The applications of 3D CAD software in Water Jet Cutting is multiple and varied. One of them is the programming of water jet cutting machines. Water jet cutting is a mechanical process based on erosion, using water pressures at extremely high speeds (4137 bar or more) to cut any type of material. Below we explain how this system used in combination with Solidface 3D CAD software can be very useful in your work.
Water jet cutting systems can be pure or abrasive. Both serve to execute very precise cuts of a wide variety of materials, including metals, without any area being affected by heat, because it works just cold. Precise cutting occurs when the surface of the material is hit with a jet of water fired at high speed.
The “pure” water jet is one that only uses water to make a cut, while the “abrasive” jet system adds other elements such as silicon carbide or oxide powders aluminium to dry air (or nitrogen), to accelerate the cutting of the material.
A stream of dry air (or nitrogen) is pointed at high speed with abrasive particles to the surface of the piece. This shock generates a very concentrated force that is used to make cuts of metallic and non-metallic materials. It also serves to debur or remove chips or simply to clean parts with irregular surfaces.
Various soft materials can be cut through the stream of pure water, such as plastic, fiberglass, rubber, paper, joints, carpets, food and foam. In contrast, the abrasive water jet is used in the process of cutting other materials of greater hardness such as metal, stone, glass, ceramics and wood.
Water jet abrasive systems usually use garnet and the grain size ranges from 50 to 220 meshes, with 80 being the most common. Some water jet machines are very versatile, because they combine or allow the immediate change of the pure water jet cutting system by the abrasive jet cutting system.
Contribution of PCs to system development
The water jet cutting system began to develop in the 1970s. One of its creators, Dr. John Olsen, recounts its beginnings. “I had been reading about some experiments done in rock cutting in England and a friend of mine and I thought it would be fun to try to build a bomb and cut something. That was a kind of alley operation; I was in my garage and in your garage.”
He states that, curiously, the advent of the PC was what contributed to making the abrasive jet system more practical. “A jet is not a very rigid tool: it bends everywhere and narrows and what you have. To make precision parts, you need enough computing power to predict what the shape of the jet will be and to compensate for it. At that time, they told us: nobody will ever accept a PC in the factory. Doesn’t it sound funny today? “.
Water jet software
Water jet cutting software is necessary for programming the cutting machine. Even some software that comes with the original equipment is integrated into the machine; but other times manufacturers and builders prefer to incorporate non-original software, called CAD / CAM nesting software. These programs offer additional functions and have the added advantage of facilitating the programming of several machines simultaneously of different brands and models.
Certain types of CAD / CAM water jet software can also control and automate the entire operation that runs the water jet cutting. Some support programmable parameters such as abrasive flow and control, cutting speeds and heights, indentation commands, drilling heights, types of drilling (dynamic, stationary, circular or random waving), time and pressure.
CAD (Computer Aided Design) draws the object or a part of it and is subsequently processed in 2D or 3D modeling software. The result is usually obtained in a CAD file that is then imported into the CAM software. This, of course, helps to simplify the work of the machine operator and helps the company increase its productivity. Water jet softwares also have other functions such as:
– Dynamic calculation of water jet speed
– Common line cut
– Collision evasion
– Nest around material defects
– Color selection for water jet quality
– Tabulation of parts
– Types of water jet
– Gradually turn off and on
– Abrasive / Non abrasive
– Cutting of hard or soft materials
Industrial water jet applications
On the other hand, water jet cutting is recommended for use in industries and markets that use raw materials or materials in general, which may suffer alterations if the cuts are made with a system that uses heat. Likewise, in those companies where you work with highly variable materials such as production workshops.
The industries and sectors where water jet cutting technology has the highest demand are:
- Military and defense
How SolidFace can help you with this technology?
Our versatile and adaptive 3D CAD software is a multipurpose solution with applications in various industries. The water jet cutting machine can be programmed through our CAD package. Its flexibility in design, quality and precision, as well as the improvement of production capacity and the ease it offers for teamwork, make SolidFace 3D CAD an indispensable resource for successful creation and manufacturing.
Try SolidFace and adapt this extraordinary work tool to your water jet cutting machine and start to be more efficient and productive using this technology recommended by hydraulic engineers worldwide.
