Stanley Black & Decker Internship

Computer-Aided Engineering (CAE) Team

I was fortunate to have the opportunity to work with Daming Chen, John Zhang, and Ryan Zhao on the CAE team at Stanley Black & Decker’s (SBD) Towson campus in Maryland. The group’s purpose is to use computer simulation software to aid the DeWALT power tool engineers in the design process. Below I have listed out several projects I worked on during my time with the team.

1. Circular Saw Guard Design Tool
2. FEA Post Processing Automation
3. Tool to Hand Vibration Model
4. Intern Innovation Challenge

Circular Saw Guard Design Tool

I was tasked with building designer-friendly GUI software that solves the equations of motion describing the motion of a circular saw blade guard’s return mechanism. Once the user cuts through the material, the guard should spring back into place to protect them from the blade, as seen in the video below.

In order for circular saws to meet safety standards, the guard must cover the blade in within a specific time limit. The design team requested a tool that would allow them to input simple design parameters (geometry, weight, spring constant/preload, etc.) and would output the expected close time and impact force. I derived the equations of motion and built a lightweight program using MATLAB App Designer that solved these equations.

The accuracy of the program was verified by comparing data to high speed camera footage and several improvements were made in response to design team feedback. In the end, the program predicted close times within 9 percent of actual close times. Using this program the design team is able to save time and avoid modeling saws that do not meet safety standards or fail from high impact forces.

FEA Post Processing Automation

Design teams often request drop simulations from the CAE team and one of the most time consuming parts of these finite element analysis (FEA) simulations is post processing. For every single drop orientation, my coworkers had to generate the same model verification graphs, animations, effective plastic strain/von Mises stress contours, and more. I took on a project to automate these steps using Python and batch scripts.

The main software that my team used for post processing is LS PrePost (LSPP). Initially, I studied the simulation input file and the LSPP command file structures. After discussing post processing workflows with several teammates, I wrote a Python script that parsed input data and generated an LSPP command file that would generate the necessary plots, contours, and animations, take screenshots, and insert them into a PowerPoint file that users could refine into their simulation reports.

I presented my script to multiple CAE teams at SBD, including the Power Tool team and the Outdoors team. The script was able to save several hours for each drop simulation orientation, drastically expediting the FEA post processing and overall design process.

Tool to Hand Vibration Model

My manager wanted to start exploring tool-to-hand vibration analysis and tasked me with implementing a model from this paper in ANSYS Motion as a proof of concept. After spending a couple weeks in ANSYS Learning Hub to get familiar with Mechanical and Motion, I created the 5 degree of freedom mass-spring-damper model.

Then, I analyzed the displacement over time in ANSYS Motion and performed a Modal Analysis in Mechanical to compare results with the paper. I found resonant frequencies within 5 Hz of the ones shared in the paper, successfully showing that ANSYS Mechanical/Motion could be used to model tool-to-hand vibration.

Intern Innovation Challenge

Every year, interns at SBD are split into small teams to compete in the “Intern Innovation Challenge”. This year, the challenge was to create new solutions to various business problems—my team’s focus was culture. We were tasked with increasing employee engagement in SBD sponsored community events and elevating the DeWALT brand.

I led my team of eight people—two marketing, one supply chain, one finance, one IT, and three engineering interns—in organizing a well-structured timeline, managing different project roles, and unifying our team’s vision. We met with several different department heads at SBD for information and guidance, eventually forming a solution to improve workplace communication of events. At the end our our 10 weeks at SBD, we finalized our solution with a detailed implementation plan and presented it to business leaders.