Flash Prevention in HPDC

Welcome to steady die casting solutions. We are at steady die casting solutions keep on continue to give die casting solutions. In this paper we will discuss how we can predict flash location in die and how we can correct before die making or after die making. We also discuss how we can calculate individual tie bar load when we load a die, tie bar load will change on each die changeover because of it’s center of gravity. We discuss how casting shot centroid will effect tie bar load which directly responsible for flash. All this things we try to explain with an example, I hope it will be help full. Thank you very much, “keep learning till death”. Keywords: Flash, tie bar, machine tonnage, machine center, die, hpdc, casting defect and clamping force

Geometric Error Modeling and Sensitivity Analysis of Single-Axis Assembly in Three-Axis Vertical Machine Center Based on Jacobian-Torsor Model

The influence of component errors on the final error is a key point of error modeling of computer numerical control (CNC) machine tool. Nevertheless, the mechanism by which the errors in mechanical parts accumulate to result in the component errors and then impact the final error of CNC machine tool has not been identified; the identification of this mechanism is highly relevant to precision design of CNC machine. In this study, the error modeling based on the Jacobian-torsor theory is applied to determine how the fundamental errors in mechanical parts influence and accumulate to the comprehensive error of single-axis assembly. First, a brief introduction of the Jacobian-torsor theory is provided. Next, the Jacobian-torsor model is applied to the error modeling of a single-axis assembly in a three-axis machine center. Furthermore, the comprehensive errors of the single-axis assembly are evaluated by Monte Carlo simulation based on the synthesized error model. The accuracy and efficiency of the Jacobian-torsor model are verified through a comparison between the simulation results and the measured data from a batch of similar vertical machine centers. Based on the Jacobian-torsor model, the application of quantitative sensitivity analysis of single-axis assembly is investigated, along with the analysis of key error sources to the synthetical error ranges of the single-axis assembly. This model provides a comprehensive method to identify the key error source of the single-axis assembly and has the potential to enhance the tolerance/error allocation of the single axis and the whole machine tool.

Effect of the dynamic stiffness of a five-axis machine tool on the quality of sculptured surface

To achieve high quality of sculptured surface, a five-axis machine center must have excellent dynamic behavior. This article gives a new way to characterize and present the performance of machine center on milling sculptured surface which is constrained by the dynamic stiffness. First, the formation mechanism of surface quality is explained in intermittent milling process. It is mainly affected by the vibration frequency of cutting behavior. Second, the concept of dynamic stiffness of machine center is proposed and calculated based on the movement of multi-axis. To elaborate such effect, the map of dynamic stiffness on a sculptured surface, S part is obtained. The change of stiffness causes the different vibration frequency and then leads to different surface quality. Finally, experiments are conducted on S part by microscope and the waviness measurement. The results demonstrate the proposed method is very close to the true one. Presenting, measuring, and controlling the surface quality are easy for the user to understand the challenging performance of the machine center on milling sculptured surface.