WNMG Insert a complete guide for mechanics

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WNMG Insert: Double-sided trigon insert with a stable cutting edge designed for medium- & semi-roughing on steel and cast iron. (-) Trigon Inserts with Two Sides for General Use(+).

WNMG Insert Varieties


Finish cutting (FH) is the First choice for carbon steel, alloy steel, and stainless steel finishing. Chip breaker with two sides. Even at shallow depths of cut, chip control is stable

Cut depth: up to 1m

0.08 to 0.2mm feed rate


LM stands for light cutting. Burr control is excellent. Because the sharpness qualities and cutting edge strength are optimized with varying rake angles, the incidence of burrs is dramatically reduced.

Cut depth: 0.7 – 2.0

Feeding frequency: 0.10 – 0.40


LP – Very light cutting. Butterfly protrusions are tailored to specific cutting circumstances. Chips curl upwards, reducing cutting resistance and resulting in better surface finishes. The breaker protrusion is exceptionally resistant to wear even during high-speed milling, allowing for lengthy durations of steady chip breaking. Excels at copy machining: has a sharp edge shape that produces good chip breaking during copy machining and reverses direction face machining.

Depth of cut: 0.3 – 2.0

Feed rate: 0.10 – 0.40


GM – The primary LM and MM chipbreaker’s sub breaker. For light to medium cutting, it has excellent notch resistance.

Cut depth: 1.0 – 3.5

Feed rate: 0.10 – 0.35


MA – For medium carbon and alloy steel cutting. Chip breaker has two sides and a positive land for the strong cutting action.

Cut depth: 0.08 to 4mm

0.2 to 0.5mm


MP feed rate – Medium slicing. It is suitable for various copy-turning situations, removing the need for different insert kinds. The inner side of the butterfly protrusion features a sharp gradient, which improves chip-breaking efficiency on minor cuts.

Cut depth: 0.3 – 4.0

Feed rate: 0.16 – 0.50


MS – Medium cutting rate for difficult-to-machine materials. Ideal for nickel-based alloys, titanium, and stainless steel.

Cut depth: 0.40-1.8

Feed rate: 0.08 – 0.20


MW – Wiper inserts for medium carbon and alloy steel cutting. Chipbreaker has two sides. The wiper can double the feed rate. The large chip pocket reduces jamming.

Cut depth: 0.9 – 4.0

Rough cutting feed rate: 0.20 – 0.60


RM Outstanding fracture resistance. High cutting edge stability is accomplished during interrupted machining by adjusting the land angle and honing geometry.

Cut depth: 2.5 – 6.0

Rough cutting feed rate: 0.25 – 0.55


RP The peninsular protrusion has been optimized for rough cutting. The increasingly slanted cutting face decreases crater wear and prevents clogging. High fracture resistance: the cutting flute has a robust flat-land form and a large chip pocket to prevent clogging and fracturing during chamfering.

Cut depth: 1.5 – 6.0

Feeding frequency: 0.25 – 0.60

Include problems.

What factors should a shop consider when selecting an indexable insert for a cutting application? In many circumstances, this is likely not how the decision is reached.

Instead of defaulting to the familiar, the best way is to examine the cutting process in detail and then pick an insert with the appropriate features to satisfy the needs and requirements of that application. Insert providers might be of great assistance in this respect. Their expertise can guide you to an insert that is ideal for a specific work but will also assist maximize productivity and tool life.

Before deciding on the best insert, businesses should assess if a detachable cutting tip is a better solution for a project than a reliable tool. One of the most appealing aspects of inserts is that they typically have more than one cutting edge. When a cutting edge becomes worn, it can be replaced by rotating or flipping the insert, commonly known as indexing, to a new edge.

However, indexable inserts are not as hard as solid tools and hence are not as precise.

Starting the Procedure

When the choice to use an indexable insert is made, retailers are faced with a plethora of possibilities. Decide what you want to achieve with the insert as an excellent place to start selecting. While productivity may be the key concern in certain organizations, others may value flexibility more and prefer an insert that can be used to produce several sorts of comparable components, he noted.

Another factor to consider early in the insert selection process is the application, namely, the material to be machined.

Modern cutting tools are material-specific, so you can’t just pick an insert grade that works well in steel and expect it’ll work well in stainless, superalloys, or aluminum.”

Toolmakers provide several insert grades — from more wear-resistant to harder — and geometries to handle a wide range of materials, as well as material circumstances such as hardness and whether a material is cast or forged.

If you’re (cutting) a clean or pre-machined material, your grade option will be different than if you’re (cutting) a cast or forged component. Furthermore, geometry choices for a cast component will differ from that of a pre-machined component.”

Shops should also consider the machines in which an insert will be employed.

Some machines have horsepower restrictions, while others have spindle rpm restrictions. If you don’t consider things, you can pick a carbide grade that has to operate at a higher rpm to be effective but can’t because of machine restrictions.”

