Day in the life of a process scientist

One of our Polymer Process Scientists, Dylan Crane, lifts the lid on a typical day working at FET.

Firstly, I am a Polymer process scientist who has been with the company for just under a year. Igraduated from the university of Strathclyde (Glasgow) with BSc chemistry with drug discovery. Since then, I have gained a wide knowledge of different extrusion processes from melt spinning to wet spinning. This is a typical day for myself and other employees here at FET.

  • Arrive at 8.30am, put on all required PPE (Lab coat, safety goggles, safety shoes). In the Fibre Development Centre, ensure that the melt spinning extruder is hot/heating, the polymer has dried correctly, spin pack is heating/hot, the lab area is clean and that all the modular components of the monofilament line are set and/or heating. This is vital as any of these can add a minimum of an hour delay.
  • If the extruder isn’t hot, the screw (if not already in) will no longer go in, the polymer will not be able to melt and travel and can lead to blockages – thankfully the solution is simple and just involves waiting for the extruder / screw to reach the correct temperature.
  • If the polymer hasn’t dried correctly it can lead to detrimental effects. This is due to the fact that if moisture is present, the tensile / elongation / quality of the fibre is significantly decreased. As drying is often 8 hours plus, it can often lead to the properties of the fibre not being optimised to the fullest ability of the polymers.
  • Go to the office on the mezzanine floor and check emails, ensure the run sheets and relevant information are placed into the trial folder.
  • Once the extruder/screw is hot, the system is purged with the polymer used that day (PDO) to remove all residual from previous trial days.
  • Once the machine has been purged, the spin pack is placed into the extruder, ensuring the spinneret is the correct orientation, as we were running a double-winged monofilament spinneret, and said spin pack is torqued to the correct level. If the spin pack is over torqued, the screws that hold the spin pack in the extruder can snap, which requires getting the hole tapped (drill the screw out of the hole and recurve the threads). If under torqued the polymer can leak, needing the whole pack removed and a fresh one added in its place as well as having to clean up the hot polymer. Thankfully these two issues are avoidable and can be fixed quickly if they occur. 
  • This is when the customers normally arrive – usually, we ask for around 10 am to allow us to ensure everything is in working order. They are greeted and offered refreshments and left to settle and confirm if the previously discussed plans are still the route they want to take.
  • Begin the threading up procedure to get the filament onto the winder to assess the initial denier / tensile values and therefore change conditions to amplify the original values to be closer to the targets set by the customers. 
  • Invite the customers in to talk through the line. Advise them about the original conditions and what we have changed to try and improve the yarn.
  • In this particular trial, we achieved the target properties within a couple of hours (which is not always the case!), so there were several hours to complete even more of the customer targets and show them how amending the conditions changes the yarn and how some targets are just not realistic without the fibre breaking. As this was using a double winged spinneret, it was important to use the microscope to ensure that the shape of the filament stayed the same throughout the drawing process.

Figure 1: Pouring the polymer into the hopper. (A stunt polymer was used in the image above as PDO is highly sensitive to moisture)


  • While the system was running efficiently, I moved to the other building to assist with a spun bond factory acceptance test.
  • To ensure the material was correct for spun bond an MFI was found. MFI is the melt flow index, meaning the grams of a polymer per 10 minutes in a known volume of space. We can either do this to find a specific value or to see how a polymer melts and draws. This is particularly useful when seeing how well a recycled polymer will extrude. 
  • Spun bond is very different to the monofilament melt spinning, as instead of the filament(s) going from the extruder (via an air quench zone) onto 5 pairs of godets and then on a winder, the filament(s) are split between four air aspirators, blown onto a conveyor belt passed through calendar roller (compresses fibre) and onto a winder.
  • It is also harder to thread up a spun bond machine as you have to ensure the air aspirators are all blowing at an even rate, as well as having to split the filaments by hand into the four aspirators. The operator has to ensure that filaments do not get tangled with each other and that it is done quickly to prevent the fibre being too large to go through the aspirator.
  • Once the filaments are lying nicely on the conveyor belt the next objective is to get the fibre through the calendar roller, ensuring that it is evenly pressed as this can be detrimental to the fibre.
  • Winder – in this trial the winder caused us lots of issues, as it would move throughout the run causing the yarn to sag or be too tight. Or the sample on it would get caught on the upcoming layer of yarn resulting in an uneven yarn.
  • Collect samples and close the machine off – purging excess polymer, removing spin pack and pulling screw. 
  • Return to original trial to review with the customers and discuss the next steps, ensure they are happy and say goodbye to customers, then packaging the samples made that day for despatch.


Figure 2: Testing the MFI of the spun bond material.

As you can see, days here are normally very busy and offer up a wide range of activities to complete. This really makes the days fly! As a scientist who had limited knowledge of the extrusion process and only some knowledge of polymers, the volume of information / processes to learn was large but very rewarding. Looking back to when I first started the difference in my knowledge is immense. 

Unlike a lot of roles which can be very repetitive, I enjoy my position at FET because there is a high level of variety in the day-to-day activities – preventing the job becoming monotonous. Although the constant variety often means you are carrying out (similar but ultimately new) practices, which can be challenging especially if it is a customer trial. However, these challenges stretch you professionally and increase your knowledge. Trials can also go wrong for reasons listed previously as well as a multitude of different reasons (as you can imagine in R&D) but this allows you to think on your feet and ultimately can aid the solution to future problems.


Figure 3: At the wrap wheel to find the denier of the yarn for the customer trial.

Challenges that occurred through this day were:

The most regular and obvious one is time, especially if things are not going to plan. Thankfully this particular day, time was not a major issue as both the trial and factory acceptance test ran semi-smoothly. 

The air aspirators for spun bond were causing twisting of fibre so difficult to separate into each of the respective aspirator tubes. The solution to this was that the tubes had to be modified by filing down the top section and ensuring that they were clean and even.

The calendar roller was causing slight updraft from the belt, which caused the yarn to snag onto the side of the belt and go through lopsided. To solve this the airflow was lowered and IR was introduced to anneal the yarn and keep it as a singular unit. 

Trying to stay on top of emails / enquiries while the trials are processing is also a challenge. This is more of an issue following a conference or event but can be any time of the year when a customer requires an immediate response.

For any other issues that I encounter where I can’t readily find a solution, it is greatly valued that FET is a multidisciplinary company, that contains members of staff with a vast wealth of knowledge and experience within the textile industry as well as the chemical and engineering industries.  

More positively, getting to follow a project from the initial enquiry to the happy customer at the end of their trials is very fulfilling, including having to solve the issues and think on your feet. I also enjoy getting to interact with a wide range of individuals from across the globe, who have acquired an extensive range of knowledge. It also makes you understand fully, how vast the industry is and realise how many applications that the fibre / machines produced by FET have. I also very much enjoy working with my colleagues as it is a very welcoming environment.