Finishing to avoid rejects
SK90 and clamping tower in the work area of the Heckert HEC400. The sealing surfaces of directional control valve disks are finished to 10 µm and milled to a length of +/- 3 µm using sharp cutting instead of opressive finishing.
The solution is: sharp cutting instead of opressive finishing. As a result, material no longer comes loose from the pre-machining feed grooves during thermal deburring. The process is now safer and more productive.
CLAAS Industrietechnik (CIT), based in Paderborn, is a system provider and the main location of the CLAAS Group for drive technology and hydraulics. From the idea to series production, 700 employees develop and produce system solutions for the agricultural machinery, municipal technology and construction machinery sectors.
Automation and safety
This involves the finishing of pre-machined cast iron workpieces with spheroidal graphite content. The workpiece is a 4/3-way LS proportional valve, a component of an assembly for mobile hydraulics. A total of 12 parts are machined in 2 set-ups on one clamping tower. OP10 with 3 x 2 parts and OP 20 with 2 x 3 parts, stacked. All sealing sides are finished. The surface quality requirement is a roughness depth of Rz 10 µm.
Finished and unfinished part of the directional control valve disks made of cast iron EN-GJS-400-15. The SK90 finishes the sealing surfaces to Rz 10 µm and machines the control edges with a tolerance of +/- 0.03 mm.
Innovative solutions for machining
The material of the directional control valve disks is GGG40. Wide finishing cutters were previously used for finishing. With the wiper effect, a large radius on the cutting insert presses or pushes material into the pre-machining feed grooves. During the subsequent thermal deburring process, the pressed-in material is released again and the surface quality deteriorates to > Rz 12 µm. The result is a fluctuating reject rate.
The unique cassette system of the SK90. Quick and easy adjustment to the µm and high surface quality finishing.
The more precise the setting, the better the surface quality and the service life of the indexable inserts – quick and easy with ZOLLER.
Future outlook
Avantec’s solution is cutting instead of opressive finishing. This means no change in surface quality after the deburring process. With 8 of the 4-edged SN indexable inserts in SKY77 quality, the high-precision SK90 with wide face cutting edge and sharp cut finishes the required Rz 10 µm. Additional effect: Due to the high accuracy of the tool, it is also used to maintain shape and position tolerances. Setting it on the ZOLLER setting device is extremely reliable and time-saving. With the easy-to-adjust cassette system of the SK90, the tool is set to an accuracy of +/- 3 µm. The more precise the setting, the better the surface quality and the service life of the indexable inserts is.
“The SK90 from AVANTEC is a high-precision finishing cutter with a unique cassette system. A top tool for high and stable surface quality in cast materials.”
Hans-Georg Nondorf, Technical Sales Avantec
Tool Tech
Material: Cast iron EN-GJS-400-15
Batch size 10.000 parts/year
Machining: Finishing of the sealing surfaces to Rz 10 µm, Machining of the control edges +/- 0.03 mm
Tool: Finishing cutter SK90 with Ø 125 mm, standard program
Cutting data: Cutting speed Vc = 325 m/min, feed per revolution fn = 3.2 mm/rev
Shortcut
User: CLAAS Industrietechnik GmbH | Paderborn
Sector: Agricultural technology | Municipal technology | Construction machinery
Process: Cast iron machining | Directional valve disks | Finishing of sealing surfaces
Focus: Process reliability and quality
Solution: Sharp-cutting finishing
Result: Reliable process | stable surface quality | significantly increased productivity