Why am I getting chips when cutting porcelain panels?

Chipping is a common problem for fabricators

Adam, a tile and stone expert at TST, got a call this morning about a fabricator with a frustrating problem. The fabricator was cutting porcelain panels with a bridge saw blade and getting poor edge quality, rough finish, chipping along the cut line. His saw was running this 14 inch diamond blade at 1,700 RPM on a large porcelain panel and he couldn’t change to a higher RPM. What can he do to reduce chipping on cutting porcelain?

How to cut porcelain chip-free?

It’s a situation Adam hear about regularly. And the fix is simpler than most people expect. Below, we identify 4 easy fix when cutting porcelain and provide expert advice on how to avoid these pitfalls.

#1 what is the material being supported by?

“We recommended to place a rubber or foam under your porcelain slab to reduce vibration,” says Adam. Proper slab support is one of the most overlooked factors in clean porcelain cutting.

WHY

Rubber or foam help absorb vibration generated by blade rotation, machine motor/spindle movement, and resonance through the bridge saw table. They act as vibration dampers, reducing the amount of vibration transferred into the slab. They also provide more uniform support across the slab surface, which helps reduce slab flexing and localized stress during cutting.

#2 Check your Speed Settings & blade’s Max RPM

The best way to reduce chipping on porcelain panels is to increase the blade speed. Higher RPM helps reduce chipping and produces a finer finish, as it creates shallower ‘scratches’ with the diamonds. The faster the blade spins, the shallower those scratches are. Shallower scratches mean a smoother edge.

The number is at least 2,200 RPM for cutting on porcelain panels to reduce vibration.
That’s how you get a finish-grade edge. The edge comes off clean. Minimal cleanup, close to factory finish.

Disclaimer: Use the blade within the required safety specifications. For full Bridge Saw Blade maximum RPM information, please refer to the TST Technical information page.

WHY

Porcelain is an artificially sintered material, so it is extremely hard and dense, but also very brittle and prone to edge blowout, chipping, and micro-cracking. For this reason, blades are typically operated at similar or slightly higher RPM compared to granite or quartzite cutting. If the RPM is too low, it can generate more vibration and impact against the material, increasing chipping and blade glazing.

Here’s the Catch,
what to do when you CAN’T change your RPM?

If your saw is locked at a lower speed and you cannot change your RPM, you can still achieve a professional finish by switching to a larger blade, such as an 18-inch diameter.

WHY

The speed at the outer rim of the blade—where the cutting actually happens—is significantly faster on a larger disc even at the same revolutions per minute. “It is exactly like putting bigger tires on a truck; your speedometer might show the same speed, but you are actually covering more ground much faster,” says Adam. By increasing your blade size, you increase your Surface Feet Per Minute (SFM), allowing the diamonds to strike the stone at the optimal velocity for a cleaner, smoother cut.

#3 Is your blade “SHARP” enough?

Try dressing the blade. “The only way I know to ensure the blade has a fresh layer of new diamond is to run the blade through about 20’ of engineered (abrasive) stone with the blade.” said Adam. This wears away the metal bond and reveals new, sharp diamonds, helping the blade cut cleaner and faster.

Can’t 1” dressing stone work on bridge saw blade?

A traditional 1” dressing stone can help open up a blade, but it may not be enough to fully expose a fresh layer of diamonds, according to Adam. For better results, he recommends dressing the blade with an abrasive stone.

For larger-diameter blades, such as a 14” bridge saw blade, Fredrick H., founder of Stone Forensics, offers another practical option. When asked whether he would still use a dressing stone, he said, “You could use a dressing stone, I have, but if you just place a concrete block on the saw bed..that should work as well.” When asked how many linear feet of concrete block would be needed to expose a fresh layer of diamonds and properly dress the blade, Fredrick explained, “that all depends. a few passes though the long side of a concrete brick should do the trick.

#4 Do you have the right Porcelain Panel Blade?

Porcelain blades typically have finer diamond grits, thinner segments, and softer bond because porcelain is extremely hard, dense, and brittle. “Many porcelain blades have smaller slot gaps to minimize vibration and improve cut quality,” says Kayla K., a diamond tool engineer at TST.

Granite blades generally have medium diamond grit and medium bond hardness, since granite has moderate hardness and abrasiveness. Since quartzite is often harder and more abrasive than granite, quartzite blades may use softer bond and lower diamond concentration to maintain sharpness and reduce cutting load.

Call us for more recommendations

If you’ve checked all of these and you’re still getting chipping on glazed porcelain specifically, the issue may be blade selection rather than speed. Try our ZENESIS™ Nano Wet bridge saw blade, which was designed to cleanly cut through porcelain panels with a glazed (glass) coating. The ZENESIS™ Carbon 2 bridge saw blade is built for sintered stone, Dekton®, and porcelain, but not glazed panels. That’s a different conversation, and we cover it in the next article.