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Daily cleaning consists of rinsing down the machining area with coolant. When it comes to periodic cleaning of your machine tools, be ready for a much larger task. The best way to begin is just to roll up your sleeves and dig in. Yes, this normally can be a mess; and, yes, you probably will be, too. But, don’t worry — it looks much worse than it is. When the covers are removed, machine tools take on a different look. Those who don’t know much about the internals of machine tools might be alarmed by their appearance. Removing the Cover Some machines have well-engineered cover schemes. However, from my experience, most machines don’t. For example, if you are machining graphite, the dust will penetrate everything, including your protective covers. I was called by a customer to repair a spindle motor fault. When I removed the cover from the motor area, I found the motor completely engulfed in carbon dust. I couldn’t see the motor at all, and it was rated at 25 hp (not a small motor, by any means). Many times, I have removed covers to inspect ballscrews and had to chip away cast iron clumps of rusted chips with a hammer and chisel just to look at it. I think, by now, you’re getting the point. No matter how good covers are, they should be pulled back, and the covered component area should be cleaned. Change the Wipers While you have the cover open, change the wipers. I suggest that you inspect the machine wipers a month prior to performing a PM, so that they can be changed during scheduled downtime (that is, during the PM). In addition, don’t forget to check the drain holes in your casting. They are usually located between your axis ways. If they back up, they could eventually fill up with coolant, contaminate the ballscrew and bearings, and short out the axis motor. This could be a very expensive repair — all due to a clogged drain hole that could have easily been avoided. Remove Foreign Objects I don’t think that I need to explain the damage that foreign objects can cause. In case I have any doubters out there, I will give you a couple of examples. What do you think will happen to your feed systems (ballscrew and bearings) if they are covered with chips? How about your spindle belts? Let’s go a step further: chips versus linear guide packs. Who do you think will win? Let’s not forget all those power supplies that are blown due to 24-volt shorts. The chips from machining are generally very sharp and could easily penetrate most switch cables. Chips also will wear through hoses. Even braided, steel-covered hoses will eventually rupture due to rubbing on chips. Chips are like oil: if they are present, they will find their way into everything. Needed Tools The tools you will need are fairly basic. First and foremost, you will need to invest in a decent wet/dry vacuum. It is the easiest way to remove chips, and it is much more efficient than trying to wipe them out by hand. If you must use compressed air, be very careful. Use protective goggles, because when you blow out chips from blind holes, you may get a face-full. You also will need an abundance of rags and some type of safe degreaser. I would suggest being careful when picking out your cleaner. Some say they are safe to breathe, but you may be getting a pretty good dose of this stuff before your task is through. Be watchful when spraying cleaner on the machine: electrical components don’t like conductive fluid cleaners. The machines don’t need to be spotless; just simply cleaned. I think everyone would be surprised at the amount of times a machine fault is due to chips. Cleaning is not fun, but it is extremely essential. Next month, we will address the electrical cabinet and what needs to be done to PM it. Talk to you then. Mike Breen has been an aircraft electrician in the U.S. Army’s 101st Airborne, as well as a Certified Electronic Engineer with 14 years’ experience in machine tool repair. He has recently been a Field Service Engineer with Ellison Machinery Company of Wisconsin, holding this position for more than six years. During this time, Mike has designed and implemented complete preventive maintenance programs for many successful companies resulting in significant increases in their machines’ performance. For comments and inquiries about these articles, his e-mail address is mbreen@ellisonwi.com - September 2000 |
We talked months ago about daily cleaning of your machine tools and how important it is.