How It’s Made – Hypodermic Needles

IS Needles logo

This is very similar to what I saw when I visited Industrial Strength LLC Sharp Ass Needles, without the hubs, followed by cleaning and chemical passivation. They are ready to be sterilized and used.IS needles sticker

We use 304 SST and keep on file for every lot of needles we make a passivation certificate. We also have an MSDS on our coating as well.

We follow ISO 9626 International standard for SST needle tubing, ISO 13485 International standard for Quality, ISO 1469 Quality System, GG-N-196 US Gov specifications for Hypodermic needles and ASTM A-05 (E1) passivation… and tender love and care :)

Maria Pinto, Industrial Strength LLC

An example of an excellent quality needle
Video thanks to Mike Hill of Broad Street Studio


To be clear: I want every manufacturer to meet fair and transparent standards. Sharps are essential to our trade, and the slight variations between manufacturers can be quantified.

Point configurations ASTM F1840

X1.1 Because there is a clinical need for a variety of surgical suture needles for surgical procedures, they are manufactured in various configurations and from various materials.

For practical purposes these devices supplied by different manufacturers necessitate a defined system of terms.

Penetration testing similar to what we might use is described by: ASTM F3014  Standard Test Method for Penetration Testing of Needles Used in Surgical Sutures


The purpose of this test method is to provide a common method for fixturing and measuring the penetration force of a surgical needle. Most surgical needles are coated to facilitate passage through tissue. This coating needs to be both lubricious and durable. The lubricity of the coating acts to lower the penetration force, while the durability of the coating maintains the needle’s ability to pass through tissue multiple times with minimum increase in penetration force. It has been observed that, when a coating is found to be more lubricious, that coating is often less durable. Likewise, when a coating is found to be more durable, that coating is often less lubricious. Comparative measurements of lubricity and durability can provide an expectation of how the coated needle may perform during actual use. This standard does not presently address the testing medium. Test medium will be addressed in the next phase of this test method development. However, this test method does require certain medium characteristics to be identified.

Katana Needles

I also received straightforward answers to my questions from the Katana manufacturer:

*How are the needles passivated after they are ground?

Google Translated :~Thank you for your help. Inquiry of matter, passivation is the passivation treatment of the needle. It is aimed at preventing corrosion by making an oxide film. For all the needles for your company this is carried out. We also do silicone coating. Our company has acquired ISO9001, ISO13485 certifications.~

Roughly translated, it says they passivate and silicone coat (another form of passivation) all their products, and that they meet ISO 9001 and ISO 13485 quality standards)

1. Purpose of passivating

Surface of metal, such as iron and aluminum, will become oxidized and produce very thin layer of acidic compound when exposed to air.

Red rust that is often observed on iron will continue to corrode the surface when left for some time if the metal is in vulnerable state, without any protection.

This corrosion will change the metal into a very weak, fragile structure.
The surface passivation layer of stainless steel alloy on the other hand is produced when exposed to oxygen, protecting the surface with this very thin layer.

We intentionally create this protective layer by adding the passivation process in production for our needles.

The structure of this protective surface is very intricate, blocks many of these external “damages” and allows the needle to become more stable.

2. How we evaluate

Our testing for passivation is done according to ISO9626 Annex D, or JIS T 0302 Standard.

Surface of subdermal needle tend to have large frictional resistance, due to the nature of the production process of the raw tubing and the surface characteristic of stainless steel.

This resistance causes the pain and irritation to the patient when inserting a needle into human body. Silicone coating is applied to reduce this penetration resistance.

*How is the Silicone coating applied?

The lubricant used for this coating is Dow Corning’s MDX4-4159. Diluent is added to the silicone prior to coating; needle will be dipped into the lubricant, and dried thoroughly to finish off the process.

As a result, the frictional resistance of the bevel and outer surface of the needle will be reduced, allowing the patient to feel less irritation during insertion.

Penetration resistance (sharpness) graph before and after coating is recorded.

Here is the MSDS from the Katana needles manufacturers.
The coating itself is:  DOW CORNING® MDX4-4159 50% MEDICAL GRADE DISPERSION

A Q&A supplement to the MSDS from Dow Corning answers more of the required questions.

*Was this coating specified for needles?

4. What are the principal healthcare applications for Dow Corning MDX4-4159, 50% Medical Grade Dispersion?

The product can be used for treatment of most substrates but is particularly useful for siliconization of reactive (metal) surfaces with which the functional groups on the silicone can bind. Indeed, it was patented principally for use to treat cutting edges such as stainless steel blades and has since become widely accepted for lubricating hypodermic needles.

*What sort of sterilization processes was the coating validated for?

12. Can articles treated with Dow Corning MDX4-4159, 50% Medical Grade Dispersion be sterilized, and by what methods?

Siliconized articles may be sterilized by the usual methods such as autoclaving, dry heat, radiation, and ethylene oxide (ETO). If ETO is used, proper out-gassing must be completed before the article is suitable for use. Sterilization should only be done on fully cured articles as excess moisture in such processes as autoclaving may inhibit the curing process if it is not complete.

Radiation may increase the rubbery nature of the coating and lubricity may change so users are encouraged to validate their treatment and sterilization conditions relative to their intended application(s).

I hope this clears every doubt on the quality of Katana needles.


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