PVD coatings in the salon industry
By Ian Desmond
Millions of pairs of PVD coated scissors are produced every month, here’s why.
PVD coatings stand up to most endurance tests and are now performing well at the sharp end – that is as a coating on scissors used in hairdressing salons and barbers.
Cutting to the quick; how are PVD coated shears better than simple stainless steel scissors?
The coating applied to the scissors is a layer of TiN (Titanium Nitride) by using the PVD metal coating process. With this coating the scissors become considerably more robust. The measured hardness of the TiN layer is something in the order of 2500 Vickers, which is around four times greater than that of tempered steel. Coating the surfaces with a layer of protective metallic vapours (such as with ionic plating, a PVD process) any tools can have their lifespan increased from 50% to 500%. In a nutshell the benefits of coating scissors can be summarised as: exceptional superficial hardness (1000-2500hv), high wear and abrasion resistance, resistance to UV ray exposure, resistance to solvents, acids, alkali and most household cleaning products. They are also more resistant to human sweat and if you have eczema problems while holding stainless steel shears, titanium-coated scissors are less likely to aggravate the condition. Importantly they are also ecological as the PVD process is environmental friendly since no pollutants are used.
Stainless steel scissors coated with a titanium thin film makes them not only more attractive but they do their job better gaining in sharpness. This sharpness or cutting edge if you like lasts longer if scissors are titanium coated. Scissors with titanium also look professional and eye-catching, they come in many colours, perhaps most strikingly, is rainbow coloured, but there’s also blue and golden titanium.
All barbers’ scissors which need to be coated are enclosed in a vacuum chamber. This vacuum chamber is then gently heated to a specific temperature. Deposition material such as titanium is vaporised by means of an electric arc. These now highly charged titanium ions are mixed with a nitrogen gas forming plasma. This positively charged titanium plasma is attracted to the negatively charged part to be coated. Ion by ion, the titanium bonds to the part, growing a thin, hard film on the surface. The intense plasma generated by the arc evaporation source continually bombards the substrates during the coating cycle.
By applying a coating the life of the products is extended meaning additional savings quickly add up from reduced replacement costs. Overhead costs associated with purchasing, receiving, and reconditioning also add to the overwhelming benefits of using coated products in the salon industry.
One study was carried out to test a recommended TiN coating’s performance when applied to a pair of scissors. It was unsure that the performance improvements reported for metal-cutting tools could be achieved in other items such as scissors. In one test, uncoated and coated scissors, made of 420 stainless steel, were both put through their paces. During the test scissors were automatically opened and closed repeatedly to simulate use, with cutting edges periodically checked for wear and rounding of the edges. Results showed that the uncoated scissors made an average of 12,000 cuts before the edges blunted. In comparison the coated scissors averaged 100,000 cuts before showing rounding and wear – an increase of a massive 800%.
The layer of TiN also gives good resistance to erosion and to chemical agents, far superior to uncoated steel, and in corrosion tests in saline mist chambers, the results obtained with this type of coating are even better than those with chrome coatings. This coating technology, as mentioned previously, is normally used in cutting and machining tools since it provides parts with greater resistance to wear and abrasion. However used for hairdressers’ scissors it can be used to help performance for example impede the sliding of the hair, to compensate the deviation of the cut and guaranteeing straight lines. Getting straight to the point – it’s a technology that brings results.