The positioning system is the part of the waterjet machine that moves the waterjet nozzle. The more accurately the nozzle can be positioned, the more precisely you can make parts.
Although not every application calls for high precision, having a precise machine means that you do not have to turn down high tolerance work, and that you can often eliminate secondary processes. With modern waterjets, it is entirely possible to make parts with a precision of better than ±0.003″ (0.076 mm). Also considered here are features that are important for best surface finish.
An X-Y positioning system with the bellows removed, showing precision gearing
Most waterjet machines uses an X-Y positioning system, meaning the nozzle moves up-and-down and back-and-forth. In general, the positioning system is not a wear item on a waterjet, as long as you take care to keep it clean and properly lubricated.
The more accurate your machine is, the more jobs you are capable of taking. Some machines can easily make parts in the ±0.002″ (0.05 mm) range, and with a little effort, do even better. This can be important if you want to compliment or compete with wire EDM, or milling. It can also be important if you want to reduce the number of secondary operations on parts you make. If you can make the part within tolerance on a single machine, then you can reduce your costs and increase profits by avoiding secondary operations.
Each manufacturer has a different way of stating accuracy. Find out what they are talking about. Here are some things to look for:
Positioning accuracy vs. final part accuracy
Just because a machine positions within 0.001″ (0.025 mm), does not mean that your final parts will be within 0.001″ (0.025 mm). Final part accuracy is a function of many variables including material, thickness, positioning accuracy, feed rate, controller, nozzle setup, machine vibrations, operator skill, and much more. While positioning accuracy is necessary for final part accuracy, it is not the only factor.
Dynamic vs. static measurements of positioning accuracy
Was the positioning accuracy measured by moving the machine, then coming to a complete stop, then measuring (static positioning accuracy)? Or was the machine measured while it was moving (dynamic positioning accuracy)? Many machines will position well at rest, but at speed it is more difficult. Be sure to ask how well the machine tracks position at higher speeds, such as 150 inches/min (38 cm/min)? At slow speeds you don’t get the same servo following errors that you do at higher speeds.
Repeatability is a key factor in obtaining precision. If you make five of the same part in different places on the machine, do the parts come out the same? Have your sales person do some tests while you watch, if possible. It is important to watch your test parts being made, to insure that they are not making a lot of your parts, and then only showing you the one that came out best.
Depending on the part you are machining, some waterjets are capable of accuracies as close as ±0.0005″ (0.013 mm). But this is only under certain rare conditions, specifically using a thin material and careful setup by an advanced user. If a manufacturer claimed such high precision, they would get themselves into a lot of trouble with a new user who just bought a machine, and is cutting something where such precision is impossible. For this reason, most manufacturers have found that it is better to quote something more reasonable that covers a typical user making typical parts. In other words, they are cautious when quoting tolerances.
On the other hand, some manufacturers, in order to gain a selling advantage, are a little less cautious when quoting precision. Therefore, you will find that there is a wide variation in actual part precision, but a less wide variation in claimed precision by manufacturers.
You watch parts being made on the machine, then measure the results. Do not run “canned” parts, where the sales person has had time to tweak the program. Create parts from scratch, that you draw at the controller from an idea in your head. This will not only give you a better idea of how the machine is programmed, but it will also help show you what kind of real world tolerances you can expect.
Protection from dirt, dust, and moisture
The bearings and drive mechanism of the X-Y positioning system are precision equipment. Attached to a waterjet, they are in an environment where there is a lot of abrasive, which can destroy that precision. Moisture is also not good on the inner components of your machine. How easy is the machine to keep clean? Are there spots for dirt to collect? Look for fully sealed X-Y guides and ball screws to eliminate the risk of abrasive contamination of precision surfaces. Bellows should not have horizontal “pleats” that can trap dirt and abrasive material and cause bellow failure. Also look for other places where dirt and moisture might cause problems. If you are buying a used machine, be careful of dirt in expensive places.
You probably don’t need to go very fast (more than 50 inches per minute or 1.3 meters per minute) if you are using the machine for abrasivejet machining. For nearly all parts, you will be limited by how fast the machine cuts, rather than the speed of the positioning system. Only if you do a lot of pure waterjet cutting, or cutting of extremely thin material, will maximum speed be important.
Waterjet machines come in a variety of sizes, and most machines are measured by the size of the “table,” where the material sits. This is usually larger than the machining area, as the nozzle can’t travel all the way to the edge of the table. The catcher tank is sized to fit the table. When purchasing a waterjet, one thing you will have to decide is the size of the table.
