FOCUS ON ALIGNMENT: Alignment secrets
By John Lambert
After spending over 30 years in industrial maintenance, I have had my share of experience installing new equipment. I have been involved in moving many large machines, some as little as a few feet, ot...
After spending over 30 years in industrial maintenance, I have had my share of experience installing new equipment. I have been involved in moving many large machines, some as little as a few feet, others from one plant to another.
In one of those jobs, the plant’s central engineering group supervised the work that was being done by a contract millwright company. I was the overseer of this work because I was to be the maintenance supervisor when the new line was turned over to us. We were told that this was a turnkey process, meaning that all we would have to do when they finished the project was push the button to start it up. Those of you who have had a similar experience can imagine how accurate that statement was.
This line had its own tank farm with the usual process pumps. The caustic and acid were the safest of the nasty chemicals we had. It had high-pressure pumps, 100 ft of conveyer ovens, incinerators, high speed fans and much more. It was a nightmare.
There always is a bit of excitement around moving or installing a new piece of machinery, even in challenging facilities like that. It takes you away from your normal, everyday work and almost everyone likes a change — just ask maintenance mechanics if they would like to do the installation or have contractors do it. I am sure most would like to be involved.
I also think there is a great benefit to their involvement, because the mechanics will be the ones who must maintain the machinery later. They have a vested interest in making sure the setup is done properly. That’s not to imply that the contractor would not do it right, but both groups usually approach their work differently. Like sprinters and long-distance runners, both are runners, but their approach to a race is different.
Moving machinery into place
I like to use the strength of both groups when moving and setting up equipment because safety is of such great importance. I like to use the contractor, who usually has more experience with rigging work, to assist the crane operator in getting the machine off the flat bed, and then use the plant’s own people to position and align the machine.
The real work starts when the machinery arrives on site. Before it is taken off the flatbed, we have to know where it is going. In the old days, this meant marking the floor, moving the machine in, drilling the floor and bolting the machine down. That’s where the problems started.
During the fabrication of the machine (lets say it is a large conveyer), the fabricator would have started by levelling the base frame material he was going to use, say channel or tubing, before welding. He would then maintain the level and squareness of all subsequent parts being added to it. This would mean that the conveyor was relatively flat when it was finished.
When we install it, we have to be concerned with keeping it flat. If it’s out of level, we do not have to be overly concerned, but if it is twisted, it will affect its operation. I have seen large head rollers break in half because a conveyor that was installed 10 months earlier was twisted. Packaging machines, for example, can have large cylinders with leaking rod seals just because the bed is twisted.
You can see this problem this when you install a motor. You check under the feet to see if there is a gap. If there is, we say the foot is soft. To correct it, we pack shims under the foot. A definition of soft foot is that the plane of the machine’s feet does not lie in the same plane as the base. Think of the analogy of a table that rocks on the floor in a restaurant. To stop the table from rocking, you pack something under the leg. What is happening is that the plane of the table’s feet do not lie in the same plane as the floor.
But what would happen if the table was very heavy? Its own weight would pull it down and the top of the table would twist. That’s what happens to large machine units, big gear boxes, motors, heavy packaging machines, conveyors, etc.
What you need to do is measure the flatness of the floor or the base to which you are going to bolt your new machine. The best way to do this is to use a laser system. A good system can provide standard flatness, straightness, squareness and parallel programs. Or, if you have a decent shaft alignment system, you can measure the twist of the frame or base. (If you need to know how to do this, send a note to me and I will fax the procedure to you.) Once you have measured the flatness of the floor, you can map out what size flat plates you will need to make the plane of the floor flat.
The next step is to mount the machine onto the plates, drill the floor, and bolt the machine down. If you choose to, you can also make it level. As long as you adjust the base equally all around, it will stay flat and you will reap the benefits of doing less maintenance to the machine. Ignore flatness and you’ll see your maintenance work increase.
John Lambert is president of Benchmark Maintenance Services Inc., and can be reached at 1-800-598-1117, fax 905-509-6478, or via e-mail at email@example.com. The company’s web site is www.easy-alignment.com.