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Common Issues in Machining Stainless Steel with Lizhou Turning Inserts
time：
2026-04-21 08:57
source：
Lizhou
Table of Contents
- What is the naming convention for turning inserts?
- What are the types of turning inserts?
- Which turning inserts can be used to machine stainless steel?
- What are the differences between internal and external turning inserts?
- Common issues with turning inserts?
I. Naming of Turning Inserts
Naming conventions for turning inserts vary across the market, with each manufacturer employing its own system. Next, let’s take a look at Lizhou’s naming rules for turning inserts:
Image of Turning Insert Naming Rules
II. What are the types of turning inserts?
There are many ways to classify turning inserts; they are generally divided into negative-rake inserts and positive-rake inserts. Negative-rake inserts, in turn, are further categorized as triangular, square, peach-shaped, and diamond-shaped inserts.
1 What are some common negative-rake inserts?
Triangular, square, peach-shaped, and diamond-shaped turning inserts all feature negative-rake inserts; typically, negative-rake inserts are double-sided, whereas positive-rake inserts are single-sided.
2. Can blade inserts of different shapes all be used to machine stainless steel?
Generally, cutting inserts are selected based on the specific operating conditions; each insert geometry is capable of machining stainless steel.
III. Which turning inserts can be used to machine stainless steel?
Stainless steel machining can be categorized into finish machining, semi-finish machining, and rough machining, each of which calls for different turning inserts. Today, we will focus on the machining methods themselves and discuss how to select the appropriate turning inserts for each:
1. Finish Machining:
Recommended turning inserts: WNMG080404 or VCMT110304 These are peach-shaped and diamond-shaped turning inserts, suitable for internal machining of stainless steel. / External cylindrical finishing
2 , Semi-finishing:
Recommended turning inserts: TNMG160404 This blade is triangular, 6 Positive rake angle, smooth cutting, reduced vibration—ideal for external turning. / Inner hole.
3 1. Rough machining:
Recommended turning inserts: CNMG120404 This blade is a square-shaped, negative-rake, thick-coated blade. + Tough matrix, suitable for 304/316 Rough turning.
IV. What are the differences between internal-diameter and external-diameter turning inserts?
Many newcomers to CNC machine tools wonder: Can internal-turning inserts and external-turning inserts be used interchangeably? Although they may look similar in length, their actual applications differ significantly; using them incorrectly can easily lead to insert breakage, cutting-edge chipping, or even workpiece damage. We can identify the differences between external- and internal-turning inserts by following these methods.
1. Different sizes and shapes
External turning inserts: the typical dimensions tend to be on the larger side; for example, the ones we commonly see... SNMG1204\TNMG1604 Wait—typically, the shapes are square, peach-shaped, or large triangular, with high cutting-edge strength.
Internal turning dimensions: generally slightly undersized, for example CCMT0602\CCMT09T3 Wait a moment—typically, small diamonds and small triangles are used, which have a small volume and a sharper cutting edge.
2. Different rake angle and cutting edge design
External-diameter inserts typically use negative-rake inserts, which feature a robust cutting edge, excellent impact resistance, and are well-suited for rough machining, intermittent cutting, and workpieces with blackened surfaces.
External-diameter inserts are typically positive-rake inserts, which enable lighter, smoother cutting with lower cutting resistance, thereby reducing vibration during internal-hole machining and preventing tool-holder deflection.
3. Different installation and usage scenarios
The external-diameter insert is mounted on a robust, rigid external turning tool holder, primarily used for turning external diameters, end faces, external grooves, and external threads, among other operations.
Internal-diameter inserts are typically mounted on internal-bore boring bars, which are slender and long, resulting in relatively poor rigidity. They are primarily used for boring internal holes, internal tapered surfaces, and internal grooves.
V. Common Issues with Turning Inserts
Q1: Why are turning inserts prone to chipping?
Answer: The primary causes are improper cutting parameters, excessively hard workpiece material, significant impact from intermittent cutting, insufficient insert toughness, or poor machine tool rigidity leading to excessive vibration.
Q2: What causes blade wear to be too rapid and resulting in a short service life?
Answer: Typically, this is caused by insufficient cooling, excessive cutting speed, mismatch between the insert grade and workpiece material, or inadequate wear resistance of the insert itself.
Q3: What should you do if the tool sticks during machining or metal chips adhere to the cutting blade?
Answer: This is most commonly observed in sticky materials such as stainless steel, titanium alloys, and aluminum alloys.
Q4: Is the surface of the turned workpiece rough?
Answer: Common causes include blade dulling, an excessively small nose radius, and significant machine tool vibration.
Q5: Can turning inserts be used interchangeably for outer and inner diameters?
Answer: Ideally, it should not be universal.
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