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Lab Testing of Metalworking Coolants via Microchip Testing

For decades, the Falex Pin and V-Block machine was the primary laboratory method for evaluating lubricating properties of metalworking coolants. This test apparatus is a friction producing device that provided load and torque data, but does not replicate the metal cutting (chip formation) operations occurring at customer’s facilities. It was also limited to evaluations on steel.

Other bench top lubricity analyzers have been developed that more closely duplicate actual machining operations. One of these is the Micro tap Tapping Torque Tester.

The Micro tap Tapping Torque Tester is an industrial tapping machine modified for lab testing of coolants on various types of metallurgy. Such standard metals which are commonly tested include 1018 Steel, 6061T6 Aluminum, and 316 Stainless Steel.

How is the Test Run?

The Micro Tap Tapping Torque Tester uses a standard HSS ( high strength steel) tap to machine threads into predrilled holes in a 2 inch x 14 inch test bar.

The force or torque required to tap the hole is measured as coolant is applied to the tap and metal test bar. Test results are reported as either a torque value in Ncm (Newton centimeters) or as % efficiency.

Evaluating the Cause of Foam

The % Efficiency is the ratio of the torque value of a control coolant to the torque value of the test coolant.

%Efficiency = Torque value control / Torque value test

The control coolant is typically assigned an efficiency of 100% and test coolants will fall above or below this number. Metalworking Fluids coolants with lower torque values and higher efficiencies have better lubricating properties. Coolants with efficiencies within 5% of each other have comparable lubrication characteristics.

The MicroTap Tester has been used to compare lubricity properties of the new Chemetall metalworking coolants as well as numerous competitor’s products. See the data below:


Product
Conc %
Torque, 1018 Steel
% Efficiency
Torque, 6061 T6 Alum
% Efficiency
Torque, 316 SS
% Efficiency
Ncm
Ncm
Synthetics







Gardocool C 9116
5
194
120.1
238
105
88
98.9
Castrol Syntilo 9954
5
179
130.2
251
99.6
88
98.9
Houghton Hocut 767
5
267
87.3
307
81.4
87
100








Neo-Synthetics







Gardocool C 9156
5
264
88.3
258
97
86
101.2








Semi-Synthetics







Gardocool C 9127
5
266
87.6
248
100.8
88
98.9
Gardocool C 9157
5
233
100
250
100
87
100
Gardocool C 9158
5
254
91.7
241
103.7
88
98.9








Soluble Oils







Gardocool C 9179
5
169
137.9
141
177.3
82
106.1
Master Trim E 206
5
238
97.9
196
127.6
79
110.1
Blasocut BC40NF
5
284
82
194
128.9
111
78.4





How Can Galling Be Eliminated In Stamping Operations?

When galling occurs in a metal stamping operation, it is often first thought that the choice of lubricant is the culprit.  But if we look more closely at the root causes of such failures we can easily see that there are physical changes and requirements at the die face that needs to occur before this phenomena can be eliminated.

In many operations things like plastic bags, cellophanes, even plastic wraps are often used over face of the die and work piece to assist and eliminate this issue. Usually you would use plastic only as a last-resort lubricator, but with tighter and tighter tolerances and less effective lubricants, it's possible you may need it for use in a production pinch. The intention is to introduce a slippery membrane between the tooling and work material to reduce friction and encourage metal flow.

You can use plastic to make more metal flow in specific corners, or on one side as a way to determine the height and location of draw beads or pad pressure in tryout. Some parts require that extra advantage to even run production, and several companies have rigged a simple stand and electric motor to feed a roll of plastic into the die with the material.

It is possible that increasing the efficiency of the lubricant application to the work site can also minimize galling in a localized area. Lubricant application is a technical issue, and every situation will have specific demands and need individual assessment. Just looking at your die is not always enough to know if you are applying lubrication as effectively as possible. For some operations, spraying Metalworking fluids lubricant from outside the die might be a good choice, while others might require application of lubricant directly to the coil or blank. Working with your lubricant supplier as well as your application equipment engineer can assist in locating the ideal setup and application.

The next time galling is an issue- remember that the choice of lubricant is only part of the answer. Understanding the setup and die requirements, along with some industry tested application methods will certainly help in minimizing these occurrences. But like any good solution, the keys are to determine the correct application and experience.

To learn more about the full range of our products, visit us on www.chemetallamericas.com and we would be pleased to assist you with your requirements.

EVALUATION OF METALWORKING COOLANTS USING THE MICROTAP TAPPING TORQUE TESTER

For decades, the Falex Pin and V-Block machine was the primary laboratory method for evaluating lubricating properties of metalworking coolants. This test apparatus is a friction producing device that provided load and torque data, but does not replicate the metal cutting (chip formation) operations occurring at customer’s facilities. It was also limited to evaluations on steel.

Over the years, other bench top lubricity analyzers were developed that more closely duplicated machining operations. One of these is the Microtap Tapping Torque tester, an industrial tapping machine modified for lab testing of coolants on various types of metallurgy. Standard metals include 1018 Steel, 6061T6 Aluminum, and 316 Stainless Steel.

The MicroTap Tapping Torque tester uses a standard HSS tap to machine threads into predrilled holes in a 2 inch x 14 inch test bar. The force or torque required to tap the hole is measured as coolants is applied to the tap and metal test bar.

Test results are reported as either a torque value in Ncm (Newton centimeters) or as percent efficiency. The % Efficiency is the ratio of the torque value of a control coolant to the torque value of the test coolant. The control coolant is typically assigned an efficiency of 100% and test coolants will fall above or below this number. Metalworking fluids with lower torque values and higher efficiencies have better lubricating properties. Coolants with efficiencies within 5% of each other have comparable lubrication characteristics.

The MicroTap machine has been used to compare lubricity properties of the new Chemetall metalworking coolants as well as numerous competitor’s products.


Product
Conc %
Torque 1018 Steel
% Efficiency
Torque 6061 T6 Alum
% Efficiency
Torque 316 SS
% Efficiency
Ncm
Ncm
Synthetics







Gardocool C 9116
5
194
120.1
238
105
88
98.9
Castrol Syntilo 9954
5
179
130.2
251
99.6
88
98.9
Houghton Hocut 767
5
267
87.3
307
81.4
87
100








Neo-Synthetics







Gardocool C 9156
5
264
88.3
258
97
86
101.2








Semi-Synthetics







Gardocool C 9127
5
266
87.6
248
100.8
88
98.9
Gardocool C 9157
5
233
100
250
100
87
100
Gardocool C 9158
5
254
91.7
241
103.7
88
98.9








Soluble Oils







Gardocool C 9179
5
169
137.9
141
177.3
82
106.1
Master Trim E 206
5
238
97.9
196
127.6
79
110.1
Blasocut BC40NF
5
284
82
194
128.9
111
78.4