It’s ironic how quickly perspectives can change. In February life was normal. We were going about our daily lives meeting customer deadlines, rolling out the next product upgrade and planning the summer vacations. Suddenly, COVID-19 appears and we find ourselves worrying about loved ones, our jobs and community.
When the initial shock wore off, many of us in the plastics industry began thinking of ways to help the frontline doctors, nurses, caregivers and even the grocery store clerks. Several have switched production over to manufacturing masks, face shields, ventilators and other devices. Each company was put into a position to analyze what its strengths are and how those capabilities can be adapted to produce critical components.
If you are still contemplating how you can contribute, here’s a case study of what we, at PTI did. We hope it will spark some creativity of your own.
Because we design, manufacture, mold and test plastic packaging, we quickly identified that we could design a face shield, manufacture a mold and produce parts.
Step 1
Of course, in order to be most relevant, speed was critical. To avoid starting from scratch and bumbling through iterations, we reached out to healthcare industry professionals who guided us to readily available face shield designs. To our amazement, we found actual editable CAD files ready for download.
Step 2
We quickly put together a team of designers, analysts, machinists and plastic processing experts to guide us. During the first couple of days we furiously worked remotely to select the best face shield CAD design, and then 3D printed and tweaked it to produce a viable part.
Step 3
We relied on our partners who jumped in with support:
Tekni-Plex donated 10,000 feet of extruded PET sheet in various thicknesses so that we could validate what worked best;
Braskem donated polypropylene resin which we used to produce headband fixtures.
Dana Corp. helped us modify and simplify the shield design so that we could puncture the PET sheet to accept the headband with a commonly available three-hole file puncher.
We went through a couple of iterations to make sure the headband was the right fit around the forehead and nose, and even comfortable for someone wearing glasses. For the most part, we were able to execute this step remotely.
Step 4
The real challenge was building the mold. Do we build it in aluminum, which is easily machinable? The downside is that the metal’s softer properties were more prone to damage if a stubborn part needed to be extricated from the mold. On the other hand, making it of steel implied longer machining time. (We have learned to always keep an extra stock of molding material in our tool shop because that specialized shipment takes time.)
Machining a 250-pound stack of steel while social distancing is a challenge where you cannot ask for a helping hand to lift or move it into the correct alignment. A wrong move or drop would push you days behind. In the end the steel mold was persisted with as a better choice for longevity of the tool and potential number of molded parts.
Step 5
Six days after receipt of the mold material, the mold was finally installed into the machine. The barrel heaters came on and the ejector pins tried to thrust the part off the cavity, but it would not budge. Vice grips were needed to pull the distorted part out. However, the processing experts did not give up. Changing the mold temperatures and hold pressures did the trick. The solution worked beautifully and even optimized cycle time to 26 seconds.
For two days, the team worked to trim the gate, cut the shields to size and punched the holes.
Step 6: The Finish
The result was more than 4,000 completed shields delivered to healthcare facilities in Northwest Ohio. This included ProMedica, UT Medical College of Ohio, The Toledo Clinic, St. Luke’s and St. Vincent.
Ultimately it is a dedicated team that gets you across the finish line. It also forges an even stronger bond between the employees and the community and that’s what makes it such a worthwhile effort.
Author: Sumit Mukherjee is the chief technology officer of PTI. He has 25 years of experience in
package design, materials characterization, process simulation and modeling, and finite element analysis (FEA) for package performance prediction.
About PTI
PTI is recognized worldwide as a major source for preform and package design, package development, rapid prototyping, pre-production prototyping, and material evaluation engineering for the plastic packaging industry. For more information: www.pti-usa.com.
