There are compelling reasons for many producers to adopt (or revisit) the use of ceramic cutting tools. Ceramic tools, on the other hand, are unlikely to function to their full potential if programmers continue to "think in carbide" and insist on blindly adopting the same tactics that they have always used. Following a recent meeting with Mr. Howard, the following are 6 suggestions for individuals considering a trial or re-evaluation of ceramic tools:

Tip 1: Prioritize the speed of the surface

"When you're experiencing difficulties, it's natural to slow down," Mr. Howard explains. "It's like when you're driving on a poor road—we all do it. However, when it comes to ceramic tools, this is a huge mistake."

These cutters have a strong desire for surface speed. They have a particular fondness for heat. In contrast to the shearing action of carbide, ceramic melts the material of the workpiece that is in front of it. It is preferable to generate tremendous pressure at the cutting zone, where temperatures can surpass 1,200 degrees Fahrenheit, as opposed to generating chips that transfer heat out from the area. Also read a thorough explanation is provided of everything it does how it.

Ceramic inserts, unlike carbide inserts, do not contain a binder substance such as cobalt, and are therefore specifically engineered to endure the heat-generating pressure. Inserts are typically thick, and chip breakers are virtually non-existent in most cases. If the application permits it, large, rounded corner radiuses are the recommended alternative. The goal, according to Mr. Howard, is to "push the forces into the middle of the insert."

Running at speeds 8 to 10 times faster than a carbide tool might be intimidating, especially when the cutting zone spits red- or even white-hot chips, but sustaining speed is important for effective cutting. If you fail to maintain an acceptable surface feet per minute (sfm) or if you begin to ramp up the speed too slowly, the cut will become mechanical. Cutting speed and tool life both suffer as a result.

Tip #2: Keep in Touch

Disengaging from the workpiece causes the tool to cool, which is detrimental in the case of ceramics. When interruptions are unavoidable, programmers should push through rather than proceeding cautiously, as they would with carbide. In fact, during milling, programmers should make every effort to keep the tool in touch with the workpiece for as long as feasible.

Feeding Tip #3: Feed Quickly

A high spindle speed is an unavoidable prerequisite for achieving sufficient sfm production. Aggressive feed rates are likewise desired, albeit for a different and maybe contradictory reason: to reduce tool wear during the cutting process. "The fewer rotations an insert completes, the longer it will endure." "You don't want to back down in an attempt to defend it," Mr. Howard explains further. Whenever possible, programmers should try to keep the spindle speed (and hence the sfm) as high as possible if the feed rate must be reduced for any reason other than a steep corner.

Tip 4: Be Extra Careful Around Corners

Ceramic's hardness and heat tolerance come at a cost, however: brittleness. Even when using a strong insert, it is recommended to lower feed rates in corners by half as a general rule. When a larger amount of the insert engages the material, this method may be effective in preventing excessive pressure.

Sharper corners and insert points in the shape of diamonds require further attention. Unlike a carbide tool path, which may easily drive the insert around a 90-degree curved corner, engaging a ceramic cutter to this amount is likely to cause it to break, according to Mr. Howard. It is best to first cut along one wall, pull away, and then engage the other wall and feed in the opposite direction (as seen in the photo gallery above) (in this case, removing the tool from the material and allowing it to cool slightly is preferable to subjecting it to forces that may break it). In order to reduce notching and to allow for feeding in both directions, the cut should be made below the 45-degree mark on the cutter radius.

Tip 5: Roughen Sharp Corners and Edges

The modest T-land or sharpened edge is commonly recommended by NTK even when the geometry dictates a thinner, more brittle insert. When used in conjunction with heat-resistant alloys, such characteristics can help to decrease notching, flaking, and built-up edge.

This suggestion is applicable to more than simply inserts. Before machining begins, programmers should take care to round off any regions where the cutter will enter or exit the workpiece. In any other case, the insert may chip or break.

Tip 6: Make Shallow a Priority

Because of the common occurrence of broad, rounded nose radii, machinists may be inclined to cut too deeply while working with this very brittle metal. "They'll shatter the insert and then claim that 'ceramic doesn't function,' but in reality, they've overtaxed it," Mr. Howard explains further.

In turning operations, such events are extremely common. Chip thinning, a phenomena that reduces cutting pressure and is more common when milling with triangle- or diamond-shaped inserts, can be aided by using a round insert. For Mr. Howard, using a round insert results in greater benefits from chip thinning because the depth of cut is decreased. "Once you reach a particular depth of cut, the front of the insert is no longer thinning. It is bearing the full force of the entire feed load.