Insulin Pump Case Study


Imagine This: A brand new insulin pump device Product Manager on track to make an aggressive product launch deadline. Everything humming along till... The device starts failing.

Inconsistent plunger forces are causing variability in dosage accuracy. If that isn't bad enough -- high absolute plunger forces are requiring excess power to operate the pump. They changed plunger geometry... it didn't work. (Hint: the solution was something most medical device R&D leaders don't think about but can cause an insulin pump or artificial pancreas device to fail).


A medical device company, developing a continuous infusion pump for insulin delivery for Type II diabetes thought they were on schedule for their much-anticipated product launch. 

The cartridge was a user-filled insulin container with elastomer plunger seals.

Silicone oil was used as the lubricant to facilitate the movement of the plunger. 


1. Inconsistent plunger forces causing variability in dosage accuracy.

2. High absolute plunger forces requiring excess power to operate the pump.

The client had already tried optimization of the cartridge geometry and plunger interference.

Our testing revealed that the lubricant was being displaced by the compressive forces between the plunger and barrel.

This caused the stick-slip movement of the plunger, leading to variability in dosage accuracy.

TriboGlide-DS® Proof of Concept (1-month)

TriboFilm demonstrated the feasibility of replacing the cartridge lubricant with the TriboGlide-DS® immobilized lubricant system. The initial feasibility was demonstrated on a lab scale setup.

The plasma crosslinked PFPE lubricant was immobilized on the surface of the cartridge, which prevented its displacement under plunger compressive forces. The result was a uniform extrusion force independent of the plunger movement speed.

TriboGlide-DS® Scale up to Pilot Scale (9-months)

1st level of scale-up involved a semi-automated rotary dial machine that integrated all three process steps for the TriboGlide-DS® technology. The machine had a limited throughput of 10 parts per min and required manual operation for loading and unloading of parts.

The pilot machine was built by Midwest Engineered Systems (MWES), WI.

TriboGlide-DS® Manufacturing Scale (18 months)

Since MWES had built the initial pilot machine the client elected to have them build the manufacturing scale machine. The fully automated machine had a throughput of up to 30 parts per minute.

Click here to view a video of the fully Automated Machine Built by Midwest Engineered Systems (MWES), WI, for TriboFilm’s Device Client.

Image 1: Automated bowl feeder

Image 2: Rotary Dial Indexing System

Image 3b: TriboGlide-DS Downstream Atmospheric Plasma process.

Image 4: ZebraSci Vision System for 100% parts inspection for verification of coating uniformity.

This machine is a fully automated solution which included:

Bowl Feeder – A vibratory bowl was used to feed the parts to the machine and also orient the parts automatically in the correct orientation.

Dial Assembly – A servo indexing rotary dial indexing system moved the parts through the coating process.

Ionizers – Ionizers were used to blow-off and dust particles and dissipate static charges prior to the coating process.

TriboGlide-DS® Pretreatment and Final Plasma Stations – The TriboGlide-DS® process utilizes a downstream gas plasma at atmospheric pressure. The plasma steps are performed before application of PFPE lubricant to activate the surface and then once again after the PFPE application to complete the crosslinking reaction.

IVEK Sonicair® spray station – TriboFilm partnered with IVEK Corporation to use their Sonicair® lubricant spray system to precisely control the location and amount of the PFPE lubricant sprayed into the cartridge.

ZebraSci Vision System – To ensure uniformity of the lubricant spray the machine integrated the ZebraSci vision system for 100% parts inspection to verify the consistency of the spray process.

If you're in the process of bringing a medical device (or a prefilled syringe) to market, watch the video below to find out how we can help you de-risk your lubricant choice so that it doesn't delay your product launch (or waste millions in recalls): 
We use a data-driven approach to selecting lubricants using a process called the Battle of the Lubricants. Watch the video below to see how we help reduce forces and particles, and improve your chances of launching your combination device, patch pump, or prefilled container on time and on schedule: 


Set up a no-obligation consultation to discuss your specific medical device with us in total confidence.

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We look forward to our conversation!

Jackson Thornton

Dr. Jackson Thornton

Vinay Sakhrani

Recommended Reading: 

Problems We Solve > Forces


If you are struggling with protein aggregation, glass delamination, or inconsistent forces in your pre-filled container or device, set up a no-obligation call with us. Whether our solution is right for you or not, we do our best to point you in the right direction. With over 18 years in the industry, we can often save you time and money by connecting you to the right solution for your specific challenge. We respond within ONE business day to all requests.