Syntactic Foam for Plug Assist Module 3

Agenda

Processing HYTAC Syntactic Foam

A Best Practice Guide to CNC Milling HYTAC Syntactic Foam

Machining Syntactic Foam is Different

• Most machining experience relates to wood or metal • Syntactic foam is a combination of hollow glass microspheres bound together by epoxy, copolymer blends or thermoplastic materials • It is not like wood or metal • It requires a different approach

General Machining Guidelines

• Syntactic foam behaves like plastic during machining • Big chips are better than small chips • Controlling the heat of the cutting tool is critical • Start a conversation with your tool vendor

• • • Goal: Consistent Surface Finish Feed rate = chip load x spindle RPM x # flutes Remove the largest chip possible as quickly as possible Avoid heat build-up in the tool

Where to Start: Milling Tools

• 2 flute Straight “Z” • Solid Carbide or PCD • Good for rapid removal of large amounts of material • Reasonable “floor” finish • Climb milling generally required • Generally must be “ramped” • 2 flute upcut spiral • Solid Carbide • Good for rapid removal of large amounts of material • Excellent “floor” finish • Conventional milling recommended • May be “ramped” or “plunged” • 2 flute Ball • Solid Carbide • Excellent finish for contoured surfaces • Conventional milling recommended

Conventional vs. Climb Milling

Optimizing & Refining the Process

1. Increase feed rate until part finish begins to deteriorate 2. Reduce rate by 10% to get starting point 3. Decrease RPM by set increment until surface finish begins to 4.

deteriorate Increase speed back to last “good” RPM where results were satisfactory

Optimizing & Refining the Process

• Coolant not required • Pay attention to proper settings • Keep tool at room temperature

Thermoset Epoxy

Syntactics Very Dusty (HYTAC-W, WF, WFT)

Copolymer Syntactics

Small shavings/curls (HYTAC-FLX, FLXT, C1R)

Thermoplastic Syntactics

Large shavings/curls (HYTAC-XTL or B1X)

Machining: Best Practices

1. Use sharp tools for abrasive plastics 2. Keep heat out of the tool 3. Understand the variables 4. Refine the process

Online Resources

http://www.cmtmaterials.com/machining-guides/

End of Module 3

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