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Hard Turning or Grinding – Why Grinding is the Better Choice

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Hard Turning or Grinding – Why Grinding is the Better Choice

Posted on by elitech_machine
Hard Part Turning or Grinding, Why Grinding is the Better Choice
17 March 2025

Advancements in CNC turning centers and cutting tools have significantly improved the feasibility of hard turning. However when it comes to precision, cost-effectiveness and process stability, grinding often emerges as the superior choice. At Elitech, we firmly believe that grinding provides better results in many applications.

Elitech is well-known for its Cylindrical OD and ID CNC Grinders, offering cutting-edge solutions for precision grinding. While our expertise extends to both hard turning and grinding, we frequently recommend grinding over hard turning for several key reasons:

1. Superior Surface Finish Tolerance and Roundness

Grinding is unmatched in achieving the highest surface finish standards, holding size tolerance as tight as below 0.010 mm and delivering roundness within 2 microns. Hard turning, while effective, struggles to maintain such consistency across large production runs.

2. Cost-Effective for Hard Materials

Grinding provides a more economical and stable process for materials like ceramic, carbide, which require diamond (PCD or CVD) inserts in turning operations. These inserts wear out quickly, leading to frequent replacements and size variations. In contrast, grinding wheel experience gradual wear and can be dressed to maintain cutting efficiency without stopping production.

3. No Risk of “Lead” on Shaft

A common issue in hard turning is the lead pattern, a spiral texture left by the cutting tool. This surface defect can cause premature seal failures in critical components. Grinding eliminates this issue completely, ensuring a perfectly smooth surface.

4. Grinding Meets Industry Standards

Many industries-including automotive, aerospace, bearing manufacturing – mandate ground finishes for critical components. In such cases, grinding is the only viable option to meet stringent quality requirements.

5. Handles Interrupted Cuts Without Tool Damage

Workpieces with features like keyways or splines create interrupted cuts, which can damage cutting inserts in turning. Grinding wheels, however, are not affected by such interruptions, making them a more reliable choice for complex geometries.

6. Grinding Wheels Offer Better Tool Life & Cost efficiency

A single grinding wheel can last for minimum 10,000 parts before needing replacement, making it significantly more cost-effective than frequently replaced turning inserts.

For example, consider a grinding wheel with a diameter 400 mm and width of 40 mm. The wheel will run until its diameter reaches 300 mm. If 0.010 mm per-piece dressing is applied, the wheel can be changed after 10,000 pieces.

  • Grinding Wheel Grade: A60-L5-V10 (commonly used for hardened materials like EN-8, EN-24, EN-31).
  • Wheel Cost (Estimate in Year 2025): ₹ 4,000.00
  • Cost Per 10,000 Components: ₹ 4,000.00
  • Per-Piece Grinding Wheel Cost: ₹ 0.40

Now, compare this with CNC hard part turning:

  • CNC Tool Cost (Estimate in Year 2025): ₹ 600.00 per insert
  • Tool Change Frequency: After every 50 pieces (angle shift)
  • Tool Corners Available: 3 per tool (total 150 pieces per tool)
  • Per-Piece Insert Cost: ₹ 4.00

This means that grinding is 10 times more cost-effective than hard turning when considering tooling expenses alone.

7. Minimal Downtime, Maximum Productivity

In CNC lathe, inserts must be frequently changed due to wear, causing production downtime. Grinding wheels, on the other hand, last much longer, reducing machine stoppages and increasing throughput.

Consult the Experts at Elitech

Choosing between hard turning and grinding is not always straightforward. It requires in-depth knowledge of both processes to determine the most efficient and cost-effective approach. At Elitech, our team of experts and technology partners can help you make the right decision based on your specific application.

While we continue to expand awareness of high-performance grinding solutions, our ultimate goal is to maximize your productivity and efficiency. If you are looking for precision, consistency and saving, grinding is the way forward!

For expert consultation and cutting-edge grinding solution, contact Elitech today.