Real-time inspection is strongly desired across the industry. Electroimpact offers real-time inspection to ensure ply-fill.
Electroimpact AFP cells verify ply fill (ply boundary, lap/gap, tow error) by measuring tow end placement and evaluating layup surface profile.
This proprietary inspection system identifies the location of tow ends. It evaluates system inputs and many feedback mechanisms on the AFP head to estimate tow end placement in real time. The system identifies the location of tow ends 100% of the time.
Lap/Gap
3rd Party profilometer system:
Similar to the sensor used in tow end measurement, this sensor is used for lap/gap measurement. It offers the following capability:
Gaps:
Mean error |
less than 0.005" |
Standard deviation |
less than 0.005" |
Repeatability standard deviation |
less than 0.003" |
0.007" < Detection size < Tow width / 2 |
Laps:
Mean error |
less than 0.010" |
Standard deviation |
less than 0.010" |
Repeatability standard deviation |
less than 0.003" |
0.015" < Detection size < Tow width / 2 |
NOTE on spar type parts. Due to the sharp corner geometry of the box shaped spar, there is a blind spot for lap gap measurement in the spar corner region. This is potentially impossible to overcome because the measuring device trails the rotation center. As such it ends up pointing in space as the machine traverses the 45- and 90-degree ply orientation in the spar corner region.
Tow Present and Twisted Tow Detection
The profilometer system can detect twisted, missing, broken and folded tows with high accuracy. It reports location of the defect, which can be sent to the laser projector system to assist the operator with locating the defect on the part. The twisted tow and missing tow detection is not delivered with the profilometer system by default, as it requires the profilometers to be spaced more tightly; it can be purchased as an option.
FOD
Eliminate FOD – Keep the Head Clean
This is our preferred strategy and is working out very well in our internal AFP4.0 tests. The PEK, combined with planned maintenance, will reduce FOD to a very small amount. Buildup of resin and fuzz doesn’t occur with the materials we’ve tested.
Detect FOD – 3rd Party Profilometer
We are currently developing a FOD detection system that uses a 3rd party laser profilometer. This is at TRL 5-6. Initial results show reliable FOD detection of features greater than the following dimensions: .1" x .1" x .05" tall.
Detect Poly Backer
For AFP material systems that use poly backer, we have a poly backer detection system that looks to see if any poly backer is attached to the tow as it enters the final redirect. This ensures that the poly backer is not getting fed onto the part.
Process Error Detection
Drive Roller Wraps
We detect when material wraps around the drive roller by monitoring torque disturbances on the drive motor. When a wrap is detected the motor stops motion to limit the wrap severity.
Backing Film Detection
We offer an option to add sensors on the head to detect if backing film travels beyond the backer take-up spool. Upon detection the payout is stopped before the backing film ever makes it onto the part.
Compaction Roller Wraps
With the adoption of the VSS laser heater, compaction roller wraps have essentially been eliminated as a source of error. Even so, we do have a camera system for detecting compaction roller wraps that typically stops the machine before two revolutions, and often before even one. This significantly reduces damage to the part and limits the amount of rework required.
Optical Laser Template (OLT)
Electroimpact offers Aligned Vision laser projectors. These can be fixed-mounted on lighting truss posts or mounted on a moving AFP machine to provide enough range to cover the entire work zone.
Electroimpact offers full featured laser projector integration. Our software is capable of displaying:
- Ply boundaries |μ +/- 2σ| < 0.05"
- Individual tows or courses
- Tow ends
- Programmed overlaps and gaps
- Tooling locations
- Course direction
- Defects
The user interface includes a full 3-D model of the current ply to allow for easy operator identification of errors or areas of concern. The CGTech programming system outputs the laser files for each ply automatically—no need to program them separately.
The OLT identifying a specific tow within a course.