Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Isometric process control method utilizing PVT (pressure-volume-temperature) relation of polymers

A technology of relational characteristics and process control, which is applied in the field of specific volume process control, can solve the problem of establishing a connection with the PVT database without polymers, and achieve the effects of uniform cooling shrinkage, reduced specific volume, and reduced orientation force

Inactive Publication Date: 2012-06-13
BEIJING UNIV OF CHEM TECH
View PDF4 Cites 10 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most of the existing control methods of injection molding machines are aimed at the separate control of the two variables of polymer melt pressure and temperature, and the pressure holding process has not established a connection with the PVT database of the polymer.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Isometric process control method utilizing PVT (pressure-volume-temperature) relation of polymers
  • Isometric process control method utilizing PVT (pressure-volume-temperature) relation of polymers
  • Isometric process control method utilizing PVT (pressure-volume-temperature) relation of polymers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0015] The specific implementation method of an isosteric process control method using the PVT relationship characteristics of polymers in the present invention is as follows: first, according to the physical parameters of different materials, the PVT curve of the injection molding material is obtained, and the molding process route is determined. Get the process route of A-B-C-D-E-F in the PVT curve, such as figure 1 As shown, point A is the starting point of the injection molding process. From point A, the molten material is injected into the cavity from the nozzle. Point B is the moment when the sensor installed in the cavity monitors the pressure and temperature signals, that is, the material just touched the molten material. When it is in the body, the temperature will suddenly rise to the maximum value, and the pressure will also rise to a certain extent, but the change value is not large. The pressure rising slope is related to the injection pressure and injection speed....

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses an isometric process control method utilizing PVT (pressure-volume-temperature) relation of polymers. An injection process includes a first step: a PVT curve of an injection molding material is obtained according to the category and the characteristics of the material, an A-B-C-D-E-F process route is obtained from the curve, and an A-B-C section is an injection molding stage; a second step: constant-pressure packing is realized under the maximum packing pressure for a period of time, then isometric packing is carried out, and a C-D section is an isobaric compression stage; a third step: a D-E section is an equal-ratio volume packing stage, a material in a cavity cannot be changed, and cannot backflow or be increased along with reduction of the temperature of the cavity, and packing pressure of melt is obtained by means of calculation by the aid of a Tait equation and physical parameters provided by a PVT database; and a final step: an E-F section is a constant-pressure cooling stage. The constant-pressure packing is realized before the equal-ratio volume packing is realized, the melt is in a flowing state during the constant-pressure packing, accordingly excessively packing alignment is avoided, warpage is low, and quality repeat precision is high.

Description

technical field [0001] The present invention relates to the field of polymer material processing, in particular to a method for controlling the isospecific volume process of injection molding products using the PVT relationship characteristics of polymers. The method is based on the PVT characteristic curve of polymers, and adopts the process control of equal volume pressure. It can improve the dimensional uniformity of the product, reduce warpage and deformation, and improve the repeatability of product quality. Background technique [0002] Polymer materials are formed from pellets (or powder) through plasticization, filling, compression, pressure holding, cooling and setting into products, which is the general process of injection molding. In these processes, the control of the pressure-holding stage is the key to the quality of the product. Only when the pressure-holding stage is well controlled, the surface quality, dimensional accuracy, and quality repeatability of the...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): B29C45/77
Inventor 谢鹏程张盛桂丁玉梅杨卫民
Owner BEIJING UNIV OF CHEM TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com