The ideal abrasive waterjet shop would have several small machines, one medium sized one, and one large one, running two or more nozzles. However, if you are only buying one machine, then the choice is not as clear, and depends a lot on the kind of work you currently do, and the kind of work you want to get into.
Big machines are more expensive to purchase and operate, but you are not limited in the size of a part you can make without indexing it.
Small machines are less expensive to purchase and operate, and are small enough that it is more fun to use the machine. It is more convenient to use the machine for smaller jobs, and for “machinist” type work. For small parts, you can be more profitable, because you are not trying to pay for a big machine.
There is no good answer to this, however, so ultimately it is up to you. Keep in mind, however, that most sales people would rather sell a big machine than a small machine, because that is where they make the most money. When purchasing a machine, you need to determine how you will be making the most money.
Table size and nozzle travel
You will pay more for a bigger table, bigger tables tend to be less accurate, and bigger tables take up a lot of space. You also need to have more work for the machine to pay for it. Smaller tables can often work with the occasional big piece of material with a little setup, so you might not miss out on as much work as you think. If you are a production or fabrication shop, where you do a lot of work with huge sheets of material, then you should look at the bigger tables
Rule of thumb
The table should be sized to easily hold stock material of standard sizes and the nozzle travel should be great enough to cut at least 1″ or 2″ (2.5 or 5 cm) greater than standard-sized material. For example, a machine shop generally using 2′ x 4′ (60 cm x 120 cm) stock material should have a nozzle travel of at least 26″ x 50″ (66 cm x 127 cm) and a fabrication shop using 4′ x 8′ (60 cm x 240 cm) material should have a nozzle travel of at least 50″ x 98″ (66 cm x 250 cm). This gives you a little room to move, fixture, and clamp material to the table.
Here are some measurable things to consider regarding tank and size:
How much space does the entire machine take up? Don’t forget ceiling requirements. Will it fit in your shop?
What is the biggest cut you can make without having to move the material?
What is the biggest sheet of material you can fit in the machine, yet still cut submerged? Cutting with the material submerged is much quieter and cleaner than cutting in the open.
What is the biggest sheet of material you can cut by feeding the material through the machine? Can you feed the material through the machine? In some cases this dimension may be that the biggest material you can machine is equal to the width of the machine in one dimension, and infinity in the other.
Be sure to think about other factors such as how you will load and unload the material, how will you pull the finished parts from the machine, and are there things in the way such as bellows that might get damaged in the process.
Cutting with the material submerged greatly reduces noise and splash from the tank. This is important if you are operating in a machine shop environment, and don’t want to make a mess or have to wear hearing protection. Here are some things to consider:
How fast does the water level raise / lower?
It should be possible to raise or lower the level of water on the cutting surface by at least one inch per second (2.5 cm/sec) to insure rapid and convenient operation. Otherwise, you spend a lot of time waiting for the water to rise instead of making parts.
What is the deepest you can submerge?
For good noise and splash protection you will want the water level at least 0.5″ (10 mm) from the top of the material. It is even nicer to raise the water level up to 2″ (5 cm) above the material being machined for maximum noise and splash protection. Some people prefer to cut without submerging so that they can watch that the nozzle does not break on loose material. This is unnecessary if your nozzle is properly protected, and you program your paths with collision avoidance in mind.
Material handling and fixturing
You want to consider how you will get material into your machine, which will depend on how large the table is. Questions to ask about material handling and fixturing include:
What is the biggest piece of material you can fit submerged in the machine?
Remember that this will be smaller than the largest piece of material you can fit on the table. Make sure you can fit a standard size sheet of the material you work with the most.
What if your material is bigger than the table?
If the material you want to cut is larger than the table, can you put the material on top of the machine, or are there guards in the way?
What is the actual cutting envelope of the machine?
The cutting area of the machine is usually smaller than the table size, and it can be further reduced by some accessories you may purchase.
How does the cutting envelope compare with standard material sizes?
If the cutting envelope is smaller than your standard material size, you may not be able to use as much of the material as you want. One of the advantages of waterjets is that you can use most of the material, because of the small kerf and small sideways forces.
What options do you have for fixturing your material?
How will you make sure that your material doesn’t move during machining? Most fixturing with waterjets involves clamping the material, so make sure that there are places where you can attach clamps.
