Often we ask the machine operator how often he checks his machines lubrication system. The normal reply is that it’s checked every time the alarm goes off in the control prompting his attention. He finds the filthy funnel that everyone uses for everything, he pours the lube (maybe the correct kind) through the filthy funnel and the alarm resets. If this plan is not bad enough we’ve all seen the machine sitting with the funnel either sitting to drain in the machine lube tank, or the funnel is dropped into the five gallon bucket of oil that he poured into the machine. This is trapping grinding dust and shop contaminants into your clean oil.
How your system works:
On most CNC machines that use oil instead of grease a centralized oil system distributes the oil from one pump. The oil can go through several banks of distribution blocks. Oil leaves the pump and goes into the block under pressure. A pressure switch normally looks for a pressure signal. Each of the small injectors can send a measured dose of oil to your ball screws, ways or thrust bearings. These injectors are very sensitive to dirt or contaminants. If the injectors become contaminated they can “stick”. This means the machine sees pressure, but oil is not delivered through that injector. The operator never sees the alarm and does not have to fill the tank as often. He is much more likely to complain about filling it too often instead of less frequently.
The lubrication system on your CNC machine has several built in safeties. Filtration, low lube level and pressure switches are normal on most machine tools.
The lube in the tank can build sediment over time. The tank below is a real example of a machine in production. The sediment will settle to the bottom of the tank and needs to be cleaned periodically.
The sediment below came from this tank. The whole cleaning process took less than thirty minutes.
Years ago we had a box way machine become contaminated. The operators couldn’t remember the last time he had added oil. The ball screws and the ways were damaged to the point of us recommending replacement of the machine.
The next time you ask about has your operator “checked” his lubrication, take a closer look.
You don’t have to be a lube “Goo”rue
Every machine is different, so check your manual. It takes less than 30 minutes to increase the life and productivity of your machine and you will be a lube guru.
Serving as an apprenticeship in a relatively up-to-date factory with modern equipment, I had been sheltered from the old ways of doing things. I received a call about interest in some new equipment from a company that manufactured bicycles. I pulled up in front of an old, but beautiful, well kept building. I went to the lobby and introduced myself to the receptionist (yes, they still had those then) and she called for a gentleman who came to get me and offered to give me a plant tour. Knowing what an honor that was, I quickly accepted. That was the beginning of my enlightenment. This company was known for its expensive, elite, beautiful bicycles and I was about to see how they made them happen. I’m not sure what I expected to see, but words cannot express my amazement when he led me down stairs to a room with several rows of tables where women were making wheel assemblies – putting spokes in the rims and then adding the tires by hand. The real shocker was seeing the earthen floors and the ceiling with line shafts that powered their machines.
My point is that it was my first encounter of a beautiful mass-produced product done with the most archaic methods. While these beautiful bicycles were not as efficiently produced by humans as they could be by machines – I have to wonder if it wasn’t the human touch that made them the prized possession that people desired.
It was the mid to late 1960’s and I was a young toolmaker embarking on a new career in machine sales. I received a call from a company wanting to buy a new punch press. Never having called on the company, this new lead filled me with a mixture of excitement, enthusiasm and fear. I already knew a great deal about presses having been a toolmaker from a company with many punch presses. However, I wanted to make a good impression and be prepared for any question that I might be given. I spent my last half hour in their parking lot studying and memorizing every single spec and feature for the machine that I would be quoting. In I go, armed with volumes of information. I felt confident that I could answer any question he could throw my way. Pete took me into his office and after a few minutes of niceties his first question was one that I couldn’t answer. It stopped me in my tracks. I would never have guessed he would want to know the answer to – What does this press weigh? What I didn’t know is that back then, many machines were purchased based on weight. The lesson wasn’t too costly. It hurt my pride, but I made the sale.
As I think back, I always remember a new shop owner I knew who suffered with insomnia. He made many attempts to cure his insomnia with drugs, reading, counting sheep, music, etc. and none of them worked. It so happened that his new shop was in his basement below his bedroom and he could hear noises from the shop at night. One evening he had a job running that would cut off motor bell ends for which he got $0.25 each. As these parts dropped off the lathe in a box, they did so with a kind of rhythm. He started counting $0.25, $0.50, $0.75…It worked! His insomnia was cured.