Калькуляторы
Empirical Principles, Rules, and Laws in CNC and Metalworking
Empirical Principles, Rules, and Laws in CNC and Metalworking
Computer Numerical Control (CNC) machines and metalworking in general are based on a number of empirical principles that have been derived from years of experience and research. These principles help optimize machining processes, increase tool life, improve surface quality, and enhance the accuracy of finished products.
Contents
- 1. Taylor's Tool Life Equation
- 2. Minimum Feed Step in CNC Machining
- 3. Spindle Resonance Criterion
- 4. Chip Thinning Effect
- 5. Sandvik Principles for High-Speed Machining
- 6. Stability Lobe Diagrams
- 7. Dimensional Ratios in Milling
- 8. Surface Roughness Formulas
- 9. Vibration Control Rules
- 10. Cooling and Lubrication Principles
- Sources
1. Taylor's Tool Life Equation
Taylor's tool life equation, formulated by Frederick Winslow Taylor in the early 20th century, is one of the fundamental empirical laws in the field of metalworking. This law establishes the relationship between cutting speed and tool life.
Taylor's Formula:
V × Tn = C
where:
- V — cutting speed (m/min);
- T — tool life until critical wear (min);
- n — exponent depending on the tool material;
- C — constant dependent on the combination of tool and workpiece materials, as well as cutting conditions.
The exponent n typically takes the following values:
| Tool Material | Value of n |
|---|---|
| High-Speed Steel (HSS) | 0.1 - 0.15 |
| Carbide | 0.2 - 0.3 |
| Ceramic | 0.4 - 0.6 |
| Cubic Boron Nitride (CBN) | 0.5 - 0.7 |
| Polycrystalline Diamond (PCD) | 0.6 - 0.8 |
Taylor's tool life equation allows you to determine the optimal cutting speed for a given tool life or predict the tool life at a given cutting speed.
Calculation Example:
If for a carbide tool when machining structural steel C = 350, n = 0.25, and the required tool life T = 60 minutes, then the optimal cutting speed will be:
V = C / Tn = 350 / 600.25 = 350 / 2.78 ≈ 125.9 m/min
Modern extension of Taylor's tool life equation also takes into account the influence of feed rate and depth of cut:
V × Tn × fm × ap = C
where:
- f — feed rate (mm/rev);
- a — depth of cut (mm);
- m and p — empirical exponents.
Important: Taylor's tool life equation is empirical, and its coefficients must be determined experimentally for specific machining conditions.
2. Minimum Feed Step in CNC Machining
The empirical rule for minimum feed step in CNC machining states that the feed step should be at least 0.01 times the tool diameter to ensure a stable cutting process and prevent premature tool wear.
fmin ≥ 0.01 × D
where:
- fmin — minimum feed step (mm/tooth);
- D — tool diameter (mm).
This rule is based on the need to ensure sufficient material for chip formation. With too small a feed, the tool begins to rub and compress the material rather than cut it, which leads to:
- Increased heat generation;
- Accelerated wear of the cutting edge;
- Deterioration of the machined surface quality;
- Work hardening of the surface layer;
- Vibrations and process instability.
| Tool Diameter (mm) | Minimum Feed Step (mm/tooth) | Recommended Feed Range (mm/tooth) |
|---|---|---|
| 1 | 0.01 | 0.01 - 0.02 |
| 2 | 0.02 | 0.02 - 0.04 |
| 4 | 0.04 | 0.04 - 0.08 |
| 6 | 0.06 | 0.06 - 0.12 |
| 8 | 0.08 | 0.08 - 0.16 |
| 10 | 0.10 | 0.10 - 0.20 |
| 12 | 0.12 | 0.12 - 0.24 |
| 16 | 0.16 | 0.16 - 0.32 |
| 20 | 0.20 | 0.20 - 0.40 |
Rule Application Example:
For an end mill with a diameter of 8 mm:
The minimum feed step should be at least 0.01 × 8 = 0.08 mm/tooth.
If the mill has 4 teeth and the spindle speed is 5000 rpm, then the minimum feed rate will be:
Fmin = 0.08 mm/tooth × 4 teeth × 5000 rpm = 1600 mm/min
Warning: Programming a feed rate below the minimum recommended can reduce tool life by 50-70% and significantly deteriorate machining quality.