Water jet material cutting
The practical applicability of water jet systems is what makes this technology so versatile and useful. Pure water run systems can cut soft materials such as rubber, polypropylene, vehicle upholstery, paper, cardboard, rubber, foam, fiberglass, packaging materials and any other type of non-metallic material.
The vice president of global marketing for Flow International Corporation, Chip Burnham, says that in his entire career there are only two things he has not been able to cut with this cutting system:
“One of them is tempered glass, although some people still do, tempered glass must be sealed again because it has tensions and when you cut it with a water jet you relieve it” and adds that:
He cut “beautiful things from tempered glass and I surprised glass manufacturers in the early years of the water jet just to go back to the lab the next day and find it in a million pieces because it broke overnight.”
Water jet cutting performance is almost identical in any type of material, says Scott Wirtanen, regional sales manager for Jet Edge. “Therefore, the versatility of the water jet, both in materials and thicknesses, has no parallel.”
Is the key to the water jet pressure?
The system is based on the pressure exerted by water and the abrasive material on the materials. The pressure used in water jet cutting is very high and is measured in terms of maximum pounds of pressure per square inch (psi).
The pressure variation used by the water jet ranges from 60,000 – 90,000 psi. For some engineers at higher pressure, faster is the cut, however for others, what really counts is the efficiency of the engine.
Those who defend the thesis of a pressure of 90,000 psi argue that increasing from 60 k to 90 k psi also increases the speed of the current, consequently causing an increase in cutting speed by 50% or more, depending on the application.
They also argue that cutting at a pressure of 90,000 psi substantially reduces the consumption of abrasive material used, since each garnet particle or any other element used receives more energy. Likewise, by applying greater pressure to pierce and cut, delamination in composite materials is reduced.
The cutting process begins when water conduction is accelerated through a nozzle directed at a speed of 1094 yards / second. This is possible thanks to a high-tech pressure intensifier of up to 4000 Bar.
In this process the cutting speed is very important and depends on several factors such as the diameter of the nozzle, the pressure of the pump together with the capacity of the intensifier, the quantity and quality of abrasive used and, finally, the thickness of the piece.
“The cutting speed is directly related to the power of the nozzle. Therefore, the power consumed is a function of the amount of water that comes out of the hole and the pressure. A small hole with low pressure consumes very little energy and cuts slowly,” says Chip Burnham.
If the nozzle has a larger hole and is subjected to high pressure, the energy consumption will be greater and it will cut faster. “It is the amount of water and the pressure that the power demands,” complements Burnham.
Wirtanen agrees with this statement and notes that when using an equal orifice-nozzle combination, along with the same amount of abrasive and a similar volume of water, 90,000 psi would also exceed 60,000 psi.
Those who support the pressure of 60,000 psi explain that by increasing this then the size of the nozzle should be reduced. The power is proportional to the amount of pressure per volume flow, that is: Power = kPV.
One of the most important elements is the nozzle through which the jet comes out; it depends on the cohesion of the jet that largely determines the technical viability of the application, because if the jet is conical, cutting power, precision, quality and dry cutting characteristics are lost.
The diameter of the nozzle of the water cutting machine measures between 0.08 mm and 0.45 mm in diameter. The water and the abrasive, or the mixture of both elements, are expelled at a high pressure according to the requirement of the cut and the configuration of the water cutting software.
Types of water jet pumps
Water jet pumps are classified into two basic types: the linear intensifier pump and the direct drive rotary pump. Both are reliable to make precise cuts. The direct drive uses a nominal pressure of up to 4150 bar, while the intensifier pump has a pressure level of up to 6500 bar.
Each has associated advantages and disadvantages, depending on the maintenance cost that the user is looking for. Wirtanen explains that “direct drive pumps are inherently a simpler design, but require much more maintenance than an intensifying pump. Because they are a simpler designer, they are less expensive for an initial investment, but in the long run, intensifying pumps have a much lower cost of ownership.”
For those looking for less expensive equipment, the direct drive pump is the best option, but if what you are looking for is a lower maintenance cost, then unquestionably that the intensifying pump will be a better option. Like any product, manufacturing and preference for one or another model depend on its practical application.
How expensive is water jet cutting?
