Applications

Medical Tubing Extrusion Line

A medical tubing extrusion line produces catheter and clinical tubing to a tolerance the rest of the extrusion industry never has to meet: an outer diameter held within ±0.01 mm, on bores from 0.8 mm to 17 mm, at line speeds up to 150 m/min. Single-lumen, multi-lumen and multilayer structures all come off the same line with a different die head.

What separates a medical line from an industrial one is not precision alone. It is that the line has to find the defect itself. A tube that drifts out of tolerance cannot be caught at final inspection, because by then it is inside a sterile pack heading for a patient, so a closed-loop laser gauge measures continuously and the line rejects the length before it reaches the winder.

Tell us the lumen layout, the inside diameter, and the material. Those three answers set the die head, the sizing tank and whether the line needs a second extruder before anything else is specified.

Single-Lumen, Multi-Lumen or Multilayer: Three Constructions

Almost every medical tubing enquiry resolves to one of three constructions, and the construction decides the die head and the number of extruders. It is worth settling first:

Construction	What it does	Typical device
Single-lumen	One continuous bore	Infusion sets, gastric and drainage tubes
Multi-lumen	Several isolated channels in one wall	Central venous catheters, guide-wire channels, dialysis
Multilayer	Two or three co-extruded walls	Light-shielding, antibacterial, soft-tip and lubricious constructions

Multi-lumen is where the difficulty jumps. A single bore only has to be round and concentric; several channels in one wall have to hold their individual dimensions and their positions relative to each other, and the webs between them are the thinnest material on the line. Multilayer adds a second extruder and a second melt stream into the same die head, which is how an opaque outer wall or an antibacterial inner surface is produced in one pass rather than two.

What a Medical Tubing Line Produces

One line covers a wide range of clinical devices, separated by lumen layout and compound rather than by the machine:

Vascular and central venous catheters. Multi-lumen, the tightest tolerance work on the line.
Infusion and transfusion tubing. Single-lumen, high volume, where line speed decides cost per meter.
Anesthesia, endotracheal and gastric tubes. Larger bores with wall flexibility specified to the procedure.
Urinary catheters and dialysis tubing. Long runs with surface finish as critical as dimension.
Drainage, perforated and multi-lumen specialty tubes. Often with a guide-wire channel.
Multilayer and light-shielding tubing. Co-extruded for photosensitive drug delivery.

The line runs PVC, polyurethane (PU), thermoplastic elastomer (TPE), polyethylene (PE) and ethylene vinyl acetate (EVA). Material affects more than the compound cost: a soft TPE tube behaves differently at the sizing tank than a rigid PVC one, so the cooling and the haul-off are set per material rather than once per line.

How Medical Tubing Is Made

A complete medical tubing line runs six stations, and on each one the medical requirement is different from the industrial equivalent:

Drying and feeding. Medical-grade resin is dried and dosed automatically. Contamination control starts here, which is why the feed path is stainless steel and the design is anti-static rather than simply enclosed.
Extruder. Single or twin screw, with an auxiliary extruder when the structure is multilayer. Multi-zone temperature control keeps the melt stable, because on a 0.8 mm bore a small temperature swing is a large percentage of the wall.
Die head and sizing. Single-lumen, multi-lumen or multilayer die heads combined with low-pressure vacuum sizing. Vacuum level here sets both outer diameter and, on multi-lumen, whether the internal webs hold their position.
Cooling. Vacuum or water tanks with spray cooling, in stainless steel. Cooling is staged rather than rapid, because a tube chilled too fast holds stress that shows up later as curl on the coil.
Servo haul-off. Closed-loop servo control matched to extruder output. Speed stability translates directly into wall thickness, and the servo loop is what holds ±0.03 mm across a full run.
Cutting, winding and inspection. Planetary cutting for fixed-length or continuous cuts, with a dual-station oscillating winder. A closed-loop laser diameter gauge measures throughout and the PLC adjusts screw and haul-off speed in real time, rejecting any length outside tolerance.

Because the finished tube goes into a clean-room assembly process, the line is built for that environment: stainless steel and corrosion-resistant alloys on every contact part, anti-static and dust-controlled design, and a control system that stores recipes and logs production data for traceability. We have supplied medical extrusion equipment for over twenty years to customers in Asia, Europe and the Americas with GMP and ISO compliance requirements.

FAQ

What is a medical tubing extrusion line?

It melts medical-grade polymer and forms it through a die head into catheter or clinical tubing, sized under vacuum and measured by laser throughout. Six stations, from drying to cutting and winding.

Single-lumen or multi-lumen?

Single-lumen suits infusion and general drainage. Multi-lumen carries several isolated channels or a guide wire in one wall, and is used for central venous, dialysis and multifunctional catheters.

What tolerance can the line hold?

Outer diameter within ±0.01 mm, and ±0.03 mm across a full production run, on inside diameters from 0.8 mm to 17 mm. Closed-loop laser measurement and vacuum sizing hold both.

Why does the line measure and reject in real time?

Because a medical tube cannot be checked after packing. The laser gauge feeds the PLC, which corrects screw and haul-off speed continuously and rejects any length that drifts outside tolerance.

Can it produce multilayer or light-shielding tubing?

Yes, through co-extrusion. A second melt stream in the same die head builds a dual or triple wall, which is how opaque outer layers and antibacterial inner surfaces are made in one pass.

What do you need to quote a line?

Three things: the lumen layout, the inside diameter, and the material. Tell us your output target and clean-room requirement and we will confirm the die head and downstream configuration.