Sometimes the best information that you can get about your machining process requires your sense of touch to feel the vibration.
In many shops, the definition of a problem is “something that is not easily seen.”
Unwanted vibration in our machining processes can cause variation, unsatisfactory surface finish, and dimensional variability. Unwanted vibration is not easily seen.
A friend who plays fingerstyle guitar sent me a link to a video that got me to thinking about the role of vibration, harmonics, and chatter in our shop processes. The genius of the video is that it makes something not easily seen- easily seen!
The video is convincing that the sounds we hear are tied to a wave form on the string.
The sounds that we hear from our machining processes similarly are tied to a ‘harmonic’ or standing wave vibration in the workpiece or in the tool and machine. Sometimes, this sound is lost beneath the noise of other processes in the shop.
So when a machine operator complains about variation while machining, I ask him to lay his hands on a safe part of the machine and tell me what he feels.
If it is more like a Rock Concert than a smooth constant vibration punctuated with noticeable jolts from the indexing, I suggest that rather than looking at material, we look at the machine itself and the rigidity of the tooling as the likely cause of the variation being experienced.
Mass in machines is used to attenuate this kind of unwanted vibration.
Wear in machines or any kind of looseness can decouple the tool from that mass, promoting vibration, and thus variation.
In the guitar photo and video, the displacement of the string appears to be far greater than we could imagine possible.
And it turns out that it is an illusion created by the sampling rate of the CMOS camera ‘shutter’ in the iPhone Camera.
Regardless, it serves us a great picture of the unseen and reminds us that in noisy shops, feeling a vibration on a machine may tell us more about the process than our control charts or reading of the tools.
The M-List is curated by the Manufacturing Institute to include those institutions that offer NAM endorsed metalworking skills training and certification.
PMPA partners with the Manufacturing Institute to promote the growth of credentialed metalworking professionals following the NAMEndorsed -NIMS Skills Credential Model.
The M-List recognizes high schools, community colleges, technical schools, and universities that are teaching manufacturing students to industry standards. Specifically, these schools offer students the opportunity to earn NAM-Endorsed Manufacturing Skills Certifications as a standard part of their manufacturing education programs.
The NAM-Endorsed Skills Certification System is a system of stackable credentials that can apply to all sectors in the manufacturing industry. These nationally portable, industry-recognized credentials validate the skills and competencies needed to be productive and successful in entry-level positions in any manufacturing environment.
Right Skills Nowis an acceleration of the NAM Endorsed Manufacturing Skills Certifications Program designed to fast track qualified candidates into a career in precision machining / advanced manufacturing.
If there is no M-List program in your area, don’t despair. PMPA has prepared a database of institutions that offer relevant skills training for precision machining (some of which offer the same NAM endorsed -NIMS Manufacturing Skills credentials here: PMPA Career Training Database
If you are one of the unhappy college graduates mentioned in Forbes- perhaps you should consider bringing your talents to work in our industry.
The book and its message are heavily pointed at achieving institutional clarity through reducing chaos.
That is a great takeaway, but was not the best one for me.
The One Lesson that I took from Karen’s presentation was that the Shewart Cycle- Plan- Do- Study- Adjust- is the authentic model for continuous improvement.
First proposed by Walter Shewart, and edited, published, and improved by Deming, the Shewart cycle was recast by Japanese executives into PDCA- Plan-Do-Check-Act- and this is how many of us have learned it.
According to Karen Martin
In the 1980’s Deming felt that the model had been corrupted by translation difficulties.
Deming recommended replacing PDCA with PDSA- which he felt was closer to Shewart’s original intent.
“Deming continued to refer to the cycle as PDSA and dubbed it the “Shewart cycle for learning and improvement.” (The Outstanding Organization, pp.128-129.)
So why am I a fan of Karen Martin’s PDSA reframing?
Certainly not because of this little bit of historico-semantic revisionism?
Actually, it is because unlike all of the other graphics that you can find on PDSA on google images, Karen Martin’s book has depicted this cycle as Shewart and Deming have relayed it- a continuous, ongoing process of continuous feedback- ongoing process improvement.
This is the One Lesson I Learned from Karen Martin.
Ditch the PDCA wheel visual-Embrace the continuous cycle of cycles model of PDSA.
There is no reason that the vast majority of new manufacturing jobs have gone to men, but they have.
Why has womens’ representation in manufacturing dropped for two decades?
PMPA Vice President Darlene Miller testified before the Senate Joint Economic Committee last week on the topic of Women in Manufacturing.
As a shop owner, STEP Women in Manufacturing honoree, and member of the President’s Job Council, Darlene has some real world insight into the issue.
Here are her 4 Steps to Encourage Women in Manufacturing Careers
1) It is absolutely essential that businesses engage with local community colleges to assure relevant skills sets are being taught;
2) Equipment needs to be current, not old and outdated. We have high tech $400,000-$500,000 equipment per machine.
3) We really need really excellent math and problem solving skills; we need to tell the Schools what those are.
4) We need to get into middle schools to engage female students at a younger age to potential careers.
Watch the testimony: