Making method of composite material tube

Abstract

The invention provides a making method of a composite material tube. The method comprises the following steps: making a solid mandrel by using a foamable substance or a substance with a large expansion coefficient and a soluble substance; attaching the outer peripheral face of the mandrel with a composite material; putting the mandrel in a die, and heating to make the mandrel have an increasing volume and expand in order to make the composite material expand toward and push the inner wall of the die and also make the composite material compact, hardened and molded to form a tube; and dissolving the mandrel by using a solvent, and allowing the obtained solution to flow out of the tube. The strong and solid tube with a compact structure can be obtained through the making method, and the making method has the advantages of simplification of a mandrel removal step, good dimensional precision, and substantial increase of the yield.

Description

technical field [0001] The invention relates to a method for manufacturing a composite material bicycle pipe. Background technique [0002] Known bicycle pipes, such as wheel frames, are made of composite materials. Generally speaking, as described in Taiwan Patent I341800, an air bag is often used as a mandrel, and the composite fiber is attached or wound on the air bag. Outside the bag, put it into a mold with a predetermined inner wall shape, further inflate the air bag, so that the composite material can be stretched and tightly attached to the inner wall of the mold, then subjected to high temperature and high pressure treatment, and finally hardened and formed into A composite pipe fitting. However, in these methods, the high temperature is easy to break the air bag, resulting in poor yield, and the air bag is not easy to take out, and usually has to be left in the pipe. The most important thing is that the hardness of the air bag is likely to be insufficient when att...

AI Technical Summary

Problems solved by technology

In this case, only the foam material was used as the mandrel, and after the pipe was formed, it was subjected to high temperature treatment to raise the temperature to the melting point or vaporization temperature of the foam material to remove the mandrel from the pipe. However, the melting point of the foam material Or the gasification temperature is very high. If it is heated to such a high temperature, the pipe structure has already been damaged by high temperature and cracked, and it cannot be produced at all.

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