Water jet cutting plastic has revolutionized the process of handling plastic on an industrial level. Waterjet cutters are more efficient, hazard-free, and versatile than most plastic cutting tools. While it is simple on the surface, how a waterjet cutter cuts plastic is a multi-layered process. So, many folks aren’t too aware of how it works.

Waterjet cutters are very precise, but you must use the correct settings, abrasives, and pressure levels to achieve the ideal performance. To know those things, you must first understand how a waterjet cutter works and familiarise yourself with its different components. This guide will help you do exactly that.

Can A Water Jet Cut Plastic?

Most certainly, a water jet can indeed cut plastic. It does a fine job of it too. Waterjet cutting technology is highly versatile and can cut almost anything solid. That is, of course, as long as you use the right kind of abrasive and high enough water pressure.

Plastic, by nature, is one of the simpler materials for a waterjet machine. Most plastic types do not require any added abrasive material. Regular water with roughly 50,000 psi works just fine for such jobs. However, no one would stop you if you want to use some garnet anyway. It won’t lower your cut quality. But it won’t improve the cut quality by much, either. At least not enough to justify the extra cost.

You can also do a wide range of precise detailing on plastic with a water jet. Making small cogs and gears is entirely possible due to how refined the waterjet cutting method is. In fact, it is much better than laser or plasma cutters because waterjet cutters do not produce heat.

How Does Water Jet Cutting Plastic Work?

ウォータージェットカッティング is a multi-layered process, so quite a few things happen during the operation. In simple terms, the water gets fed into a pressure pump, runs through a pipe that connects to the cutting head, and blasts out of an even tinier orifice with enough force to break the sound barrier. That thin blast of water cuts through whatever material you place in front of it.

That was a rough explanation of the entire process, and there are a lot of technical details attached to this, which we’ll go over in the following section:

1. Filtering

The first step of the cutting process is the filtering. When pressurizing water to 50,000 psi and above, which a waterjet cutter is usually going to do, you need incredibly pure water. Any foreign mineral in the water can cause wear and tear on the components.

So waterjet cutters usually come with water filters you need to connect to the pumps. These filters will usually be 5-micron filters or better. The more pressure you put, the purer the water you’ll need to use. So ガントリー models with very high water pressure tend to use multiple stages of water filtering.

First, the water goes through a 5-micron filter, then a 1-micron, and then a 0.5 micron. The purer the water, the less wear you’ll get on your machine. But plastic is easy to work with, so you wouldn’t need the same firepower that cuts through obsidian. A 5-micron filter should suffice in such cases, but having more won’t hurt.

2. Pressure Pump

After the water’s been thoroughly filtered, it goes into the pressure pump. The pressure pump needs to pressurize the water to give it its potential energy. There are a couple of different pumps for the job.

• Intensifier Pump

The intensifier pumps are usually seen in higher-pressure water jets. You’re looking at a pressure that can reach up to 94,000 psi. These pumps are bulky and require a dedicated cooling system to stay in operation.

There are two main components to the intensifier pumps. One of those is responsible for pressurizing the water. It achieves that by moving two high-pressure plungers in an oscillating motion. That action turns the low-pressure water into high-pressure water. A separate cylindrical chamber stores the pressurized water and stabilizes it.

• Direct Drive Pump

Direct drive pumps are less intense than intensifier pumps(no pun intended), which cap around 60,000 psi. These pumps use a single electric motor. The motor drives a belt that drives a crankshaft connected to several pistons. The movement of the piston generates the water pressure.

3. Abrasive Hopper

The next major component is the abrasive hopper. The abrasive hopper is the storage unit where you put your abrasive. The garnet goes into this thing that suspiciously looks a lot like a wheat hopper. You put the abrasive through the filter screen at the top.

Below the hopper’s storage area is the pressure tank. That is a small pressure chamber that adds a bit of force to the abrasive grains. The pressure generated in this section is only strong enough to push the abrasive through a pipe to the cutting head. It has no other purpose. The tube connects to the side of the cutting head.

4. Cutting Head

The cutting head is where the pressurized water comes from the machine. You’ll use it to cut through materials like metal, mineral, or plastic. While it may look small compared to other components of the waterjet cutter, it has quite a few interesting modules.

