Method for improving injection molding defects of thermosetting composite material

A composite material, injection molding technology, applied in the field of injection molding, can solve problems such as product shrinkage defects, poor mold temperature gradient, low temperature, etc., to improve injection molding defects, improve product molding quality, and improve the effect of apparent quality

Pending Publication Date: 2022-02-22
亨弗劳恩(江苏)复合材料研发有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In the prior art, for thermosetting composite parts produced by the HP-RTM process, the high-pressure RTM mold used is usually designed with a reserved hole in the middle for placing the injection head, and the heating runner inside the mold cannot completely penetrate the reserved hole area , causing the temperature in this area to be lower than other areas, resulting in a temperature gradient difference in the mold, such as figure 1 shown
The temperature in the reserved hole area of ​​the mold is low, coupled with the principle of high-pressure injection resin flow, the curing direction of the resin in the mold spreads from the surrounding to the injection port, such as figure 2 As shown, the resin in the injection port is the freshest and the last cured resin. The curing of this part of the resin will absorb the resin from part of the product area, causing shrinkage defects on the surface of the product in the area around the reserved hole, such as image 3 As shown, affect the appearance quality of the product

Method used

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  • Method for improving injection molding defects of thermosetting composite material
  • Method for improving injection molding defects of thermosetting composite material
  • Method for improving injection molding defects of thermosetting composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A method to improve the injection molding defects of thermosetting carbon fiber aviation aircraft door side beams, the volume of the required molding mold is 6010cm through 3D model calculation 3 .

[0024] Use Araldite® LY 3585 epoxy resin as component A, and Aradur® 3475 epoxy resin as component B. Mix components A and B in proportion to a mixed density of 1.1g / cm 3 mixed resin, as injection resin.

[0025] According to the product of the resin density and 0.45 times the volume of the molding mold, the total amount of epoxy resin required for debugging is 2975g, and then injected. All 2975g of mixed resin is injected at a flow rate of 50g / s into the molding machine preheated to the molding temperature of 110°C. In the mold, it was cured at a constant temperature for 270s, and the mold was opened. The surface of the obtained thermosetting carbon fiber aircraft door side beam had obvious shrinkage defects.

Embodiment 2

[0027] The difference from Example 1 is that 2800g of mixed resin (accounting for 94.2% of the total mass of the resin) is injected at a flow rate of 50g / s into a molding mold preheated to a molding temperature of 110°C, treated at a constant temperature for 60s, and then secondly injected , that is, 175g of mixed resin is continuously injected into the molding mold at a flow rate of 50g / s, and continues to cure for 270s. After curing and molding, the mold is opened. The shrinkage defect of the injection port area of ​​the obtained thermosetting carbon fiber aircraft door side beam is improved compared with one-time injection molding.

Embodiment 3

[0029] The difference from Example 1 is that 2850g of mixed resin (accounting for 95.8% of the total mass of the resin) is injected at a flow rate of 50g / s into a molding mold preheated to a molding temperature of 110°C, treated at a constant temperature for 60s, and then performed a second injection , is about to continue to inject 125g mixed resin in the molding mold with the flow velocity of 50g / s, continue to solidify 270s, mold is opened after curing and molding, the shrinkage defect of the injection port area of ​​the obtained thermosetting carbon fiber aircraft door side beam still exists, but compares embodiment 2 has improved.

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Abstract

The invention discloses a method for improving injection molding defects of a thermosetting composite material, which comprises the following steps: calculating the total amount of required resin according to the size of a to-be-molded thermosetting composite material, then injecting the required resin into a molding mold at intervals for multiple times, and curing to obtain a finished thermosetting composite material. According to the method for improving the injection molding defect of the thermosetting composite material, the required total amount of resin is injected into the molding mold at intervals in batches, so that the shrinkage defect of the surface of a product in a preformed hole area caused by curing of the resin in an injection hole can be effectively prevented, and the apparent quality of the thermosetting composite material product is effectively improved; and the product forming quality is improved.

Description

technical field [0001] The invention relates to the technical field of injection molding, in particular to a method for improving injection molding defects of thermosetting composite materials. Background technique [0002] The HP-RTM (High Pressure Resin Transfer Molding) process is an RTM process technology introduced in recent years for the production of high-performance thermosetting composite parts. It adopts pre-forming, steel mould, vacuum-assisted exhaust, high-pressure injection and other process methods to complete the resin impregnation and curing process under high pressure to achieve low-cost, short-cycle (large-volume) and high-quality production. [0003] In the prior art, for thermosetting composite parts produced by the HP-RTM process, the high-pressure RTM mold used is usually designed with a reserved hole in the middle for placing the injection head, and the heating runner inside the mold cannot completely penetrate the reserved hole area , causing the te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B29C70/48
CPCB29C70/48
Inventor 顾勇涛曲志伟余文俊
Owner 亨弗劳恩(江苏)复合材料研发有限公司
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