It’s true that when it comes to glass, it is indeed a brittle material, but that doesn’t mean that it cannot be cut. In fact, by using an abrasive water jet glass can be cut quite easily and the results are generally amazing. Most of the times though, glass is going to be cut for artistic purposes.
The image above was found at www.eltigeraso.com and shows section of a glass cut with Jordon Waterjet machine.
A few factors should be considered when cutting glass, including:
- The design of the part.
- The glass’ support.
- Water delivery and abrasive.
- Glass quality.
Quality of glass
Since there are different types of glass, some of them can be cut easier than the rest. In general though, thicker glass is a lot less easier to cut compared to the thinner type. The temperature at which the glass was tempered is also an important factor that influences the difficulty of cutting the glass. If the temperature was high, then the glass becomes brittle and can shatter easily.
Water delivery and abrasive
During the piercing of the glass, the timing of the abrasive delivery is essential. The recommended pressure should be between ten to twenty thousand PSI and the abrasive should hit the glass almost at the same time as the water starts to flow. If it doesn’t, then it’ll cause the glass to crack.
Some examples of cutting the glass using the previous tips include:
- The abrasive should be turned on period to turning on the water.
- Pulling abrasive though the nozzle should be done using the vacuum assist.
- Take the force out of the water by using a sacrificial material on top of the glass.
- Cut from a previously drilled hole or from the edge of the sheet so that before it reaches the glass, the abrasive and water flow are fully stabilized.
- Increase the pressure slowly starting at 0.
The glass’ support
The glass should be properly supported on the bottom side by using something that’s both soft and can offer even support so the jet won’t frost the bottom surface. For this very purpose, waterjet brick is an excellent choice.
The part’s design
If you’re designing a part cut from glass, there are a few adjustments that can be made for minimizing of any possible cracking may have on the part. You should also know that there is a wide range of piercing methods that can be easily used with glass. With a great setup, you’ll realize that any of them can be very simple to use, but it’s true that some of them are a bit better than others. Therefore, if you’re having trouble getting a great pierce with glass, just consider a different piercing method.
If you’re planning on cutting something that has multiple pierce points, there is a much higher chance it’s going to crack at a minimum of one pierce. That is why before you begin, you should pre-pierce all the start holes and lastly, cut all the other features. In this case, even if something were to crack, you’ll be able to just throw it away and start again without wasting too much money and time.
Other things to consider: Temperature
You need to be on the lookout for sudden changes in temperature between cold air and the hot water tank since this can cause your glass to shatter. For instance, if you just pulled a freshly cut piece of glass out of hot water, you shouldn’t hose it with cold water at all. Instead, wait until it cools down a bit or just let it cool down naturally.
It’s a fact that a great quality abrasive is going to provide superior waterjet parts, yet most of the times it’s going to come in handy when working with finicky materials such as glass. You’ll find that greater mesh sizes can give some pretty smooth results with minimal microchipping on the edges.
At the end of the day, it’s very important how you approach glass cutting and that you always do it by the book. Sure, sometimes you may want to rush things in order to finish a project faster, but you will only do so at your own risk. So take your time to do what you have to do instead of getting your money and time wasted just so you can finish a project a few minutes earlier.
Check this waterjet in action: