Polyamide Molding Material Reducing Burr Formation
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Solution Overview
Problem
Existing polyamide molding materials for producing housings and electronic device components suffer from significant burr formation, warpage, and poor surface quality, particularly at tool temperatures of 90°C, which complicates the manufacturing process and requires time-consuming manual deburring.
Innovation Solution
A polyamide molding material composition comprising a blend of partially crystalline and amorphous polyamides, glass fibers with flat cross-sections, and non-halogenated flame retardants, optimized to minimize burr formation through specific weight percentages and processing conditions, achieving reduced burr length and improved surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass-fiber-reinforced polyamides are pressed during compression phase, then high stiffness and structural integrity are achieved, but burr formation occurs at the tool parting line
Solution Approach 1:
The patent modifies the polyamide blend composition by specifying precise ratios of fully aromatic to partially aromatic polyamides (1:4 to 4:1), along with controlled amounts of amorphous polyamide (5-30 phr) and crystalline polyamide (5-30 phr). This parameter optimization changes the melt's viscoelastic properties, reducing burr formation while maintaining stiffness.
Solution Approach 2:
The invention uses a composite polyamide system combining fully aromatic polyamides (for stiffness), partially aromatic polyamides (for processability), and amorphous/crystalline polyamides (for flow control). This multi-component composite approach balances structural requirements with reduced burr formation.
2Manufacturing precision
If polyamides are pressed into the tool parting line, then complete mold filling is achieved, but flash formation occurs
Solution Approach 1:
The patent optimizes the polyamide blend parameters including the ratio of fully aromatic to partially aromatic polyamides (1:4 to 4:1), viscosity modifiers (5-30 phr amorphous polyamide), and crosslinking agents (5-30 phr crystalline polyamide). These parameter changes control melt viscosity and elasticity, enabling complete mold filling without flash.
3Manufacturing precision
If manual deburring is performed, then burr removal is achieved, but processing time increases
Solution Approach 1:
The patent converts the harmful effect of burr formation into a benefit by using the pressurization phase to deliberately press polyamide into the parting line, creating a sealing effect. The optimized material composition ensures this pressurization fills voids completely while the controlled burr formation (≤30 μm) eliminates or minimizes the need for manual deburring.
4Ease of operation
If high flowability is achieved through polyamide composition, then good injection molding performance is obtained, but burr formation increases
Solution Approach 1:
The patent precisely controls the polyamide blend parameters: fully aromatic to partially aromatic ratio (1:4 to 4:1), amorphous polyamide content (5-30 phr for flow), and crystalline polyamide content (5-30 phr for structure). This parameter optimization achieves high flowability while controlling burr formation through balanced viscoelastic properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The material exhibits reduced burr formation, low warpage, and enhanced surface quality, meeting the requirements for producing high-quality electronic device components with improved processing efficiency and flame retardancy.
Implementation Method 1
the at least one partially crystalline, partially aromatic polyamide (A) has a glass transition temperature (Tg) of at least 105° C.
Implementation Method 2
melting point of 300-330°C
Implementation Method 3
40-70 wt.-% glass fibers (C) with flat cross section
Data Source
AI summary
A polyamide molding material is proposed, which comprises at least one partially crystalline, partially aromatic polyamide (A) and at least one amorphous polyamide (B). The polyamides (A) and (B) together make up 30-60 wt.-% of the polyamide molding material. Furthermore, the polyamide molding material comprises 40-70 wt.-% glass fibers (C) having flat cross section, 0-15 wt.-% of at least one nonhalogenated flame retardant (D), and 0-10 wt.-% further additives (E), the components (A) to (E) adding up to 100 wt.-% of the polyamide molding material. The at least one partially crystalline, partially aromatic polyamide (A) has a glass transition temperature of at least 105° C. The polyamide molding material according to the invention is preferably distinguished in an injection-molding burr formation test in that, at a melt temperature of 320° C. and a tool temperature of 90° C., and a dynamic pressure of 100 bar and a holding pressure of 400 bar, at the flow path end of a mold arm having a vent gap dimension of 30 μm, burrs having a length G of at most 30 μm result. Such a polyamide molding material results in molded parts having good surface quality and low warpage when injection molded and is suitable for the production of housings or housing parts of electrical and electronic devices.