Metal forming is a fabrication process in which manufacturers create a range of structural parts and components from metal sheets or tubing, bending, or deforming a piece of metal into its desired shape without any removal.
“In metal forming, anyone who’s had problems with lubrication, surface finish, or other friction-related issues understands that friction testers are a key piece of equipment. Unless they accurately test, they won’t know if they have a sporadic or recurring problem, which can lead to costly, out-of-spec products, until corrected,” says John Bogart, Managing Director of Kett US, a manufacturer of a full range of static and dynamic friction testers as well as surface property analyzers for various industries.
The challenge is that traditional friction testing equipment is not always up to the task.
As a solution, portable, handheld friction testers have been developed that enable fast, lab quality, non-destructive testing by essentially anyone without specialized training. With this capability, in situ testing of various materials and surfaces can be completed in seconds, even at an angle, upside down, or with contours.
The benefits of portable friction testing
The handheld units can be utilized anywhere virtually instant, in situ, friction testing is needed in the metal forming process. For instance, friction can be measured on metal surfaces when receiving raw materials, in production to adjust lubrication, or during QA checks further downstream.
Examples of the portable friction analyzers include two handheld, battery operated models, the H94Ai and H37 3D by Kett. Both units can measure the static coefficient of friction (SCOF) on dry, wet, or lubricated metal surfaces and are designed for use with minimal training. The operator simply places the unit on the surface to be tested, presses the “measure” key, and the static coefficient of friction is measured to 0.001 precision in seconds, with accuracy and reliability comparable to lab models.
The frictional interaction of metals with lubricants or other liquids
“Basically, anyone can pull a workpiece from the production line and test the friction in multiple places with these portable units. If the item is in spec, they can put it right back on the line. If not, they can quickly adjust on the fly,” says Bogart. “Measuring friction is completely dependent on the two interface materials. So, quickly changing out the fixture to accommodate the testing of different metals is important,” says Bogart.
He notes that exchanging test fixtures can be used to simulate solid/solid interfaces and solid/liquid interfaces, which can be helpful in determining the frictional interaction of metals with lubricants or other liquids.
While the H94Ai must be held level when measuring, the newer H37 3D has integrated angle adjustments that allows it to be used at any angle – from horizontal to vertical in three dimensions, even upside down. The combination of the H37 3D’s integrated angle adjustments, along with the ability to exchange test fixtures, enables measuring friction in angled, contoured, and rounded metal surfaces. This facilitates more versatile, static coefficient of friction (SCOF) measurement of metal surfaces, machinery, and tooling, which can improve production quality and equipment longevity.
“By being able to hold the instrument at any angle, you can get accurate measurements without having to worry about either orienting the piece or orienting your hand to make sure that the instrument is completely horizontal,” says Bogart.
Ensuring quality, longevity
The bottom line for the metal forming industry is that it is now easier to ensure quality and protect machinery from the problems created by either too much or too little friction in the process. With portable SCOF testing, they can ensure that all metal surfaces are within production specifications anywhere as needed.