DeltaWing Manufacturing knows composites. Most of the company’s 30 employees are dedicated to some critical step in manufacturing composite components, from making the molds to curing (hardening) the parts in a massive autoclave (a pressurized oven). However, composites expertise isn’t DeltaWing’s only asset. Kevin Bialas, vice president of manufacturing, says CNC machining has always been considered a core competency.
Without this and other value-added services, the company’s recent growth would not have been possible, he says. Likewise, future growth requires futher investments in machining. The most recent is a milling machine that occupies a space nearly as large as the one dedicated to the autoclave. By bringing critical pattern-making operations in house and eliminating tedious hand-trimming work, DeltaWing’s advance into large-capacity, five-axis machining has been and will continue to be essential for expanding beyond the company’s auto-racing roots.

Race cars still greet visitors to DeltaWing’s 40,000-square-foot facility outside Atlanta, and the company is still involved in that business. However, a look beyond the lobby reveals a deeper focus on structures and assemblies for planes, drones, and increasingly, commercial vehicles. Most are made from carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (fiberglass). A good portion could not be photographed. CNC machining contributed to the growth that made this shift possible in three ways:

Shortly after the 1997 founding of DeltaWing’s predecessor company, race car builder Elan Technologies, the in-house machine shop began producing discrete metal parts for customers in addition to fixtures for internal use. Since the company began pursuing aerospace parts in earnest about five years ago, capacity has increasingly been filled by more sophisticated prototype parts in aluminum, steel and titanium. Many are for sensitive defense applications.

Along with the press brakes and other equipment in the fabricating area (including a new waterjet for large 2D work), the machining division provides metal portions of composite structures that are built in house. These include both metal parts that are assembled with composites and metal parts that serve as cores — essentially, “skeletons” that provide strength to the surrounding composite structure. Combining machining, fabricating and assembly services with composites manufacturing helps customers simplify their supply chains. 

Whether for race cars or airplanes, most composite parts require trimming after curing. CNC milling and turning machines can perform these operations more quickly and more accurately than doing the work by hand. Workhorse equipment includes a Haas ST20 lathe with live tooling and two Haas VF4s VMCs, both of which replaced older machines within the past five years. Each VMC is equipped with a rotary fourth axis to consolidate setups.

Continuing to grow the Carbide Aluminum Inserts company’s composite-part business requires more direct CNC machining support, Mr. Bialas says — hence the investment in the big new machine. In production since mid 2018, the F122E from C.R. Onsrud features an articulating spindle that slides 82 inches along a fixed-bridge X axis overtop a 60- by 120-inch twin table that moves 186 inches along the perpendicular Y axis. Z-axis travel is 41 inches.

For DeltaWing, large-capacity five-axis capability is important for two reasons. First, a greater variety of jobs, tighter deliver schedules and more stringent quality control requirements leave no room for hand trimming composite parts that are too large and/or too complex for smaller equipment.

Mr. Bialas points out that trimming the large fiberglass bus panel depicted above could take as long as half an hour Carbide Inserts by hand, compared to less than 10 minutes on the new machine. As is the case with wing spars, tail booms and other large aerospace structures, machining this part also would be impossible without a sizeable workzone. Others, like the ducting component on the right, would require multiple setups on the company’s smaller machine tools. As for precision and repeatability, he says hand trimming the bus panel could achieve tolerances no tighter than ±0.015 inch, compared to the five-axis machine’s ±0.005 inch.   

Second, large-volume five-axis capability has enabled the company to machine all its own patterns. A pattern is a replica of the final component, typically machined from epoxy tool board as the first step in producing a composite part. Curing layers of composite around this pattern forms a rigid mold with a service temperature of 350º to 450ºF.

For a company that aims to control its process, a step as critical as pattern-making is too important to leave to outside machine shops. When patterns were too large and/or complex to machine practically on the smaller VMCs and lathe, “We were essentially leaving our scheduling and quality control in someone else’s hands,” Mr. Bialas says. “Without a good pattern, you don’t get a good mold, and without a good mold, you don’t get a good part.”