How rigid is the table? This affects the accuracy of the final part. Is the positioning system connected to the tank or separate? If they are separate, you may find that the two systems move independently of each other, and therefore, the part you are cutting also moves independently of the machine. If they are not rigidly attached, then a forklift driving by, or the machine’s motion itself could cause vibration marks on your parts. This will result in a less precise part with worse edge quality.
Also check the rigidity of the nozzle attachment to the table. It does not have to be super rigid, as the cutting forces exerted by the jet are not very strong, but it should not move easily either, or it may be pulled by the high pressure tubing. Relative vibrations between nozzle and part are a common source of fine errors when trying to achieve maximum precision with some machines.
What happens to spent material and water? Some systems have optional tank clean-out systems, or you may have to shovel the tank out by hand. Shoveling by hand is a lot cheaper than an automatic clean out system, but finding volunteers can be difficult.
There are also some after market clean-out systems available.
As long as you are not cutting toxic materials, your waste water can be sent down the drain, although you can recycle it if you want. If you are cutting toxic materials, you will need to have a water recycling system and a way to dispose of your waste garnet, as it will be contaminated with small pieces of the material.
Water recycling is sometimes useful in areas where water/sewer is expensive, or if you are cutting hazardous materials regularly. You don’t have to get a water recycling system from the same place you get your waterjet, however.
Material is supported in the tank by a system of slats, typically spaced about 1″ (2.5 cm) apart. With time, the slats will get cut by the nozzle and need to be replaced. You should look for material support slats that can be quickly changed on an individual basis as needed or removed completely for simple installation of special holding fixtures.
Can the machine be easily moved to a new location?
Some machines are easy to move with a forklift, while others (especially big ones) may require significant effort, rebuilding, and calibrating. This may or may not be important depending on how often you re-arrange or move your shop or whether you ever intend to sell the machine.
Choosing a nozzle doesn’t just happen when you purchase your waterjet machine. You can also purchase new nozzles throughout the life of your waterjet, as technology advances and newer and better nozzles come out. Regardless of the technology, however, there are still some basic features to look for.
Look for a precision nozzle assembly with fixed alignment jewel orifice and mixing tube. It should be possible to change or exchange either an abrasivejet nozzle or a pure waterjet nozzle in under five minutes without special tools. It should be possible to completely overhaul a nozzle in less than 15 minutes.
Mixing tube guard
Check that the nozzle has a mixing tube guard that protects the mixing tube from side impacts that can happen if the operator accidentally runs the nozzle into the side of piece of material stock. Many nozzles expose the mixing tube out where they are easily broken. The mixing tube is delicate, so make sure its protected.
Mixing tube protectors will also reduce the amount of splash as well, especially during piercing. You can always remove the protector for special needs, but having the protector will save you a lot of money and frustration.
Mixing tube life
Mixing tube life is quoted differently by every manufacturer. Most manufacturers use the same mixing tube material from Boride, and thus they wear at similar rates. Mixing tubes are like drill bits: when is a drill bit worn out? That depends on what you are using it for. If you are using it for precision machining, then it is considered worn out earlier. For rough work, you can say it lasts longer. Mixing tube life is strongly affected by water quality .
Mixing tube size
Longer mixing tubes give slightly better focus, and perhaps last a little longer. Smaller inside diameters give slightly faster cutting, and more precision, but wear a little quicker. Thicker mixing tubes are less likely to break when they hit something.
Mixing tube diameter
Smaller mixing tube diameters offer greater precision, reduced taper, and reduced kerf. They also do not require much pumping power, because they are typically used with a correspondingly smaller jewel. However, they do not cut as quickly as larger ones connected to larger pumps.
Diamond, ruby, and sapphire jewels
Most jewels used in waterjets are made from rubies, because they are relatively cheap and relatively durable. Rubies and sapphires are the same thing, except that rubies have a slight impurity that makes them red. Diamond jewels usually last longer but are more expensive.
You typically replace the jewel at the same time you replace a mixing tube, and the cheap rubies work well. If you don’t like replacing your jewel, you can use a diamond jewel. This should not make or break a buying decision, because most manufacturers offer the option of either jewel type (as well as the after-market). Water quality significantly affects jewel life. With clean water, jewels and mixing tubes last longer.
With the high pressures created by waterjets, making sure the jewel is accurately aligned can dramatically affect wear on the mixing tube and cutting efficiency. Most nozzles are pre aligned, but some require that you do it manually. If your jewel doesn’t align well, then you will wear your mixing tube out prematurely because the water is hitting the side of the tube instead of shooting straight down it. Also, you will not cut as effectively.
