Kyocera GER250-020B KW10 Internal Grooving Insert

Product Overview

The Kyocera GER250-020B is a precision-engineered uncoated carbide indexable grooving insert optimized for internal grooving operations within bores and cavities. Manufactured in Japan to stringent ISO standards, this KW10-grade insert provides two usable cutting edges for cost-efficient machining of internal grooves, recesses, and seal seats.

The GER250-020B features a B chipbreaker profile and 0.008" nose radius specifically engineered to minimize cutting vibration and ensure stable chip evacuation from confined internal spaces. The KW10 substrate delivers the hardness and wear resistance necessary for high-precision internal grooving in cast iron, non-ferrous materials, and titanium alloys.

ISO Designation Breakdown

Engineering Dimensions & Geometry

Grade Details — Key Grade Characteristics

KW10 Grade Characteristics

The KW10 grade is a premium uncoated fine-grain tungsten carbide specifically developed by Kyocera for machining non-ferrous metals, cast iron, and titanium alloys. This grade combines high hardness with exceptional edge stability.

• Substrate: Ultra-fine grain tungsten carbide (WC) with cobalt binder optimized for internal grooving applications
• Hardness: 92.0 HRA (approx. 1600 HV30) — provides excellent wear resistance at elevated cutting temperatures
• Transverse Rupture Strength: ≥2,600 MPa — resists chipping in interrupted cuts
• Grain Size: Sub-micron (0.5–0.8 μm) — ensures sharp cutting edges and superior surface finish
• Coating: Uncoated — ideal for materials where coating adhesion is problematic (aluminum, copper, titanium)
• ISO Application Group: K10-K20 (cast iron, non-ferrous metals, non-metals, titanium alloys)
• Color Code: Natural carbide gray (uncoated) for easy grade identification

Key Performance Advantage: The absence of coating eliminates built-up edge (BUE) formation on aluminum and copper alloys, delivering mirror-finish surfaces without edge degradation. The fine-grain structure maintains edge sharpness even at low cutting speeds common in small-parts and micro-machining operations.

Grade Comparison Matrix

Note: KW10 is the optimal choice for uncoated applications requiring maximum surface finish and minimal built-up edge. For ferrous materials, consider PR905 or PR930 coated grades.

Chipbreaker Profile

Chipbreaker Profile Analysis

The B-profile chipbreaker features a medium-land geometry with a shallow groove designed for general grooving applications. It provides balanced chip control across a wide feed range and ensures smooth chip evacuation in both continuous and lightly interrupted cuts.

• Chipbreaker Code: B
• Chip Control: Good — medium groove for general applications
• Feed Range: 0.05–0.25 mm/rev
• Depth of Cut: 0.5–5.0 mm
• Chip Form: 6-shaped / C-shaped segments

Recommended Applications & Workpiece Materials

Recommended Applications & Workpiece Materials

The GER250-020B KW10 is specifically engineered for the following material groups and application scenarios:

• Aluminum Alloys: Excellent — internal grooves for hydraulic cylinders and pneumatic valves with superior finish
• Cast Iron (Gray & Ductile): Very Good — stable internal grooving for pump housings and engine blocks
• Copper Alloys: Excellent — internal seal grooves in plumbing and HVAC components
• Titanium Alloys: Good — internal recesses for aerospace fasteners and medical devices
• Brass & Bronze: Excellent — internal grooving for bearing seats and snap-ring grooves
• Non-Metallic Materials: Very Good — internal grooves in ceramic and composite sleeves

Material Compatibility Note: This uncoated grade is NOT recommended for unhardened steels (>0.3% C) or stainless steels where crater wear and built-up edge will rapidly degrade tool life. For ferrous materials, select a PVD-coated grade such as PR905 or PR930.

Application Map by Operation

Recommended Cutting Conditions

Internal Grooving Note: Chip evacuation is critical in internal grooving. Use through-tool coolant whenever possible. Reduce cutting speed by 20% compared to external grooving to compensate for reduced rigidity in internal toolholder configurations.

Operating Guidelines

Operating Guidelines & Best Practices

• Toolholder Selection: Use only Kyocera-approved toolholders with matching insert pocket geometry. Incorrect holder selection will result in poor chip control and premature insert failure.
• Insert Seating: Ensure the insert seats fully in the pocket without rocking. Clean the pocket and seating surface before every insert change. Torque clamping screws to manufacturer specifications.
• Run-In Procedure: For new installations, run at 70% of recommended cutting speed for the first 5 minutes to allow the cutting edge to stabilize and micro-polish.
• Chip Evacuation: Direct coolant nozzles to flush chips out of the groove immediately. Chip recutting is the primary cause of poor surface finish and edge chipping.
• Vibration Control: Minimize tool overhang. Use the shortest possible toolholder and ensure workpiece rigidity. Vibration will destroy cutting edge integrity in micro-grooving and small-parts operations.
• Edge Inspection: Inspect the cutting edge under magnification (10× minimum) after each machining cycle. Replace the insert when flank wear exceeds 0.15 mm or when chipping is visible.
• Speed/Feed Adjustment: If built-up edge (BUE) forms on aluminum or copper, increase cutting speed by 20% or switch to high-pressure coolant delivery.
• Depth Limitations: Do not exceed recommended maximum groove depths. Deep grooves require multiple passes with incremental depth increases of 0.5–1.0 mm per pass.
• Internal Grooving Protocol: Pre-drill the bore to at least 1.5× the groove width larger than the nominal internal groove diameter. Ensure through-tool coolant pressure exceeds 20 bar for reliable chip evacuation from deep bores.

Toolholder Compatibility

Toolholder Compatibility & Mounting

The GER250-020B is compatible with Kyocera SIGE series internal grooving holders and standard internal grooving bar systems. Key compatibility requirements:

• Holder Series: SIGE (primary), SIE (alternative for shallow grooves)
• Insert Pocket: GE-style pocket with right-hand orientation
• Clamping: Top-clamp or screw-clamp depending on holder model
• Coolant Delivery: Through-tool coolant mandatory for grooves >10 mm depth
• Holder Overhang: Maximum 4× bore diameter to maintain rigidity
• Minimum Bore: Bore diameter must exceed groove diameter + 2× holder thickness

Mounting Verification: Before first use, verify that the insert sits flush in the pocket with no visible gaps. Use a dial indicator to check cutting edge height relative to the toolholder reference surface. Edge height should be within ±0.02 mm of centerline for optimal performance.

Packaging & Ordering Information

Packaging & Ordering Information

• Standard Packaging: Individual insert in protective plastic blister pack; 10 inserts per sealed plastic container
• Labeling: Each container includes ISO designation, grade, batch number, and manufacturing date code
• Minimum Order Quantity: 1 insert (bulk pricing available for quantities ≥50)
• Stock Availability: Standard stock item; typically ships within 24 hours of order confirmation
• Storage Recommendation: Store in original packaging at 15–25°C in a dry environment; avoid exposure to corrosive atmospheres
• Country of Origin: Japan (manufactured at Kyocera Precision Tools facility)
• Certification: ISO 9001:2015 quality management; inserts traceable to production batch
• Warranty: Full manufacturer warranty against material and manufacturing defects

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