Given that this goes for any composites manufacturer, DeltaWing devotes excess capacity to making patterns and trimming parts for others. Along with the discrete-parts business, this work has contributed to a threefold increase in direct machining revenue since the company’s deliberate shift toward new markets five years ago.

Based on testimony from DeltaWing personnel, programming an additional axis of motion did not present much of a learning curve. “The fact that we haven’t done a lot of square, simple parts over the years has been a real advantage,” says machine shop manager Ron Snarksy. However, cutting parts, patterns and fixtures from lighter, lower-density materials requires a different approach. He cites the following tools and strategies as critical to making the most of the new five-axis machine:

The new machine took longer than usual to install because the building that houses it  — once a storage area — had to be fitted with adequate electrical power as well as an industrial filtration system from Camfil. This is critical because the Onsrud cuts materials that essentially turn to dust when machined. Even with the dust collection system, respirators are always on-hand for employees working nearby.

Horsepower and chip load, which set the limits for metalcutting operations on the smaller machines, generally are not significant concerns for the new machine. It is designed specifically for fast, shallow cutting. The idea is to speed cutting by shaving thin layers of material in multiple passes rather than one deep pass, whether from light, porous fixtures; urethane and epoxy patterns; or CFRP, fiberglass and aluminum parts. To that end, the machine’s 15-horsepower spindle offers a maximum speed of 24,000 rpm (compared with 12,000 rpm for the other mills).

Although stepovers on the Haas equipment are generally limited to between 25 and 40% of the cutter’s diameter, full radial cutting tool engagement is not uncommon on the new machine. This is possible in part thanks to serrated flutes, which help ensure efficient evacuation of powdery machined material emerging from the cut. 

For abrasive composites like CFRP, brazed tools can last longer. Brazed or not, edges must be sharp to shear cleanly through CFRP and other composite materials. Dull edges result in heat buildup that can melt the workpiece material’s bonding resin and lead the layers of composite pulling apart, a phenomenon called delamination. Delamination, as well as splintering, (essentially a less severe form of delamination) can also be a result of machining parameters that are too aggressive to let the cutting edge do its job. Drills should also be chosen with care to prevent fiber breakout through the back side of the hole. To this end, many of DeltaWing’s drills feature brad-point geometry that helps score the outer edges of the hole as the tool spins. 

Making the most of the new machine required more than just upgrading the company’s MasterCAM software to support five-axis motion. One common composite machining strategy this software facilitates is moving the cutter up and down as it feeds. This oscillation spreads the cutting action over more of the edge to ensure even wear. Programmers have also found that carefully plotted five-axis tool paths can provide the same advantages with ballnose tools. 

Using a spindle probe to inspect parts on the machine saves time in the event of rework, eliminates the need for hand-gage measurements and confirms proper setups. This is the case for both the large five-axis and smaller equipment. However, adding probes to the 12-position toolchanger on the new five-axis machine has been particularly beneficial. Parts too large for the CMM historically have been inspected with a portable measurement arm, but repeatedly moving this arm takes time and risks compromising precision.

The rigidity of materials like fiberglass and CFRP is an advantage for thin structures such as those used in aerospace applications. However, thin structures are also particularly subject to vibration during machining. Materials used for workholding and pattern-making also tend to be less dense than metals, and thus are more reactive to cutting forces. For most jobs, vacuum workholding is a necessity. “The most important part of machining is holding onto the part,” Mr. Snarksy says. “You can’t put any of this stuff in a vise or a clamp, or you’ll crush it.”

Epoxy tooling board for patterns typically arrives in billet form with flat bottoms that can be placed directly on the vacuum table. Holding parts for trimming is generally more complicated, requiring fixtures machined from porous materials and machined to match the underside of the workpiece geometry to form an airtight vacuum seal. Machining additional channels and bores into fixtures helps channel air and pressure where needed to ensure sufficient clamping force.