The calculation of labor costs with the water jet is not as simple as it could be with other types of industrial machines. There are a number of factors that are involved in the consideration of cost calculations, including the programming time of the trajectory, the risk of breakage with fragile material and the number of times the material needs to be drilled.
Also the cost of consumables, the time of installation, download and maintenance and the amount of order. The most practical and precise approach to calculate these costs is in dollars per part, since it is not easy to calculate the costs per hour of work of the machine. Water jets can be configured with single or multiple cutting heads, affecting cutting times.
The costs for a water jet of a single cutting head are approximately $ 100 -135 per hour. However, high-end pieces can raise this cost up to $ 2,000 per hour, depending on the type of piece to be cut, the type of material and its thickness. For this reason it is so difficult to calculate the costs of the water jet per square inch of cut. The three variables mentioned above affect the material cutting times.
According to all these cutting parameters (a type of material, hardness, and thickness) the cutting time of the piece can range from 15 minutes to more than 40 hours. This time will be what ultimately determines the price of the cut. In the process, it is also necessary to determine the type of cut to be obtained. Regardless of the material to be cut, water jet cutting can be very rough or very perfect. It will depend in any case on the utility that you want to give the piece.
Other benefits of water jet cutting
In the metalworking, aeronautical, automotive, aerospace, manufacturing, and nautical industry, among many others, water jet cutting is increasingly used. Its precision and low generation of contaminating particles, 0 surface oxidation and waste such as chips, make this technology the best option.
The water jet machine comes with a raft, on which the water jet is projected while holding the pieces that will be cut by means of a fence that keeps the material firm on the work surface. In turn, it allows both the water mixture and the material waste to be deposited inside it. This prevents the projected liquid from spilling or splashing other parts outside the cutting area, giving the possibility of the abrasive being recycled.
One of the most important characteristics of the water jet cutting process is that it does not affect the materials it cuts at all since it does not harden or deform them. It is a clean method that is often more useful and beneficial than other cutting methods such as laser or plasma when jobs are required to have a good finish.
Advantages of water jet cutting
Here are some of the most important advantages of running water jet cutting jobs:
– Its versatility and simplicity give the water jet a great advantage over other systems.
– Makes quality cuts with great precision on the edges of the materials it cuts. On the other hand, plasma and flame cutting are methods that use heat that affects the cut areas and can lead to bad finishes.
– Do not add heat to the cutting process. Unlike other cutting systems such as plasma, flame cutting or laser, which use heat, work with the water cutting system does not affect the materials because it works cold, with water.
– It does not produce residual tensions by not generating cutting efforts in the process.
– It does not produce pollution, gases or dust, therefore it does not harm the environment.
– It generates savings and high productivity by requiring less time to adjust and fix the material that will be cut.
– It allows to increase the amount produced by executing multiple cuts of parts or materials.
– Allows simultaneous use of multiple cutting heads which increases productivity.
– It is a method that generates minimal material waste.
Disadvantages of waterjet cutting
– It could have a limited depth of cut compared to other systems. However, the abrasive cut cuts thicker materials.
– Compared to plasma and laser, water jet cutting is slower.
– Waterjet cutting machinery is more expensive than plasma and flame cutting. Like the laser, especially if it is used to cut thick materials.
– It requires more workspace than plasma.
– The waterjet demands more electricity and is more expensive in terms of consumables and consumables compared to other systems.
Expert opinion on the waterjet
Some totally wrong concepts and opinions have been poured over the water jet cutting method. Although previously waterjet cutting was considered an inaccurate technique, these errors or inaccuracies of the first machines that were used with abrasive jets were left in the past.
Another wrong opinion about water jets is related to the ability of waterjet machines to cut thick materials. Dr. Burnham explains it this way: “People say that water and abrasive cannot cut thick [sections], but we can cut more than one foot thick in virtually any common material. We will have to cut slower, but has the ability to cut thick.”
Waterjet cutting has its practical applications, but also its advantages and disadvantages, compared to other systems. What should be clear to those who use it is the purpose of the work; so that you get the best results. Whatever the application of this technology, the final result must always be taken into account to optimize its use.
Dr. Olsen states that some misconceptions about the uses and benefits of water jet cutting “are beginning to change now, but for at least ten years I would say that was the case.” This technology “has become popular and now it is used as the first operation for almost anything a person wants to do. Many stores are using waterjet that way.”