• Diamond orifice

The diamond orifice is the tiny hole that pushes the pressurized water out. The orifice is so small you’ll need a microscope just to see it. The role of the orifice is to boost the water pressure. It follows the same principle as holding a finger over a water hose to make the water flow thinner and stronger.

• Abrasive tube

Right below the Diamond orifice is a tube that connects to the abrasive tank. It carries a mixing chamber above the cutting head. The mixing chamber is a large cylindrical tube that stores the garnet. From the mixing chamber, the garnet will flow into the mixing tube below the diamond orifice through another pipe.

• Mixing tube

The mixing tube below the diamond orifice is a hollow tube with a very narrow diameter. But it is practically a giant hole compared to the diamond orifice. So when the water rushes in from the diamond orifice, it creates a vacuum in this chamber. The vacuum pulls the garnet from the mixing tube, and it then mixes with the high-pressure water and comes out of the nozzle.

5. Tank

The space below the cutting head is your workstation. For industrial waterjet cutter models, the workstation is above a storage unit known simply as the tank. The tank is a large area where water and debris will accumulate once you start cutting. 

There are support ribs above the tank. You can use toggle clamps to secure your material to the support ribs. Doing so will prevent the water jet from moving the material around when cutting. Do note that the support ribs will wear down with use, and you’ll need to replace them occasionally.

6. CNC

You control the movement of the cutting head with a computer. Most waterjet cutters come with a very easy-to-use computer menu where you can pre-program how to cut your material. The software will also include presets for different material types. So selecting those will automatically calibrate your machine to fit the material in question better.

What Types Of Plastic Can Be Cut With A Water Jet

You can cut all types of plastic with a waterjet cutter. That includes both thermoplastics and thermosetting plastics. Here’s a name of a few most common ones:

• アクリル
• Fiberglass
• Polyester
• Polycarbonate
• polypropylene
• Vinyl or PVC
• Epoxy
• Silicone
• Rubber
• Cyanate ester
• HDPE – High-Density Polyethylene
• Unplasticized polyvinyl chloride (uPVC)

Applications Of Water Jet Cutting Plastic

The plastic industry makes good use of the waterjet cutting technology because the material is highly compatible with this cutting method. Here are some common sectors you may expect to see waterjet cutting plastic:

1. Automotive Industry

The automotive industry is one of the largest to benefit from waterjet cutters. Automobiles these days use many plastic parts, from carbon fiber exteriors to seats, paddings, and many other mechanical components. Even the windshields are often made using acrylic sheets.

Waterjet cutters have extremely precise cutting capacity and can cut 3d objects. So they are an excellent tool for cutting plastic components without damaging their integrity.

2. Naval Engineering

The naval engineering industry makes practical use of waterjet cutters, much like the automotive industry. Modern shipbuilding uses a lot of hard-plastic and marine-grade plastic for various components. Waterjet cutters are a good tool for handling said parts.

MArine-grade acrylic, for example, is a very tough material that can withstand rough wear and tear. But shipbuilding requires precision cuts. Waterjet cutters come in handy when dealing with such materials.

3. Residential And Nonresidential Construction

Construction and decorations often use plastic material. For example, things like plastic window frames are almost exclusively made using rigid PVC. You will also find nylon building blocks these days because it is a much sturdier alternative to regular blocks. These materials can be cut, shaped, and finished using a waterjet cutter.

4. Toy Industry

The toy industry predominantly uses various molding techniques to make its products, but there’s been a recent surge in using waterjet cutters for the job instead. The main reason is that waterjet cutters are easier to operate, have more efficiency, and are a cost-effective alternative.

Many toys or toy parts are made using waterjet cutters. Another reason people use it is because there’s very little material wastage when using waterjet. That leads to lower production costs.

Advantages Of Water Jet Cutting Plastic

The advantages of waterjet cutters in the plastic industry are plenty. The new 5-axis cutting heads added 3d cutting capabilities opening the window for more opportunities. Here are classic  advantages:

1. Good For Cutting Heat-sensitive material

Waterjet cutters cut without producing any heat, fume, or chemical reactions. That makes it the perfect method for cutting heat-sensitive materials like plastic. The high-pressure water cuts the plastic by grinding the plastic layers with erosion. This method is excellent because it can let your machine cut materials that you otherwise couldn’t put in a CNC machine, like a laser or plasma cutter.

