Custom PTFE Tubing for Endoscopy: Flexibility and Lubricity Explained

If you are in the business of designing endoscopes, you know the drill. You need a working channel that offers virtually zero resistance, but you also need the tube to navigate the tortuous path of the GI tract without kinking or collapsing. It’s the classic engineering headache: the battle between pushability and trackability.

At Teflon X, we’ve spent years arguing with physics to get this balance right. We aren’t just extruding plastic; we are crafting the veins of minimally invasive surgery. Today, I want to cut through the marketing fluff and talk about the real science behind Custom PTFE Tubing, why friction is your enemy, and how we actually solve these problems on the production floor.

The Friction Addiction: Why PTFE Wins Every Time

You’ve probably looked at FEP or PFA. Maybe you even considered HDPE for a second before realizing it can’t handle the heat. But you always come back to PTFE (Polytetrafluoroethylene). Why?

Because friction is a killer in endoscopy.

When a doctor is manipulating a bronchoscope or a colonoscope, tactile feedback is everything. If the liner has high friction, the “slip-stick” phenomenon occurs. The instrument jerks. Precise movement becomes impossible.

Here is the math that governs our lives in medical extrusion:

F = u * N

Where:

• F is the Force of friction (what you are fighting against).
• u (mu) is the Coefficient of Friction (COF).
• N is the Normal force (the pressure of the instrument against the wall).

In a curved endoscope, N increases dramatically at every bend. If u isn’t as low as humanly possible, F sky-rockets.

PTFE is the only material that gives you a static coefficient of friction around 0.05 to 0.1. That is nearly as slippery as wet ice on wet ice. Nothing else comes close. FEP is great, but its COF hovers around 0.2. That difference sounds small, but over a 2-meter working channel, it’s the difference between a smooth procedure and a device that fails in the field.

The Flexibility Trade-Off: Don’t Kink It

Here is the controversial part that some suppliers won’t tell you: Pure PTFE is naturally stiff.

Yes, it’s lubricous, but if you just extrude a thick chunk of it, it’s going to be rigid. In endoscopy, rigidity is dangerous. You need the tube to bend with the scope.

So, how do we make PTFE tubing flexible enough for a distal tip deflection of 180 degrees?

1. Wall Thickness is King

We have to push the limits of extrusion. We aren’t talking about standard plumbing here. We are talking about ultra-thin walls. For endoscope channels, we frequently extrude liners with walls as thin as 0.001 inches (0.0254 mm).

Reducing the wall thickness reduces the “moment of inertia” of the tube cross-section, drastically lowering the flexural modulus (stiffness) of the final assembly.

2. The Etching Factor

You can’t just shove a PTFE liner into a braided catheter and hope it stays. PTFE hates sticking to things. That’s its whole point. To bond it to the outer jacket (usually Pebax or Nylon), we have to chemically etch the surface.

At Teflon X, we use a sodium-naphthalene complex etching process. It rips fluorine atoms off the surface, leaving a carbonaceous layer that adhesives can actually grab onto.

Pro Tip: If your current supplier is sending you etched tubing that looks patchy or light brown instead of a consistent dark brown, send it back. Bad etching creates delamination, and delamination causes the liner to collapse inside the patient. Not good.

Real Data: PTFE vs. The Competitors

I hate generic statements, so let’s look at the actual numbers we see in the lab.

Property	PTFE (Teflon X Custom)	FEP	PFA	Nylon 12
Coefficient of Friction (Static)	0.05 – 0.10	0.20 – 0.25	0.20 – 0.25	> 0.40
Melting Point	327°C (621°F)	260°C (500°F)	305°C (581°F)	178°C (352°F)
Flexural Modulus (Stiffness)	~0.5 GPa	~0.6 GPa	~0.6 GPa	~1.2 GPa
Sterilization Resistance	Excellent (EtO, Autoclave)	Good	Good	Fair
Biocompatibility	USP Class VI	USP Class VI	USP Class VI	Varies

You can see why low friction tubing almost always implies PTFE in this industry. Nylon is too sticky; FEP is too stiff for the extreme distal ends.

