FAQ – Frequently asked questions page 2
Further frequently asked questions:
We have noticed that when initiating a machine stop (e.g. triggered by tool monitoring) the machine is no longer coming to an immediate standstill. The upper section of the tool runs into the lower section two or even three times before the machine stops. Mispitching can lead to the strip stock accumulated in the punching tool causing punch breakage. What can we do to counter this? Do we have to replace the brake and clutch unit?
A certain brake angle is entirely normal at high speeds. However, if the brake angle rises above that indicated in the diagram (see Operating Instructions/Manual) the brake linings might be oiled-up. In this case, please contact our Service Department.
We optimise our tools at speeds around 250 spm. Subsequent operating speed is 750 spm. At full speed, the display is indicating a change in feed length (BBV 202) of approx. + 0.15 mm. Why is the previously set feed length changing by this amount?
During feeding, acceleration rates rise in accordance with increases in spm/rpm. The actual factor of increase is ninefold. (see also Question 8)
On BRUDERER punching presses, the ram guiding system is located exclusively at strip level. Punching presses by other manufacturers feature guiding systems below and above strip level. Does the location of the ram guiding system affect tool life?
Yes – locating the ram guides at strip level has a significant effect on tool life. As the guides are located at strip level, the tilt angle of the punch is also at strip level. This significantly reduces wear on the tool – even in the case of eccentric load – and extends tool life.
How often should the oil level of the shock absorbers be checked or the oil changed?
As long as the machine does not run at resonance stroke rate (150 spm) in standard punching mode, the shock absorbers will not need to be checked regularly and are in this respect also maintenance-free.
Where the design of punching tools is concerned, what do we need to be aware of in respect of eccentric loads on punching presses (BSTA 800-145B)? Can stamping and bending stations in the punching tool also be located remotely (e.g. away from the two pressure columns)?
Yes – BSTA presses can support eccentric loads, see the corresponding diagrams in the Operating Instructions/Manual. Please contact our Service Department for more information.
How precisely do the strip pressure pads and strip guides need to be set on a BBV 190 type strip feed unit?
These settings need to be adapted individually to the relevant application and have little to do with the type of strip feed unit being used. In respect of strip feeds, please note that settings must be as precise as possible (in relation to the strip feed direction). A tolerance of 0.10 mm needs to be observed between punch strip and strip feed.
What do we need to be aware of when integrating a rather small punching tool (side length = 500 mm) into a relatively large punching press (BSTA 500-110B) with a tool installation space of 1100 mm?
In this case you need to ensure an exact strip feed (vertical & horizontal) between feed and tool in order to avoid warping of the strip stock prior to insertion into the tool.
What is the difference between the insertion depth measurement offered so far in relation to the analogue ram depth control (eddy current sensors) with distance measurements in the die?
At the present version of the insertion depth measurement the position of the ram is measured by a magnetic tape. Due to the fact that the measuring system is attached to the ram and the guide support, only the ram position is measured and not the actual die position. The new measuring method is very close to the actual stamping process as the sensors are mounted in the die itself. Obviously, this improves the process and parts accuracy.
Is it reasonable to integrate the insertion depth measurement if the tool is equipped with mechanical stopper blocks?
The insertion depth measurement at the ram / guide support has its limits when using tools with stopper blocks. For this purpose the measurement unit is too far away from the process (or the stamping die respectively). With the analogue BRUDERER ram position control, the distance is measured by means of eddy current sensors, which are located in the die. Therefore this system can detect displacements of the ram in BDC more accurate or stop the machine in case the set limits are exceeded.
Why is a relatively large oil circulating quantity necessary for stamping machines?
The heat must be dissipated from the individual bearings and interior parts of the mechanism. 60% of the entire power dissipation is through the lubrication oil. A constant machine temperature is also essential to achieve optimal process reliability.