Modeling of the Broaching Process By: Sara Whitby Matthew Glisson Anton Galkin

Problem Statement Linear broaching is material removal using a toothed tool Tool is pushed through material in a line High force Very fast Complications: Expensive Difficult to design No interchangeable parts

Motivation Automate computationally intense parts of design process Allow for rapid iteration through different design options Explore applications of course materials

Approach: Matlab Model of Slot Broach User Input: sketch of final profile parameters: cutting speed, number of teeth, workpiece length, basic tool geometry, etc. Pre-Processing determine intermediate profiles calculate discrete chip areas Force Calculation numerically calculate and sum forces Output graph results

Program Procedure: Input to GUI

Program Procedure: Outer Profile Takes a.png image 255 x 250 pixels (x,y)=(0,0) at bottom center start and end of line must touch bottom of image each black pixel can only have two neighbors outer profile cannot double over line radiating from (0,0)

Program Procedure: Generate Profiles Use MATLAB's polyfit function to fit curves to x and y vectors Re-relate new x and y Find specified number curves evenly spaced from start profile plot all profiles

Program Procedure: Find Output Data Finds small areas between teeth along each profile Plugs incremental chip thicknesses and widths into oblique cutting function Outputs forces, velocities, angles, and geometries for each tooth Graphical Outputs: All tooth profile shapes Total forces over time Minimum and maximum tooth force profiles Force profile for user selected tooth

Graphical Output Example

Graphical Output Example (continued)

Project Outcome A program which can simulate a slot broaching process in a wide range of situations o Creates evenly spaced tooth profiles from digital images o Calculates the lateral, thrust and cutting forces over the perimeter of a specific tooth o Finds the total lateral, thrust and cutting forces over time o Automatically displays the highest and lowest lateral, thrust and cutting forces over the perimeter the first and last teeth (min and max total forces, respectively) The tool can be used when designing a broach to quickly and easily experiment with different tooth profiles and forces

Future Improvements Find intermediate profiles based on total chip areas Model force of gradual entry into workpiece by oblique tooth Allow for more flexibility in inputs and outputs Model different kinds of broaching More versatile starting profiles Fix distribution of points for outer profile

Questions? References: Vijayaraghavan, L., R. Krishnamurthy, and H. Chandrasekaran. "Evaluation of Stress and Displacement of Tool and Workpiece on Broaching" (1981) Ozturk, Ozkan, and Erhan Budak. "Modeling of Broaching Process for Improved Tool Design" Shi, D., D. A. Axinte, and N. N. Gindy. "Development of an Online Machining Process Monitoring System: a Case Study of the Broaching Process" (2007) Kokturk, U., and E. Budak. "Optimization of Broaching Tool Design" (2011) Ozlu, E., S. Engin, C. Cook, T. El-Wardany, and E. Budak. "Simulation of Broaching Operations for Tool Design Optimization"