Milling feeds and speeds

	C	D	E	F	G	H	I	J	K	L	M	N	O	T	U	V	W	X	Y	Z	AA	AB	AC	AD	AE	AF	AG
1
2	Speed (RPM for HSS cutter)
3					Cutter diam'r :	(mm)
4			tooth speed	tooth speed	3	4	5	6	8	10	12	16	19	Aluminium			3	4	5	6	8	10	12	16	18	25
5	Material	Hardness, Bhn	feet / min	m/min											Hardness, Bhn
6	Plastic		250	76	8089	6067	4854	4045	3033	2427	2022	1517	1277			Speed in m/min
7	Aluminium		250	76	8089	6067	4854	4045	3033	2427	2022	1517	1277		?	76.2	2000	2000	2000	2000	2000	2000	2000	1517	1348	971
8	Brass, bronze	80-100	200	61	6471	4854	3883	3236	2427	1941	1618	1213	1022				grey = machine limit
9	Steel (low carbon)	< 150	110	34	3559	2669	2136	1780	1335	1068	890	667	562
10	Steel	180 to 220	80	24	2589	1941	1553	1294	971	777	647	485	409	Chipload (thou)
11	Steel	220 to 300	60	18	2589	1456	1165	971	728	582	485	364	307	End Mill	6mm cut depth		XX	XX	XX	XX	XX	XX	3	4	6	8	yellow = my
12	Steel	300 to 400	40	12	1294	971	777	647	485	388	324	243	204		1mm cut depth		1	1	1	1	1.5	3	3	5	8	10	interpolates
13
14	RPM 3-4* higher for carbide
15	RPM - lower for steel if no pumped coolant (and DO use lubcricant)													Feedrate (mm/s)	Flutes	4
16														End Mill	6mm cut depth		XX	XX	XX	XX	XX	XX	10	10	14	13
17	Chipload														1mm cut depth		3	3	3	3	5	10	10	13	18	16
18	feed in thou per tooth for HSS milling bit		(slots?)			(slots?)				face mill		form relieved
19			end mill			end mill				shell end mill	side mill	cutter			half feedrate for 2 flutes
20			Depth of Cut 6mm			Depth of Cut 1mm
21		Cutter diam'r :	9mm cutter **	18mm	25mm +	3mm	9mm	18mm	25mm+
22
23
24	Plastic		3	8	10	2	4	10	14	20	12	6
25	Aluminium		3	6	8	1	3	8	10	12	8	5
26	Soft brass	80-100	3	8	10	1	4	8	10	14	8	5
27	Steel (low carbon)	< 150	2	4	6	1	3	6	8	12	6	4
28	Steel	180 to 220	2	4	5	1	3	6	8	10	8	4
29	Steel	220 to 300	1	2	3	0.5	2	3	4	8	5	3
30	Steel	300 to 400	0.5	2	2	0.3	1	2	3	4	3	2
31
32	Bronze 150-250 as per steel 150-300 depending on operation
33	** Go slow as depth > radius
34	1 thou = 25 microns ;)
35
36	Feed rate
37	Feed in mm / second for given RPM and chipLoad (in thou) for 4 fluted cutter
38	For steel - needs lubricant and coolant to get anywhere close to these!
39	Flutes:	4	RPM->
40	ChipLoad (thou)	ChipLoadMicron	500	750	1000	1250	1500	1750	2000
41	0.3	8	0.3	0.4	0.5	0.6	0.8	0.9	1.0
42	0.5	13	0.4	0.6	0.8	1.1	1.3	1.5	1.7
43	1	25	0.8	1.3	1.7	2.1	2.5	3.0	3.4
44	2	51	1.7	2.5	3.4	4.2	5.1	5.9	6.8
45	3	76	2.5	3.8	5.1	6.4	7.6	8.9	10.2
46	4	102	3.4	5.1	6.8	8.5	10.2	11.9	13.5
47	5	127	4.2	6.4	8.5	10.6	12.7	14.8	16.9
48	6	152	5.1	7.6	10.2	12.7	15.2	17.8	20.3
49	8	203	6.8	10.2	13.5	16.9	20.3	23.7	27.1
50	10	254	8.5	12.7	16.9	21.2	25.4	29.6	33.9
51	12	305	10.2	15.2	20.3	25.4	30.5	35.6	40.6
52	16	406	13.5	20.3	27.1	33.9	40.6	47.4	54.2
53	20	508	16.9	25.4	33.9	42.3	50.8	59.3	67.7
54
55
56	2 flutes: half the feed rate of 4
57
58
59	http://its.foxvalleytech.com/machshop3/speedcalc/SpeedRPM.htm
60	http://www.southbaymachine.com/setups/cuttingspeeds.htm
61	http://its.foxvalleytech.com/machshop3/speedcalc/feedratecalc.htm
62
63
64	Cutting limits:	tool strength	usually the limiting factor
65		machine rigidity	might be an issue
66		machine power	unlikely to be an issue!
67		surface finish	shallower cuts give better finish
68
69
70	Accurate slot cutting
71		slot, accurate width, 5 passes
72			cut centre slot
73			then cut half the remaining diamater
74			then final pass (now with known tool deflection)
75
76	max depth = tool radius
77
78	"a chip load that is too small will cause excessive tool wear"
79
80	In general you can slow down the RPM, but don't reduce the feed too low - this reduces tool life and screeches horribly if the cutter fails to dig into the material
81	Don't mill off thin slices - this concentrates all the wear into the end of the mill
82	If you have a choice, don't use the end of the mill (it's stronger higher up, and wears the end less)
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