Composite Material Machining: Types, Techniques & Best Practices

In composite material machining, composite materials are cut, shaped and drilled using different techniques. This machining performs an important part in manufacturing of advanced products as composites provide improved durability and better performance.

Therefore in this blogpost we will cover different types of composite material and their machining techniques. We will also go through applications and best practices for composite machining.

Common Types of Composite Materials Used in Machining

Polymer Matrix Composites (PMCs)

Polymer matrix composites are engineered materials in which polymer matrix for example polyamide or epoxy, is reinforced by particles or fibers. These composites provide greater strength, lower weight and outstanding corrosion resistance, and are normally divided into these three categories.

Carbon Fiber Reinforced Polymers

This type of polymers has carbon fibers embedded in polymer matrix which makes it lightweight but extremely strong. These composites have impressive fatigue durability as well as corrosion resistance. Hence they are suitable for high performance applications such as automotive parts & aircraft structures.

Glass Fiber Reinforced Polymers

GFRP consists of glass fibers embedded within polymer matrix. These materials have good mechanical strength and resistance to corrosion. And it is commonly used in marine, construction and transportation applications.

Aramid Fiber Reinforced Polymers

In AFRP aramid fibers such as Kevlar are used for reinforcement in polymer matrix. These composites are characterized by their strength, longevity and resistance to impact and abrasion. They are normally used in security and military equipment.

Metal Matrix Composites

MMCs combine metal matrix with ceramic or carbon fiber reinforcement. These composites provide extraordinary thermal conductivity, wear resistance and strength to weight ratio.

Because of their higher ceramic content, MMCs are more difficult to machine than PMCs.

Cemented Carbides

Cemented carbides combine metallic binder such as cobalt with hard carbide particles like tungsten carbide. Besides that they show impressive thermal stability, wear resistance and hardness which in turn makes them perfect for mining equipment, cutting tools and other heavy duty applications.

Fibre-Reinforced Plastics

FRPs consist of such polymer matrices that are reinforced with fibers such as carbon, aramid or glass. These components are corrosion resistant and very lightweight. Therefore they are generally used in applications where strength to weight ratio is very important. For example, in automotive, marine and structural applications.

Ceramic Matrix Composites

CMCs are made by integration of ceramic fibers into ceramic matrix. These materials perform best in temperatures above 1000°C. Their advantages include outstanding thermal conductivity, abrasion resistance & fracture toughness. Thus they are useful for applications such as aerospace and industrial machinery.

Machining Techniques for Composite Materials

Conventional Machining

Drilling

Drilling creates precise holes in composite materials. In this technique stepped drills and diamond-coated tools are used at controlled speeds with accurate feed rates. This technique is suitable for applications where highly-precise holes are important for structural integrity and assembly such as in aerospace industry.

Milling

In CNC milling, material is removed from composite workpiece using special cutting tool with positive rake angle and rotary cutting action. This process operates at controlled field rates with fast spindle speed in order to avoid delamination. Moreover this technique is best for surface profiling and edge trimming of components such as GFRP and CFRP.

Turning

In turning the composite workpiece rotates and cutting tool removes the material to create cylindrical shapes. This method provides tight tolerances, fast production times as well as outstanding accuracy.

Turning is suitable for making bearings and composite shafts. But it faces challenges in high-precision aerospace applications specially when controlling fiber orientation.

Non-Conventional Machining

Laser Machining

Laser machining drills and cuts composite material using fiber or CO₂ lasers. This technique gives clean cuts with minimum heat-affected zones because of no physical contact with composite workpiece. CO₂ lasers are suitable for organic compounds whereas fiber lasers are better for metal matrix composites. Both these types provide outstanding edge quality without any mechanical stress.

Ultrasonic Machining

Ultrasonic machining is another composite machining in which material from composite workpieces is removed by using high frequency vibrations. This process not only provides great accuracy with less heat generation but it is also suitable for brittle materials such as glass and ceramics. In spite of that, this process has some limitations such as that it removes material slowly and requires specially skilled operators.

Electrical Discharge Machining (EDM)

An electrical discharge machine uses controlled electrical sparks in order to machine conductive composites with good precision. This non-contact process removes tool wear and mechanical stress as well as provides best surface finishes.  

This process is perfect for machining ceramic composites, hard materials and MMCs. Hence it is perfect for manufacturing parts with complicated features such as precision molds.

Water Jet Cutting

In water jet cutting high pressure water mixed with abrasive materials is used to cut composite materials. It cuts thick composites well and also preserves fiber integrity. This process not only prevents stress but also provides clean edges without distorting material structure.

Thus it is good for cutting with great precision in industries where tight tolerances and complicated shapes are needed.

Tooling for Composite Material Machining

Tool Materials

The tool material strongly affects both tool longevity and quality of final workpiece along with machining proficiency. Diamond coated tools provide outstanding hardness and wear resistance which make them suitable for abrasive composites. On the other hand, carbide tools are better for fast speed operations because of their toughness and strength.

Tool Geometry

Tool geometry directly affects cutting proficiency and surface quality during machining of composite materials.  Positive rake angles decrease cutting forces thereby reducing risk of delamination in composites. Further optimized drill bit geometry minimizes thrust forces during drilling which in turn increases tool life and provides smooth hole quality.