For micro-milling and machining of difficult-to-machine materials, special adjustments to this rule may be required taking into account the specific features of the process.
3. Spindle Resonance Criterion
The spindle resonance criterion states that for stable operation, the spindle must operate at frequencies below the first natural frequency of the system to avoid resonance phenomena that can lead to increased vibrations, reduced machining accuracy, and accelerated wear of mechanical components.
foperational < fnatural
where:
- foperational — operational rotation frequency of the spindle (Hz);
- fnatural — first natural frequency of the spindle-tool-workpiece system (Hz).
The natural frequency of the system depends on many factors:
- Rigidity of the spindle and its supports;
- Mass and geometry of rotating parts;
- Length and diameter of the tool (overhang);
- Tool clamping method;
- Rigidity of machine components.
The influence of tool overhang on the natural frequency of the system can be approximately estimated by the formula:
f ∝ (E×I / (ρ×A×L4))1/2
where:
- E — modulus of elasticity of the tool material;
- I — moment of inertia of the tool cross-section;
- ρ — material density;
- A — cross-sectional area;
- L — tool overhang length.
From this relationship, an important practical conclusion can be drawn: when the tool overhang is doubled, the natural frequency decreases by approximately 4 times.
| L/D Ratio | Approximate Reduction in Natural Frequency | Recommended Reduction in Rotation Speed |
|---|---|---|
| 3:1 | Baseline (100%) | Not required |
| 4:1 | up to 70% | 10-15% |
| 5:1 | up to 50% | 20-30% |
| 6:1 | up to 35% | 35-45% |
| 7:1 | up to 25% | 50-60% |
| 8:1 | up to 15% | 65-75% |
Special methods are used to determine the natural frequencies of the system:
- Modal analysis using accelerometers;
- Test runs with gradual increase in rotation frequency;
- Sound spectrum analysis during machine operation;
- Finite element modeling of the system.
Resonance Assessment Example:
If the first natural frequency of the spindle-tool system is 600 Hz (36,000 rpm), it is recommended not to exceed 80% of this value, i.e., 480 Hz or 28,800 rpm, to have a stability margin.
Recommendation: For high-speed machining, it is advisable to use specialized tool holders with damping elements that increase the first natural frequency of the system and allow operation at higher speeds.
4. Chip Thinning Effect
The chip thinning effect occurs when milling with a radial engagement of less than 50% of the cutter diameter. Under such conditions, the effective chip thickness becomes smaller than the programmed feed per tooth, which requires adjustment of cutting parameters to maintain optimal tool load.
heff = fz × sin(θ)
where:
- heff — effective chip thickness;
- fz — feed per tooth;
- θ — cutter contact angle with the workpiece.
To compensate for this effect, a correction factor is used:
Kct = 1 / √(ae / D)
where:
- Kct — chip thinning compensation factor;
- ae — radial depth of cut (milling width);
- D — cutter diameter.
The corrected feed per tooth is calculated as:
fz_corr = fz × Kct
| ae/D Ratio | Kct Factor | Recommended Feed Increase |
|---|---|---|
| 50% | 1.41 | 40% |
| 40% | 1.58 | 60% |
| 30% | 1.83 | 80% |
| 20% | 2.24 | 120% |
| 10% | 3.16 | 220% |
| 5% | 4.47 | 350% |
Calculation Example:
If when milling with a 10 mm diameter cutter, the standard recommended feed is 0.05 mm/tooth at full radial engagement, then with an engagement of 20% (ae = 2 mm), the corrected feed should be:
Kct = 1 / √(2/10) = 1 / √0.2 = 1 / 0.447 ≈ 2.24
fz_corr = 0.05 × 2.24 = 0.112 mm/tooth
Important: Increasing the feed rate with small radial engagement helps maintain optimal chip thickness, preventing tool overheating and improving chip evacuation, which is especially important in high-speed machining.
5. Sandvik Principles for High-Speed Machining
Sandvik Coromant, one of the world leaders in metalworking, has formulated a number of empirical principles for high-speed machining (HSM) that help optimize the process and increase productivity.
5.1 Material Removal Rate Constancy Principle
According to this principle, the volume of material removed per unit time (MRR - Material Removal Rate) should be kept constant to ensure process stability.
MRR = ae × ap × vf = const
where:
- ae — radial depth of cut (mm);
- ap — axial depth of cut (mm);
- vf — feed rate (mm/min).
