Tool Selection For Composites

Here is a summary of some cutting tool designs for composites, and how those tools are used.

Article From: 8/5/2008 Modern Machine Shop

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PCD “Serf” Cutter

PCD “Serf” Cutter

One Shot Drill Reamer

One Shot Drill Reamer

Solid Carbide Burr Cutter

Solid Carbide Burr Cutter

PCD 8-Facet Point Drill

PCD 8-Facet Point Drill

Nano-Crystaline Thin Film Diamond Drill

Nano-Crystaline Thin Film Diamond Drill

Solid Carbide “Un-Ruffer”

Solid Carbide “Un-Ruffer”

Solid Carbide Kevlar Drill

Solid Carbide Kevlar Drill

Double Margin Piloted Step Drill

Double Margin Piloted Step Drill

Solid Carbide 8-Facet Drill

Solid Carbide 8-Facet Drill

Solid Carbide Carbon Graphite Cutter

Solid Carbide Carbon Graphite Cutter

Step Drill/Reamer

Step Drill/Reamer

Drivematic Drill And Countersinks

Drivematic Drill And Countersinks

In composite materials, standard metalcutting drill or end mill designs would be like to wear quickly and/or produce defects such as delamination. Various alternative cutting tool designs have succeeded in milling and drilling various composite materials. Cutting tool supplier Onsrud offers this summary of some cutting tool designs for composites and how the tools are used.

 

 

 

Solid Carbide Kevlar Drill

■ Designed to produce a clean hole in Kevlar materials.

■ The point geometry prevents whiskers and delamination during drilling.

■ Coatings can be applied to increase tool life.

■ Basic cutting parameters: 0.0005 to 0.001 ipr feed rate and 300 to 4,000 rpm spindle speed.

 

 

Solid Carbide 8-Facet Drill

■ The 8-facet drill was designed to produce a clean hole in composite materials and eliminate delamination.

■ Typically the 8-facet point consists of two point angles—90 degrees and 118 degrees—with two ground facets (primary and secondary) on each angle.

■ Basic cutting parameters: 0.025 to 0.075 mm per revolution feed rate and 3,500 to 5,000 rpm spindle speed. In 0.25-inch carbon fiber sheet, 0.05 mm per revolution at 3,000 rpm.

 

 

PCD 8-Facet Point Drill

Application: Designed for drilling abrasive materials such as graphite epoxy and carbon fiber material.

Design:

■ 8-facet point grind improves hole accuracy because the secondary point angles offer a self-seating, reaming action that resists lateral pressures.

■ Point also has good chip breaking properties because the primary and secondary cutting edges produce an angular formed ribbon that breaks more readily and prevents damage to the CFRP hole wall.

 

 

Nano-Crystaline Thin Film Diamond Drill

Application:

■ Lower-cost alternative to PCD-tipped drill.

■ Designed for drilling abrasive materials such as graphite epoxy and carbon fiber material.

Design:

■ Parabolic flute design to accommodate and evacuate large volume of chips.

■ High helix angle provides increased rake suitable for machining of composites and aluminum.

■ Split point design reduces thrust and creates additional cutting edges for reduction in drilling torque.

■ Secondary point angles offer a self-seating, reaming action that resists lateral pressures and directs chips away from the inner hole wall.

 

 

Drivematic Drill And Countersinks

Application:

■ Designed for use in automatic fastening machines.

■ Drill and countersink rivets in one operation to a tolerance of 0.003 inch

Design: Tailored for various “Drivematic” series machines.

 

 

One Shot Drill Reamer

Application:

■ Drill and ream in one shot in graphite epoxy and carbon fiber material.

■ Most often used in manual applications.

■ Used in single sheet applications.

Design:

■ Reduced web thickness reduces thrust required to penetrate material.

■ Lead taper allows for ease of reaming by displacing load over a longer cutting surface.

■ Two distinct cutting edges: one for drilling and one for reaming.

 

 

Double Margin Piloted Step Drill

Application:

■ Designed for drilling close tolerance holes (typically within 0.003 inch) in composite stacks.

