Accuromm Central Europe

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Slim profile ensures good machining accuracy!

  • High approachability with compact clamp structure
  • High-precision valve seat machining

High precision machining with the shortest reamer protrusion

Stable machining accuracy by reamer runout adjustment mechanism

Amazing facts!

── Introducing ideas and technologies ──

Plunge-cut valve finishers are available in two types of reamer holding mechanisms: “NLC (Nut-less Collet)” and “Side Lock”.
The NLC type eliminates the clamp nut required for a conventional collet chuck, thereby slimming down the holder body and avoiding interference with the workpiece, making it possible to minimize the amount of reamer protrusion with good accessibility to the workpiece.
The reamer’s runout can also be adjusted to obtain stable machining accuracy of the valve guide hole.

Two types of reamer holding mechanisms

Good!

Nut-less collet (NLC) type

Side lock type

Structure

Reamer runout accuracy

Reamer protrusion

Usability

Price

Legend:
○ Good
◎ Best

This is the point!

NLC type has the shortest reamer protrusion

Excellent!

Conventional product

Nut-less collet (NLC) type

This is the point!

NLC type special collet removal/installation method

Excellent!

Dedicated two-side detachable wrench​

Usage on the machine​

Process engineering

1st process (roughing): pilot hole + valve seat mouth surface machining
2nd process (finishing): valve guide hole finishing + valve seat 45° face finishing

Development / product concept

“Current status and challenges”

  • The machining of valve seat surfaces and valve guide holes in heads with high accuracy requirements has shifted from traverse machining on dedicated machines to plunge machining on machining centers in order to reduce investment, but the machining accuracy was not stable.

“Development points”

  • In plunge-cut type holders, the NLC type eliminates the clamping nut for the reamer with our unique technology.
  • For the side lock type, the run-out adjustment mechanism of the reamer has been downsized to achieve a slimmer holder.
  • This avoids interference with the workpiece and realizes the shortest reamer protrusion and enables stable plunge-type high-precision machining and contributes to investment reduction.

Processing example

NLC type

Machining work

Cylinder head / valve guide hole

Cylinder head / valve seat

Work material

Sintered metal

Tools used

Plunge cut valve finisher
6-flute carbide reamer

Plunge cut valve finisher
Carbide bite

Cutting conditions

Roughing

Finishing

Spindle speed: n = 4600 min-1
Cutting speed: Vc = 80 m/min
Feed: f = 0.3 mm/rev

Spindle speed: n = 1600 min-1
Cutting speed: Vc = 150 m/min
Feed: f = 0.13 mm/rev

Spindle speed: n = 4600min-1
Cutting speed: Vc = 80 m/min
Feed: f = 0.3 mm/rev

Spindle speed: n = 1600 min-1
Cutting speed: Vc = 150 m/min
Feed: f = 0.1 mm/rev

Coolant

Internal coolant

Tooling

Machining accuracy