Besides nozzle design in general, one thing that can cause jewel misalignment is accumulated minerals caused by poor water quality. The accumulated materials will change the geometry of the jewel, and disturb the jet. Another thing that can cause jewel misalignment is dirt under the jewel, which can occur when rebuilding the nozzle. Always do your nozzle rebuilds in a clean environment, and clean the items you are rebuilding to avoid this kind of problem. Likewise, if you rebuild something upstream, such as the pump, you should remove the nozzle and flush the system, to insure no upstream debris can damage or plug the jewel.
Running multiple nozzles is a reasonable way to increase productivity without buying a second machine. You will need a large pump, or several small pumps to operate multiple nozzles at once. Then, simply mount your nozzles next to each other on the same machine. There is some risk, however, that a nozzle clog or snag on one nozzle can ruin all the parts underneath the other nozzles.
Note that when running multiple nozzles, some precision is lost because of the inability to compensate for tool wear exactly over both nozzles, but in most applications it’s still possible to get good precision.
If you are doing lots of the same part over and over, you can produce more at once with multiple heads. Many high production waterjet shops cut with multiple cutting heads, and most job and machine shops use a single head.
Some manufacturers offer a “MiniJet” nozzle, which is a nozzle with a smaller jewel and mixing tube that can produce a very thin cut, as thing as 0.020″ (0.5 mm). These MiniJet nozzles are good for cutting very small pieces, where the tiny cut allows intricate features to be cut, such as for jewelry. They are also good when cutting expensive material or precious metals where you want to preserve as much of the material as possible.
Because the waterjet stream is narrower, they will cut slower than a standard nozzle. Still, many machine shops find it useful to keep a MiniJet nozzle handy for specialty work.
The abrasive feed system makes sure that there is a steady flow of abrasive to the nozzle where it is mixed with the water. Flow rates are typically about a pound a minute (0.5 kg/min). You have some choices in types of hoppers for your waterjet machine.
If you do long runs of cutting, you will probably want a hopper that gives you lots of time by holding a lot of abrasive. Hoppers with capacities of 300 lb to 600 lb (135 to 275 kg) are pretty common, and are a good option to invest in.
Eventually your will get a mixing tube clog and water will shoot back into your abrasive system. Look for a design that doesn’t make you empty your hopper if water backs up the abrasive line.
If you like to adjust and tune your system, then you might want to change abrasive types for certain materials. This is not necessary for most machine shops, but if you do glass, or other non-metallic materials, then you may want to machine with a finer or softer abrasive. In that case, you’ll want to have an abrasive feed system that makes it easy to use other types of abrasives.
Similarly, you may want to be able to adjust abrasive flow rates to get the best machining for different materials. Some feed systems have a single flow rate, while others let you adjust the flow rate as desired.
The basic abrasive feed system designs are discussed below.
Hopper next to nozzle
Having the hopper next to the nozzle is sometimes called a “mini hopper.” In this case, there is a metering device underneath the hopper that opens up to allow gravity to drop the abrasive through an orifice and into the abrasive tube.
Mini hopper mounted on positioning system to feed abrasive to nozzle
- Fast abrasive delivery to nozzle
- Easy to change abrasive types
- Very accurate and consistent abrasive flow
- You can see the abrasive level easily
- Low capacity and must be refilled often
- You need to be able to reach the hopper to refill it; if it needs refilling in the middle of making a part, you might have to interrupt machining to refill it
The common application of this design is for shops that do lots of single piece production, and don’t do long runs.
Bulk abrasive hopper fed from floor
In this case, suction from the nozzle is used to draw abrasive from a large abrasive tank on the floor that is typically pressurized with air into the nozzle.
A bulk abrasive hopper
- Easy to load in the abrasive, even from heavy bags (no need to lift up the bags)
- Very high capacity that will last many hours before refill is needed
- No warning before abrasive runs out
- Typically the abrasive metering is not very accurate or consistent
- More expensive
- Harder to change abrasive types, unless you have more than one hopper where you can switch abrasive feed tubes
- If water goes up abrasive tube (as in case of nozzle plug), then you may have to empty several hundred pounds of abrasive (depending on system)
- To add abrasive, you have to first depressurize the system. This can be awkward if you need to do this while the machine is cutting, unless you also have a second small hopper to act as a buffer to give you time to fill.
A combination of mini hopper and bulk hopper
In this setup the larger hopper feeds the smaller hopper located next to the nozzle.
