Machining Composites
Much like other materials can be machined, so can composites. Everything from basic fiberglass fabrications to advanced composites materials can be machined to add details and features.
This can be accomplished using hand-held tools guided by fixtures and measurements. Hand tools such as air routers, drills, and saws. A disadvantage is that the operator can commit errors and must be protected from safety hazards. These hazards include airborne dust, bending strain, lifting strain, and physical cuts.
For high volume or high precision applications, there are CNC routers that can be employed. These are fast, efficient, and safe. They may be expensive though.
Several manufacturers make CNC routers, and Thermwood is one as shown below.
This video shows several different applications and parts that can be routed with this large machine.
UK Promotes Composites Manufacturers
I ran across an interesting video demonstrating case studies of composite manufacturers in the United Kingdom. This video paints a very pretty picture of companies that use these materials to manufacture a wide range of items including: aerospace, bicycles, bridges, auto racing parts, etc.
This video has some great video footage of automated composite manufacturing using advanced composites materials. Automating these processes has long been a challenge and hurdle to using composite materials for commercial applications.
This video seems to be done by a UK government agency called the “Department of Business Innovation & Skills” promoting a national strategy for composites industry growth. It supposedly demonstrates companies working together to develop new composites technology.
Non-Destructive Testing with Ultrasound
Composite materials can become damaged in many different ways. There can also be flaws in the original manufacturing process. Many times it is necessary to identify any damaged areas within the composites layers that cannot be detected with the eye.
Inspection of composites fiberglass and carbon fiber structures may be required for advanced critical applications of composites materials. Identifying any potential problems with the composites structure is extremely important.
Of course problems can be identified through destructive testing-drilling holes, making cuts, etc. It also may be necessary to do testing in a non-destructive manner, i.e. not cutting into the laminate that is being tested.
One method of accomplishing non-destructive testing of composites laminates is using ultrasound. This Youtube video demonstrates the use of this method.
As you can see, the damage is found in this carbon fiber laminate. This information is a flag that can be used to decide whether to make a repair or replace the structure.
Delamination within the fiberglass or carbon fiber part will result in a much weaker structure than the design intended. Other areas of the composites part will be further strained by weaknesses in other areas and may also fail.
This ultrasonic test can help to identify otherwise invisible problems with either the original manufacturing process or damage during the life cycle of the composite part.
Machining Composites CNC Video
Much like other materials can be machined, so can composites. Everything from basic fiberglass fabrications to advanced composites materials can be machined to add details and features.
This can be accomplished using hand-held tools guided by fixtures and measurements. Hand tools such as air routers, drills, and saws. A disadvantage is that the operator can commit errors and must be protected from safety hazards. These hazards include airborne dust, bending strain, lifting strain, and physical cuts.
For high volume or high precision applications, there are CNC routers that can be employed. These are fast, efficient, and safe. They may be expensive though.
Several manufacturers make CNC routers, and Thermwood is one as shown below.
This video shows several different applications and parts that can be routed with this large Computer Numerically Controlled machine.
Environmentally Friendly Composites
Many experts argue that composites already are very environmentally friendly based upon their long life span and their good strength-to-weight ratio that saves energy. Many composites structures have long made use of end-grain balsa wood as a core material. This is a renewable resource that is favorable to the carbon footprint.
The strikes against fiberglass composites as being environmentally friendly point out that most of the resin systems are derived from oil and natural gas feedstocks. Most of these feedstocks come from the extra byproducts of making diesel and gasoline. Fiberglass reinforcements consume lots of energy in their manufacturing process.
Resin and reinforcement companies have been working to “green” composites materials. BioResins have been successfully made and used in products that see the real world. These resins use soybean and corn feedstocks to replace the oil and natural gas derivatives to make them from a renewable source. Much work has been accomplished with reinforcements to move towards natural materials. Hemp has proven very useful in this application. Recycled thermoplastics have also been applied to composites products as a reinforcement.
Further research and development, along with identifying appropriate real-world applications will allow composites to flourish as a true sustainable material. It has already proven to be a great material for lightweighting vehicles and structures to result in great energy and material savings. The long life and durability of composites keeps it from landfills to minimize environmental impact.
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