Case Study: The “Jittery” Biopsy Forceps

I want to share a story (names changed, obviously) about a client we helped recently. Let’s call them “ScopeCo.”

ScopeCo was developing a new duodenoscope for ERCP procedures. They were using a standard off-the-shelf PTFE liner from a general industrial supplier.

The Problem:
During the elevator mechanism activation (the part that lifts the tool), the biopsy forceps were stuttering. The doctors complained about “loss of fine control.” The supplier told them, “It’s PTFE, it’s slippery, it should work.”

The Teflon X Diagnosis:
We requested samples and put them under the microscope. Two things were wrong:

1. Inner Surface Roughness: The previous extruder was running their RAM extruder too fast. This caused “bambooing” or melt fracture on the ID (Inner Diameter). It wasn’t smooth; it was microscopically ribbed.
2. Tolerance Slop: The ID tolerance was +/- 0.003″. That’s too loose. The gap between the tool and the wall was varying, causing the tool to rattle and bind.

The Solution:
We re-engineered the PTFE Tubes using a slower sintering profile and tighter tooling.

• We achieved an ID surface finish of < 16 Ra (micro-inches).
• We tightened the ID tolerance to +/- 0.001″.

The Result:
The stutter disappeared. The actuation force dropped by 35%. ScopeCo moved to full production with us three months later.

Manufacturing: It’s Not Just Melting Plastic

A lot of buyers don’t realize that you don’t screw-extrude PTFE like you do PVC. You can’t. It doesn’t melt and flow like honey; it turns into a thick gel.

We use RAM Extrusion. Think of it like a giant, high-pressure syringe. We mix fine PTFE powder with a lubricant (naphtha), compress it into a billet, and ram it through a die.

Then comes the oven. We have to sinter (bake) the tube to burn off the lube and fuse the particles.

Why does this matter to you?
Because if the sintering temp is off by even a few degrees, you get “uncured” tubing that is weak and chalky, or “over-cured” tubing that degrades and creates particles. Particle generation in a medical device is a massive FDA red flag.

We monitor our temperature profiles 24/7. It’s boring work, but it ensures that when you get a shipment from Teflon X, it’s fully sintered and clean.

Customization Options for Endoscopy

We don’t really do “standard” here. Most of what we ship is built to a print. Here is what we are seeing demand for in 2024 and 2025:

Multi-Lumen Tubing

Single lumen is easy. But now engineers want 3, 4, or even 7 lumens in a single PTFE tube profile. One for the camera wire, one for water, one for air, one for the tool. Maintaining thin walls between these lumens without them blowing out during extrusion is an art form.

Radiopacity

Sometimes you need to see the tube under X-ray (fluoroscopy). We can blend Barium Sulfate (BaSO4) or Bismuth Trioxide into the PTFE paste before extrusion. Usually, a 20% loading gives you good visibility without ruining the mechanical properties.

Tie-Layers

For advanced catheter construction, we can co-extrude (well, technically co-process) layers, or provide etched liners ready for reflow with Pebax jackets.

FAQ: Questions We Get Asked Daily

Let’s Solve Your Tubing Headache

Look, sourcing components for medical devices is stressful. You have ISO standards to meet, FDA 510(k) submissions to file, and engineers breathing down your neck about “tactile feel.”

You don’t need a vendor who just sells plastic straws. You need a partner who understands medical extrusion.

At Teflon X, we specialize in the hard stuff. The tight tolerances. The thin walls. The custom profiles that other extrusion houses decline.

If you are working on a next-gen endoscope or just sick of your current liner failing QC, reach out to us. I’d love to take a look at your drawings and see if we can shave off that friction.

Ready to talk specs?

• Visit our product page:Check out our PTFE Tubes
• Drop me an email directly: Allison.Ye@teflonx.com
• Contact us via the web:https://teflonx.com/contact-us/

Don’t let friction kill your device’s performance. Let’s get it smooth.