Dr. Olsen's Lab

OMAX offers two distinctly different computer-controlled tilting cutting heads for two distinctly different applications.  The A-Jet is designed to make beveled cuts at any angle specified by the user, ranging from vertical to 60 degrees from vertical.  It is ideal for applications such as weld preparation, cutting angled part features and creating beveled artwork.  The user simply specifies the angle of tilt desired on any given section of the part and the computer controller tilts the cutting head as needed as the part is being made.  The A-Jet is available as an option on either our high-precision OMAX systems or our industry-standard MAXIEM systems.  The Tilt-A-Jet, on the other hand, is designed to make the most accurate possible two-dimensional part in the least amount of time by automatically eliminating the natural taper found in an abrasive waterjet.  It utilizes a unique OMAX-developed computer model to determine in advance the anticipated natural taper in all segments of the planned part, depending on part geometry, material, thickness and jet parameters.  Then the Intelli-MAX controller automatically programs the precise angular motion of the Tilt-A-Jet to compensate for the computed taper.  In addition the controller can also program a “tilt forward” capability in the Tilt-A-Jet to maximize average cutting speed.  The Tilt-A-Jet hardware is designed to make relatively small angular motions with extremely high precision so that taper in a 1” thick piece of steel, for example, can be held to less than +/-0.001”.  The Tilt-A-Jet is available as an option only on our high-precision OMAX cutting systems.

OMAX Tilt-A-Jet Nozzle and OMAX A-Jet Nozzle

I have often been asked why OMAX doesn’t just make a single tilting head to accomplish both bevel cutting and taper elimination.  The answer is simple:  A system designed to accomplish both tasks is not really very good at either.  Bevel cutting requires a very wide range of angular motion while taper elimination requires very precise angular control over a much smaller range of motion.  A little bit of trigonometry shows the inherent problem in providing both in the same system.  A claimed angular accuracy of “better than +/- 1 degree” sounds pretty good and might be fine for cutting beveled surfaces.  However the dimensional offset caused by taper angle can be calculated using the equation

Taper offset = (material thickness) X (tangent of taper angle)

Using this equation we can compute that an angular accuracy of +/- 1 degree means +/-0.017 inches of taper in a piece of 1″ thick material.  This level of angular control is totally unsuitable for taper compensation.  Indeed, one is better off with no compensation at all!  Similarly a claimed accuracy of “20 minutes of arc” also sound pretty good until you realize that 20 minutes of arc is 0.33 degrees, which translates into 0.006″ of taper in a piece of 1″ thick material–still not nearly good enough for taper control.  When you are trying to design a tilting system with the accuracy needed for +/-0.001” of taper in 1” thick material, you are looking at a necessary angular accuracy of better than +/-0.06 degrees!  This is virtually impossible in a bevel-cutting mechanism that is also required to quickly move +/- 60 degrees.  Thus either taper-control accuracy or bevel-cutting speed or both must be compromised.

A Swiss Army knife can be an OK thing.  It can be used as a knife or a can opener.  However it is most certainly not the best available knife nor is it the best available can opener.   For optimum performance one needs two different tools for two different applications.  So it is with tilting abrasive waterjet cutting heads.  That is why OMAX offers two options—the A-Jet for bevel cutting and the Tilt-A-Jet for precision taper control.