The Coordinate Measurement Machine (CMM) is stealing your shop's productivity.
Being the darling of the quality department, it is sometimes used as the lazy way to measure. Let me explain.
There has been a trend in aviation MRO and other manufacturing sectors to send every part that requires measurement to the CMM. While this might seem like a great idea, as technology is generally beneficial, it is sometimes the wrong approach.
1️⃣ The CMM can be likened to a hammer, echoing the saying, 'when all you have is a hammer, everything is a nail.' This analogy holds true when you invest in your first CMM. It's a substantial financial commitment, and the temptation to use it for everything is strong.
Consequently, you begin sending parts for measurement. This is good initially, but it can lead to the abandonment of other more cost-effective measurement methods in favor of the CMM.
The consequence of this shift is that your shop may lose proficiency in hand measurements, becoming overly reliant on the CMM and its operator. 'Just send it to the CMM!' becomes the battlecry.
2️⃣ The CMM can become an expensive bottleneck. As your shop begins to shift more parts to the CMM, the CMM room can turn into a black hole that engulfs parts.
Why does this happen? Because every new part requires initial setup and programming before any measurements can be taken, and this is typically handled by few trained operators. The result is that parts start piling up, waiting for a simple diameter measurement.
In the meantime, the part has been removed from your CNC, disrupting the mill setup. When the part is put back into setup, it's never quite the same.
Furthermore, your CNC machinist is left waiting, leading to idle machines. Your CMM is overwhelmed, and the solution being considered is purchasing another CMM that costs over $120,000 to alleviate the bottleneck.
3️⃣ The CMM is often overkill. With everyone embracing the CMM trend, everything ends up being measured in your CMM room. This includes bearing diameters, simple dimensions, and clearance holes for fasteners, and the list goes on.
Before you know it, you're dealing with part rejections of a mere 0.0001 of an inch in part of a clearance hole, because the entire hole was scanned.
You've scrapped a perfectly good part due to narrow focus.
In conclusion, I am not opposed to using the CMM for measurement; quite the opposite, I believe it's a valuable tool for production. However, I have witnessed instances where it has turned into a sort of monster.
Unfortunately, people remain oblivious to this phenomenon, often due to a bias toward technology, lack of awareness, or sheer laziness.
Ultimately, it's your shop, and I'm not the one purchasing your next CMM!
#grownostr #engineernostr