IPD Technical Conference February 19 th 2008 Industry: Automotive – Circuit Board Mounting Screw Application: Screw with Silicon Rubber Collar Assembly Inspection Presented by: Scott Montgomery / DALSA - IPD

Metal Screw with Green Silicon Rubber Collar Assembly and Measurement Inspection Thread Silicon Rubber Collar Automotive part – used to bolt mini circuit board to center console inside a Jeep Wrangler. Silicon collar used to keep water from penetrating. i.e. four-wheeling

Inspection Requirements  Measure Silicon Rubber Collar Rib Diameter:  mm + / mm  Check Silicon Collar for Following Surface Flaws (or defects):  Yellow Pigment Stains  Foreign Material, i.e. fibers, thread, etc.  Gas Pockets in the silicon mold  Flash and Short Shots  Missing, Rotated, Misplaced or Reversed Collars  Check for Following Thread Defects:  Foreign or Extra Material in Shoulder  Missing Threads

Critical Measure: Rib Diameter Rib Diameter + / mm

Surface Flaws in Collar Yellow Pigment Stains Foreign Material Gas Pockets Flash Short Shots

Misplaced and Reversed Collar Reversed Collar Collar Properly Placed Misplaced Collar (pushed downward) Head Diameter Larger Head Diameter Smaller

Thread Defects Missing Threads Foreign Material in Shoulder

Vision System Overview  Vision System : VA-41 w/ Sherlock  2 Cameras, TM2 640 H x 480 V  Camera 1: Lighting and Optics:  TML Telecentric Lens  24v. White LED Pad Light, size 75mm x 75mm  Aluminum Polished Block  Camera 2: Lighting and Optics  Fujinon 35 mm Lens w / 5mm ext. ring  24v. White LED Ring Ling ( 45 deg. angled LEDs )  Initial trigger pulse sent from PLC, then custom DALSA IPD I/O trigger module – generates a trigger pulse train  User Interface – Visual Basic front end

Camera 1: Collar and Thread Inspection Aluminum Block ( simulates a backlight ) Front Pad Light ( white LED )

Camera 2: Insertion Inspection (misplaced collars) Ring Light ( 45 deg., white LED )

Machine Overview  Screws and green silicon collars are “bowl fed” independently to pick-and-place grippers  Screws are dropped into a pocket on an indexing rotary table  As the table indexes, a gripper inserts a silicon collar over the screw head  At the next station, a motorized drive engages, lifts, and presents the screw assembly to the vision system – CAMERA (1)  The completed assembly is spun 360 degrees to perform 100% surface flaw and thread inspection, and rib diameter measurement  The vision system snaps a picture every 18 deg. of rotation – 20 triggers total for one completed revolution

Machine Overview (continued)  The table indexes the assembly to the next station to check for proper collar insertion – CAMERA 2  The vision system outputs a separate “PASS” signal at each inspection station to the PLC  If the assembly failed either inspection, a pick-and-place gripper will discard the part at the next indexed station  Otherwise, the part moves to the final station and is placed onto a conveyor that drops the completed assembly into a shipping carton  Once the desired lot quantity is reached the carton is sealed and ready for delivery.

Application Challenges  Achieving Full 360 degree, 100% Surface Inspection  Using a pulse train of input triggers from DALSA IPD trigger module ‘matched’ to the desired speed of rotation – 1 sec.  Finding a “One Light Fits All” Solution  Green collar absorbs standard ‘RED’ LED wavelength of light  Motion blur and minimal background contrast  Lighting on a cylindrical surface produces centerline hotspot  Detecting Subtle Surface Flaws and True Flash Defects  Discriminating between real defects and acceptable surface imperfections – TEXTURE TOOL  Discriminating between true flash and acceptable flash  Keeping Within Rib Diameter Tolerances  Minimizing drive wobble and slippage  Detecting drive slippage  Minimizing perspective distortion

Capturing a Full 360 degree Field of View (using a pulse train of input triggers) PLCVA-41 DALSA IPD Custom I/O Module 1 Trigger Pulse 20 Trigger Pulses ** ** Input triggers are fed to the trigger input on VA-41 I/O breakout board ( PIN 2 ) Begins Inspection Cycle Begin to Capture and Process Images

Finding a “One Light Fits All” Solution Aluminum Block ( simulates a backlight ) Front Pad Light ( white LED )

Lighting Challenges ( creating a well-contrasted background with diffuse foreground ) Center line hotspots ( skunk stripe ) Polished aluminum block reflects light, providing a bright background Green silicon rubber absorbs most LED light

White LED Pad Lighting Suits All Inspections Requirements Edge Profiling Surface Inspection Flash

TEXTURE TOOL ( Detecting Subtle Surface Flaws ) Gas Pockets TEXTURE tool is effective for measuring texture based on edge density where the edge sensitivity can be ‘tuned’ to discriminate between true defects and natural surface variations - TOTAL EDGE COUNT is primary measure

Other Surface Flaws Foreign Material

True Flash vs. Acceptable Flash Acceptable Flash True Flash

Tracking Independent Reference Points Left side Reference PointRight side Reference Point Flash Tools ( tracks laterally )

Minimizing Drive Wobble ( critical for rib diameter measurements ) Measuring Rib DiameterTracking Spin Motion

Detecting Drive Slippage Tracking thread motion to detect drive slippage

Minimizing Perspective Distortion Conventional Lens Telecentric Lens

Conventional vs. Telecentric Lens Conventional Lens Perspective Distortion Telecentric Lens Flat - No Distortion

User Interface

Summary  Overall cycle time per part : 2.0 seconds  Inspection time – 800 msec.  Shuttling part in and out – 1.2 seconds  Machine runs at less than 1.0% percent scrap rate  Produces about 40,000+ parts per week  Customer Quote : “ Thanks to IPD, now I can sleep at night “

O.K. Guys, It’s a Wrap ! ! ! Tom “ the builder ” “Vision Guy” “ Dr. V.B. ”