How important is roll forming lubrication compatibility?
At first glance, it doesn't seem that the compatibility of the lubricant used in the roll forming process needs much attention. You'd better look again. It may surprise you that the chemical and physical properties of the roll forming lubricant leave fingerprints in at least six different areas of the operation.
Let's begin with the plant environment. Environmental guidelines mandate safe handling and disposal of lubricants. You must determine if the various lubricants you are using are hazardous, requiring special controls and perhaps, a licensed waste hauler for proper disposal.
Lubricant waste can be controlled in different areas in the process. Selecting the proper application technique is a good place to start. When using evaporative compounds, make sure to apply them by microspray or airless spray. These methods reduce consumption and eliminate disposal problems.
Another area of concern is the control of water extendable lubricants. There are several guidelines to help minimize waste issues. Check the plant water condition. This is not a given. Sometimes the lubricant properties have to be adjusted to be compatible with the water condition. In some instances, water treatment may need reverse osmosis or de-ionization to achieve complete compatibility.
Coolant control charts should be set up to prolong coolant life and reduce waste by following coolant concentration guidelines and clarification recommendations.
It's important to select the right lubricant for the material being formed. Lubricants affect material surfaces, and using the wrong lubricant can do more harm than good.
Let's look at the different types of surfaces. Generally, inactive surfaces, such as cold-rolled steel and hot-rolled steel, are compatible with most ferrous metal lubricants, as long as the lubricants are stable.
On the other hand, active surfaces are a totally different ballgame. Here the overriding factor is compatibility of lubricant to material. It's important to understand the properties of the lubricant used to form the various types of galvanized coatings. The proper lubricant should be stable and not contain harsh extreme pressure agents or other harmful ingredients that can bring about white rust, staining, or spotting. These compatibility concerns also apply to forming aluminum, copper, and brass.
All active surfaces need stable, gentle lubricants that will not attack the material surfaces, either chemically or physically. Lubricant compatibility must be checked in every instance for positive results.
The Rust Factor
Using the wrong lubricant can cause parts to rust. One of the main causes is nesting parts processed with water extendable lubricants. Most water extendable lubricants are not compatible with nested storage conditions. Processed parts must be well drained before they are stored or shipped. As indicated earlier, all galvanized surfaces are ideal candidates for white rust. To achieve rust-free compatibility, lubricants have to be selected carefully. Humidity cabinet tests should be performed to determine compatible lubricants and screen out the undesirable ones.
Other considerations are inter-plant and long distance parts shipping. In-process and near-term rust protection of formed parts can be achieved with the use of tested quality roll forming lubricants.
The physical properties of the roll forming lubricants used in the recirculation system should be able to settle metal fines satisfactorily and separate the tramp oil generated by cold-rolled steel, hot-rolled steel, and aluminum. The best lubricants for recirculating systems are synthetic and semi-synthetic solutions. Water solubles generally are not well-suited for settling metal fines, unless clarification and filtration equipment are available.
The finishing process at the end of a forming operation usually determines the type of preservative coating to be used. Secondary operations can benefit from a well-chosen lubricant that has a potential not only for performing the roll forming process, but also has the capability of allowing pre-punching, post-punching, cut-off, and welding. Selecting the right roll forming lubricant can increase productivity.
Another area impacted by the lubricant selection is process equipment maintenance. The grease used in the roll stand bearings should be compatible with the coolant being used. Many synthetic and chemical solutions will wash out conventional greases. Special chemical-resistant greases are available.
The paint on the roll forming machine should be resistant to erosion by the coolant. Too often, conventional paints wash off from lubricant contact. Heavy-duty shop enamel paint is highly recommended.
Careful selection of the lubricants used in your roll forming process can help ensure a smoother, more efficient operation.
Joseph Ivaska Jr. recently retired from his position as vice president of engineering at Tower Oil & Technology Co., 205 West Randolph St., Chicago, IL 60606, 312-346-0562. He now serves the company as a consultant. Inquiries can be directed to firstname.lastname@example.org.