Pvd Coatings Cuttingtools

PVD Coatings, Cutting Tools and Workpiece Materials in Machining
• Coatings improve cutting tool performance – What does it mean to the customer – Machine shop economics Technical review of functional coatings – Understanding tool materials – Understanding workpiece metallurgy and machinability – Role of coatings in metal cutting New coatings introduced in the market – How do coatings fit theapplication – Coating applications guide

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Dr. Dennis T. Quinto, SECA

What does the coating do for the machine shop?
• Tool life increases, 30% to 200%, depending on application – save on tool costs – fewer tool changes and less downtime on machine • Higher speeds (sometimes higher feed rates) are possible • Dry (or near-dry) machining in certain operations – environmental impact –decrease coolant disposal costs

Increase productivity, decrease costs of machining.
Dr. Dennis T. Quinto, SECA

Machine shop economics
Coatings impact tooling as well as other cost factors significantly

Although coatings only show up as a percentage of tooling costs, the right coating can further reduce costs in machining, downtime, and coolants (and disposal) significantly.
Dr. DennisT. Quinto, SECA

Technical review: materials science, tool coatings and machining processes
• • • • • • Some basic considerations in metal cutting Workpiece mechanical properties and heat generation during machining Tool failure mechanisms Coatings enlarge the tool safe zone in operation Coating properties and control by PVD process Matching the coating to the application

Coating propertiesgreatly determine the tool response to the wear environment.
Dr. Dennis T. Quinto, SECA

Technical review: materials science, tool coatings and machining processes
Some basic considerations in metal cutting Workpiece mechanical properties and heat generation during machining Tool failure mechanisms Coatings enlarge the tool safe zone in operation Coating properties and control by PVD processMatching the coating to the application

• • • • •

Coating properties greatly determine the tool response to the wear environment.
Dr. Dennis T. Quinto, SECA

The metalcutting puzzle tool performance factors tool material coating edge geometry
(with edge prep.)

machining operations
turning, profiling grooving, threading drilling, tapping reaming, broaching milling, hobbing - speeds,feeds, doc

workpiece materials
carbon, alloy steels cast irons stainless, superalloys aluminum alloys titanium alloys - surface finish - chip control

B A

- continuous to interrupted cuts

Dr. Dennis T. Quinto, SECA

Workpiece – tool surface interactions: affected by the coating at the cutting edge

Secondary shear zone

Primary shear zone

Rubbing zone

Heat originates fromplastic deformation energy a) of the workpiece at the primary shear zone and at chip/tool contact areas governed by tribology/friction (i.e. coating) at b) chip secondary shear zone / tool rake face c) machined surface tertiary shear zone / nose/flank face of the tool
Dr. Dennis T. Quinto, SECA

Technical review: materials science, tool coatings and machining processes
• Some basicconsiderations in metal cutting Workpiece mechanical properties and heat generation during machining Tool failure mechanisms Coatings enlarge the tool safe zone in operation Coating properties and control by PVD process Matching the coating to the application

• • • •

Coating properties greatly determine the tool response to the wear environment.
Dr. Dennis T. Quinto, SECA

Workpiece machinabilityof steels
Strength and Ductility of Steels
600 550 500
Higher Cutting Force
HARDENED ALLOY STEELS

~90+ PVD coating ~85 ~70 Carbide tool HSS tool

HRc
56 54 51 47 42 NON-HARDENED ALLOY STEELS 35 30

450 Hardness, HB 400 350 300 250 200 150 100 50 0 0 10

PLAIN CARBON 23 STEELS

20

30

40

Elongation to fracture, % Longer chips
Dr. Dennis T. Quinto, SECA

Relative...