This means that when changing one parameter, it is necessary to correspondingly adjust the others to maintain a constant MRR.
5.2 The "10-6-2" Rule
For high-speed machining of aluminum alloys, Sandvik recommends the following ratios:
- Radial engagement: ae ≤ 0.1×D (10% of tool diameter);
- Axial depth of cut: ap ≤ 0.6×D (60% of tool diameter);
- Feed per tooth: fz ≈ 0.02×D (2% of tool diameter).
5.3 Material Removal Rate Principle for Finishing
Q = (π × D × ae × vf) / 1000
where:
- Q — material removal rate (cm³/min);
- D — tool diameter (mm);
- ae — radial depth of cut (mm);
- vf — feed rate (mm/min).
| Machining Type | Radial Engagement (ae) | Axial Depth (ap) | Recommended Feed per Tooth |
|---|---|---|---|
| Roughing HSM of Steel | 15-20% D | 1-1.5×D | 0.015-0.03×D |
| Semi-finishing HSM of Steel | 10-15% D | 0.5-1×D | 0.01-0.02×D |
| Finishing HSM of Steel | 5-10% D | 0.2-0.5×D | 0.005-0.015×D |
| Roughing HSM of Aluminum | 20-30% D | 1-2×D | 0.02-0.04×D |
| Finishing HSM of Aluminum | 5-15% D | 0.5-1×D | 0.01-0.03×D |
5.4 Minimum Internal Radius Principle
When high-speed machining internal corners, it is important to observe the ratio:
Rinternal ≥ 0.15 × D
where:
- Rinternal — internal corner radius;
- D — tool diameter.
Recommendation: In HSM, strive for gradual changes in machining direction, avoid sharp changes in trajectory, and use strategies with constant radial engagement, such as trochoidal milling.
6. Stability Lobe Diagrams
Stability Lobe Diagrams (SLD) are an empirical tool for determining zones of stable and unstable machining depending on the depth of cut and spindle speed. They are based on the theory of the regenerative effect and help avoid vibrations in metalworking.
The key phenomenon described by stability lobe diagrams is self-excited vibrations or "chatter," arising from the regenerative effect when the tool passes over the surface left by the previous tooth.
6.1 Formula for Determining the Width of the Stability Lobe
nc = 60 × fc / (N × (k + ε))
where:
- nc — critical spindle speed (rpm);
- fc — system vibration frequency (Hz);
- N — number of cutter teeth;
- k — integer (k = 0, 1, 2, ...);
- ε — phase shift (usually taken as 0.25 for milling).
The limiting depth of cut at the stability boundary can be estimated by the formula:
alim = -1 / (2 × Ks × Re[G(ωc)])
where:
- alim — limiting depth of cut;
- Ks — specific cutting force;
- Re[G(ωc)] — real part of the system transfer function at the vibration frequency.
Practical Application: Stability lobe diagrams allow selecting optimal machining parameters at which the depth of cut can be increased without vibrations, which significantly increases productivity.
6.2 Methodology for Determining Machining Stability
In engineering practice, the following methods are used to construct stability lobe diagrams:
- Modal analysis of the machine and tool to determine the transfer function;
- Experimental determination of stability boundaries by gradually increasing the depth of cut at various spindle speeds;
- Analysis of the vibration spectrum during machining;
- Use of specialized software that simulates the cutting process.
Example of Use:
If the first natural frequency of the spindle-tool system is 800 Hz, and the cutter has 4 teeth, then the most stable spindle speeds will be:
nc(k=0) = 60 × 800 / (4 × (0 + 0.25)) = 48,000 rpm
nc(k=1) = 60 × 800 / (4 × (1 + 0.25)) = 9,600 rpm
nc(k=2) = 60 × 800 / (4 × (2 + 0.25)) = 5,333 rpm
7. Dimensional Ratios in Milling
In metalworking practice, there are a number of empirical relationships connecting the geometric parameters of the tool and cutting modes. These relationships help optimize the machining process and avoid problems with vibration and premature tool wear.
7.1 Tool Overhang to Diameter Ratio Rule
L ≤ 4 × D
where:
- L — tool overhang (length from the holder to the end of the tool);
- D — tool diameter.
