Machining a Deep Sea Pump Shaft with Precision on a Ziersch ZR600 Grinder

Ziersch ZR600 Cylindrical Grinder Overview

• 💡 The ZR600 from Ziersch is a compact, versatile, accurate, and rigid cylindrical grinder being demonstrated.
• 🎯 This machine is ideal for real-world applications like machining a pump shaft for a subsea component.

Pump Shaft Machining Process

• ⚙️ The part is made from 4140 steel and functions as a pump shaft for a subsea component that pumps oil from the ocean floor.
• 📏 Critical dimensions must be precisely ground, making the ZR600 suitable for plunge grinding and traverse grinding.
• 🛠️ The setup utilizes Morse taper #5 in the headstock and #4 in the tailstock for enhanced rigidity, reducing chatter and improving finish.

Traverse and Plunge Grinding Programming

• 📈 The machine's control allows programming up to eight diameters, with this demo using two programs: traverse and plunge grind.
• ➡️ For traverse grinding, the operator programs the length of the shaft, material removal, and Z-axis travel. A gray button indicates traverse mode.
• ⬇️ For plunge grinding, a green button signifies the cycle. The operator manually moves the wheel to scratch the workpiece, teaches the starting location, and sets material removal parameters.
• 💨 Feed rates for plunge grinding are set at 0.02 mm per minute for roughing and 5 microns per pass for finishing, with a spark out count of three.

Wheel Dressing and Grinding Parameters

• 🔄 Wheel dressing can be programmed before, after roughing, after finishing, or after the part. The operator opts for dressing after the roughing cycle for a clean wheel for finishing.
• ⚙️ Key parameters include workpiece speed (120 RPM) and wheel speed (1200 RPM for breakdown, 1261 RPM for grinding), ensuring a good grind and finish.
• 📐 A one-degree taper is dressed into the wheel to enable shoulder grinding without burning the part, creating a crosshatch finish.

Precision and Performance Verification

• 📏 The critical long OD of the pump shaft is checked for taper using a Mitutoyo snap mic, revealing less than a tenth of a taper across a 7-inch length.
• ✅ This demonstrates the impressive accuracy of the ZR600 cylindrical grinder, capable of holding tight tolerances even on long components.
• 🌟 The Ziersch machines are known for being cost-effective, accurate, and rigid, with high-end companies like Shunk using them.