This design generally offers the best of both worlds, specifically:
- The small gravity fed hopper provides an even and precise abrasive flow rate
- Provides faster response of abrasive delivery, which is essential for piercing brittle materials
- Provides early warning, should the larger abrasive hopper run out.
- Depending on the design, it can make it easy to change abrasive types for special purposes
- Depending on the design, it can make it easy to change the abrasive flow rate for special purposes
- Costs the most money
The “brain” of a waterjet machine is called the controller because it controls the high-pressure water pump, the abrasive flow, and the movement of the nozzle. Unlike older machine tools which are controlled by humans, waterjets are controlled by computers because of the complicated nature of the waterjet stream.
The software running on the controller is extremely important. You should look at your programming options thoroughly before purchasing a system. Make sure that you like the included software, and also make sure that you have other programming options available. Can you import files from AutoCAD, MasterCAM, Adobe Illustrator, and other popular CAD / CAM / Drawing packages?
Watch out for proprietary software with unpublished file formats to store your CAD data, or tool path files. If you decide later on that you don’t like the software that comes with the system, it is nice to be able to export the data to a different CAD package. You may also want to use some other third party software for nesting, gear generation, or other special shape generation.
Also watch out for software that you must pay lots of money to upgrade, or pay money for extra seats (each computer the software is installed on is called a “seat”). Often, it is to your advantage to run the software on several computers. Perhaps one seat on the machine, one or two in the office, and another seat at home, or on your laptop. It is of course also to your advantage to run recent software with all the latest features and bug fixes.
You should also ask about maintenance and upgrade fees for the controller software. These hidden costs can be large, and upgrading software is something you will want to do at least once per year because of the rapid developments in this area, and for simple bug fixes.
Choosing a good controller, then, is a key decision when purchasing a waterjet. You want to make sure that the controller does its job well, and that it’s easy for you to use. Following are a number of factors you should look at when choosing a controller.
Jet behavior compensation
The waterjet stream exhibits chaotic behavior—it’s difficult to accurately predict what it’s going to do, especially when the nozzle is moving. Not only is the stream lagging behind the nozzle, but it’s also bouncing off the material you are machining.
Older waterjet systems required you to set “feed rates” (how quickly the nozzle moved across the material). Most modern waterjets calculate these for you automatically and provide precise control of the nozzle. Still, there are differences in how well controllers compensate for jet behavior.
You should look for a motion control or programming system that calculates optimized nozzle travel speeds and speed variations based on the materials and shapes being machined prior to cutting the part. This type of control is critical to controlling wash-out and irregularity at corners and around curves. For ultra-precise machining, the control system should be capable of setting different speeds at very fine intervals, especially around curves and corners.
The controller should at a minimum compensate for the following
As the nozzle moves forward, the jet lags behind it. The faster the nozzle moves, the more the jet lags behind. This becomes even more complicated when the nozzle moves around corners as the jet can move outwards (bouncing off the walls of the cut more) and even cut into the corner itself. The controller should also “look ahead” on the toolpath, so that it can compensate for features that are coming up, such as corners, and slow down as needed.
Kick-back when accelerating out of a corner
As the nozzle moves out of a corner, it’s possible for the jet to bounce off the walls of the corner just cut, gouging them out. This is called “kick-back” and is controlled by adjusting the nozzle speed when exiting the corner.
Kerf width (Tool offset)
The kerf width refers to the amount of material removed by the waterjet stream. The width of your cutting stream will vary from nozzle to nozzle, and as a result of wear. Virtually any controller should compensate for this, typically by letting you enter a value that you’ve measured.
The controller should automatically predict and compensate for taper, typically by either slowing the cutting rate down or by tilting the nozzle.
The controller may use other optimizations the controller does for you to improve speed or precision such as automatic corner passing, corner looping, and automatic pierce assignments.
How the machine pierces materials is important. Ideally the controller should offer a full range of piercing methods to deal with different situations.
Automatic dual pressure support
Your high-pressure water pump may support dual pressure, but that does little good if the controller doesn’t. Make sure that your controller will automatically switch the pump pressure for piercing. Otherwise, you will either not be able to use dual-pressure piercing, or you will be forced into the awkward condition of having to pre-pierce all the holes at low pressure, then cut at high pressure.
Error mapping and compensation
It is possible to compensate for low-grade components through software by using techniques such as “error mapping”. Error mapping can also be used to gain an extra measure of precision from an already high precision machine. Can you adjust the machine for a stretched ball screw? Do you need mapping? Is the machine in question constructed with cheap components, and compensated for through mapping?
