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Sensor Applications for Die Sensor Applications for Die ProtectionProtection
The DiemastersThe Diemasters
2100 Touhy Avenue2100 Touhy Avenue
Elk Grove Village, IllinoisElk Grove Village, Illinois
Thediemasters.comThediemasters.com
847.640.9900847.640.9900
Part of our “Manufacture Smarter” series
What is Die Protection?What is Die Protection?
• A die protection system monitors material A die protection system monitors material movement and critical events in the movement and critical events in the stamping processstamping process
• The goal of die protection is to stop the The goal of die protection is to stop the press press beforebefore it makes a bad hit. it makes a bad hit.
How Does it Work?How Does it Work?
• Sensors are installed in and around the dieSensors are installed in and around the die
• The sensors monitor The sensors monitor specificspecific events, signaling a events, signaling a controller when events occurcontroller when events occur
• When the system detects a problem, it will open When the system detects a problem, it will open a stop relay to stop the pressa stop relay to stop the press
Proximity SensorsProximity Sensors
DefinitionDefinition
A proximity sensor is a sensor that can A proximity sensor is a sensor that can
detect, without actual physical contact, detect, without actual physical contact,
the presence of a metallic objectthe presence of a metallic object
Proximity Sensor OperationProximity Sensor Operation
When power is applied to a prox, When power is applied to a prox, an invisible sensing field extends an invisible sensing field extends from the face of the sensorfrom the face of the sensor
The sensor actuates when a metal The sensor actuates when a metal object touches the sensing fieldobject touches the sensing field
The target does not have to block The target does not have to block the sensing field, it only needs the sensing field, it only needs touch to touch the edgetouch to touch the edge
Proximity Sensor PackagesProximity Sensor Packages
Tubular, both threaded Tubular, both threaded and unthreaded barreland unthreaded barrel
Low-profile flat packageLow-profile flat package
Prox Sensor Detecting a Pilot Prox Sensor Detecting a Pilot HoleHole
StripStrip
Sensing fieldSensing field
Prox Sensor Detecting a Pilot Prox Sensor Detecting a Pilot HoleHole
Prox Sensor Detecting a Pilot Prox Sensor Detecting a Pilot HoleHole
Prox Sensor Detecting a Pilot Prox Sensor Detecting a Pilot HoleHole
Spring Loaded Proximity SensorSpring Loaded Proximity Sensor
Bottom DieBottom Die
Sensor Sensor CableCable SpringSpring
BushingBushing
StripStrip
Proximity Sensor at the End of the DieProximity Sensor at the End of the Die
Strip too high, misses sensing fieldStrip too high, misses sensing field
Strip too low, misses sensing fieldStrip too low, misses sensing field
Sensor with Spring Loaded Plunger Sensor with Spring Loaded Plunger
FeedFeed
PlungerPlunger
SpringSpring
CaseCase
SensorSensor
SensingSensingFieldField
Misfeed SensingMisfeed Sensing
8 mm Prox Sensor8 mm Prox Sensor PlungerPlunger
SpringSpring
Misfeed SensingMisfeed Sensing
Overfeed is detectedOverfeed is detected
Misfeed SensingMisfeed Sensing
Shortfeed is detectedShortfeed is detected
Misfeed SensingMisfeed Sensing
Misfeed SensingMisfeed Sensing
Move the sensor closer to the plunger for more precise detectionMove the sensor closer to the plunger for more precise detection
Misfeed SensingMisfeed Sensing
Back it off for looser feed tolerancesBack it off for looser feed tolerances
Through-Beam PhotosensorThrough-Beam Photosensor
Also called opposed-mode photosensor
Light beam from emitter shines directly at receiver
Long range (up to 700’) - Very high excess gain
Can be made very precise by using apertures.
