal shear effect between material and screw rod, machine barrel, the spiro rod plasticizing process will be occupied an leading position gradually from the energy of shear heat, and external heat will account for secondary status, and shear heat depends primarily on factors such as the physical property of the shape of screw channel and each section physical dimension and material and rheological property.When solid material is brought L into from expecting mouthful adding and the screw rod that is rotated ₁Realize Solid Conveying and Melting in the dark screw channel of section, enter into the L that screw channel shoals gradually then ₂Be compressed plasticizing in the section, enter the L of dark screw channels such as having again ₃Section is subjected to the further strong homogenization of shearing, and flows into screw front end at last, waits for next time being injected into mold cavity in the injection process.

The problem that this conventional three-stage screw exists have following some:

First: because the L of this screw rod ₃Section is longer, makes L ₂And L ₁Segment length shortens relatively, and the thermal history of material in screw channel is restricted, and makes to enter into L ₂The material of section is difficult to complete fusion, promptly can't normally enter into the more shallow L of screw channel ₃In the section, so just produce material by the asphyxia by external pressure on the chest and abdomen phenomenon, cause the rising of screw axial pressure and moment of torsion, the screw rod overload maybe can't be rotated, therefore, have to take the slow-speed of revolution to remedy the pile-up phenomenon of material, make screw rod under high rotating speed, not work, have a strong impact on the raising of production capacity with the way of time of staying of prolonging material.

Second: because L ₃The existence of section shallow screw channel section, when material at L ₂And L ₁After the effect that is rubbed continuously and shear, again at L ₃Section is subjected to more violent shear action, has caused the bulk deposition of energy, and temperature of charge is risen, for the materials such as hard vinyl chloride of thermostability difference, be easy to therefore produce thermal decomposition, cause the carbonization of material, and produce poison gas, injection can't be carried out.

Three, present, people attempt to adopt the way of the structure that reduces rotating speed and cancellation band check ring screw head to reduce thermal decomposition and the pile-up material problem that shear heat causes, but when the hard vinyl chloride the part with complicated structure of processing, owing to runner and the complicated increase that causes the die cavity resistance of die cavity, and then the very big back-pressure of generation refluxes, can't guarantee high filled film pressure, so can't mold qualified UPVC goods, this also can't use the reason place of UPVC moulding the part with complicated structure just up to now.

The purpose of this utility model just is to overcome the above-mentioned shortcoming and defect of existing in prior technology, and provides a kind of by two-part screw rod main body with have the threaded screw head of check ring and the high productive capacity that constitutes, do not produce thermal decomposition, be applicable to the efficient injection screw of no metering section of moulding UPVC the part with complicated structure.

The purpose of this utility model is to realize by following technical scheme, is connected with the threaded screw head that has check ring at the front end of the screw rod main part of having only two sections compositions, and screw rod main paragraph L is divided into the transportation section L with dark screw channel ₂With the fluxing zone L that deepens screw channel ₂, L=(18-20) D, L ₁=(9-10) D, L ₂=(9-10) D, dark screw channel groove depth h ₁=(0.14-0.16) D, compression ratio ε=h ₁/ h ₂=2.1-2.3, because the change of above structure and design parameter, increased effective plasticizing length of first and second section relatively, increased the thermal history of material, material can be pushed ahead on the basis of fully fusion, the cancellation of the metering section of shallow screw channel has reduced shear heat effectively, has prevented the thermal decomposition of some material.

Therefore: remarkable result of the present utility model is:

1, material is difficult for blocking, and rotating speed is improved, so the production capacity height.

2, not only can process common material, and be suitable for the processing of the materials such as UPVC of poor heat stability, enlarge the scope of application.

3, because screw rod shearing heat reduces, can realize low-temperature plasticizing, make material reach the high de-agglomeration degree, so can be provided with the screw head of check ring, prevented the backflow of material effectively, improved cavity pressure, so UPVC goods that can the forming shape complexity.

4, the two-part screw rod is convenient to processing, can reduce manufacturing cost.

Concrete structure of the present utility model is realized by the following examples and accompanying drawing thereof.

Fig. 1 is existing conventional screw structure chart.

Fig. 2 is a structure chart of the present utility model.

Be described in detail below in conjunction with 2 pairs of concrete structures of the present utility model of accompanying drawing:

The utility model is made of with the screw head 2 that is connected with screw rod main paragraph 1 front end screw rod main paragraph 1, and it is characterized in that: screw rod main paragraph 1 is by transportation section L ₁With fluxing zone L ₂Constitute, screw head 2 is provided with screw thread 2A, is movably installed with check ring 3 on the optical axis section 2B of screw head 2.Referring to Fig. 2

Architectural feature of the present utility model also is:

Transportation section L ₁Length be 10-20D, fluxing zone L ₂Length be 9-10D, screw rod main paragraph total length L is 18-20D, h ₁Be 0.14-0.16D, screw compression is than ε=h ₁/ h ₂=2.1-2.3.Referring to Fig. 2.

Working mechanism of the present utility model is:

Owing to cancelled metering section L ₃Even under the constant situation of screw rod length overall, also equal to have increased by second section L ₂With first section L ₁Length, increased the thermal history of material at this section, fusion is unlikely at L fully to make material ₂Section is stifled squeezes, and its rotating speed can be enhanced about more than once when the identical material of processing.Production capacity is greatly improved.

Owing to cancelled the metering section L of shallow screw channel ₃, the ratio from shear energy of storing up, make that has greatly reduced the material energy is controlled, and has increased the ratio of external heat source control, prevents thermal decomposition with the way of accurately controlling temperature of charge, to adapt to the processing of goods such as UPVC.

Because screw rod shearing heat reduces, so can realize low temperatureization, make material reach high decomposition temperature, therefore, can add the threaded screw head 2 of being with check ring 3, the setting of screw thread 2A on the screw head, prevented that not only melt from decomposing in the viscous flow of its head, and the melt owing to anti-stream has been subjected to the sealing of check ring 3 when injection, so can set up higher model pressure, therefore, can mold complex-shaped UPVC goods.

In some cases, very short L also can be set ₃Metering section, this moment L ₃Length be (0-1) D.

Claims

1, the efficient injection screw of no metering section is made of with the screw head 2 that is connected with screw rod main paragraph 1 front end screw rod main paragraph 1, and it is characterized in that: screw rod main paragraph 1 is by transportation section L ₁With fluxing zone L ₂Constitute, screw head 2 is provided with screw thread 2A, is movably installed with check ring 3 on the optical axis section 2B of screw head 2.

2, according to the efficient injection screw of the described no metering section of claim 1, it is characterized in that: transportation section L ₁Length be 10-20D, fluxing zone L ₂Length be 9-10D, screw rod main paragraph total length L is 18-20D, h ₁Be 0.14-0.16D, screw compression is than ε=h ₁/ h ₂=2.1-2.3.