WES

Acknowledgements

Project Advisor: Dr. Kristy Csavina

Technical Advisor: Prof. Jeffrey Wheeler

Donations Made by: Milwaukee Tool

Video

Elevator Pitch

One of the largest failure points when manufacturing cutting, and reciprocating blades is the joint between the tooth material and the dissimilar backing material. Being able to quantifiably evaluate the joining strength of different materials is imperative to understanding overall tool strength. By isolating a single tooth and breaking it with a linear actuator our system can quantify the strength of a welded joint. 

The Milwaukee Tool Welding Evaluation Team consists of 7 students who began this adventure in August 2020. They have diligently worked throughout a whole year to design a system that will benefit Milwaukee Tool in assessing the quality of their dissimilar material cutting accessories. The team gained a wealth of knowledge on different welding methods, various subsystems such as electronics and visual systems, and spent a significant amount of time researching, designing, and in the machine shop. Even mechanical engineers can learn electrical engineering and coding. 

In the initial phases, this project taught the team over and over again to keep the concepts broad. Narrowing in too soon on specifics could take away from the numerous avenues that the team had yet to explore. Once the team investigated different methods, the WES team decided on a mechanical system. The system design consists of a pushing test on the dissimilar material of the tool which gathers the data of the forces as the test runs. Using an integrated LabVIEW program to interpret the data, the team developed a visual system that gives an optical component for Milwaukee Tool to visually see the results. This project design presented numerous challenges that the team overcame in order to produce a system that fulfilled all of Milwaukee Tool’s needs and desires.  

Design Approach

Apparatus used by CSM Mechanical Engineering department that inspired the design

First mock-up of our design using 3D printed fixtures

Design Solution

The testing apparatus is used to test finished and unfinished parts to ensure quality control standards were met throughout the manufacturing process. Our solution consists of a fixturing system to constrain the movement of the cutting accessories and a component for applying force to the parts being tested. The system then records and compiles information on the failure to provide an analysis of the strength of the joints in the batch tested. This system will allow for quantitative analysis of the accessory’s strength, outputting values of forces required to break the joint of the tool, to ensure that additional money and time is not invested in batches of accessories that do not meet the quality standards. By compiling quantitative data on the strength of bonds, Milwaukee Tool is better able to understand how their manufacturing process impacts the part’s functionality. 

The design consists of a rigid I-beam backbone with a linear actuator as the force component, the actuator pushes on a load cell which leads through other system parts to a small tip on the opposite end of the system which pushes on the tool being tested, breaking it and creating an output log of forces measured during the test. The tests are controlled through an accompanying computer where the test results will be generated. A visualization system is also incorporated for two purposes: (1) to align pieces being tested and (2) to analyze the failure. From the visual system, crack propagation can be studied to further understand the properties of the tested parts. The design solution presented is capable of testing reciprocating blades, but fixtures can be developed to test other blade geometries to obtain the most useful information based on the geometry of the joint being tested. For this solution to be useful to the client, the development of a testing protocol was necessary. This serves to standardize the testing, giving validity to the numerical data generated from the load cell.  

Next Steps

Due to time limitations, not all the features that were discussed made it into the final product. Automation was a major stretch goal that did not make it into the final design because it involves several subsystems to accomplish. The implementation of automation requires a complete redesigning of the fixturing system to enable the blades to move so that one tooth after another can be tested without human intervention. The next step in automation involves changing out blades so that several blades can be tested in a row.  

Another stretch goal that did not make it is the ability to test multiple blade geometries. The tester delivered is capable of testing reciprocating blades only. To expand the functionality of the tester, fixtures to test oscillating and circular saw blades should be made. This can be done by utilizing a similar design as the delivered fixture including the same mounting interface. 

There is potential functionality to be gained from machining the parts within the assembly out of a stronger alloy metal such as steel, alongside this creating tighter tolerancing could help to keep everything working properly over a longer period. Redesigning and remaking the load cell mount to be stouter on the edges that the pin go through could add rigidity and avoid potential failure/cracking of the part. The reciprocating blade fixture could likely be fine-tuned to be made from less material and integrate fillets into the 90-degree angled edge to reduce the stress concentrations. Utilizing a clamping system could be beneficial for the two reciprocating bade fixtures, instead of using the bolts to tighten down on, if the geometry of these two parts were changed there could potentially be a way to cleverly use a clamping system to keep the blade being tested tight between them when testing but quickly removed when the part being tested needs changed out. 

Meet the Team