Penetration Rate

		PENETRATION RATE, INCH PER MINUTE (RPM)										Metric Conversion IPM x 25.4 = MM/Min.
FEED CURVE		1	2	3	4	5	6	7	8	9	10	11	12	13
		0.004	0.006	0.008	0.01	(0.012)	0.014	0.016	0.018	0.020	0.024	0.028	0.035	0.045
S U R F A C E F E E T P E R M I N U T E	20	0.31	0.46	0.61	0.76	0.92	1.07	1.22	1.38	1.53	1.83	2.14	2.67	3.44
	40	0.61	0.92	1.22	1.53	1.83	2.14	2.44	2.75	3.06	3.67	4.28	5.35	6.88
	60	0.92	1.38	1.83	2.29	2.75	3.21	3.67	4.13	4.58	5.50	6.42	8.02	10.31
	80	1.22	1.83	2.44	3.06	3.67	4.28	4.89	5.50	6.11	7.33	8.56	10.70	13.75
	100	1.53	2.29	3.06	3.82	4.58	5.35	6.11	6.88	7.64	9.17	10.70	13.37	17.19
	125	1.91	2.87	3.82	4.78	5.73	6.69	7.64	8.60	9.55	11.46	13.37	16.71	21.49
	150	2.29	3.44	4.58	5.73	6.88	8.02	9.17	10.31	11.46	13.75	16.04	20.06	25.79
	175	2.67	4.01	5.35	6.69	8.02	9.36	10.70	12.03	13.37	16.04	18.72	23.40	30.08
	200	3.06	4.58	6.11	7.64	9.17	10.70	12.22	13.75	15.28	18.34	21.39	26.74	34.38
	225	3.44	5.16	6.88	8.60	10.31	12.03	13.75	15.47	17.19	20.63	24.07	30.08	38.68
	250	3.82	5.73	7.64	9.55	11.46	13.37	15.28	17.19	19.10	22.92	26.74	33.43	42.98
	275	4.20	6.30	8.40	10.51	12.61	14.71	16.81	18.91	21.01	25.21	29.41	36.77	47.27
	300	4.58	6.88	9.17	11.46	13.75	16.04	18.34	20.63	22.92	27.50	32.09	40.11	51.57
	350	5.35	8.02	10.70	13.37	16.04	18.72	21.39	24.07	26.74	32.09	37.44	46.80	60.17
	400	6.11	9.17	12.22	15.28	18.34	21.39	24.45	27.50	30.56	36.67	42.78	53.48	68.76
	450	6.88	10.31	13.75	17.19	20.63	24.07	27.50	30.94	34.38	41.26	48.13	60.17	77.36
	500	7.64	11.46	15.28	19.10	22.92	26.74	30.56	34.38	38.20	45.84	53.48	66.85	85.95
	550	8.40	12.61	16.81	21.01	25.21	29.41	33.62	37.82	42.02	50.42	58.83	73.54	94.55
	600	9.17	13.75	18.34	22.92	27.50	32.09	36.67	41.26	45.84	55.01	64.18	80.22	103.14
		1	2	3	4	5	6	7	8	9	10	11	12	13
		FEED CURVE NUMBER

SFM x .3048 = SM/minute IPM x 25.4 = mm/minute

Step 1.

Get Surface Feet per Minute and the Feed curve Number from page 2 and page3.

Step 2.

Use the chart above to determine the approximate Inch per Minute penetration rate based on the intersection of Surface Feet per Minute and the Feed Curve.

Example:

To drill a .3346 hole in 316 Stainless Steel using a tool in group A, the suggested speed is 90-150 SFM and a Feed Curve 5. For a medium difficulty stainless such as 316 select a starting point in the middle of the SFM range (120 SFM) and use the chart to approximate the inch/min. penetration rate at 5.73 IPM.

Step 3.

To determine specific RPM =

SFM x 3.82
Tool Diameter

120 SFM x 3.82
.3346"

= 1370 RPM

Step 4.

To determine specific feed Inch/Revolution (IPR) =

Feed Multiplier (F/M) x tool diameter in inch
012 F/M x .3346 = .0040 IPR

Step 5.

Begin machining at 1370 RPM x .0040 IPR = 5.48 IPM and adjust the speed and/or feed per revolution up or down to optimize chip formation. Deep hole drilling and large diameter tools above .750" diameter may require up to a 20% reduction in Feed/Rev. Correct starting procedures should be followed when using longer length tools, see page 7.

NOTE:

These speeds and feeds are estimates of starting parameters based on a rigid set up with adequate coolant flow. Speed and feeds may have to be adjusted up or down depending on the machine or fixture rigidity. Chipbreaking cycle or peck drilling may be necessary depending on the material being machined and the times diameter depth.