Stamping Quality Control And Production Process Optimization Of G-series Forklift Engine Hood

Forklift engine hood has complex irregular geometer contour. The hood forming process is often affected by a great of factors such as blank shape, stamping speed, blank holding force, draw-bead parameter, friction lubrication conditions, die gap and so on, among which some would lead to a series of quality problems, like serious thinning, wrinkling, distortion, crack and inadequate stretch, for example. Not only it can not be guaranteed technically but also the cost also has no advantage, and it will hinder new type forklifts to the market as soon as possible that find the best forming parameters and the structure of die if only according to experience of repeated tryout. Sheet metal stamping CAE software not only can predict forming defects of forklift engine hood which only can be exposed through the repeated tryout, but also can optimize stamping process parameters and die design plan, shorten development cycles, improve product quality,guarantee the vehicle assembly quality and reduce production costs.In this dissertation,based on the theory of sheet metal forming and the software of Dynaform, the drawing and springback processes of G-series forklift engine hood from Anhui Heli Ltd. were studied, and the drawing process parameters were optimized by using orthogonal experiment. The research was mainly focused on the blank holder force, punching speed, drawbead height,friction coefficient and die gap of which the affects on local minimum thickness, wrinkling, crack and inadequate stretch of the work-piece in the drawing process. And based on numerical simulation, the reasons which causes wrinkling, crack and inadequate stretch were completely analyzed, and a corresponding solution of drawing quality was put forward. Finally, according to enterprise production the engine hood processing before and after the planning improved was compared, including production efficiency, labor intensity, work environment, defective goods rate and economic results.The research result shows that: (1) Numerical simulation technology not only can predict the forming defects of hood part which can be only exposed through die tryout, but also can optimize stamping process parameters and die design plan by using numerical simulation results.(2) The parameters related to hood drawing can be more quickly determined by combining orthogonal test and numerical simulation so as to provide the reliable technical supports for shortening the time of debugging process and trying.(3) For drawing of G-series forklift engine hood the optimal plan proposed in the dissertation is blank holder force 4430KN, draw-bead height 6mm, punching speed 1000mm/s and die gap 1.575mm.(4) In order to apply effectively the results of numerical experiment to actual production, it is necessary to analyze comprehensively the data difference obtained from simulation and physics experiments, consider fully the interaction of various process parameters, handled and used correctly the data from numerical simulation and orthogonal experiment.(5) The hood belongs to rectangular-box part of which space shape is more complex and drawing depth is greater. Moreover, in the hood forming blank thickness is larger, plastic deformation sufficient, stress-strain distribution reasonable. So before and after trimming the spring-back deformation quantity of the drawing work-piece does not exceed the scope required by technology.(6) Using stamping as the main working procedure in the hood production not only can guarantee product quality, but also boost production efficiency, reduce labor intensity and production costs, and improve the working environment.