Nickel Machining Services


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Nickel Machining Services - Monday, April 11, 2016

Nickel isn’t the easiest of materials to machine. Its high shear strength causes it to produce high heat while it is cut, resulting in fast hardening that can attach to the surface of the cutting tool and warp small parts. The only way to machine nickel alloys is by following the standard best practices, like those below.

Boring

Although face-turning and boring are simple, drilling large holes and tapping requires plenty of power. When chip flushing and lubricant flow are difficult, the use of solvents will increase the performance of small diameter hole operations. Use them alone or pair the solvent with lard or mineral oils.

Tooling

Ensure that tools are kept sharp with the use of lubricants and cooling systems. Engine lathes and vegetable oil-based fluids in CNC equipment are a plus. Wire or feathered edges should be removed from tools before beginning.

Turning

Stick with high speed tools for cutting off. Carbide tools won’t achieve the desired result. Use a feed of roughly .001" per revolution. Give the tools a front clearance of 7°. Pair it with the larger 25° tip. Use positive rake angles.

Tapping

The metal will flow into the cut, so a tap drill that’s sized up from the standard drill for conventional threads would be ideal. Automatic machines, however, should use a two or three-fluted tapping tool. For those taps that fall below 3/16”, stick with the two fluted and grind the hook angle 8° to 10°. Keep the speed steady at 20/FPM.

Drilling

Large boreholes, tapping, and drilling operations benefit from the application of a light viscosity petroleum cutting oil. Insert drills in CNC machining will use the same speeds (SFM) for boring, facing, and turning. Drill jigs and stub drills are recommended. Make sure that feed rates are .002” per revolution. If twist bits are used, opt for cobalt drills. Keep the drills short, using heavy web-type drills with nitride or electrolyzed surfaces. Set the drill ground to a point angle of 118° to 120°. Clean the holes of debris often to avoid breaking the drill if it takes hold.

For deep holes, crankshaft drills have a heavy web and a helix angle that runs higher. The web will be thinned at the chisel point. For those drills with a diameter greater than ¾”, grind small grooves through the lip, and extend it back along the clearance of the lip. Stagger the grooves between both cutting edges to prevent fouling in the helical flutes.

For heavy drilling, like those with a diameter 1 ½” and above, spade drills handle those deep holes with their carbide tips. Secured by a steel head, attached to a rigid bar, the bearing support will fit between the tailstock and the work.

Gun drills are a good option for deep holes typically 2” in diameter and less, though it may occasionally be used on 2 ½” diameter holes. Use an oil that’s highly sulfurized for deep hole drilling. Keep the fluid pressure at 800 psi for 3/16” holes. For 2” holes, decrease it down to 200 psi.

Reaming

Keep the feed at three times the drill speed with a margin on the land that runs from .005” to .010” with the chamfer at .005” to .10” and the chamfer angle held around 30°. The tools should stay short, possessing a minimal face rake ranging from 5° to 8°.

For consistent quality, contact Digital Machining Systems. In the Louisiana gulf area, there’s only one name that stands out for any precision machining need.


 

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