Fault detection and diagnosis of linear bearing in auto core adhesion mounting machines based on condition monitoring

Figures & data

Figure 1. Head gimbal assembly (HGA).

Figure 2. HGA process (a) Adhesive dispensing, (b) Slider attachment, (c) Adhesive cure and (d) Soldering.

Figure 3. (a) ACAM machine and (b) clamping unit in ACAM machine.

Figure 4. (a) The impact of vibrations on reference hole positioning and (b) fault position of adhesive dispensing and (c) attached slider misalignment.

Figure 5. (a) Linear bearing and (b) ball bearing element.

Figure 6. Ball bearing structure and physical parameters.

Figure 7. Spectrum of the vibration signal.

Table 1. The influence of speed on fault frequency.

Motor speed (m/s)	Ball speed (m/s)	Fault frequency (Hz)
0.25	0.125	26.5
0.50	0.200	53.0
1.00	0.500	106.0

Figure 8. FDD non-model-based classification.

Figure 9. (a) The experiment set-up and (b) DAQ system.

Figure 10. Microphotograph of the damage on the ball bearing element.

Figure 11. Ball bearing loss.

Figure 12. Removal of contaminate and lubricant using ultrasonic cleaner.

Figure 13. The sequence of data collected.

Figure 14. (a) Spectrum signal; (b) box plot of spectrum signal at speed 0.25 m/s $(f_{\text{ball}}=26.5\text{Hz})$.

Figure 15. (a) Spectrum signal; (b) box plot of spectrum signal at speed 0.50 m/s $(f_{\text{ball}}=53\text{Hz})$.

Figure 16. (a) Spectrum signal; (b) box plot of spectrum signal at speed 1.0 m/s $(f_{\text{ball}}=106\text{Hz})$.

Table 2. Analysis of variance of current at a motor speed of 0.25 m/s.

Analysis of variance
Source	DF	Adj SS	Adj MS	F-value	P-value
Factor	5	215,314	43,062.8	498.57	0.000
Error	294	25,393	86.4
Total	299	240,707
Model summary
S	R-sq	R-sq (adj)	R-sq (pred)
9.29367	89.45%	89.27%	89.02%
Fisher pairwise comparisons
Grouping information using the Fisher LSD method and 95% confidence
Factor	N	Mean	Grouping
Ball bearing loss + Starved lub	50	1029.88	A
Ball bearing damage + Starved lub	50	933.4	B
Ball bearing damage	50	983.44	C
Ball bearing loss	50	965.32	D
Starved lubricant bearing	50	958.46	E
Healthy bearing	50	949.22	F

Note: Means that do not share a letter are significantly different.

Table 3. Analysis of variance of current at a motor speed of 0.50 m/s.

Analysis of variance
Source	DF	Adj SS	Adj MS	F-value	P-value
Factor	5	1,618,742	3237.48	707.04	0.000
Error	294	134,621	458
Total	299	1,753,363
Model summary
S	R-sq	R-sq(adj)	R-sq(pred)
21.3985	92.32%	92.19%	92.01%
Fisher pairwise comparisons
Grouping information using the Fisher LSD method and 95% confidence
Factor	N	Mean	Grouping
Ball bearing loss + Starved lub	50	1286.08	A
Ball bearing damage + Starved lub	50	1144.78	B
Ball bearing damage	50	1104.48	C
Ball bearing loss	50	1097.90	CD
Starved lubricant bearing	50	1093.93	D
Healthy bearing	50	1060.56	E

Note: Means that do not share a letter are significantly different.

Table 4. Analysis of variance of current at a motor speed of 1.00 m/s.

Analysis of variance
Source	DF	Adj SS	Adj MS	F-value	P-value
Factor	5	1,354,029	270,806	562.88	0.000
Error	294	141,447	481
Total	299	1,495,476
Model summary
S	R-sq	R-sq (adj)	R-sq (pred)
21.9342	90.54%	90.38%	90.15%
Fisher pairwise comparisons
Grouping information using the Fisher LSD method and 95% confidence
Factor	N	Mean	Grouping
Ball bearing loss + Starved lub	50	1322.28	A
Ball bearing damage + Starved lub	50	1281.96	B
Ball bearing damage	50	1188.98	C
Ball bearing loss	50	1183.44	C
Starved lubricant bearing	50	1170.30	D
Healthy bearing	50	1128.68	E

Note: Means that do not share a letter are significantly different.

Table 5. Summary of motor current for all bearing conditions.

	Current (mA)			% Increase of motor current
Bearing condition	0.25 m/s	0.5 m/s	1.0 m/s	0.25 m/s	0.5 m/s	1.0 m/s
Ball bearing loss + starved lubricant	1029.88	1286.08	1322.28	8.50%	21.26%	17.15%
Ball bearing damage + starved lubricant	993.40	1144.78	1281.96	4.65%	7.94%	13.58%
Ball bearing damage	983.44	1104.48	1188.98	3.61%	4.14%	5.34%
Ball bearing loss	965.32	1097.90	1183.44	1.70%	3.52%	4.85%
Starved lubricant bearing	958.46	1093.92	1170.30	0.97%	3.15%	3.69%
Healthy bearing	949.22	1060.56	1128.68	0.00%	0.00%	0.00%

Figure 17. Vibration signals in the time domain.

Table 6. Crest factor comparison of faulty conditions (0.25 m/s).

Target	Bearing condition	Avg	Delta	%
Healthy	Ball bearing loss + starved lubricant	3.98	0.30	8
	Ball bearing damage + starved lubricant	3.97	0.29	8
	Ball bearing damage	4.07	0.39	11
	Ball bearing loss	4.14	0.46	12
	Starved lubricant bearing	3.79	0.10	3

Table 7. Crest factor comparison of faulty conditions (0.5 m/s).

Target	Bearing condition	Avg	Delta	%
Healthy	Ball bearing loss + starved lubricant	4.05	0.25	7
	Ball bearing damage + starved lubricant	4.17	0.37	10
	Ball bearing damage	4.19	0.39	10
	Ball bearing loss	4.20	0.40	11
	Starved lubricant bearing	4.05	0.25	7

Table 8. Crest factor comparison of faulty conditions (1.0 m/s).

Target	Bearing condition	Avg	Delta	%
Healthy	Ball bearing loss + starved lubricant	5.65	0.28	5
	Ball bearing damage + starved lubricant	5.66	0.29	5
	Ball bearing damage	5.80	0.43	8
	Ball bearing loss	5.78	0.41	8
	Starved lubricant bearing	4.86	0.49	9