Continuous Processing Technique And Mechanism Based On Thermoforming And Rolling For Plastic Honeycomb Panels

Plastic honeycomb panels can offer weight saving and high strength.As these panels are capable of easy forming,environmental protection and excellent mechanical properties,they have high research and application value in light weight.It can be widely used in the fields of automobile,building and container transportation.However,according to the traditional processing technique for panels,honeycomb sandwich are fabricated by panels and honeycomb core respectively,and followed by heat fusion or adhesive film.From traditional methods,it is evident that sandwich panels are still produced by bath process and the processing efficiency is low.Morever,the bond area between honeycomb cell wall and cell wall is a line contact,resulting in a weak bonding strength.The small bond area between core and panels is very easy to cause the honeycomb core disbanded from sandwich panels,which limits the application and development of honeycomb sandwich panels.A continuous processing method based on thermoforming and rolling for plastic honeycomb panels,has been firstly developed.The mathematical model for plastic honeycomb panels' s continuous process was established.Specially,the quantitative relationship between quasi-honeycomb's thickness and its height was obtained.Also,the quantitative relationship of rolling pressure between equipment's structure and process parameters was obtained.The theoretical model of continuous process is verified by experiment,which shows that theoretical anlysis is in a good agreement with the experimental results.Moreover,the corresponding continuous machine is developed successfully to produce high density polyethylene(HDPE)honeycomb panels with a whole structure for both panels and core.Also,a series of continuous processing experiments were carried out to produce HDPE honeycomb panels.The effects of key process parameters for honeycomb panel process,such as preheating temperature before rolling,roller temperature,forming speed and rolling gap were analyzied respectively.Mechanical properties and thermal properties of plastic honeycomb panels were tested and characterized,and the effect of process parameters for continuous process on plastic honeycomb panels' properties was studied.The optimized process parameters are obtained.When preheating temperature before rolling is 220 ?,HDPE honeycomb panels can get suprior mechanical properties.Specially,bending strength and flat compressive strength are up to 25 MPa and 14 MPa respectively,and impact strength is up to 17.8 KJ/m2.Additionaly,the failure forms of HDPE honeycomb panels under tensile,bending and compression were studied repectively.Panels and core can maintain a good constraint under bending and compression.Interestingly,the core layer would not be peeled off from panels in loading process,which can solve the disbonding problem in existing methods.Additinaly,some properties between continuous processing honeycomb panels and other sandwich panels were compared.Results reveal that the innovative HDPE honeycomb panels show supior bending strength and tensile strength,which are 1.4 times and 17 times bigger respectively than thoase of glass fiber reinforced plastic honeycomb sandwtich panels.Also,breaking load for HDPE honeycomb panel in tensile test is five times as big as excellent that of corrugated panels.The success of continuous processing manchine development for plastic honeycomb panels based on thermoforming and rolling will improve mechanical propeties of honeycomb panels,which can promote the development of honeycomb panels processing technology and promote the development and application of plastic honeycomb panel.It has great economic value and practical significance.