Some materials are particularly challenging, such as foam composite-part cores with densities as low as 3 lbs/ft.3 (for comparison, the same measurement is 42 lbs/ft.3 for epoxy and 168 lbs/ft.3 for aluminum). “Sometimes we have to hold things in place with hot-melt glue or two-sided adhesive tape,” he says.

However well a machine tool is built, maintaining precision throughout a large workzone is challenging because the slightest imperfections amplify as machine axes get longer. At DeltaWing, machining tolerances can be relatively tight. Examples cited by Mr. Snarsky include hole position callouts as tight as ±0.003 inch and patterns requiring surface profile tolerances as tight as ±0.005 inch.

This is why the company purchased a volumetric error compensation package with the machine tool. Performed after machine installation by technicians from metrology company Automated Precision Inc. (API), this process is an alternative to traditional means of compensation that require multiple setups for multiple laser measurements. Instead, representatives from API use a laser tracker to create a map of possible tool-tip positions throughout the workzone. Feeding this information to the CNC facilitates real-time error compensation.

Whatever the merits of the method, volumetric error compensation “would never work if the machine weren’t precise in the first place,” Mr. Snarksy says. After all, the elements detailed above would be for naught were it not for a machine designed specifically to cut large, complex parts from plastics, composites and non-ferrous metals like aluminum.

If and when the company purchases another machine, it will be for a different purpose entirely. “We’re working on a quote right now, and the customer’s process requires some heavy-duty metal tooling that we have to outsource,” Mr. Bialas says. “We may add a second waterjet reasonably soon as well.”

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005954890402.html

Avoid skimping on the diamonds in composite drilling applications, and you can avoid leaving your parts literally in the rough. That’s the idea behind the CX1, a drill from Seco Tools that employs a dome-shaped, solid polycrystalline Tungsten Steel Inserts diamond (PCD) tip to avoid the fraying and delamination problems common to PCD vein or dual-brazed tip designs. The tool also features a third drill flute that is said to improve stability compared to traditional twin-flute designs. Other benefits include high cutting speeds, long tool life, low friction, improved heat transfer, capability for multiple re-sharpenings and reliability.

The primary advantage of a solid PCD tip is edge sharpness, the company says. This is critical in composite applications because the thin fibers that constitute the material are difficult to cut. Failing to shear cleanly through these fibers can result in material fray and premature part replacement. Further, additional stress on the material created by insufficiently sharp cutting edges can reduce mechanical toughness through delamination. Such problems are more likely with coated PCD than a solid PCD tip because wrapping the coating around the cutting edges can create a dulling effect.

Compared to twin-flute, coated PCD drills, the CX1’s third flute reduces vibration and improves both stability and roundness in “plain” composite materials, the company says. Furthermore, the CX1’s dome-shaped tip features a double-angle geometry that is said to reduce uncut fibers and delamination in composite-only applications. Grinding this geometry would be impossible with tools that make use of brazing or similar PCD techniques, the company says. Plus, the dome cap also makes it possible for the drill point to be reconditioned.

The solid PCD dome tip also offers superior thermal conductivity, the company says. This results in enhanced product stability and higher cutting speeds. This thermal conductivity advantage is particularly important for composite materials that melt fast. Given that composite machining operations rarely employ coolant, it is important to transfer the heat away from the cutting area as quickly as possible.

Although solid PCD-tipped drills are more expensive than PCD-coated drills at the front end, the overall return on investment can be substantial when drilling a large number of holes. According to the company, the CX1 geometry can effectively drill two to three times more holes than a PCD-coated drill, essentially spreading VNMG Insert out the costs.

The company adds that investing in solid diamond-tipped drills also makes sense when hole quality is of the utmost importance. Delamination is becoming more of a safety concern for aerospace industry work because of the increasing use of composite materials, particularly in components that constitute the tail sections of airplanes.

The CX1 series includes a mix of dimensions for holes ranging from 0.125 to 0.375 inch in diameter. Chamfers can be incorporated into drill designs for further application flexibility. The company also offers special PCD geometries.

