Selecting the Proper Metalworking Fluid

Canadian Industrial Machinery asks Milacron Canada’s Sales and Marketing Manager Craig Brydges and Technical Service Manager Steve Renon how to select a MWF

December 1, 2009

Q: Why is coolant used in metal cutting?

A: The basic functions a metalworking fluid performs are cooling the part and tooling to increase tool life; reducing friction; protecting the machine tool and part from corrosion; providing antiweld properties between the metal and the tooling; and washing away chips.

Q: What are the steps to choosing a fluid?

A: First, consult a reputable metalworking fluid company and have a site survey conducted. Most metalworking fluid suppliers have specialists on staff to properly evaluate a customer’s manufacturing operations and make the appropriate product recommendations.

Some of the variables to consider are:

• Part type and material.
• Machine type and operation.
• Coolant tank size and filtration.
• Water quality.
• Desired improvement.
• General plant environment/conditions.

Q: Is it possible for a single fluid to be used in all applications?

A: Yes, one fluid for all applications and materials is generally preferred and desired for most shops to effectively monitor and control metalworking fluids. If you want however, application- and material-specific metalworking fluids should be considered in the following examples:

• Grinding of carbide / thermal spray coatings
• Machining of magnesium
• High-pressure applications
• Hard-water conditions
• Specialty tooling applications (e.g., Mapal reaming, roll form tapping)

These are just a few examples of applications that require special consideration when selecting a metalworking fluid for your shop.

Q: How have fluids changed recently?

Synthetic metalworking fluid technology will outperform heavy-duty soluble oils in similar operations. Titanium and aluminum aerospace applications, for example, are well suited for this technology.

Milacron’s new HFP line of metalworking fluids include soluble oils, semi synthetics, and synthetic fluids designed for high-pressure and high-flow type applications where foam control is critical.

Also, CIMCOOL has just released a complete line of “green” fluids under the CIMFREE® Botanicals name. These are metalworking fluids developed from renewable resource-based components. Our chemists have improved the performance of these fluids when compared to conventional vegetable-based fluids.

Q: Have environmental concerns led to these changes?

A: Being “green” is a hot topic today, as are the environmental perception of a company and government regulations.

Q: How important is it for the fluid not to react chemically with the material?

A: This is very critical to any manufacturing plant or shop using a metalworking fluid. Part staining and corrosion on the material being cut can lead to increased scrap, which ultimately leads to increased manufacturing costs.

Most metalworking fluids are generally multi metal-capable; however, a number of factors can contribute to corrosion of the part being cut, including:

• Incorrect metalworking fluid selected for the material being cut.
• Poor water quality (well water can have high levels of sulfates and chlorides that can react with the material being cut).
• Poor concentration control methods.

Q: Is it important for fluids to be microbe-free?

A: Yes. Microbes can lead to fluid degradation (a short tank life equals increased waste hauling cost, which equals increased machine downtime) and a poor shop environment (odors).

To help prevent this, shops should assign someone to be responsible for the control of metalworking fluids. Concentration control also is one of the key factors in keeping fluids microbe-free, as is using the correct fluid for the shop conditions. Tank-side additives can also be used, but only if recommended by your metalworking fluid supplier.

Q: How does proper maintenance affect coolant usage?

A: Proper working metalworking fluid controls are critical to ensuring long fluid life. Every shop should follow these simple maintenance steps:

1. Assign the responsibility for control.
2. Always maintain the fluid concentration according to the manufacturer’s recommended ranges.
3. Involve your metalworking fluid supplier in training and laboratory support.
4. Employ good housekeeping practices.
5. Know the water type for your area.
6. Use additives only as needed.

Proper fluid maintenance also leads to longer sump life, increased tool life, less machine downtime, and less scrap.

Q: How important are proper disposal techniques?

A: In Ontario, for example, all manufacturing facilities that generate waste require a waste generation license through the Ministry of the Environment (MOE), and all waste haulers are licensed through the MOE.

For more information, visit www.cimcool.ca.