Depending on construction of the machine, this feature may or may not be necessary, although even on a precisely constructed machine, it is possible to get an order of magnitude greater precision with error mapping. Therefore, there are really two different applications for it:
- Making a very low cost machine that is still reasonably precise. The biggest flaw to this strategy is that you need to perform the error mapping, which in itself is fairly expensive to do, and often needs to be done more than once. This is a complex solution to a problem that in many cases could be much better solved with precision components to begin with.
- Making a precise machine more precise. If you have a machine that is already as precise as you can make it mechanically, then error mapping can increase precision by a factor of ten. Once you get to a certain level of precision in positioning accuracy, however, many other effects of waterjet machining will dominate, and additional positioning accuracy is pretty much useless except for someone doing something highly specialized such as researching cutting models
User interface issues
The interaction between you and the controller software is called the “user interface,” and it should be easy for you to understand how it works. To some extent, this is a matter of personal preference—some people like a very visual user interface, while others like lots of text. While you won’t become an expert after a few minutes of working with it, you should feel comfortable and commands should make sense and work the way you think they should.
Try drawing a part from scratch. Don’t watch a “canned” demonstration of a memorized part. Is it easy to make just one part, and does it turn out good the first try—or do you have to make a part, then adjust your program , then make another part?
Does the programming system have automated features to speed up common processes such as tool path creation and geometry fixing?
If the programming system makes the tool path for you, can you override what it did, if you don’t like what it did? This may be quite important for collision avoidance. Probably more so than for other machines such as lasers where parts that are cut can simply fall under the table, and not pose a collision hazard. In waterjet machining, the parts will tend to tip on the supports, and present collision hazards. Falling into the tank is not desirable for various reasons—especially the fact that the blast from the nozzle may cut up the part as it falls.
Part creation options
Look at the options available for creating parts, since this is a key activity in running your waterjet. Most controllers include software for drawing parts and preparing them for creation on the waterjet. Making parts on a waterjet requires some special adjustments, such as surface finish and hole drilling, so you’ll probably need to use the controller software for at least part of this.
You may also want to use software from other companies with your waterjet. If you are already familiar with a CAD / CAM package, check that the controller can import those files and work with them. Again, try it out. Don’t rely on assurances that it will work–people who have worked with computers for years don’t believe anything until they see it work.
No single nesting software package will suit everyone’s unique needs. There are many widely varied nesting software packages out there, and they each have their strengths and weaknesses for a given task. Nesting software ranges from about $1000 to over $25,000, depending on capability. Be sure to check upgrade prices for this software.
- Does the company that makes your abrasivejet publish their file formats publicly?
If not, then you may not have many choices of nesting software, and may be locked into whatever package the manufacturer of your machine has to offer. This is not necessarily bad, but you will not have much choice in the matter.
- Do you need to output files to your other machines?
If so, make sure that the nesting software you get can post to your other machines as well. Some nesting software can post only to lasers and waterjets and other “beam cutting” tools, while other nesting software can also do punch presses and other tools.
- Do you intend to nest a single part over and over to fill a sheet of material, as in a production environment?
Or will you instead start with a piece of material, then fill it up with a wide variety of different parts?
The answer to this question will mean a huge difference in price of the nesting software. Most waterjet users cut the same part over and over, and don’t fill sheets with all sorts of different shaped parts. Therefore, think about this carefully before purchasing the more expensive nesting software options.
You may want to wait until you have your machine for a few months, then decide if you need nesting software, and what features you really need.
If you are an OMAX Customer, be sure to read the “nesting software buyers guide” in the OMAX Interactive Reference.
Software for scanning is useful for converting artwork from a scanned image or photograph into a vector CAD file. If you are planning on doing artwork, or reverse-engineering parts, you may want to see what kind of image tracing capabilities come with your machine. There are also third party software options in this regard such as Cutting Shop from Arbor Image, Adobe Illustrator, and others. Look for “Raster To Vector” software with your favorite search engine for other options.
Things go wrong, even with waterjet machining and you should consider how well the controller can recover if your mixing tube clogs or breaks.
How easy is it to save the part? Look for user specified machine home or “Zero” positions. Also look for the ability to stop in the middle of a cut, and backup, then resume, and the ability to quickly jump to a specific spot on the path. Find out how to recover, should the power go out in the middle of machining a $5000 part.