Tool Coatings

Advanced tool coatings improve composite machining performance with special surface treatments. DLC coatings give extraordinary toughness and decrease friction when working on GFRP and CFRP materials. Tien coatings provide outstanding wear resistance and heat resistance up to 800°C during machining advanced composites.

Industry Applications

Aerospace

In aerospace industry composite machining is used to manufacture parts such as wings, structural components, tail surfaces, fuselages etc. These materials improve corrosion resistance, strength to weight ratio and fuel proficiency in modern aircraft applications.

Automotive

Composite machining is used to manufacture automotive components that are both durable & lightweight. Such parts are engine covers, body panels, door trims, chassis, dashboard components etc.

Renewable Energy

Composite machining is used for solar panel frames, wind turbine blades and hydroelectric components. Blades that are made of GFRP and CFRP materials are both durable & strong. Apart from that, these materials decrease maintenance requirements and improve turbine performance as well.

Consumer Electronics

Composite machining produces strong and lightweight casings which are suitable for smartphones, laptops and tablets. These materials in addition to scratch resistance provide good thermal management and improve RF signal transmission.

Best Practices in Composite Material Machining

Use Coolant & Lubrication

You should use special coolants such as synthetic formulations & MQL (minimum quality lubrication) if you want to improve composite machining performance. These fluids help avoid excess heat absorption in material and keep it cool. Besides that you must check the compatibility of material before applying any fluid to prevent deterioration of composite.

Improving Cutting Parameters

You need to improve cutting settings for impressive results including depth of cut, cutting speeds, feed rates etc. So you should set feed rate around 0.076 mm per tooth & cutting speed at 550 to 760 m/min. Also keep up cut depth to 2mm and positive rake angles between 15-20° in order to obtain best surface finish and decrease delamination.

Tool Material Selection

You should pick tool materials for composite materials that can handle their abrasiveness and hardness. So both carbide and diamond coated tools are suitable for this because of thermal conductivity and wear resistance. These tools are perfect for difficult composite applications where better quality results are required in addition to outstanding machining performance.

Stability and Workpiece Fixturing

You can use pneumatic or hydraulic clamping systems with distributed pressure points to avoid deformation and for proper workpiece fixturing. Moreover if you want to assure stability and accurate alignment during high speed operations, use custom fixtures with matrix arranged mounting holes.

Dust Extraction & Operator Safety

You should use on-tool extraction systems that have cartridge style dust collectors to capture particles immediately. Operators should use proper PPE which includes protective gloves and respirators. Additionally install sealed machine enclosures containing directed airflow setups in order to prevent dust dispersion.

To Sum Up

In short composite material machining performs an important part in industries such as renewable energy, aerospace and automotive. Manufacturers can improve productivity and overall performance of machining process by proper fixturing & better cutting parameters.

If you require any kind of machining services for composite materials ─ milling, turning, drilling ─ then RICHCONN is best option. You can contact us at any time.

Related Questions

What are the primary differences between machining composites and traditional metals？

Composites have fiber structure so they need special tools and techniques. They generate more heat and fracture during machining as compared to metals that create chips．

What are the best practices for achieving high quality surface finishes on machined composite components？

You should use sharp tools, better cutting parameters, proper feed rates, stable workpiece fixturing and minimum coolants．

How does moisture absorption in certain composites affect their machining behavior？

In composites, moisture absorption causes fiber deformation, dimensional instability and swelling. As a result it affects machining accuracy, surface finish and tool life．

How does anisotropic nature of composites affect machining processes？

The anisotropic nature of composites shows that they have different properties in different directions. This can lead to delamination, uneven wear and difficulty while controlling cutting forces．

How does the thickness of composite laminate affect machining parameters？

Feed rate, cutting speed and tool pressure affect composite laminate thickness. Thicker laminates need lower feed rates, slower speed and more controlled cutting.

To Sum Up

In short composite material machining performs an important part in industries such as renewable energy, aerospace and automotive. Manufacturers can improve productivity and overall performance of machining process by proper fixturing & better cutting parameters.

If you require any kind of machining services for composite materials ─ milling, turning, drilling ─ then RICHCONN is best option. You can contact us at any time.

Related Questions

What are the primary differences between machining composites and traditional metals?

Composites have fiber structure so they need special tools and techniques. They generate more heat and fracture during machining as compared to metals that create chips.

What are the best practices for achieving high quality surface finishes on machined composite components?

You should use sharp tools, better cutting parameters, proper feed rates, stable workpiece fixturing and minimum coolants.

How does moisture absorption in certain composites affect their machining behavior?

In composites, moisture absorption causes fiber deformation, dimensional instability and swelling. As a result it affects machining accuracy, surface finish and tool life.

How does anisotropic nature of composites affect machining processes?

The anisotropic nature of composites shows that they have different properties in different directions. This can lead to delamination⸴ uneven wear and difficulty while controlling cutting forces.

How does the thickness of composite laminate affect machining parameters？

Feed rate, cutting speed and tool pressure affect composite laminate thickness. Thicker laminates need lower feed rates, slower speed and more controlled cutting.