7/10/21
Source : content from Composites World Magazine
Automatic cutting of proprietary composite materials is critical for high speed molding of military-grade pressurized camera enclosures.
Speed, accuracy and material efficiency are key performance indicators at Rapid Composites in Sarasota, Florida. They cut uniquely engineered carbon fiber fabric and hybrid materials for a proprietary composite molding process that can produce parts in a few minutes or less. The material is cut on an S125 Static Table Cutting System made by Eastman Machine Company. The machine can cut, mark, drill, and punch virtually any flexible material at speeds of up to 60 inches per second (152.4 cm/sec.). Eastman has engineered the equipment specific to cutting dry and prepreg carbon, glass and aramid reinforcements. Critical machine components are protected for harsh or high particulate environments.
For a camera enclosure part, pre-consolidated carbon fiber is rolled out onto the Eastman S125 cutting table. Precision cutting enables Rapid Composites’ ultra-fast composite molding process.
“Everything we make is molded in less than 15 minutes. In some cases, as little as 45 seconds,” says Rapid Composites founder and President, Alan Taylor. But it’s not just about speed. Rapid Composites can achieve holding tolerances of +.002” to -.001” in a high-speed continuous or discontinuous fiber molding process which is critical to serving a very demanding customer base in the aerospace/defense, opto-electronics (thermal sensors and general optronic) and automotive industries.
The cutting system operates with an X-Y gantry driven with two X-axis and one Y-axis brushless servo motors with closed loop encoders. The high-quality linear bearings and high resolution of the encoders ensures reliable position, accuracy and repeatability.
A range of tool heads are available for the machine. Rapid uses Eastman’s Heavy-Duty Tool Head to cut carbon fiber pre-impregnated materials. The proprietary and patented heavy-duty design is powered by its own brushless motor and independently controlled air supply. This allows the tool head to incorporate up to two or three different tools from Eastman’s catalog of 60 blade options, and a marking pen. The ability to use any combination of tools increases production, flexibility and minimizes downtime.
Complicated forms are cut quickly and accurately, and remnant material is repurposed for other parts, which has substantially reduced the fabricator’s scrap rate.
Typical material densities cut by Rapid Composites range from 1.0 g/cc to 1.88 g/cc. The nominal thickness of the material is anywhere from 0.04” to 0.09”. Setting up and running a new cutting routine takes a few minutes. Once the cutting program is loaded into the computer control, the material, purchased in roll form, is laid flat on the machine’s vacuum table. The material origin location is established and the job is ready to run. All layers needed for molding are cut in a single process.
The drag knife on Eastman’s Heavy Duty Tool Head is optimal for intricate cuts and the puck style depth limiter allows the user to control the blade penetration through material and not into the cutting surface. The blade is made of tungsten carbide steel and available in 30°, 45° or 55° versions.
Drag knife for Eastman’s Heavy Duty Tool Head.
While jobs can be set up and run quickly, the key enabler to overall cutting efficiency is the software used to nest material pieces and generate the cutting program. Rapid Composites uses Eastman’s patternPRO Design & Nesting Software. Its comprehensive set of tools helps design pattern pieces from the start and Rapid uses it to edit and finalize existing digital patterns, all within the same interface.
Parts are designed in Rapid Composites’ 3D modeling system and then imported into Eastman’s patternPRO software for nesting.
According to Taylor, the ability to increase material efficiency though better nesting and reduced scrap has been among the most important benefits of automated cutting. He says they measure scrap rates monthly and consider a difference of just 1-3% to be consequential. With material costs as high as $30 to $150 for some pre-impregnated PAN fiber materials and hybrid materials and even $300 per pound for Crystalline fiber solutions, maximizing raw material yield is critical to controlling their costs.
The ability to cut accurately contributes as well. Rapid’s composite molding process uses near-net-shape molding which is by design a means to more efficient material usage, particularly when little post processing scrap is generated. “With the Eastman we get almost perfect coverage of the mold and with very predictable results,” says Taylor. Moreover, they are able to repurpose blank areas rather than scrap them. Taylor calls the machine-cut pieces smart tailored blanks. “They result in less time and expense, not just in the molding process itself, but also with machining, labor, tooling and overhead,” he says.
Precision cutting enables Rapid Composites’ ultra-fast composite molding process. Parts such as this camera housing can be made stronger yet significantly lighter with carbon fiber and other hybrid composites materials.
It’s pretty much a night and day difference from when Rapid Composites was cutting materials by hand. “In an 8 hour shift the operator would have blisters on his hands from cutting with scissors, even using the proper gear, gloves and everything for this type of material. When we got the Eastman, it did the same amount of work in 45 seconds,” says Taylor. And he says it’s a value add for their customers to be able to make their products lighter, stronger and more repeatable.
Eastman’s Heavy Duty Tool Head.
Founded in 1999, Rapid Composites offers a wide array of services including industrial design, mechanical engineering, electrical engineering, software engineering, prototyping, tooling, carbon fiber molding and production. Though they serve a range of applications, the primary business focus is on electronic devices, outdoor products, e-Foil technologies, electro-optical devices, weapon systems and OEM drone/UAV systems.
As the name implies, Rapid has developed the expertise to mold composite parts with extremely short cycle times. Overall, they average 7-8 minutes per part (70% of the work is with thermosets) and when using thermoplastic matrix materials, they average just three minutes per part. Moreover, Rapid Composites has pioneered new methods allowing pre-consolidated materials to be rapidly heated, then shuttled to a mold and hot stamped in under 45 seconds to the net shape of a part. They refer to this process as high-speed composite molding. According to Taylor, this is likely the fastest continuous fiber molding process in the world. High-speed molding as Rapid Composites does it reduces both molding and finishing time, but only when material is precisely cut in the first place.
Rapid Composites’ molding process can form parts from pre-impregnated or pre-consolidated materials in as little as 45 seconds
“There are things we can live without. I put the Eastman in the category of something we cannot live without,” says Taylor. “We’ve seen how important the repeatability is and our clients expect it.” Manufacturing pressurized camera enclosures that are used by the U.S. military and government agencies places enormous pressure on Rapid Composites to deliver as promised. Taylor said the machine reliability and accuracy ensures that tolerances over as few as five to dozens of pieces are exactly the same, every time.
The Eastman Machine Company, a family business, was founded in 1888 after developing the first electric fabric cutting machine. Almost five generations later, Eastman Machine continues to support American manufacturers like Rapid Composites with custom configured, made-to-order solutions. Eastman designs and manufactures a complete line of equipment for the composites industry: manual cutters, single- to high-ply automated cutters, and material handling equipment.
Eastman’s patternPRO Design & Nesting Software.to edit and finalize existing digital patterns and then for nesting.
“Our continued focus on identifying and creating tools to enable modern manufacturing is what gives customers like Rapid Composites the confidence to return to Eastman time and time again,” says Robert Stevenson, Eastman Machine Company President and CEO. This is the third Eastman system installed in Taylor’s business ventures over the last two decades.
Beyond the machines manufactured at Eastman, the company supplies a worldwide customer network with critical parts, technical service, and remote support from its headquarters in Buffalo, NY.
FR
