Tool Wear Process And Mechanisms Analysis Of PAN-based Carbon Fiber Tow In Chopping Process

Chopped carbon fiber is the core part of chopped carbon fiber reinforced plastic(CCFRP). It is a novel kind of high performance functional material and has been frequently used in aerospace, military industry, vehicle industry, biotech, building industry, sports equipment, etc. Due to high strength property and highly abrasive nature of carbon fiber, wear of the cutting tool is evidently severe. Wear patterns and mechanisms need to be researched to prolong tool life, promote production efficiency and lower the cost. In this paper, PAN based carbon fiber has been chosen as the objection due to its high proportion in market. Two kinds of materials, original carbon fiber and polypropylene starched carbon fiber, are used to experiment and study tool wears of each.First, this paper designed and constructed two experiment platforms. The first one is chopped carbon fiber production platform, which includes starching system, drying system and cutting system. 16.6 times of cutting per minute per tool can be reached by controlling pressure of press roll, hardness of rubber roll, velocity and tool parameters. This platform is aimed to get worn tools rapidly and study tool wear patterns. The second one is cutting experiment platform, which only experiment the cutting process. This platform can provide the force on cutting tool and carbon fiber profile specimens. It is suitable to study the interaction between tool wear and cutting process.Second, this paper studied tool wear patterns of CF and PUCF separately. Tool wear during 0 to 24 k times cutting(2k interval) are observed. At cutting edge direction, tool wear presented as cresent shape. On the profile, tool wear can be separated into two stages, CER stage and rake face wear stage. Wear volume difference and wear similarity are chosen to evaluate tool life.Third, cutting experiments are done with both kinds of carbon fiber. Fully cut force and fully cut time are both increased as cresent shape wear becoming instinct. In return, increased cut force can lead to more severe tool wear. Also, tool wear caused uneven carbon fiber profile and lower the bonding within the carbon fiber. As the result, tool wear can cause bad quality of chopped carbon fiber.At last, this paper confront tool wear mechanisms by cutting force analysis, Hertz contact theory, micro tool tip properties and tool metallographic analysis. Overall, the wear mechanism during chopping carbon fiber is abrasive wear. This paper also established theoretical analyze model to analyze the causes of different wear.