Precision Engineers: Endangered Species?
Technology is a wonderful thing. For the most part, I'm more than happy with the innovations that have taken place in the last decade or so. But something has been lost. I don't know if it's because of time constraints and a need for speed, but precision seems to be getting an increasingly short shrift these days. It's something we (roughly) take for granted these days and it works well enough for most things, but there are machines that require minute tolerances — things like airplane wings or surgical instruments — that would never last long if they were built using some of this new technology. This is not a new problem by any means. The Chinese and Greeks established the concept of "exact science" thousands of years ago and modern industries such as cryogenics or metallurgy have relied on precision for centuries. The problem is that machines are built in ways that make these individual components more efficient but much less accurate.
From this article on the NY Times website: "Mitsubishi Electric, one of the world's largest electronic equipment manufacturers, has foregone precision to save money on electrical components."
The current trend in industrial production seems to be to sacrifice precision for speed by giving up a little degree of accuracy. So, rather than building a machine that is more accurate by adding more components and spending more money on parts, they build it a little faster but less precisely. In some cases this makes sense. If you're making parts to be assembled into an engine, the faster and cheaper you can make these individual pieces makes sense when it comes to mass producing the whole engine. There are good arguments for moving away from precision manufacturing to mass-production assembly lines. It's certainly a very cost effective way to go about things and it works for a lot of products. I do get the argument that with modern computer controls and lasers, this trend will reverse itself and we will start making machines with far greater accuracy than ever before.
I'm not terribly worried about this since most of the stuff I make is highly accurate and even that's a little overkill. For example, I can easily spend 10 hours with a fine tooth plane making one box but I can easily spend 5 minutes with a dremel and make the same thing. That's not to say that I don't spend a lot of time making things very precise. When it comes to something like an engine cover or something along those lines where I'm building to tight tolerances, then this new trend is troubling. This has implications for our industry as well because we often work on small things at extremely high tolerances.
To be more specific, if you look at an engine for instance, the majority of that engine is not made of aluminum or steel. It's made up of relatively small pieces like carburetors, spark plugs and valves. These parts are precision machined and they take a lot of time to make. If there is a way to mass produce these kinds of parts then it makes sense to do it. The alternative is a whole lot of hand work which is never going to be cost competitive with mass production machines. I'm not sure what's going to happen in the future but it could mean that our industry dies out as more and more jobs become automated or outsourced overseas where labor costs are cheaper and jobs easier to come by.
The thing is, precision is not only an expensive proposition in labor hours but requires a lot of skill as well. I'm not saying that automation will never improve or that we can't ever be replaced. I know for certain there will always be a place for people who can build things far more precisely than any machine could ever hope to accomplish. The problem is our industry will shrink as time goes on and machines become the norm rather than the exception. There's nothing wrong with that of course, but it does detract from the unique nature of what we do and what makes us so valuable in the first place.
I'm not going to complain too much about this since I have a job and I love what I do. It's certainly not because I think people can't do my job, because they clearly can. It just bothers me that our industry is slowly dying out. It's happened before and it will happen again. If a machine can put in 8 hours of work in a day rather than 1 hour from a person, then it makes sense to build the machine and employ thousands of people rather than spending more money on highly trained individuals who are much harder to come by.
I don't know if this trend is going to reverse itself but I certainly hope so. Precision engineers are kind of like specialist doctors or lawyers with respect to the rest of society; they're valuable and important but often less common and necessary than others. I'm sure there will always be a need to have people who know how to work on machines and build things with an extremely high level of precision.
http://www.nytimes.com/2011/12/10/science/10surroundings.html?pagewanted=all&src=pm
Posted by David Johnson at 3:50 PM No comments: Links to this post
When I first started making blades I was using a .031" shim stock which was the thickness of the blade only 1x in y direction, 2 x y, and 1 x z direction of your working area. The blades I made in this way were extremely thin, giving the knifemakers a market price drop. I did them by hand and they came out beautiful. The thinner the blade, the more difficult it is to sharpen. It may be possible to get down to .009" without getting into dangerous territory, but I did not have a .011" carbide grinder at that time so it was not in my realm of possibility.
Maybe these can be made by machine with tolerances as tight as 1/1000th of an inch or less and still come out sharp enough for some serious use.
This is an interesting question. So far, we have been discussing the number of sheets that are going to be needed for each sheet of stock. If no other considerations come into play, you can have your sheets cut and tapered to the thickness you want them and eliminate the need to grind your blade back later on. This is going to effect how thick your "carving" area will have to be to slice through your stock and how wide it will have to be.
First we take your 'home plate' dimensions and determine what size drill bit we are going to need. The thickness of home plate wall is called 'spacing.
Conclusion: The drill bit we need has a diameter of 0.788″ in order to clear the blade thickness in the y-z plane. This 0.788″ diameter is what we are going to use as our "funny" dimension when we are figuring out our blade width and length dimensions.
If you look at the shape of your blade in cross section, it's not going to be a perfect rectangle as it goes from your center line to your work piece (it will have a curve or hump). This hump represents a small amount of material that you do not need, but that you have to account for because a point must be touching something solid within x and y axes ** .