1. Development of Handheld Automotive Tool
Justin Mancovsky (ME), Marcus Pritchard (ME)
Advisor: Joe Stabile (Mechanical Engineering)
Abstract
In the automotive repair industry doors are being stripped (removing the handle, mirror, side molding) every day to be repainted. Insurance appraisers will pay for up to one hour for removal and installing door moldings. The process includes removing leftover adhesive tape and re-taping for installation. The current industry practice uses a razor blade by hand to remove the adhesive, which is timely and aggravating for technicians. The goal of this project is to develop a motorized handheld tool that removes double-sided adhesive tape from door moldings in a timely fashion. A focus for this objective was modeling a device to fit the tight constraints of the tool’s operating path (<0.3in).
Designing for Manufacturability
Alternative Designs
Over the duration of this project, our team learned the iterative process of design. In each prototype we explored different design features using intuitive approaches in each iteration. The first iterations were designed to fit an electric groomer as a power source , but we ultimately decided on using a stock 12V motor. For the problem of the blade exchange, we tried using a removable blade and head design (left column) and also a push tab selector (middle column). Learning from the mistakes of each iteration through ANSYS analysis, we ultimately decided to simplify our blade holder system to a removable pin method (right column).
After calculating theoretical values (Figure 2), we were able to check the fatigue of our parts prior to prototyping them through ANSYS. By checking the equivalent stress and max deformation we can confirm failure points on our parts. Pictured below is an example of testing a snap-fit tab and the push selector from an earlier iteration. In both cases, we wanted to check that the material chosen (P430 ABS Plus) would withstand for our application.
Push tab selector- would be displaced vertically to slide into different slots (full, operating, closed)
Figure 2:
Experimental Testing
Before creating a tool, we first had to prove an oscillating razorblade is effective method in removing adhesive tape. To do this we used a simple setup called the Scotch Yoke Mechanism which simply translates a motor’s rotational motion to linear. We were able to create and manufacture the parts with 3D printers and CNC machines but unfortunately when we finished the production and assembly of the parts, the motor we designed it around could not provide enough torque to cut through the adhesive.
Final Design
Using hand calipers our team was able to measure several hands to get a rough estimate for the amount of clearance needed for a handheld tool. Battery packs were placed in the rear of the design to offset the weight of the motor to give the user a more authentic feel while using. Removing adhesive can be a sticky process, so having exchangeable blades was a design requirement that we accomplished with the “pull tab” mechanism.
Although the experiment failed we still managed to validate our concept of an oscillating blade through a very coarse but effective alteration on an existing hair trimmer. As pictured on the right we replaced the teeth used for cutting hair with a razorblade and superglued it into place. The razorblade oscillated and when tested against a car molding with adhesive tape it was able to effectively cut through the tape with ease.
Future Work
To continue this project and improve upon our design we want to test for oscillating speed. We would like to see this in a tool catalog which is why we are also looking to file for a patent. Upon filing we would approach a parent company Black and Decker (MacTools) to develop the device further and put it in their 2019 catalog. We are trying to get this tool into the hands of mechanics who are looking for an alternative separation method.
Figure 1:
Along with experimental testing of our hypothesis we also did extensive academic research into effectiveness of removing adhesive tape. Pictured on the right is a graph that shows the effectiveness of incidental angles at removing adhesives. This graph was the basis for what angles to design our tool to approach the adhesive.
Close up of the pull tab mechanism
Product Features:
Overall size:
7.20” x 3.29” x 3.01”
Interchangeable blades
Snap-fit assembly
Bottleneck Design
12V Motor
References
Figure 1: Particles on surfaces 8 : Detection, adhesion and removal, edited by K.L. Mittal, and K. L. Mittal, BRILL, ProQuest Ebook Central
Figure 2. BASF Corporation. (2007). Snap-Fit Design Manual. Technical Expertise, Retrieved from Design Manual.pdf