Water jet machines come in a myriad of shapes, sizes, and styles, with numerous features, for a variety of applications. Waterjet cutting systems are much like other shape cutting systems utilizing computer controlled motion and post processing of tool paths, for precision cutting. The versatility of water jet machines make them ideal for cutting a wide range of materials, rubbers, plastics, stone, tiles, composites and even pre-hardened materials, making them useful in servicing all industries. For the OEM or job shop proposing the purchase of an abrasive waterjet cutting system, an important question to consider; how many cutting heads will I need? Most of the smaller and less expensive waterjet cutting systems use one cutting head, while larger and thusly more expensive water jet machines can include multi-head configurations.
The production environment in general differs largely between OEMs and job shops. OEMs might typically process a limited number of shapes and materials at a higher volume, while job shops might typically produce a large variation of shapes and materials, at a reduced volume. It’s easy to see that job shops have less need in general for multi-head systems when compared to OEMs. The single largest reason why a job shop would want a multi-head waterjet cutting system is to turnaround parts faster; lowering unit price (time is money); thus giving them a slight competitive advantage. Obviously, the drawback becomes the higher costs associated with larger equipment and then added costs for operation and consumables. A nice fit for a job shop is the dual-head configuration.
When comparing single-head cutting to multi-head cutting, some key factors to consider include tolerances, multi-head consumable differences, material condition, length of run, and setup time.
As a non-contact process, tolerances can be challenging to consistently maintain, especially when multi-head cutting. While selecting the appropriate cut quality/speed is important for targeting a tolerance range, other factors can negatively impact resultant tolerances/sizes, such as material stress, warpage, poor table construction, and multi-head consumable differences. When setting-up for a multi-head run consider the target tolerance. Let’s say you wanted a resultant shape to be within a +/- .010” tolerance, and you want to use four cutting heads, this means you will need your resultant output per head to be +/-.0025” including taper; this is virtually impossible to achieve. Thus more tolerance is ideal when multi-head cutting.
When considering single-head cutting or multi-head cutting, think about the time it takes to setup a job, the overall time to process the job, and the price being paid by the customer from the perspective of both single-head and multi-head configurations. The job may be unable to afford multi-head cutting; thus it may be quicker and cheaper to cut the job with one cutting head than to spend the time, energy, and additional costs for multi-head consumables.
Article prepared by Ron Fairchild of Cutting Edge Water Jet Service; South Beloit Illinois. Ron has nearly 15-years of experience in hands on waterjet applications. Cutting Edge Water Jet Service is a job shop provider of water jet services for all industries in the United States. They offer 60,000-psi, 90,000-psi, conventional and dynamic abrasive waterjet cutting using a variety of multi-head waterjet cutting systems.