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Minitubes is the only major IVD probe supplier with in-house tube drawing capabilities…


Tapered tips, tip geometries, surface modification, fluoropolymer.

Tapered Tips

Proprietary techniques derived from tube drawing bring the smoothest finish on diameters as small as 0.20mm (.008″) and within the transition zones, unlike with the swaging technique.
There are no limitations on the number of steps nor on their length, permitting a wide range of sampling volumes on the same probe.

Close ID dimensional tolerances down to +/- 5µ and a typical 0.10µ Ra translate into precise and repeatable sampling.

Tip geometries

Droplet formation may be influenced by minimizing surface contact of the probe with the liquid.
This can be achieved through the tube tip dimension that can be further reduced by OD conical machining to obtain a minimal flat ring at the tip.

Surface Modification

Cleaning: a choice of cleaning / degreasing techniques are available to remove surface residues on the tubing and on the fabricated tubular components, using chlorinated solvents, isopropyl alcohol, water based compounds, etc.

  • Passivation: a chemical process promoting corrosion resistance by removing free iron traces and building a chromium oxide layer on the metal surface. Dynamic passivation involves circulation of nitric acid and deionized water within the tubing ID. We can certify to international  standards and to ISO 13485.
  • Electro-polishing: this electro-chemical process removes a thin layer of metal on the outside of the components, while improving the surface smoothness, brightness and cleanness. It improves corrosion resistance and modifies the surface energy that interacts with the liquids sampled.
  • Mechanical polishing by grinding or buffing cleans and improves the surface appearance.
  • ID slurry polishing improves the surface finish by circulating abrasive charged viscous pastes under pressure.
  • Sand / bead blasting modifies surface reflectivity and cleans heat affected zones from brazing or welding.
  • Coatings may be applied on the OD and the ID of probes to promote a choice of functional requirements:
    Drop control, protein adherence, metal ion diffusion barrier
    Surface hardening to facilitate cap piercing
    Electrical insulation, often in relation with level detection

A choice of coating formulation is available: various fluoropolymers with high anti adhesive and hydro-/oleophobic properties, inorganic-organic nanocomposites, silicone resins, hard chromium, titanium nitride, DLC, parylene, etc. We will be happy to discuss with you the coating options for your probe!

Fluoropolymer Lining

Combines the inert and lubricious polymer with the mechanical strength of the metal jacket. PTFE or FEP tubing is intimately bonded to the metallic probe down to its tip.

This solution eliminates any pinhole issue that might appear with polymer ID coating. The fluoropolymer tubing extends beyond the metal pipette top and may be flanged or assembled to a connector.


Our unique drawing processes will help you meet your technical and cost challenges. Tubes can be welded redrawn or seamless.

We offer tighter dimensional tolerances than available with any standard tubing thus increasing dispensing precision. Difficult specifications and tight tolerances (up to +/- 5 µ) are part of our daily routine.

We specialize in small diameter precision metal tubing. Our tubing can be produced in straight lengths or coils. The smallest ID is 50 µ, the largest OD is 15 mm (0.6 »). We manufacture thin wall tubing with exceptional precision, even in the largest diameters:

OD from 1,50 to 15 mm (0.06″ to 0.600″)
Wall from 0.05 to 1.5 mm (0.002″ to 0.060″)


Because stainless steel is not always the best answer to your requirements for corrosion and heat resistance, strength and magnetism, Minitubes’ expertise includes manufacturing tubes in more than 100 metals and alloys.

Stainless steel, 316LVM and reinforced nitrogen grade
Exceeds the standards requirements, notably for inclusions. A stock of more than 200 references, immediately available: 304, 304L, 305, 316, 316L, 316LVM, 316Ti, 321, 347, 904L.

Nickel and nickel alloys :
Ni 200, Ni 201, Monel®, Inconel® 600, 601, 625, x750, Ni-Cr 90/10, NiCr 80/20. For non-magnetic requirements and heat resistance.

Cobalt based alloys with strong mechanical properties
MP35N ® = Co-Ni-Cr-Mo combines high mechanical properties and a good ductility at the annealed state.
Phynox®, Elgiloy®,= Co-Cr-Ni-Mo-Fe. Very high yield point.
L605®, Alloy 25 ®- Alacrite XSH ® = Co-Cr-W-Ni-Fe.
Iron alloys
Such as carbon steel, Mumetal®, controlled expansion alloys (Invar®, N48, N52, FeNiCo)

Copper alloys
Such as OFHC copper, beryllium copper, cupro-nickel: for heating functions or electrical contacts.

Precious metals and their alloys
Gold, platinum, platinum iridium alloys, for radio-opacity and electric conductivity.

Implantable material

Our specialists are available to discuss with you your requirements


Control of surface smoothness, grain size and mechanical properties

The smoothest internal surface finish, even inside the smallest probe tip, as a result of in-house plug drawing capabilities: a key to eliminating many contamination problems and carry-over issues.

ID Ra < 0.2µm

Surface control: buffing, electro-polishing, dynamic passivation, hydrophobic coatings. We can tightly join fluoropolymer tubes within a metal sheath to combine the surface properties of the former with the strength of the latter.

316L MP35N Ni Inconel

316L MP35N Ni Inconel