Page 80 - MetalForming October 2014
P. 80

In-Die Sensing
  The First Priority of
Any Good Sensor Program
... is to, as quickly as possible, imple- ment sensors to monitor strip feeding and part ejection. Here, Williams has developed a uniform approach to feed monitoring by incorporating an induc- tive proximity sensor to detect the posi- tion of a spring-loaded block that is pushed into its final, fully fed position by the strip at the end of the feed cycle. He prefers to use reflective photoelectric sensors for detecting part ejection. Note in the accompanying photos the bright yellow color, used to alert everyone in the plant that the area has sensors within it and to exercise caution working near it.
It also is the duty of the sensor appli- cations specialist to fully test photo- electric sensors for their ability to func- tion within an oily environment in the die. This easily can be done by spraying the photoelectric detecting beam(s) using a hand-held sprayer to ensure that the oil will not fool the sensors into giving a false output. The one cat-
The implementation of sensors to moni- tor cam position has become a routine application in many shops. Shown are two separate cams monitored for their respective returns with one inductive proximity sensor per cam.
astrophic mess to avoid is to have the part not be properly ejected from the die, and the photoelectric sensors fooled into sending a false ejection sig- nal caused by the oil droplets.
Sensor Protection
Throughout my 30 years of writing

columns and articles for MetalForming on sensors, and consultations with metalforming companies of all sizes, I remain astounded as to the amount of sensor destruction that takes place in many stamping companies, whether from human error or outright negli- gence. Therefore, it is paramount that all sensor cabling be protected from being crushed, nicked or cut.
This can be done in one of two ways: machining channels for the routing of the sensor cables (when possible), or by using tubing to protect the feed sensor cable. When burying cables in machined channels, be sure to cover the channels with protective plates. Note how, once again, Williams uses yellow paint on the plates to warn everyone who will be working with the die that the area houses sensor technology.
In addition to using sensors to mon- itor strip feed and part ejection, many value-added-minded metalforming companies using cam motion within the die employ sensors to monitor cam
            
    
 
 
           

  
 
       

       
 78 MetalForming/October 2014
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