Emitter Receiver
Through-Beam Photosensor
E R
Receiver Viewing Area
EmitterBeam
Target must block half of sensing beam to actuate sensor
Sensing Beam
Through-Beam PhotosensorThrough-Beam PhotosensorPotential ProblemsPotential Problems
Target is too small to Target is too small to actuate sensor (does not actuate sensor (does not block half of beam)block half of beam)
Object reflects the emitter Object reflects the emitter beam at the receiver. beam at the receiver. Even though target blocks Even though target blocks more than 1/2 of beam, it more than 1/2 of beam, it is not detectedis not detected
Through-Beam Sensor with ApertureThrough-Beam Sensor with Aperture
Aperture (also called a “slit plate”)
No aperture -Wide effective beam
Aperture installed - Narrow, more precise effective beam
Through-Beam Feed SensorThrough-Beam Feed Sensor
• • For misfeed detection applications where For misfeed detection applications where sensor can be placed at the end of the die.sensor can be placed at the end of the die.
• • Can be easily retrofit into existing dies. Can be easily retrofit into existing dies.
• • Usually used to detect the edge of material Usually used to detect the edge of material (dark-on operation).(dark-on operation).
• • Sensor has built-in apertures.Sensor has built-in apertures.
•• Extremely repeatable (as low as Extremely repeatable (as low as ++ 0.0002”). 0.0002”).
Photoelectric "Fork" SensorPhotoelectric "Fork" Sensor
Photoelectric "Fork" SensorPhotoelectric "Fork" Sensor
EmitterEmitter
ReceiverReceiver
SensingSensingBeamBeam
Sensors for Part Sensors for Part EjectionEjection
Mini-Light CurtainMini-Light Curtain
Diffuse Reflective SensorDiffuse Reflective Sensor
Impact SensorImpact Sensor
Proximity CoilProximity Coil
Mini-Light CurtainMini-Light Curtain
Part breaks the light beamPart breaks the light beamto actuate the sensorto actuate the sensor
Available with eitherAvailable with eithervisible or infrared lightvisible or infrared light
Can be speed sensitiveCan be speed sensitive
Usually mounted outside the toolUsually mounted outside the tool
Diffuse Reflective SensorDiffuse Reflective Sensor
Receiver needs to see only a very small amount of Receiver needs to see only a very small amount of light from the emitter for the sensor to actuate. light from the emitter for the sensor to actuate.
This allows the sensor to detect small, even non This allows the sensor to detect small, even non reflective objects.reflective objects.
This sensor is also prone to false actuations caused This sensor is also prone to false actuations caused by objects in the background. by objects in the background.
These sensors must be installed so that the point off These sensors must be installed so that the point off “into space” so that false actuations can be avoided.“into space” so that false actuations can be avoided.
Diffuse Reflective SensorDiffuse Reflective Sensor
Diffuse Sensor “Screen”Diffuse Sensor “Screen”
Sensing AreaSensing Area
Diffuse Reflective Diffuse Reflective SensorsSensors
Material Buckle DetectionMaterial Buckle Detection
Stripper Position MonitoringStripper Position Monitoring
Stripper PlateStripper Plate
SensorSensor
14 mm Low Profile14 mm Low ProfileProximity SensorProximity Sensor
Slug on top of strip, sensor does not turn on at BDCSlug on top of strip, sensor does not turn on at BDC
Stripper Position Monitoring
Detecting Slug StackingDetecting Slug Stacking
Through-BeamThrough-BeamPhotosensorPhotosensor
Apertures shouldApertures shouldbe installed on be installed on the sensor.the sensor.
Detecting Slug StackingDetecting Slug Stacking
Without apertures, the sensor “floods” the area with light.Without apertures, the sensor “floods” the area with light.
Parts do not block enough of beam to reliably actuate sensor.Parts do not block enough of beam to reliably actuate sensor.
Detecting Slug StackingDetecting Slug Stacking
Proximity Coil Proximity Coil SensorSensor
End of Stock DetectionEnd of Stock Detection
For More Information:For More Information:
SensorsSensors Magazine - Magazine - Helmers Publishing, Inc..Helmers Publishing, Inc..
Peterborough, NHPeterborough, NH
(603) 924- 7408(603) 924- 7408
Measurements &Measurements & Measurements & Data Corp.Measurements & Data Corp.
ControlControl Magazine Magazine Pittsburgh, PAPittsburgh, PA
(412) 343-9666(412) 343-9666
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