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