Helical-flute indexable thread mills (bottom) are quicker and more efficient than straight-flute indexable thread mills (top), and they typically wear significantly less.

Precision Instruments

Aside from machine capabilities, shops should examine the overall machining setup and assess its stiffness and stability. It comprises the machine’s steadiness and the tool holding or work holding.

“If you can’t clamp a big section of the component, you wouldn’t pick a greater radius insert since it may (raise) tool pressure, causing chatter or lifting the part out of the work holding.”

It claims that if the tool holding or work holding configuration is not firm, the outcome will be noise.

And if you have noise and a too-hard insert substrate, you have a condition that is considerably more prone to insert failure.

Tough vs. Hard

It exemplifies a crucial but perplexing aspect of insert selection: The most durable, wear-resistant insert substrate is not necessarily the best solution for a given application. Consider a case where an insert must be selected to cut forged material in hard places.

Because the tougher the insert, the more brittle it is, running into a difficult cut section might result in catastrophic insert failure.”

Similarly, the most wear-resistant grade for applications with unstable settings is usually not the best choice.

Instead, you’ll probably have to graduate to a higher grade to deal with the vibration caused by the instabilities.

The machining speed of an application is another key consideration in grade selection.

In general, he explained, the goal is to run as quickly as possible to maximize productivity but not run so fast that the pace drastically lowers tool life.

Incorrect speed and feed settings with a certain insert might result in poor surface quality and chip control. He also mentioned that inserts with bigger nose radiuses demand a higher feed rate. Generally, the bigger the nose radius, the higher the feed rate.

“If there is chatter, the natural tendency is to reduce the stream rate,” he explained. “However, in this circumstance, you should do the exact opposite. Chatter and poor surface finishes may result if you do not employ a greater feed rate with a bigger nose radius.”

Common Mistakes

Andersson identifies a few different types of errors that frequently occur when choosing inserts for a document. One’s first focus should be on selecting the optimal grade for a given application; only after that should one think about the many possible geometries with that grade.

Never consider the grade and geometry two different subjects since you may use geometry to help reinforce the grade.

Take, for example, the level of hardness possessed by an insert.

You can measure a material’s mechanical toughness attributes, but the results don’t matter that much. What is important is how the combination of grade and geometry reacts in the machine used by the end-user. And if you choose an exceptionally robust geometry, you will experience an increase in toughness behavior.

Insert microgeometry, also known as edge line condition, and what he refers to as “macro geometry,” which is the form or topography of the top side of the insert, are both examples of factors that fall under the umbrella of “geometry.” In most contexts, the latter is referred to as the chip breaker.

If you look in the catalog of any manufacturer, you’ll find that one material, like steel, typically comes in various grades and chip breakers from which to choose.

Another typical error we mentioned was the misconception that an insert with more cutting edges is invariably the superior option. That would suggest, for instance, that a WNMG insert with six edges is naturally a superior choice to a CNMG insert with only four edges.

When you first hear about the WNMG, your first instinct is probably to assume that the cost per edge would be reduced. However, this is not the case.

He said that the reason for this is because how the WNMG is positioned in its pocket is a somewhat fragile design that permits insert movement while the pocket is machined. Vibration is the direct effect, and this vibration leads to higher wear and a shorter life for the tool. Therefore, in many situations, a CNMG would cut the same number of components over time as a WNMG would.

The demand made by shops for inserts capable of cutting various distinct materials is seen as problematic by industry professionals.

In many situations, four-edge CNMG inserts can cut just as many pieces as their six-edge WNMG counterparts. That is because both types of inserts have two cutting edges.

“The more you utilize the same grade and geometry for various applications, the more compromises you impose. As a result, you start incurring penalties in tool life and chip control, ultimately setting yourself up for failure.”

Shops that choose a general-purpose grade and chip breaker also reduce their cycle time, which is counterintuitive for those seeking to optimize their operations.

On the other hand, several types of machine shops require their equipment to be adaptable enough to handle various machining circumstances.


Two-sided trigon inserts(+). Double-sided trigon inserts for steel and cast iron. First choice for finishing carbon, alloy, and stainless steel. The medium cutting rate for hard materials. Peninsular protrusion for rough cutting.

Slanted cutting face reduces crater wear and clogging. The cutting flute’s sturdy flat-land design and big chip pocket minimize clogs and fractures during chamfering. 1.5-6.0 cut depth, 0.25-0.60 feed rate. Inserts offer many cutting edges, which is a plus. Shops should examine which machines will need an insert. Some machines have horsepower and spindle rpm limits. The most robust, wear-resistant insert substrate isn’t always the greatest. To increase productivity, run as rapidly as feasible without reducing tool life. Six-edged WNMG inserts are better than four-edged ones, argues Andersson. Andersson urges never to separate grade and geometry. Microgeometry and macro geometry fall under “geometry.” A four-edge CNMG can cut as many pieces as a WNMG. Both feature two cutting edges. Additional applications using the same grade and geometry mean more tradeoffs.

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