2. 3d Precision Cutting

The 5-axis cutting head can allow you to cut plastic from a wide range of different angles. These cutting heads can move between zero to ninety-degree angles. Such angular movement allows for 3d cutting and shaping, and you can make complex designs with it.

3. Cuts Higher Volume

Waterjet cutters are much more forgiving regarding material thickness than laser or plasma cutters. You can stack up multiple layers of materials and get the same precision of cuts. Doing so saves time and reduces operating costs a whole lot.

That is particularly helpful when cutting larger objects like building blocks, stones, or metal plates. The stacking method works on sheet metal or metal plates too. You can stack them on top of each other. Doing so will let you cut more material at one time.

4. Smooth finish

Many industrial cutting methods leave serrated or tapered edges due to surface tension. Those edges later need to be ground down and second finished. But waterjet cutters cut with a smooth finish, so you don’t need a second finish. That removes an entire step from the production chain, shortening production time.

5. Eco-Friendly Operation

Waterjet cutters have minimal operational costs compared to other CNC cutters. That means it leaves fewer carbon footprints and is comparatively cheaper in the long run. The materials used for the cutting process are limited to water and garnet. Both of which can be recycled at their respective facilities. So there’s no chemical waste left.

Tips And Precautions For Water Jet Cutting Plastic

Waterjet cutters are highly precise and extremely powerful cutting tools, so there are some associated risks that you need to pay attention to. Here’s a list of some of the main ones:

1. Regular Maintenance

Waterjet cutters need regular and thorough maintenance to operate at maximum efficiency. Every time you turn on the machine, make a habit of checking every one of its components and clean what’s necessary.

Also, calibrate your machine and do a few test cuts before putting your actual material up for cutting. One wrong setting can ruin your valuable material. Follow the manufacturer’s guidelines on how to maintain the machine properly.

2. Replace Worn Out Parts

You will need to replace some parts to ensure optimal operating conditions periodically. The diamond orifice, mixing tube, blast shield, and support ribs are some of the most easily worn-down parts. You can technically continue using the support ribs as long as they don’t break, as with the blast shield. 

But the mixing tube and diamond orifice must be changed as soon as they wear out. Otherwise, that’ll affect your cut quality. Worn-out nozzles often lead to jagged cuts instead of a smooth finish.

3. Secure The Material

When cutting anything, ensure the material is firmly secured to the support ribs. Use multiple toggle clamps if you have to. Plastic is very light compared to metal slabs, so they won’t stay in place unless you use something to stabilize them.

6. Protective Gear

Always use protective gear when handling waterjet cutters. Knee guards and safety goggles are a must. The knee guards protect your foot in case you calibrate the machine wrong and the water shoots toward your feet instead.

Additionally, you must also follow any other standard guidelines of your workplace when handling such machinery. Most factories have some regulations in place for this sort of thing.

結論

Hopefully, this guide has helped you understand the importance of water jet-cutting technology. Waterjet cutting plastic is a very efficient cutting method used in many industries. Waterjet cutters are eco-friendly and have a much cheaper operational cost. So it is quickly becoming the mainstream technology in many sectors.

If you want a waterjet machine of your own, feel free to contact us at アイブイシーエヌシー. We have an extensive list of industry-grade waterjet cutters equipped with the latest technology.

FAQ For Water Jet Cutting Plastic

When discussing waterjet cutters, some questions often pop up more often than others. So here’s a list of that:

What’s the cutting speed of a water jet?

The cutting speed depends on what type of material you’re cutting. But slower cuts usually give a smoother finish

Can waterjet cutters cut thick material?

Yes, waterjet cutters can cut thick materials. Sacking multiple layers of the same material is a valid strategy with waterjet cutters because it will save you time.

Can a waterjet cut 3d shapes?

Yes, they can, but you’ll need a 5-axis cutting head for that. A 3-axis cutting head can not cut 3d shapes.

How precise is a waterjet cutter?

The movement of a waterjet cutter has a thousandth-of-an-inch precision movement in the CNC menu.