Prescription For Coolant Selection

Matching the right coolant to the right cutting tool improves tool life and surface finish.

Selecting the right coolant for your metalcutting operations is similar to a doctor examining a patient.

By applying a scientific approach to diagnosis and asking detailed questions, deciding on an applicable coolant for your medical machining operations can mean the difference between zero gain in tool life and 270%. Add in the productivity time and cost savings gained by choosing the right cutting tool and/or insert, and watch that number increase exponentially.

The experts at Valenite have a unique advantage most coolant manufacturers do not have. They also manufacture the cutting tools for milling, drilling and turning operations, as well as the indexable inserts. This means in the R&D phase, they can test and test new coolant to make sure it delivers cost and time savings to its customers.

"All coolant is not the same. All metalcutting operations are not the same. Therefore, you need to match the coolant to the metal removal operations regardless if it is considered general purpose or specialized," says Mark Goedtel, ValCool product manager.

"While it may appear the best solution is to find an ‘all purpose' coolant, in the long run it could affect productivity and overall tooling costs negatively.

It is better to narrow the focus for potential long term cost savings." Goedtel traditionally begins dialogue with customers by asking three basic questions:

• What material are you machining?
• How are you machining this material?
• What are the problems with your current coolant?

Coolants are formulated to provide optimal performance on all types of different materials. Some perform better than others in different operations, especially surface finish where quality and precision are important.

Matching the correct cutting fluid to the material can improve tool life, produce fewer burrs, create process improvements and reliability, and lower costs—all critical factors when machining medical components that require exactness.

WHAT CHOICES DO I HAVE

Goedtel relays that there are typically three choices in metalworking fluids: 1. Semi-synthetics attempt to provide the lubricity of soluble oil, and the cooling and stability characteristics of synthetics. Semi-synthetics provide longer tool life, better surface finish when compared to synthetics, and reduced consumption due to less drag out when compared to soluble oils. Semi-synthetic fluids work best across a wide variety of materials and applications.

2. Synthetics are formulated for highspeed applications and provide the highest level of cooling and stability.

Synthetics can handle the most advanced machine tool performance capabilities. It provides better cooling properties and reduced consumption due to less drag out.

Synthetics generally excel in grinding applications 3. Soluble oils provide the highest level of lubrication and excellent rust control. Soluble oils increase tool life and provide excellent surface finish as well as less re-work and lower machine maintenance.

This cutting fluid works best in applications that require a high degree of lubricity.

SURFACE FINISH

Generally speaking, the best surface finishes are provided by soluble oils and heavy-duty semi-synthetics when machining titanium and other medical materials. Heavy-duty semi-synthetics provide superior surface finish by providing two key functions: lubricity and cooling.

Proper lubricity is provided by the additive packages built into the coolants.

Extreme Pressure (EP) additives provide an extremely slippery surface film when exposed to heat and pressure.

This film allows for extended tool life and improved surface finishes.

High quality semi-synthetics will generally allow for greater cooling while machining when compared to soluble oils. Semi-synthetics, by nature, contain a greater proportion of water when compared to soluble oils.

Therefore, the increased proportion of water allows the semi-synthetic coolants to better cool and remove heat from the tool/workpiece interface. This provides better tool life and improved surface finishes.

TROUBLESHOOTING, MAINTENANCE

When considering the best cutting fluid for your machining operations, lubricity, bio-stability, sump life, tool life and performance should be considered prior to selection. Whether the trouble is the coolant is going foul quickly, leaving residue, staining parts or causing oily windows, technical support from coolant providers can help quickly eliminate these issues and provide alternative solutions.

Consider maintenance like follow up visits to the doctor. They are critical to longevity, health and usefulness of your cutting fluids. Proper care and handling of coolant products involve several important factors, including: storage, mixing, bacteria control, tramp oil control, application to the cutting zone, and proper disposal.

Just as a doctor would not diagnose a patient without checking his symptoms, the same can be said for selecting cutting fluids for your machining operations. By pinpointing your exact operations needs, you can match the right cutting fluid to the project, saving production costs and machining time.

Challenge: Develop a coolant specifically designed for its customers machining titanium that would reduce tooling costs and increase productivity.

Many current fluids do not address the qualities of newer alloys, which are poor heat conductors, notoriously difficult to cut, and exhibit these additional unique characteristics:

• Low modulus of elasticity requiring high clearance angles that weaken the cutting edge
• Low thermal conductivity transfers more heat into the tool
• High chemical reactivity leads to chips welding to the tool material
• Workhardening of the work piece
• Segmented chips increase cutting forces

Solution: Last year, Valenite introduced a new cutting fluid that can increase throughput and tool life up to 270%. Aerotech VP utilizes an innovative EP additive package to control heat and remove it from the cutting zone. With enhanced lubricity, Aerotech VP removes the heat in the cutting process as much as possible, resulting in an increase in tool life, which translates to a reduction in expenses related to tool change time and insert indexing. Aerotech VP also exhibits excellent biostability, as much as five times greater in tests against its competitors.

Valenite LLC
Madison Heights, MI
valenite.com