08Lecture-G-Code-drill - ENGR3190U: Manufacturing and...

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ENGR3190U: Manufacturing and Production Processes Lecture 08 G-codes – Drilling There are various drilling operations in milling: G81 – Spot or chamfer drilling cycle, (also called basic drill cycle). Use for drilling not too thick stock. G73 – Chip break cycle (also called fast peck drill cycle). Used for drilling deep holes, breaks chip G83 – Deep hole drilling cycle. Used for drilling deep holes, rapids out to “R” value. This course will only cover G81. To drill a hole in a part, you have to (a) use a centre drill tool to pre-drill and mark the hole (b) change tool to drill bit and drill the hole 1. Feeds F and Speeds S For Drilling Feed rate for “drill like” operations (eg., drill, reaming, countersink) F = RPM x FEED PER REV FEED PER REV = numerical value from chart RPM = spindle speed = 4 x Cutting Speed / Diameter of tool RPM formula → Fatter drill slower RPM because tool will generate too much heat if RPM too fast F = RPM x PITCH (for tapping) where Pitch = 1/# of threads. Table of feed per revolution values Drill size (inch) Feed per rev 0.125 diameter or smaller 0.001 – 0.002 0.125 – 0.250 0.002 – 0.003 0.250 – 0.500 0.003 - 0.005 0.500 – 1.00 0.005 – 0.010 1.00 – 1.50 0.010 – 0.020 Fatter drill can handle faster feed (bigger feed per rev value), skinny drill breaks more easily
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This note was uploaded on 12/09/2010 for the course MECH ENG mech301 taught by Professor Yang during the Spring '10 term at UOIT.

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08Lecture-G-Code-drill - ENGR3190U: Manufacturing and...

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