Flat Tensile Specimen Preparation Machines

What Flat Specimen Preparation Does

A flat tensile specimen is cut to a dog-bone geometry. The gauge width, the square shoulders and the edge condition decide whether the specimen breaks in the gauge and what strength it reports. A CNC mill produces the shape from the geometry held in its software, so the geometry repeats from specimen to specimen, and the same machines cut subsize and custom flat shapes in metals, plastics and composites. The range runs from a compact benchtop machine for a few specimens a day, through mid-size models for routine quality control, to larger machines for continuous production.

Standards for Flat Tensile Specimens

ASTM E8/E8M defines the shape and tolerances of tensile specimens for metals, ASTM A370 applies to steel products, ISO 6892-1 gives the international room-temperature method, and DIN 50125 standardizes the test piece geometry. The MINI and Classic Upgrade also hold JIS Z2201, and the Classic Upgrade holds ASTM E23 geometries for Charpy and Izod impact specimens with U and V notches.

What Affects Flat Specimen Quality

Spindle stability, rigid clamping, coolant and the cutting path all show up in the finish. Heat picked up during cutting and burrs on the edge lower the reported strength, so the machines combine cast iron frames, linear motion and flood or recirculating coolant. Specimen length, width and thickness also set the machine you need: the working area has to fit the longest specimen, and clamping fixtures can hold several specimens in one setup. Programs for the common geometries arrive ready to run, so the operator selects the standard, enters the material and starts the cut.

Flat Specimen Preparation Machines from NextGen

The TensileMill CNC MICRO is a compact 2-axis machine for flat tensile and impact samples. The TensileMill CNC MINI adds a 400 x 400 x 200 mm working area and a 24,000 rpm spindle. The TensileMill CNC Classic Upgrade prepares flat tensile and Charpy or Izod specimens on one FANUC platform, and with its triple clamping fixture three stacked sets of 25 mm thick specimens go through in one setup.

The TensileMill CNC XL is the large-capacity machine for volume work with a 10-station tool changer. A service plan for each machine covers preventive maintenance, operator training and performance verification against ASTM, ISO and DIN requirements.