sensor applications for die protectionsensor applications for die protection the diemasters 2100...

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

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


Overfeed is detectedOverfeed is detected


Shortfeed is detectedShortfeed is detected


Move the sensor closer to the plunger for more precise detectionMove the sensor closer to the plunger for more precise detection


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


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 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.


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.


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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