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Investigation of the tribological conditions in forming gears with oscillating ram movements

Schmidt, Wilhelm ; Heß, Benjamin ; Groche, Peter :
Investigation of the tribological conditions in forming gears with oscillating ram movements.
In: 7th International Conference on Tribology in Manufacturing Processes (ICTMP).
[Konferenz- oder Workshop-Beitrag], (2016)

Kurzbeschreibung (Abstract)

Forming forces of different cold forging operations can be reduced using oscillating instead of unidirectional ram movement. This also applies for forming gears by “axial forming”. The benefits of using oscillating ram movements are often attributed to the rebuilding of the lubricant film during the back stroke. However, the actual tribological conditions have not been investigated in detail yet. Therefore, this paper aims for the determination of the tribological conditions and the identification of factors influencing the tribological system in oscillating sliding conditions. The investigation of the tribological conditions is achieved by using the tribometer Sliding Compression Test (SCT) which enables a compression of a usually cylindrical specimen with subsequent sliding across a plate. Oil is applied as lubricant. The contact normal stress and surface enlargement achieved in the SCT correspond to the values of the forming operation. By measuring the compression force and the sliding force a friction coefficient is calculated. The SCT is used to investigate the influence of different ram movements and different tool coatings on the friction coefficient. The results show a reduction of the friction level using oscillating ram movements instead of unidirectional ram movement, which proves the re-lubrication during back stroke in “axial-forming”. Friction depend significantly on the surface roughness when coated tools are used.

Typ des Eintrags: Konferenz- oder Workshop-Beitrag (Keine Angabe)
Erschienen: 2016
Autor(en): Schmidt, Wilhelm ; Heß, Benjamin ; Groche, Peter
Titel: Investigation of the tribological conditions in forming gears with oscillating ram movements
Sprache: Englisch
Kurzbeschreibung (Abstract):

Forming forces of different cold forging operations can be reduced using oscillating instead of unidirectional ram movement. This also applies for forming gears by “axial forming”. The benefits of using oscillating ram movements are often attributed to the rebuilding of the lubricant film during the back stroke. However, the actual tribological conditions have not been investigated in detail yet. Therefore, this paper aims for the determination of the tribological conditions and the identification of factors influencing the tribological system in oscillating sliding conditions. The investigation of the tribological conditions is achieved by using the tribometer Sliding Compression Test (SCT) which enables a compression of a usually cylindrical specimen with subsequent sliding across a plate. Oil is applied as lubricant. The contact normal stress and surface enlargement achieved in the SCT correspond to the values of the forming operation. By measuring the compression force and the sliding force a friction coefficient is calculated. The SCT is used to investigate the influence of different ram movements and different tool coatings on the friction coefficient. The results show a reduction of the friction level using oscillating ram movements instead of unidirectional ram movement, which proves the re-lubrication during back stroke in “axial-forming”. Friction depend significantly on the surface roughness when coated tools are used.

Freie Schlagworte: Cold forming, Friction measurement, Tribology, Sliding Compression Test
Fachbereich(e)/-gebiet(e): Fachbereich Maschinenbau
Fachbereich Maschinenbau > Produktionstechnik und Umformmaschinen
Veranstaltungstitel: 7th International Conference on Tribology in Manufacturing Processes (ICTMP)
Hinterlegungsdatum: 04 Feb 2016 09:19
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