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005925592551.html

Four years represents an eternity in the life of metalworking tools. In that time, TP Engineering (Bethel, Connecticut) has milled a mile of aluminum without changing the inserts on a Kennametal three-cartridge, 0-degree lead, 3-inch polycrystalline diamond (PCD)-tipped high-velocity face mill.

TP Engineering, a designer and manufacturer of Harley-Davidson aftermarket motorcycle engines and related components, is using PCD milling to finish engine cases, oil pumps, rocker boxes, inner and outer primary engine covers, and transmission cases and covers.

"We couldn’t be happier with the performance of PCD milling," says Tom Pirone, TP Engineering’s president and founder. "To this day, I find it amazing that we have never changed inserts."

In this application, TP is using PCD to work on 6061T6 aluminum and 356 aluminum, a difficult-to-machine material that it mills on a Mori-Seiki SH-400, a Mori-Seiki SH-403 and two Okuma MX 40 HA horizontal machining centers.

"The secret to the PCD face mill is in the design," says Gerry Dobrynski, the Kennametal field sales representative who services the TP Engineering account. "These lightweight but sturdy milling cutter bodies are engineered to best utilize the cutting power of the PCD adjustable cartridges that are secured to the cutter body with socket-head cap screws. Each cartridge is tipped with super-hard PCD (KD100 grade) that enables faster speeds, excellent tool life and superior surface finishes when compared to carbide or high speed steel (HSS) tools."

TP Engineering’s use of PCD high-velocity face mills is enabling the company to mill 10,000 sfm at 140 ipm.

Besides increased tool life and decreased cycle time on the engine case from 1 hour to 24 minutes, Mr. Pirone is also pleased with the mirror finish that results from a Kennametal PCD face mill. "The surfaces achieve a superior finish with a phenomenal consistency that I didn’t expect when I began using PCD, and I’m sure that it influences Harley-Davidson owners to buy our products."

TP Engineering replaced a carbide end mill 6 years ago with helical and router style Kennametal NGE-I end mills. The mills use six KC725M inserts for milling steel and six KC510M inserts to mill aluminum on a Mori-Seiki SH-400 horizontal machining center to perform profile milling on connecting rods, engine cases, inner and outer primary engine covers, oil pumps and rocker boxes.

The significant values for TP Engineering’s use of an NGE-I end mill are 10,000 sfm at 120 ipm for milling aluminum and 500 sfm at 20-40 ipm for milling steel. By using NGE-I, TP has tripled productivity and tool life while improving the smoothness of surface finishes by a factor of three.

"TP Engineering has realized those quantitative and qualitative improvements because the NGE-I offers positive chip forming geometry, which results in free cutting action and lower cutting forces," says Brian Hoefler, Kennametal’s NGE product manager.

"NGE end mills are versatile and can be used for machining shoulders, slots, contours and facing," Mr. Hoefler continues. "These features, combined with the latest Kennametal ‘M’ milling grades, give users productivity advantages that are crucial to the milling requirements of many jobs that require the production of high-quality parts in record time."

Adds Mr. Pirone, "By getting 40 parts per insert edge instead of 12 or 13, having each insert cost us $12 a piece instead of $60 and having such responsive customer application and field service support, Kennametal provides the kind of value we wish all of our suppliers could give us."

Mr. Pirone has also integrated Kennametal drilling tools with his company’s manufacturing operations. For the past 2 years, TP Engineering has been using KSEM APKT Insert Sculptured Edge High Performance modular drills on an Okuma MX-40 HA horizontal machining center to drill deep holes in rocker arms made of 4140 steel that has been heat treated, machined and then hardened to 32-36 HRC.

Using a drill body that is 5 inches long and a carbide blade in grade KC7215, TP is making 400 holes per blade that are 3.600 inches deep with a diameter of 0.630 inch.

"Because KSEM’s design propels the drill into the workpiece at a tremendous penetration rate, while breaking chips effectively and maintaining stability, the user is ensured of getting precise, close-tolerance holes faster," says Kennametal’s Mr. Dobrynski.

