Allfi Waterjet - Sintered Diamonds vs Single-Crystal vs Sapphire - what's best?

Posted by David Wootton on

In the past, orifices used for waterjet cutting and many other high-pressure applications (those over 55,000psi) were a trade-off between life and cost. 

If you were OK with changing orifices out more often, sapphires or ruby orifices (all lab-grown) are cheap – most sell between $13.50 and $24.50.  But good sapphires rarely last 100 hours and most are usually worn out or fail in less than 50 hours.  I once watched three 0.005” sapphires in a row fail right out of the box from another supplier – hardly inspiring.  Sapphire is a softer mineral than diamond and is very susceptible to damage from abrasive particles or metal fragments – which leads to immediate failure.

If you wanted an orifice that would last over 100 hours you were limited to single-crystal diamonds, either mined (natural) or lab-grown. These usually last from 500-800 hours and we regularly hear about 1,000+ hour diamond orifices.  They are pretty expensive however, with orifices from most suppliers in the industry starting at around $400 and going up to $500 or more.  As you might imagine, water quality is really important with a $500 diamond – getting hit with a particle of abrasive or a piece of metal can shatter a single-crystal diamond and flush your investment right into the tank well before it wears out.

Advances in sintering very small diamond particles using heat and pressure has resulted in a material with the good wear characteristics of a diamond orifice, but without the breakage issues of single-crystal diamonds.  Since there are no cleavage planes in a sintered diamond it reacts more like concrete to getting hit by a particle of abrasive – it might chip, but won’t shatter, where single-crystal diamond breaks along the cleavage planes that are part of its structure.  So basically, a sintered diamond orifice is tougher than a single-crystal orifice but keeps the hardness and wear resistance.

Because sintered diamond uses very small man-made diamond particles that are cheaper to create, it is much less expensive to produce.  Allfi Waterjet, Inc. NanoDiamond orifices use nano-sized diamond particles bonded together with heat and pressure (not binders like those found in PCD tooling) into a solid diamond material.  These orifices promise the long-life of a single-crystal diamond, with much less risk of early failure or breakage, at a much more economical price.  As a special, introductory offer we are selling these orifices for $120/each through July – after that our regular price will be right around $200, still less than half the price of a single-crystal diamond.  Available in multiple mount types (OMAX style, Flow style, Accustream style, KMT style, etc.) and sizes.  For information or to place an order go to, or call us at 816-429-6507.

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