When exceeding this ratio, it is necessary to reduce cutting parameters according to the table:
| L/D Ratio | Correction Factor for Speed | Correction Factor for Feed |
|---|---|---|
| 4:1 | 1.0 | 1.0 |
| 5:1 | 0.9 | 0.9 |
| 6:1 | 0.8 | 0.8 |
| 7:1 | 0.7 | 0.7 |
| 8:1 | 0.6 | 0.6 |
| 10:1 | 0.4 | 0.4 |
7.2 Minimum Wall Thickness Rule in Milling
tmin ≥ 0.2 × D
where:
- tmin — minimum wall thickness;
- D — diameter of the cutter used.
When machining thin walls, it is recommended to:
- Use support (stops) on the opposite side;
- Apply alternating material removal from both sides of the wall;
- Reduce the depth of cut and increase the number of passes;
- Use cutters with a larger number of teeth and a positive rake angle.
7.3 Slot Depth to Width Ratio
h ≤ 2.5 × w
where:
- h — slot depth;
- w — slot width.
When it is necessary to mill deeper slots, it is recommended to use other technologies (such as electrical discharge machining) or special long-edge cutters.
Example of Applying the Rules:
For a 10 mm diameter cutter:
- Maximum recommended overhang: 4 × 10 = 40 mm
- Minimum thickness of the machined wall: 0.2 × 10 = 2 mm
- For a 10 mm wide slot, the maximum recommended depth: 2.5 × 10 = 25 mm
8. Surface Roughness Formulas
Surface roughness of the machined surface is an important indicator of the quality and functionality of the part. There are a number of empirical relationships that allow predicting roughness depending on machining parameters.
8.1 Theoretical Roughness in Milling
Rt = fz² / (8 × R)
where:
- Rt — theoretical height of irregularities (mm);
- fz — feed per tooth (mm/tooth);
- R — tool radius or nose radius (mm).
For a flat-end mill when machining with the side:
Ra ≈ 0.032 × fz² / D
where:
- Ra — arithmetic mean roughness (μm);
- fz — feed per tooth (mm/tooth);
- D — mill diameter (mm).
8.2 Theoretical Roughness in Turning
Rt = f² / (8 × rε)
where:
- Rt — theoretical height of irregularities (mm);
- f — feed (mm/rev);
- rε — tool nose radius (mm).
To convert the theoretical height of irregularities Rt to the Ra parameter, an approximate relationship is often used:
Ra ≈ 0.25 × Rt
| Feed (mm/rev) | Nose Radius (mm) | Theoretical Ra (μm) | Practical Ra (μm) |
|---|---|---|---|
| 0.1 | 0.4 | 0.78 | 1.0 - 1.5 |
| 0.1 | 0.8 | 0.39 | 0.6 - 0.9 |
| 0.05 | 0.4 | 0.20 | 0.35 - 0.5 |
| 0.05 | 0.8 | 0.10 | 0.2 - 0.3 |
Practical Aspect: Actual roughness is usually 1.5-2 times higher than theoretically calculated due to the influence of additional factors: vibrations, tool wear, material heterogeneity, deformations, etc.
Calculation Example:
When turning with a feed f = 0.2 mm/rev and a tool nose radius rε = 0.5 mm:
Rt = 0.2² / (8 × 0.5) = 0.04 / 4 = 0.01 mm = 10 μm
Ra ≈ 0.25 × 10 = 2.5 μm
Taking into account practical factors, an actual roughness Ra in the range of 3.5-5 μm can be expected.
9. Vibration Control Rules
Vibrations are one of the main problems in metalworking, affecting accuracy, surface quality, and tool life. There are a number of empirical rules that help minimize their impact.
9.1 Tooth Entry Frequency to Natural Frequency Ratio Rule
fz ≠ fn / k
where:
- fz — tooth entry frequency into the material (Hz);
- fn — natural frequency of the system (Hz);
- k — integer.
The tooth entry frequency is calculated as:
fz = n × Z / 60
where:
- n — spindle rotation speed (rpm);
- Z — number of cutter teeth.
9.2 Variable Pitch Cutter Usage Rule
Cutters with variable tooth pitch are often used to suppress vibrations. The effectiveness of such an approach can be estimated by the formula:
ΔΦ = Φi+1 - Φi = 360° / Z ± Δ
where:
- ΔΦ — angular pitch between adjacent teeth;
- Z — total number of teeth;
- Δ — angular variation magnitude (usually 10-15%).
