Ceramic blades in safety knives are safer than steel blades – right? Well, not necessarily. Nick Grinnell explains why…
The term ‘safety knife’ can be somewhat misleading, as – in reality – many of the products labelled as safety knives could never be described as 100% ‘safe’.
At the end of the day, we’re talking about cutting tools with sharp blades, so there is always going to be a risk when using them that you cut your skin in the process.
Or is there?
A safer safety knife
At iSB Group, a lot of the cutting tools we recommend to our customers are made by Slice® - an award-winning company known for its trademark finger-friendly® ceramic-bladed safety cutters.
The company prides itself on creating easy-to-use and ergonomically-designed safety knives that reduce all the risks of injury and accidents associated with using cutting tools.
But this isn’t just down to their ceramic blades – it is due to the way in which those blades are designed.
Ceramic vs steel in safety knife blades: which is safer?
Ceramic blades have become increasingly popular over the past few years, whether that’s in the craft or even kitchen knives we use at home, or the cutting tools we use at work. But what exactly is a ceramic blade, and is it any safer than a steel one?
When most people think of ceramics, they might picture something fragile like pottery or porcelain, but there is a high-tech sub-category of ‘engineered’ or ‘advanced’ ceramics that perform highly in industrial applications.
One of these is zirconium oxide, which is lightweight yet incredibly hard, chemically-inert, non-conducting, non-magnetic, and capable of withstanding heat up to 1,600°c. Because it is naturally so hard, it doesn’t need to be sharpened as much as steel in order to cut materials and have a useful shelf life – but it does need to be sharpened in the right way in order to be safer than steel blades.
How sharp does a safety knife blade need to be?
The answer to this question is: less sharp than you think.
Traditional metal safety knife blades are made from steel, a relatively soft material that dulls very quickly. So, in order to give steel knife blades a useful working life, manufacturers sharpen them far beyond what is necessary to effectively cut materials. Steel blades are thin, with a long, double-edged initial cutting zone, so the entirety of the blade forms the primary cutting edge. This means that it doesn’t take much for them to cut skin.
Because advanced ceramics like zirconium oxide are so hard, a ceramic blade will not only be sharper than steel, but will stay sharp for longer. This makes ceramic blades sharpened in this way more dangerous than steel blades.
Blade retraction mechanisms, caps and guards can only offer so much in the way of protection, and they do nothing to safeguard against injury when changing or maintaining the blades.
Why doesn’t it cut you? The science behind the Slice® blade
Slice® ceramic blades are safe to touch and handle. They cut materials with ease, but resist cutting skin. In fact, you could run one over the surface of a balloon and it wouldn’t pop.
How is this possible?
Slice® signature finger-friendly® blades are thicker than standard safety knife blades, and ground in such a way that they have two different angled cutting edges: a micro-edge to make the initial cut, and a primary edge for further cutting capability.
The micro-edge – the most dangerous part of the blade – is very small, and has a wider cutting angle which ensures cutting force is displaced in the event of it coming into contact with skin. This makes it very difficult to cut yourself, with much more force than usual required, meaning the likelihood of sustaining an accidental injury while using or handling a Slice® blade is incredibly low.
If you currently use ceramic blades or are being told to use ceramic blades because ‘they are safer’ check how they have been sharpened because it’s likely they be as unsafe as steel blades for longer.
Speak to us if you’re unsure or want to trial Slice® knives in your workplace.
For more information on the Slice® range, you can check out our dedicated web pages here.