What makes a technology take hold?  Technologies come and go; even some that seemed so permanent at the time, such as kerosene lamps, typerwriters and record albums. One of the reasons waterjet has remained one of the fastest growing major machine tool processes in the world for the past 20 years is due to adaptability.  The waterjet process was invented in the 50’s by Dr. Norman Franz, but it didn’t begin commercial use until the 70’s with the explosion of disposable diapers (which in this case is a good thing).

Then ultrahigh-pressure water was adapted to hard material cutting (metal, stone, composites, ceramics) with the invention of the abrasive waterjet in the late 70’s, really beginning industrial use in the mid 80’s. This important technology was invented by a team of engineers and research scientists led by Dr. Mohamed Hashish.  Here is a brief excerpt of the abrasive waterjet master’s tale.

Mohamed first became interested in waterjets when on a PhD scholarship in 1973 at Concordia University in Montreal, Canada.  He happened across an article using waterjets for mining, became intrigued, and true to his nature started digging for more knowledge. Digging uncovered the 1972 BHR proceedings on the first conference ever on waterjet.  The topic interested him so much that he changed his PhD topic to fluidics on waterjet cutting (how cool is that).

“I finish my PhD in 1977 on the theory of waterjet cutting and developed several models for the process.  In order to perform experiments, I built a waterjet system using air driven commercial pumps.  I ganged four pumps to get enough flow rate to power a 0.005 inch jet at 50,000 psi.”

Since that time I can tell you Mohamed has never lost his excitement or enthusiasm for ultrahigh-pressure waterjet technology.  Let’s put this into perspective.  Mohamed has developed more basic physical models for waterjet and abrasive waterjet than anyone else in the world.  You can’t open a current waterjet technology paper without reference to Mohamed half a dozen times.  His work is foundational; with 42 waterjet patents, and even more on the way.

OK, story time.  Here’s Mohamed’s story of trying to make the first abrasive waterjet.

“My first try making an abrasive waterjet was while I was writing my thesis on the theory of waterjet cutting.  I was going home around 8:30 PM and somehow I noticed the shiny material in the ash tray next to the elevator.  My Styrofoam coffee cup was almost empty.  I quickly finished the rest of the coffee and scooped some of this shiny material into the cup.  Instead of going down to the lobby, I went to the basement where the waterjet machine was.  I fired it up and put a piece of wood under the jet to pierce it and repeated the same test with the grit-filled Styrofoam cup in between the nozzle and the wood.  It went faster through the wood but made some mess.  I knew then what I wanted to do after I finished my degree.  I made a list to Flow Research about many projects that I would like to do if I joined them.  On the top of the list was adding abrasives to the jet.  There were many other ridiculous ideas that I do not want to ever mention.

“I approached the Late Dr. Mike Pao (then the CEO of Flow Industries) about the need to cut steel, concrete, and hard materials by adding abrasives to the waterjet.  He was skeptical, but I made a bet with him.  I asked for a 3 months period to try to make a working abrasive laden waterjet. We won the bet: a dinner for me and my wife.  At that dinner, I gave him a piece of steel with his name crudely cut in Chinese.”

In a previous post about Eckhart Ulrich I briefly covered the cutting of thick glass mirror cores for deep space telescopes.  To add even more color to that interesting story, let’s hear Mohamed’s glass cutting story.

“The late Dave Crow of Kodak Government Systems was a true champion of waterjets.  He heard about this new tool that can cut glass and was fascinated.  He was also influential at Kodak.  After working on some projects with him for a year, he expressed his true interest was to cut very thick glass (12 inch) for space optics mirror cores and that the only way he can move this through his government sponsor is to cut him a demo part: he called it a 6-way.  It contained six triangular cells with 0.020 rib thickness.  He told me, please write me a proposal to demonstrate this technology.  I did.  When he reviewed it, he said I will double this amount but I want you to spare no idea or effort to deliver.  At that time only Steve Craigen and I were under the gun to deliver.  We didn’t even have the talents of Eck on the project yet.  We had to build a 24 inch long mixing tube to cut through the glass straight enough to produce a good surface.  There was lots of taper and bad corners and we wished we could “tilt” the nozzle.  I blew the double budget but cut the part and was completely forgiven.  Ultimately, we got the contract to build the machine and cut the glass.  The machine, with some updates of course, is still in operation today at a different facility.”

Every successful technology that adapts and lasts for the long haul has people with the guts to try and talent to deliver.  I have been lucky enough to know some of them.

Hope this was of interest.  As usual, please send comments and suggestions for future posts.
chip