9.3 Depth of Cut Rule for Unstable Milling
When vibrations occur, it is recommended to change the axial depth of cut according to the formula:
ap_stable = ap_original × (0.5 + 0.4 × sin(2π × n / 60 × fn))
where:
- ap_stable — stable depth of cut;
- ap_original — original depth of cut;
- n — spindle rotation speed (rpm);
- fn — natural frequency of the system (Hz).
| Vibration Type | Signs | Elimination Method |
|---|---|---|
| Forced oscillations | Regular texture related to spindle revolutions | Balancing of rotating parts, increasing clamping rigidity |
| Self-excited oscillations (chatter) | Irregular marks on the surface, characteristic sound | Changing spindle speed, reducing tool overhang |
| Resonance oscillations | Occur at certain rotation speeds | Changing rotation speed in the range of ±10% from resonance |
| Regenerative oscillations | Intensify with each tool pass | Using cutters with variable tooth pitch, changing feed rate |
Practical Example of Speed Selection:
If strong vibrations occur during milling at a speed of 5000 rpm, and it has been experimentally determined that the natural frequency of the system is about 800 Hz, more stable speeds can be calculated:
nstable = 60 × 800 / (4 × 2.25) = 5333 rpm
or
nstable = 60 × 800 / (4 × 1.25) = 9600 rpm
Practical Recommendation: In the absence of special equipment for modal analysis, an empirical method of gradually changing the spindle rotation speed (±20% from the current) can be used to find the stability zone.
10. Cooling and Lubrication Principles
Effective cooling and lubrication play an important role in the metalworking process, affecting tool life, surface quality, and dimensional accuracy. There are a number of empirical rules that determine the optimal cooling parameters.
10.1 Coolant Pressure and Cutting Speed Correlation Law
P ∝ V2
where:
- P — optimal coolant supply pressure (bar);
- V — cutting speed (m/min).
In practice, this means that when the cutting speed is doubled, the coolant supply pressure must be increased by 4 times to maintain cooling efficiency.
10.2 Minimum Coolant Flow Principle
Qmin = k × Ac
where:
- Qmin — minimum coolant flow rate (l/min);
- Ac — chip cross-sectional area (mm²);
- k — coefficient depending on the material (usually 0.5-1.0 l/min·mm² for steel).
The chip cross-sectional area is calculated as:
- For turning: Ac = ap × f
- For milling: Ac = ae × ap / (π × D) × Zc
where Zc is the number of cutter teeth simultaneously in work.
10.3 Emulsion Concentration Selection Rule
| Operation | Workpiece Material | Recommended Concentration |
|---|---|---|
| Regular turning, milling | Steel, cast iron | 3-5% |
| Drilling, thread cutting | Steel, cast iron | 5-8% |
| Deep drilling | Steel, cast iron | 8-12% |
| Aluminum machining | Aluminum alloys | 4-7% |
| Titanium and heat-resistant alloy machining | Titanium, stainless steel | 8-15% |
10.4 Cooling Method Selection Rule Depending on Cutting Speed
| Cutting Speed Range | Recommended Cooling Method |
|---|---|
| Low speeds (up to 80 m/min) | Abundant jet cooling, emulsion |
| Medium speeds (80-200 m/min) | High-pressure cooling (20-70 bar) |
| High speeds (200-500 m/min) | Oil mist (MQL) or ultra-high pressure cooling |
| Ultra-high speeds (>500 m/min) | Dry machining or gaseous cooling (CO₂, N₂) |
Example of Minimum Coolant Flow Calculation:
When turning steel with a depth of cut ap = 3 mm and feed f = 0.2 mm/rev:
Ac = 3 × 0.2 = 0.6 mm²
Qmin = 0.8 × 0.6 = 0.48 l/min
In practice, to ensure reliable cooling and chip evacuation, it is recommended to use a flow rate with a safety factor of 1.5-2, i.e., Q = 0.72-0.96 l/min.
Note: In high-speed machining, the application of minimum quantity lubrication (MQL) or completely dry machining is often more effective, as at high speeds most of the heat is carried away with the chip, and coolant can cause thermal shock to the cutting edge.