■ Often used as a second pass tool in multi-step drilling process

Design:

■ Pilot diameter typically 75 percent of major diameter.

■ Pilot length typically 1 drill diameter.

■ Step diameter lowers the initial drilling force and also can serve as a guide in a pilot hole.

 

 

Step Drill/Reamer

Application:

■ Designed for drilling close tolerance holes (typically within 0.0015 inch) in composite stacks.

■ Significant time savings from elimination of tool withdrawal, tool changing and tool indexing as required for normal drill and reamer operations.

■ Designed for aluminum, composite or material combinations.

Design: Step diameter lowers the initial drilling force and also can serve as a guide in a pilot hole.

 

 

Solid Carbide Burr Cutter

■ Considered the basic tool for cutting fiberglass and composite materials.

■ Considered the best tool for hand routing applications.

■ Available with endmill point or drill point geometry.

■ Can be diamond coated. Testing has shown that that diamond coating will extend tool life approximately 3 to 4 times.

■ Should be considered a single-edge cutter when calculating chip loads and feed rates.

■ Basic Cutting Parameters: 0.1 to 0.15 mm chip load and 12,000 to 16,000 rpm spindle speed.

 

 

Solid Carbide “Un-Ruffer”

■ Tool design combines benefits of a burr cutter, compression cutter and finisher in one.

■ The application for this tool is cutting composite panels

■ Testing has been conducted in the following materials:

3/16 inch Politen (glass/polyester sheet): 100 ipm, 16,000 rpm

1/4 inch Haysite UltraTrac H950 (glass/polyester sheet): 250 ipm, 16,000 rpm

3/8 inch Haysite H775: 100 ipm, 18,000 rpm

 

 

Solid Carbide Carbon Graphite Cutter

■ Developed as an improved burr design. The design offers more cutting edges than a standard burr and the chipbreaker/finisher edges reduce the cutting forces, allowing the tool to be fed at a higher feed rate.

■ Multiple upcut and downcut flutes allows for improved chip flow and chip evacuation.

■ Offers easier feeding in hand-fed operations. Can be aggressive in materials over 4 mm in thickness.

■ Testing has been conducted in the following materials:

Burnham 300ksi (carbon fiber): 150 ipm, 16,000 rpm

1/8” thick carbon fiber weave: 350 ipm, 18,000 rpm

P4-X071 (0.08 thick polypropylene/glass): 50 ipm, 14,000 rpm

Uni-Carbon PPS (0.08 thick): 150 ipm, 17,000 rpm

3/16” Politen (glass/polyester sheet): 100 ipm, 18,000 rpm

1/4” Haysite UltraTrac H950 (glass/polyester sheet): 300 ipm, 18,000 to 20,000 rpm

3/8” Haysite H775: 250 ipm, 18,000 rpm

 

 

PCD “Serf” Cutter

■ The “Serf” line has serrations with 0.047 inch peak to peak. The fine pitch provides a smooth part finish.

■ Design also provides reduced impact forces from leading edges, and improved fiber shearing action.

■ Testing has been conducted in the following materials:

Burnham 300ksi (carbon fiber): 125 ipm, 16,000 rpm

1/8 inch thick carbon fiber weave: 350 ipm, 18,000 rpm

1/8 inch Black Kevlar: 125 ipm, 14,000 rpm

G10 fiberglass: 75 ipm, 8,500 rpm

Uni-Carbon PPS (0.08 thick): 300 ipm, 14,000 rpm

Uni-Carbon PPS (0.055 thick): 300 ipm, 18,000 rpm

3/16 inch Politen (glass/polyester sheet): 150 ipm, 18,000 rpm

1/4 inch Haysite UltraTrac H950 (glass/polyester sheet): 200 ipm, 16,000 rpm

3/8 inch Haysite H775: 300 ipm, 18,000 rpm

11 mm Ultem 2300 (30 percent glass filled polyetherimide): 250 ipm, 15,000 rpm

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