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In 1992, although I knew absolutely nothing about waterjet cutting, I believed it had a great future, and would one day be a sought-after production tool by many industries. Looking back, waterjet cutting has passed even the most optimistic predictions.
The last 15 years have seen every aspect of waterjet cutting change. The machines have become easier to operate, program and service, while the capabilities and applications of waterjet cutting have done a quantum leap. Initially viewed with skepticism, for just the thought of trying to cut a piece of stone with water seemed ridiculous, water technologies are now viewed as precision machining tools, opening up new ways of addressing challenges in cutting and fabrication.
From simple, straight-line actuators slitting materials to systems running multiple 5-axis cutting heads, swiveling around high-tech parts mounted on rotational multiaxis indexers, simultaneously monitoring every aspect of the process all controlled from a remote cell phone, waterjet technology is here to stay.
Yet, as advanced as this technology becomes, there are still certain aspects that have to be understood and cared for. You can go and purchase the latest car of your dreams with every bell and whistle, but if you don't put air in your tires, you won't get far. Waterjet technology is the same. As sophisticated as the systems become, it is still vital to take care of the basics. Who would ever think a bead of sweat that dropped into the abrasive as it was being loaded into the hopper could cause a blockage and shut down a $200,000 piece of equipment?
So, what are some of the helpful tips one should know when looking to own and operate a waterjet system?
People Are Everything
Get the right person to oversee and to run the machine. It is often better to have the right characteristics in the individual, than previous experience.
Look for reliability, a willingness to learn and retain the new knowledge, and someone who is interested — ideally fascinated — with waterjet technology. When everything is running great, anyone can be in charge. But when something stops working, you suddenly need a depth of knowledge and understanding. Find someone who is inquisitive, and get as much training as you can lay your hands on. Every minute will pay for itself hundreds of times.
Safety
Very few safety issues are a must with waterjet, and recorded injuries with CNC waterjet cutting are rare, but the consequences are devastating. If your staff is not prepared to follow the rules, don't get a waterjet machine.
Most important is eye protection. You will never be able to blink in time. Ear protection could be important if sound levels are above the acceptable limit, and be sure to observe all electrical and safety rules of the machine.
Remember you are working with high pressure. Keep a medical explanation for the attending physician in your wallet, and have it attached to the machine in case of an emergency. The manufacturer of your equipment should provide this for you.
Is Waterjet The Right Process?
Take a look at other processes. Many times, the perception after watching a TV show where waterjet is used is that waterjet technology is better than other processes for the application. This may not always be the case.
Look at other methods, and compare the prices and time and motion studies of different processes. Also, calculate the return on investment of the different processes.
Look at the opportunities waterjet technologies offer that other processes don't. Remember, waterjet machines may not necessarily be the best solution to a specific application, but it can do the work of a handful of other processes.
Check cutting speeds, edge quality and tolerances. Waterjet systems cut most aerospace materials and composites, nearly every alloy and steel, the entire range of stones, glass, laminated materials, plastics, wood, leather, foams, rubber, cloth, most food products (frozen or not), and the list goes on. If your company thinks outside the box, or makes or modifies anything, waterjet machinery could be the most valuable and versatile tool your facility could own.
Get The Right Machine And Options
Waterjets come in a wide range of sizes, with an exhaustive and growing list of options to tackle virtually any application. Get a clear understanding of what options are available. Check all options which can be added at a later stage with ease. Can options be installed without the manufacturer having to visit your facility with the accompanying hidden charge?
The largest obstacle you will face will be "up time" in cutting. Regardless of the color of the machine you own, when you are not cutting, you are not making money. Make sure the manufacturer has thought about this and can show you how you can limit downtime with the way its machines are designed.
Get the right cutting envelope. Look at permutations of different sizes of your raw material. Also, check the sizes of your finished pieces, and optimize the yield, which may render the need for a larger or smaller cutting envelope.
Think about where you could improve your own production and efficiency and make up a wish list of things you would like to do with a waterjet. You may be surprised to find it already available. Like:
- Remote monitoring of all aspects of the system from your cell phone.
- Bar code recognition of part numbers.
- Etching part numbers and grain orientation onto the part prior to cutting.
The list is as long as your imagination — limited only by the manufacturer's ability to build the system to accommodate this kind of "out of the box — not just a waterjet" thinking.
Installation
Once you've made a desicion to purchase waterjet technology for your shop, the most important thing is to make sure to install your machine in the right position in your building.
Some machines allow unlimited length slabs to be fed through the waterjet — take this into account when you position the machine on the floor. Make sure you have enough power or can get more power. It can be costly to increase the power later.
Get a full layout of the installation of the waterjet in your building. Use this to plan into the future. Many waterjet companies now have multiple machines. Plan for the same success.
Dos And Don'ts Of Cutting
Waterjet cutting still relies on the same basic principles that were identified 20 years ago. Make sure you are able to apply these consistently, no matter how advanced your system is. A few basic principles to follow are:
- Make sure you have dry compressed air.
- Keep all abrasives dry.
- Never allow moisture to mix with the abrasive outside the cutting head — not even a bead of sweat when loading the abrasive into the hopper.
- Keep all contaminates out of the abrasive and only cut bags open with a knife. Never tear them open.
- Maintain the nozzle height approximately 1/16 in. above the matieral. Height sensors can make this an easy task.
- Check the speed of the z-travel. Make sure you can easily override this to limit breaking of nozzles.
- Check anti-backflow devices are in place on the abrasive delivery system which inhibit water backing up into the mini hopper — a simple but vital lifesaver.
- Make sure all repair work is done in a clean environment. Have the right materials on hand at all times to ensure this.
- Check the pump regularly, and have the operator walk around the machine once an hour just to look and see. There is certainly no harm in doing this.
- Keep the machine clean. Waterjets can get dirty fast. By keeping it clean, the pride in the machine will overflow into work ethics.
- Keep the water level lapping the underside of the materials you are cutting, or if possible cut under water. This will keep air out of the process and cutting will be silent. (This is not easy to do if you don't have a height sensor as you will risk breaking cutting nozzles.)
- Always clamp your work down to the table. Many waterjets do not have an easy way of clamping the parts down, so identify how you will accomplish this.
After The Cutting
Removing the material from the cutting table can be as important as how you put it on. Make sure you have the right tools to lift the materials off your table. This could range from straps, chains, vacuum lifters and, of course, by hand with the proper gloves.
Don't stack wet parts on top of each other. Always dry the parts as soon as they are off the table, and a host of issues will simply not appear and Murphy will be kept at bay just a little longer!
Costing And Efficiency Tips
To make sure you get the most bang for your buck with your new technology, you will want to institute easy ways to track production. Some ways to accomplish this are to:
- Make people accountable with ways to measure and reward progress.
- Provide the correct clothing for the operator who will get wet occasionally. Make sure he or she is comfortable. This will affect the costs at the end of the day.
- Constantly try to find new ways to improve production and controls.
- Maximize cutting time and limit dead time.
Waterjet cutting has to be one of the most mesmerizing processes out there. Having worked as an operator for my first three years, I know. And yet 15 years later, I am still fascinated by the technology, the advances and the capabilities of what water can do.
About the author:
Richard Ward is the founder and president of WARDJet Inc., a manufacturer of waterjet cutting machines; www.wardjet.com; 330-677-9100.
author: By Richard Ward