Key Components of CNC Machines and Their Impact on Metalworking Quality
The effectiveness of applying all the empirical principles and laws of metalworking described above directly depends on the quality and proper selection of mechanical components for CNC machines. The accuracy, reliability, and productivity of the equipment are determined by components that must meet the requirements of modern high-precision production.
Bearings as the Foundation for Rotational Accuracy
At the core of any CNC machine are various types of bearings that ensure the accuracy and smoothness of spindle rotation and other assemblies. Bearing quality directly affects vibrations and consequently the roughness of the machined surface. For high-speed machining, precision roller bearings capable of operating at high speeds without excessive heating and with minimal radial runout are particularly important. In assemblies with variable rotation direction, overrunning clutches are often used, providing quick reversal without loss of positioning accuracy. For heavily loaded assemblies and high-temperature operating conditions, plain bearings become the optimal choice, as they dampen vibrations and provide more stable machining quality.
Bearing Units and Housings
The design of bearing units plays a key role in ensuring the rigidity of the entire machine system. According to empirical observations, increasing the rigidity of bearing units by 50% can improve machining accuracy by up to 30% and significantly expand the stability ranges according to the diagrams described in Section 6. Properly selected bearing housings not only protect the bearings themselves from external influences but also serve as an important element in the machine's thermal regulation system. Temperature stability is a key factor in ensuring dimensional accuracy during long machining cycles.
Linear Movements and Their Accuracy
The accuracy of linear movements in CNC machines is ensured by a complex of components, including shafts, guide rails and carriages, as well as ball screws. It has been empirically established that to ensure the minimum feed step described in Section 2, a ball screw of accuracy class C3 or higher is required. The maximum movement speed of the ball screw must be coordinated with the resonance criterion considered in Section 3 to avoid vibrations during rapid movements. For high-speed machining, it is recommended to use ball screws with a pitch of at least 5 mm and a diameter that ensures system rigidity of not less than 300 N/μm.
Transmission and Auxiliary Elements
The complex of transmission elements forms the system for transferring movement from motors to executive mechanisms. An efficient transmission minimizes energy losses and ensures exact correspondence between the specified and actual movement. Ball supports serve to reduce friction and ensure smooth movements, which is especially important in high-precision machining. To implement the high-speed machining principles described in Section 5, precision gear racks are often used, which, in combination with servo motors, provide high dynamics and movement accuracy. It has been empirically proven that using racks with a module of 1.5-2 mm and an accuracy class of not lower than 6 allows achieving a positioning accuracy of up to 0.01 mm over a movement length of up to 1 meter.
When designing and upgrading CNC machines, it is recommended to choose components with a load reserve of at least 30% over the calculated value and to consider all the empirical principles outlined in this article to ensure an optimal balance between productivity, accuracy, and equipment durability.
Sources
- Trent, E.M., Wright, P.K. (2000). Metal Cutting (4th ed.). Butterworth-Heinemann.
- Sandvik Coromant (2020). Metal Cutting Guide.
- Altintas, Y. (2012). Manufacturing Automation: Metal Cutting Mechanics, Machine Tool Vibrations, and CNC Design (2nd ed.). Cambridge University Press.
- Childs, T., Maekawa, K., Obikawa, T., & Yamane, Y. (2000). Metal Machining: Theory and Applications. Arnold Publishers.
- Davim, J.P. (Ed.) (2008). Machining: Fundamentals and Recent Advances. Springer.
- Stephenson, D.A., Agapiou, J.S. (2016). Metal Cutting Theory and Practice (3rd ed.). CRC Press.
- Schmitz, T.L., Smith, K.S. (2019). Machining Dynamics: Frequency Response to Improved Productivity. Springer.
- ISO 8688-1:1989. Tool life testing in milling — Part 1: Face milling.
- Mitsubishi Materials (2019). Technical Guide for Metal Cutting Tools.
- Kennametal (2018). Master Catalog and Technical Recommendations.
Disclaimer
This article is for informational purposes only and represents a compilation of empirical data from various sources. The principles, rules, and formulas presented are general recommendations and may require adjustment depending on specific machining conditions, equipment characteristics, and materials.
The author assumes no responsibility for any consequences arising from the application of the information contained in this article. When conducting actual work, it is necessary to follow the recommendations of equipment and tool manufacturers, as well as observe the relevant safety standards and rules.
For accurate data on specific machining conditions, it is recommended to conduct test trials and consult with specialized professionals.
