Process for the fine blanking of workpieces and fine blanking press

Abstract

Workpieces are fine blanked from a starting material, wherein the starting material is clamped between a punch guiding plate and a blanking plate and also between a punch guided in the punch guiding plate and a counter holder guided in the blanking plate and the unit comprising the punch and the counter holder is moved relative to the unit comprising the punch guiding plate and the blanking plate whereby the workpiece is displaced with respect to the starting material along the blanking gap formed between the blanking plate and the counter holder, in particular is cut out from the starting material, while lubricant is applied into the active zone between the blanking plate and the workpiece, the lubricant being fed to the active zone through the blanking gap between the blanking plate and the counter holder.

1 . A process for fine blanking of workpieces from a starting material in a fine blanking press, comprising clamping the starting material between a punch guiding plate and a blanking plate and also between a punch guided in the punch guiding plate and a counter holder guided in the blanking plate and moving a unit comprising the punch and the counter holder is-moved relative to a unit comprising the punch guiding plate and the blanking plate, whereby the workpiece is displaced with respect to the starting material along a blanking gap formed between the blanking plate and the counter holder, thereby cutting out the workpiece from the starting material, while applying lubricant into an active zone between the blanking plate and the workpiece, the lubricant being fed to the active zone through the blanking gap between the blanking plate and the counter holder by pressurizing the lubricant, characterized in that wherein arranged in the fine blanking press, in the lower die part, which comprises the blanking plate and the counter holder movably mounted therein, there is on the side of the counter holder facing away from the starting material a spatial region which is filled with lubricant and is configured to be subjected to pressure and is subjected to pressure during the blanking operation and which is connected to the active zone via the blanking gap, while at least part of a pressure required for the feeding is generated by movement of the counter holder into the spatial region guiding the lubricant. 
     
     
         2 . The process according to  claim 1 , wherein the lubricant is fed through grooves or slots extending at least in some regions in a direction of the relative movement, and arranged in a surface of the blanking plate that is facing an opposite surface of the counter holder and/or arranged in a surface of the counter holder that is facing an opposite surface of the blanking plate. 
     
     
         3 . The process according to  claim 2 , wherein the grooves are only formed in the surface of the counter holder which, considered in a direction of a stroke of the fine blanking press, is made to extend between a lower face and an upper face of the counter holder and borders the blanking gap on a side of the counter holder. 
     
     
         4 . The process according to  claim 2 , wherein a set of all the grooves or slots extending in the direction of the stroke is divided into at least two groups of the grooves or slots, with the grooves or slots of a respective group each extending over another partial region of an entire length of the surface considered in the direction of the stroke, while the grooves or slots in two adjacent groups that follow one another in the direction of the stroke are each connected by a circumferential groove/or slot in the surface running in a circumferential direction around the direction of the stroke in the surface, with the slots/or grooves of different groups that run in the direction of the stroke having an offset in relation to one another in this said circumferential direction. 
     
     
         5 . The process according to  claim 1 , wherein the pressure is generated during and/or by displacement of the lubricant out of the spatial region in a direction of a lubricant reservoir against an effect of the line resistance in at least one line formed between the lubricant reservoir and the spatial region, with the spatial region being supplied with the lubricant from the lubricant reservoir. 
     
     
         6 . The process according to  claim 5 , wherein the displacement of the lubricant out of the spatial region in the direction of the lubricant reservoir takes place by at least one throttle valve configured to adjust a level of the pressure generated. 
     
     
         7 . The process according to  claim 6 , characterized in that wherein the lubricant is circulated between the lubricant reservoir and the spatial region by means of at least one pump. 
     
     
         8 . The process according to  claim 7 , characterized in that wherein the lubricant is passed through the blanking plate by means of a supply line and a return line of a circuit. 
     
     
         9 . The process according to  claim 7 , wherein, when there is a movement of the counter holder into the spatial region, the lubricant is displaced into the lubricant reservoir by a throttle valve in the return line, the return line being between the spatial region and the lubricant reservoir, while a check valve arranged in the supply line closes as a result of the pressure generated in the lubricant by the counter holder. 
     
     
         10 . The process according to  claim 9 , characterized in that wherein, when there is a movement of the counter holder into the spatial region, the lubricant is also displaced into the lubricant reservoir by a throttle valve which is in a supply line between the spatial region and the at least one pump and lies parallel to a check valve in the supply line which check valve is closing or closed. 
     
     
         11 . The process according to  claim 10 , wherein, in a return stroke of the counter holder away from the spatial region in the direction of an initial position, the lubricant flows through the check valve, which is open, out of the lubricant reservoir into the spatial region with the return stroke taking place by pressure bolts which pass through the spatial region and act on the counter holder. 
     
     
         12 . The process according to  claim 1 , characterized in that wherein a gap between the punch and the punch guiding plate is subjected to the lubricant only by the effect of gravity on the lubricant, the lubricant being stored in a lubricant reservoir, which surrounds a part of the punch protruding from the punch guiding plate on the side of the punch guiding plate facing away from the starting material and the blanking plate, the lubricant reservoir being open to atmospheric surroundings. 
     
     
         13 . A fine blanking press for fine blanking of workpieces from a starting material with which a starting material can be clamped between a punch guiding plate and a blanking plate and also between a punch guided in the punch guiding plate and a counter holder guided in the blanking plate and a unit comprising the punch and the counter holder can be moved relative to a unit comprising the punch guiding plate and the blanking plate, whereby the workpiece can be displaced with respect to the starting material along a blanking gap formed between the blanking plate and the counter holder to hereby be cut out from the starting material, while a lubricant can be applied into an active zone between the blanking plate and the workpiece, the fine blanking press comprising a device configured to feed the lubricant to the active zone through a blanking gap between the blanking plate and the counter holder by pressurizing the lubricant, wherein arranged in a lower die part, which comprises the blanking plate and the counter holder movably mounted therein, there is on a side of the counter holder facing away from the starting material a spatial region which is filled with the lubricant and is configured to be subjected to pressure and is subjected to pressure during the blanking operation and which is connected to the active zone via the blanking gap, while at least part of the pressure required for the feeding can be generated by movement of the counter holder into the spatial region guiding the lubricant. 
     
     
         14 . The fine blanking press according to  claim 13 , comprising a device configured to guide the lubricant through a gap between the punch guiding plate and the punch in a direction of the starting material.