130 CNC Machining
Preparing for Machining
A machinist should be aware of the following items before starting a machining process.
❏ Check toolholders and replace any missing or damaged parts.
❏ Check the size of milling cutters, especially if reground.
❏ Check cutting edges of tooling for sharpness. Regrind if they are dull,
nicked, or broken.
❏ Use the largest toolholder available for maximum rigidity.
❏ Use the shortest tool and toolholder for maximum rigidity.
❏ Use proper speeds and feeds for the type of tooling and the operation
being performed.
❏ Use the correct cutting speed for the work material and tool material
selected.
❏ Use a sufficient number of clamps and straps to fasten work to the
table.
❏ Be sure the workpiece is sufficiently placed in a vise for maximum
gripping power.
❏ Before making cuts, study the part drawing carefully to avoid
mistakes.
❏ Set up clamps close to the workpiece and keep them parallel with the
table.
❏ Always use parallels when holding the workpiece in a vise.
❏ Check for correct cutter rotation.
❏ Be sure all tools and the workpiece are clamped securely.
❏ Use the strongest inserts possible, depending on the type of cuts to be
made.
❏ Use the maximum depth of cut and a coarse feed for roughing.
❏ Be sure the machine has adequate horsepower for roughing.
❏ Use negative rake inserts for greater strength.
❏ Use inserts with the largest nose radius for good finish and greater
insert strength.
❏ Use climb milling for better finishes and longer tool life.
❏ Direct cutter force against the solid jaw of the vise.
❏ Check the cutter path to avoid striking clamps or fixtures.
❏ Remove all burrs and sharp edges from workpieces before fastening.
❏ Clean all tooling, fixturing, and workpieces before setting up.
❏ Use proper coolant to prolong tool life.
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