Speed up specimen preparation for noteched impact specimens
The conventional manufacturing of specimens for impact test according ISO148 (and other standards) need high precision adjusting of the specimen on the milling machine to receive high accuracy specimens inside the dimensional limits of the standards.
You have to adjust the height of the milling tool (to receive exact notch depth / ground of 8 mm) and also the direction of the milling (within 2° accuracy).
All this work of fine adjusting and positioning you do not need on the special notch broaching machine: Only insert the specimen, fix it with the quick clamping device and press START.
Using this specimen notching machine means sparing labour cost for time consumption adjusting and fine positioning of your specimens. Additional the precision is mostly better than the milling process because the machine is limited only for this job: The exactness is present every time: Ground depth (residual thickness after notching), the radius of notched ground, the angle of the V-notch, angle of alignment according to longitudinal specimen (at least everything related to the positioning) is perfect any time.
Even when you are not preparing this specimen day by day in hundreds of lots (with a milling machine used only for this process) this machine is a must: Suitable to notch up to 100 specimens per hour. The machine can be operated also from people those have no experience ins using milling machines. So this machine is the no. one solution for third party labs and all companies for up to 100 specimens per day to limit the labour cost for specimen production.
The machine can be used for to produce notched impact specimens for didactic: Just cut a square bar into pieces of 55 mm length (by using a simple saw) and insert these into the machine. 30 seconds later you have produces the ready to test sample (possible also by a student ).
One big advantage of this machine is: Pre adjusting of the notch process grants the residual thickness of 8.00 mm + 0,05) even if the specimen do have a thickness outside the limit (10,0 mm + 0,075) The result of the residual cross-section is every time 8.00 to 10.0 mm = 80 mm²
There is no need to position the specimen with high accuracy: Only insert and fix the specimen an press START
The machine cuts notches (V / U notches) within 30 sec. (steel) or 15 sec. (plastic) incl. loading-
The machine is mounted inside of a free standing housing. The notch braoching tool is guided by two guiding column and driven by a central spindle. The speed can be adjusted using a stepless gear box (for adjusting different speeds for different hard materials). The machine will be operated by two keys only (UP / DOWN). The electric limit switches are controlling the position. A setup can be done easily by user (no dedicated training required).
: KRME 240 (240 mm broaching tool)
: 100 pieces / hour
dimensions of width / depth / height (mm)
: 500 / 310 / 1.050 broaching tool down / 1.290 aching tool up
maximum hardness of specimens
: < 40 HRC (higher tensile strength not possible because tooth of tool will wear / brake
Space for machine approximate mm
: 800 / 600 / 1.400
Weight approximate kg
motor company LENZE (speed adjustable)
: 0,55 kW, 2.840 3.450 RPM, 120 strokes per hour
Standard power supply
: 400V / 50 Hz / ~ 3 phase / 1,5 A / 16 A CEE-plug
Other power supply
: on request - without problems
KWU - Kraft Werk Union: Comparing research between milled and broached ISO-V specimens
"The results of charpy impact tests samples with broached notch (notch impact energy, toughness and the characteristics of the instrumented test) are inside the limits of the standard. The notch broaching machine KRME is suitable for to produce notches for ISO148".
hgiht in ground
0,25 +/- 0,025
45° +/- 2°
8,0 mm +/- 0,075
For high alloyed metals with higher toughness of impact resistance we recommend a notch tool with titanium coating: This will serve an essential higher endurance. Below shown values is approximate number of sharpness life. It will be diversify depending of your material. The life time of sharpness couldnt be guaranteed. A essential point of tool life is to clean it regular (each stroke; 10 strokes ...).
The hardness of the material should not exceed the 40HRC Rockwell. If this material )<40HRC) hast to be notched we strongly recommend a special notching tool with titanium coating. Even if a coated notching tool will be used: At this hardness the wear will decrease the sharpness soon.
Notching broaching tools are wearing parts. A warranty to this is generally excluded. This especially as incorrect operation can-not be excluded: After each broaching the broaching tool has to be cleaned from broaching chips (brass brush) because residual chips in broach cause the flush teeth break off (not repairable tool).
Specimen made of
Tensile strength Rm MPa
Titanium coated notching tool
490 - 630
42 CrMo4 V
750 - 860
34 CrNiMo 6V
1.3901 (24-28% Ni)
650 - 850
no wear out