To make holes in the aluminum casting of the engine crankcase, TP is using a 5-inch drill body and a grade KC7235 blade to drill more than 2,000 holes (and counting) Face Milling Inserts at a depth of 2.01 inches with a diameter of 1.125 inches. Kennametal performs factory reconditioning of the blades.

TP Engineering’s use of Kennametal’s holemaking know-how extends to the Dynapoint Triple-Flute (TF), a solid carbide drill that TP is using to make small-diameter holes in engine and transmission cases made of 356 and 6061 aluminum. With Dynapoint, TP Engineering is making 24,800 holes per body at 0.51 second per hole. A tool that TP formerly used had an output of only 1,000 holes per drill body at 4 seconds per hole.

With three flutes, the sculptured edge drill point creates a smooth transition from the major cutting edge to the center of the drill, eliminating stress peaks and allowing the drill to actively cut metal over the entire cutting edge.

Compared to conventional drills, which are ground with flat chisel points that will push and tear the metal, the sculptured edge design is said to allow the user to handle increased chip loads for faster penetration rates and greater productivity.

Over the past 4 years, Kennametal has helped TP Engineering reduce its cost per part, decrease cycle times and increase tool life.

The Carbide Inserts Website: https://www.estoolcarbide.com/product/factory-wholesale-cnc-lathe-cutting-tools-solid-carbide-inserts-milling-inserts-bdmt11t308er-jt/

Walter Ewag UK has launched the Walter 3D laser sensor. It Carbide Turning Inserts enables the Walter Helicheck Pro and Plus tool measurement machines to scan with four times the resolution than previously possible and to process that data four times faster, according to the company.

It is suitable for inspecting high-performance tools, as used in industries such as automotive, aerospace and medical, where cutting edge geometry, pitch and spiral pitch vary widely. The company says its 3D sensor could replace two separate machines traditionally used for measuring such tools.

The 3D sensor has swivel angle ranges from -55° to 90° to enable scanning of indexable inserts. It is available as an option on the Helicheck Pro and Plus machines and their corresponding Long versions, which can accommodate tools up to 80 mm diameter and 605 mm long.

It is designed to be easily and CNMG Insert quickly programmed using wizard routines, enabling shorter setup times. The 3D sensor effectively visualizes the workpiece as a point cloud (in differing formats) and enables various measurements to be undertaken on the three-dimensional image.

When the resulting image is ‘placed’ on the tool’s three-dimensional design drawings, or a master part, any deviations can be clearly seen (via the integrated 3D Viewer) as three-dimensional comparisons of point cloud and target model, including surface reconstruction.

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005901341397.html

Star Cutter’s NTG 6RL five-axis tool and cutter grinding machine, based on NUM’s Flexium+ CNC platform, automates the high-speed production and reconditioning of complex cutting tools.

The grinder machine handles fluting, tertiary grinding, relief grinding and automated wheel changing. The NUMDrive X modules accommodate third-party linear and direct-drive torque motors as well as high-frequency grinding spindle motors. The bandwidth of the servo drive and internal processing are said to provide sub-picometer accuracy.

The platform can run grinding programs as large as 40 MB directly from the NCK memory. The CNC executes complex Cermet Inserts cycles from the system’s disk drive via a high-speed data transfer protocol, expanding CAD/CAM grinding operations.

The grinding machine’s servo-assisted popup mechanical steady rest takes advantage of the system and drive modules’ detachable axes. Users can place the rest into the machine for longer parts and remove the full motor and mechanical assembly when it is not needed.

The operator station is designed to simplify machine setup and operation. The optional six-axis robotic part loader essentially programs itself with NUMroto tool files, according to NUM. Notifications can be set to alert shop personnel of process completion or issues during unattended production.

The machine can be integrated with automation systems and handling robots. The CNC platform offers a variety of system communication busses. Measured process or post-process data can be fed back to the NUMRoto software for on-the-fly VCMT Insert corrections, facilitating adaptive, real-time control of the grinding process. Shop floor data can be shared with the plant and to the cloud with an MTConnect interface.

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005954890402.html