# Food Processing with UHP Waterjets
## 3 Waterjet Food Systems
### System Manipulators, Support Tables, Sensors, and Software  
There are many types of manipulator and feed systems used in the food cutting industry based on the food being cut and the required degree of automation. Cartesian, articulated arm, cylindrical, SCARA, polar, and delta-type robots have all been used in the food industry. In addition, custom manipulators have been built for certain classes of food such as cake and pizza cutting. There are also several types of food support and feed tables such as belts, trays, robotic grippers, and steel mesh. The following are examples to illustrate the flexibility of the waterjet tool adapting to all these types of variations. A cutting table is what the food is placed on and supported by to be cut. For example, a tray may be used to hold a cake which is then placed under a robot or manipulated under a jet. Cross feed belts, whether made from plastic or stainless-steel mesh, are widely used in high-volume production and may include one or more waterjets that are either stationary or traversed in one or two directions, X and Y, while the food is fed in the X direction. Figure 8 shows schematic examples of these configurations which may be used for vegetables, meat, fish, or poultry. The use of multiple waterjets to trim, slice, and cut is the simplest form of manipulation where the food is either fed on a belt drive under a bank of properly spaced stationary waterjets or the waterjet bank is manipulated linearly to cut a stationary food. Example trimming and cutting systems are shown in Figure 9 where lettuce and celery are trimmed and/or cut into smaller sizes, a cake sheet is cut with multiple jets, and a meat block is sliced into steak. Figure 8: Examples of food system layout concepts. Food is represented by a green color. The use of XY motion to manipulate the nozzle may be accomplished with a cartesian system or by robotic motions such as a delta or six-axis arm. These robots are particularly important when the jet needs to be tilted as in the case of cutting fish to remove the pin bone. Figure 10, Marel of Garabaker, Iceland, shows a two-bridge system for fish portioning and pin bone removal by tilting the nozzles which move on one axis only. Since the nozzles are only moving on one axis, the waterjet catcher system is simply a slot under every nozzle to catch the jet after it cuts. The nozzle can also be tilted to cut at an angle as shown in Figure 10.  
An alternative approach is to manipulate the nozzle in two axes, X and Y, over the linearly fed food. The system shown in Figure 11 uses a single cross bar for the Y motion with two bridges, and one on each side for the X motion. In this case, each jet has two degrees of freedom as shown in Figure 11.  
Figure 10: Example of dual bridge with jet tilting for fish cutting and pin bone removal. Figure 9: Example of multi-waterjet use for trimming lettuce and celery, slicing meat, and cutting cake. To add tilt angles as an additional degree of freedom to the XY motion, a delta-type robotic arm has been used for fish trimming and portioning, as shown in Figure 12. Two delta robotic arms are used while the food (fish) is traveling in the X direction on steel mesh. The use of two nozzles allows for rapid production rates with each jet cutting certain zones on the fly. Either UHP hoses or tubing coils can be used. The jet tilting is used for cutting at angles and removing the pin bones. For cake cutting, several manipulator types are being used. Six-axis articulated arm robots, as shown in Figure 13, offer great flexibility and possible cutting at angles. The robot is commonly hung over a cross-feed table where cakes (or other food) are linearly fed. High cutting speeds to the order of 1 m/s are used. However, for relatively low production rates, SCARA-type or rotary-linear manipulator systems have been found suitable for cake cutting with a minimal machine envelop size.