What is tap testing in CNC machining?
Tap testing, also known as impact testing, identifies
structural dynamics by impacting a structure and
measuring its response, in other words, tap testing
tells us how flexible a machine tool assembly is. In CNC
milling, the tip of the milling tool is excited with a
hammer to induce vibrations while collecting the
measurement with an accelerometer. The relationship
between the force (input) and acceleration data (output)
is the transfer function of the structure which is also
called Frequency Response Function (FRF). FRF represents
the dynamic stiffness of the structure across the
frequency spectrum and is used as an input for spindle
speed Optimizer to calculate recommended spindle speed
and depth of cut.
Tap Testing Champion
Angela Hill, the Partnership Engagement Coordinator at University of Sheffield Advanced Manufacturing Research Centre (AMRC), holds the current record for the fastest tap test time of 11 seconds. Despite not being a frequent tap tester, her time defies expectations in terms of how long it should take to complete a successful tap test.
How to perform a tap test?
Productive Machines offers a TapStarter kit that
includes tap testing hardware, standalone software,
access to Essential Optimization web apps and tap test
training. We have also partnered with Research Centres
to provide tap test services or on-site/remote training
for companies unfamiliar with the tap testing method.
Machining 4.0 Technology
Our partners at National Manufacturing Institute Scotland (NMIS) demonstrate how tap testing is used to determine the stable cutting parameters for the tool and the incredible benefits for the quality of the part and the efficiency of the manufacturing process.
What do we do with FRF data?
DigiTap, our tap test standalone software, calculates
the FRF data from the tap test. FRF data includes
natural frequencies, stiffness and damping ratios of the
machine tool assembly.
FRF data feeds into the Spindle Speed Optimizer to
generate a stability lobe diagram. The user then
knows to select a stable spindle speed and depth of cut
under the stability boundary.
Tap Testing enables Chatter-free Optimization
Tap testing combined with Productive Machines
technology, brings precision and efficiency to
manufacturing. It empowers operators to optimize machine
tool performance against chatter vibrations reducing
waste and enhancing product quality.
Spindle Speeds Optimizer
Find optimal Spindle Speeds for your individual machine with Productive Machines’ web application. The Spindle Speed Optimizer helps engineers select the right set of parameters for profiling, providing spindle speed and depth of cut combinations to achieve stable milling processes. Frequency Respond Function (FRF) data, obtained through tap testing, is used by the app as an input.
TapStarter - Launch Bundle
Get one year free Essential Optimization and tap test
training when
you buy DigiTap standalone software and our tap test
hardware kit.
£9,750