Peelable Heat Shrink Case Study
Human Factors, Engineering, Efficiency, Usability Testing
Overview
This is one of the most accomplished projects I’ve initiated to the executive team at Avinger. Not only did I accomplished a cost savings of $1MM+ per year, but I also brought everlasting big smiles to my workers because I’ve eliminated physical pain that they had to suffer since the company was launched.
Disclaimer: Certain content of products, tools, or process are proprietary information, and therefore not shown on this page. Most content and terms in this project are generalized to protect company rights.
Challenge
Users are experiencing blisters/calluses from a material removal process. Find a way to alleviate or reduce the amount of ergonomic/safety issues that users are going through.
My Role
I was the engineer and project manager for this process improvement project. I pushed for this project because my users have been suffering from pain, and this was something that could help them tremendously. I ended up creating this project for myself, and this became one of the most impactful project for the company.
Solution
I successfully cut the process time by 92.3% by researching into a different material, prototyping, testing, verifying, and implementing the new material, which resulted in a cost savings of around $1 million per year. I’ve also eliminated chronic ergonomic/strain issues users are experiencing from the process.
Background
Catheters, which are long thin tubes made of medical grade materials, are sometimes made by laminating a plastic layer with braided metal wires along a long length shaft.
Lamination uses heat treatment, which will require a protective layer to prevent melting the plastic layer. This protective layer is commonly known as heat shrink which is made with Fluorinated ethylene propylene (FEP).
This FEP heat shrink is designed to be removed after lamination is complete. The surface of the catheter along the entire shaft should be smooth and even.
Problem
There were three major problems with this manufacturing process:
- Ergonomic/Safety: This removal process causes people to get blisters and/or calluses, which is my#1 priority/concern.
- Process Issues: Traditional FEP heat shrink is hard to remove as it requires peeling in a spiral pattern rather than a straight peel motion, or else it would constantly break during the removal process.
- Low Efficiency: Takes 5 to 8 minutes to remove a 60-inch shaft.
Product Evaluation
I wanted to understand what we currently have in our product catalog in order to evaluate how big the project would be:
- Products used traditional FEP Heat Shrink: There were a total of 6 products with different sizes that used the traditional FEP Heat Shrink.
- Dimensional Specifications: The main specifications for FEP evaluation are the minimum expanded inside diameter (ID), which is before shrinking, and the maximum recovered ID, which is after shrinking. These dimensions would determine the shrink ratio of the FEP material. The catheter shaft final outside diameter (OD) must also be considered during product evaluation.
Material Change Proposal
After experimenting with different tools and supplies, I’ve found another way to not just reduce, but eliminate the three major problems I mentioned above: updating to a material that is far easier to use and remove.
- Research was conducted to find better material to improve the heat shrinking removal process/efficiency and to alleviate any ergonomic/safety concerns.
- Peelable Heat Shrink was found as an alterative to traditional FEP Heat Shrink. This alternative protective layer is invented by Junkosha, which offers a much easier way to remove the material using straight-peel method without any breakage.
Cost & Benefit Analysis
- Cost: Higher material cost per batch up front.
- Opportunities: 1) No blisters/fatigue for operators, 2) Saves significant time per batch, which means: no need to hire additional headcounts, no overtime, no special equipment/tools needed, and finally, use the saved time to build more products.
After this exercise, it was clear and easy for me to pitch this initiative to my executives.
Preliminary Study
- Methods: Samples were requested and tested for all 6 products. All lamination parameters remained unchanged for the purpose of keeping constants while testing the samples.
- Results: 1) Average removal time reduced from 6.5 minutes to 30 seconds, which would save 92.3% of removal time per shaft. 2) There were some issues with some samples not matching the exact same minimum expanded ID and maximum recovered ID of traditional FEP used, which led to poor surface quality.
Supplier Collaboration
I worked with our supplier for three months to understand, develop, and test different sizes of peelable heat shrink to ensure highest quality product is achieved. Multiple iterations of samples and testing have been made prior implementation.
Final Verification & Validation
A comprehensive lab notebook study for all 6 products were conducted with new peelable samples made by Junkosha. All devices produced using the new samples yielded optimal results for the catheter shafts.
As the preliminary study has stated, this peelable heat shrink material can be peeled straight without breakage, and therefore eliminates both the blisters and calluses. Also, average removal time reduction by 92.3% still applies.
Key Takeaway
The overall project was challenging but very rewarding to see how big of an impact that we’ve made for both the company and my workers.
- Business Impact: The cost savings associated with this project was estimated to be $1 million per year.
- Ergonomic Impact: People who are responsible for this heat shrink removal process brought big smiles on their faces because they no longer have to suffer any finger/hand pains and that they can do their jobs easier.
- Psychological Impact: Happiness within the workplace has increased since this new peelable heat shrink material was implemented in their daily process.
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