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DLC Coated HRC55 Tungsten Carbide End Mill, 4mm Square End for Metal Cutting
A 4mm square-end solid carbide mill with a DLC coating, specified for hardened steel up to HRC55.
Design and Construction
A 4mm square-end solid carbide end mill built for hardened steel up to HRC55. The DLC (diamond-like carbon) coating is applied over a fine-grain carbide substrate; the square end leaves a flat floor and a sharp 90-degree corner. The 4mm diameter is a common size for small-format CNC work and die work on hardened inserts.
How It Works
The DLC layer lowers the coefficient of friction at the chip-tool interface, so chips slide rather than weld to the flute. In hardened steel the coating slows crater wear; the square end cuts a flat pocket floor in one pass. Run with rigid clamping and a controlled radial engagement.
Applications
Hardened mould inserts, small-format CNC pocketing, slotting in pre-hardened steel, flat-bottom features.
Field Cases
- Mould shop: a 4mm flat-bottom pocket in HRC52 insert steel held size across a run of 40 cavities.
- Tool room: square corners on a hardened fixture plate finished without a second EDM operation.
- Jobbing CNC: small slots in pre-hardened 4140 cut dry with air blast instead of flood coolant.
Performance Data
| Metric | Value / Observation |
|---|---|
| Cutting diameter | 4 mm |
| Workpiece hardness | Up to HRC55 |
| Coating | DLC (diamond-like carbon) |
| End geometry | Square end, 90-degree corner |
| Runout control | Verified per production lot |
Suitable Materials
Pre-hardened and hardened steels up to HRC55; cast iron; not intended for aluminium or copper alloys where a polished, uncoated flute performs better.
Material Comparison: DLC vs TiAlN vs Uncoated for Hardened Steel
Coating selection for HRC45-55 work. Typical industry data, not a guarantee for a specific setup:
| Factor | DLC (this tool) | TiAlN | Uncoated Carbide |
|---|---|---|---|
| Friction against steel | Lowest | Low | Highest |
| Built-up edge tendency | Minimal | Low | Higher on sticky steels |
| Suitable hardness | Up to ~HRC55 | Up to ~HRC60+ | Up to ~HRC45 |
| Dry / air-blast running | Well suited | Well suited | Coolant preferred |
| Best workpiece | Hardened steel, graphite | Hardened steel, high-temp alloys | Aluminium, plastics, soft steel |
| Cost position | Premium | Premium | Economy |
Delivery Scope
Single end mill, protective sleeve; diameter and flute count confirmed with the order.
Why Choose VPOINT
A hardened-steel tool quoted by the numbers that matter: diameter, hardness ceiling, coating and end geometry.
Precision & Quality Control
Edge hone, coating adhesion and shank runout checked per lot; micron-level inspection with ISO 9001 batch traceability.
Specifications
Published specification:
| Item | Specification |
|---|---|
| Type | Solid carbide square end mill |
| Diameter | 4 mm |
| Coating | DLC |
| Max workpiece hardness | HRC55 |
| End | Square / flat |
| Application | Metal cutting, hardened steel |
| Inspection | Per-lot runout and edge check |
Frequently Asked Questions
Can it cut HRC55 steel?
Yes – HRC55 is the stated ceiling. Use rigid clamping, reduced radial engagement and steady feed.
Why DLC instead of TiAlN?
DLC has a lower friction coefficient, which reduces built-up edge in hardened steel and sticky alloys.
Is it suitable for aluminium?
Not recommended. A polished uncoated flute evacuates aluminium chips better.
Does the square end leave a flat floor?
Yes – the 90-degree corner produces a flat pocket floor with sharp internal corners.
How is precision verified?
Shank runout, edge hone and coating adhesion are checked per production lot.
Related Search Terms
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