New White Paper: Controlling Hem Adhesive Variation to Improve Closure Panel Quality
In automotive closure panel manufacturing, small variations in adhesive placement and volume can create significant quality and cost challenges. Excessive adhesive can lead to squeeze-out and costly manual skiving, while insufficient adhesive coverage can contribute to voids, over-hem sealer defects, rework and, in some cases, long-term corrosion concerns.
To help automotive manufacturers address these challenges, Coherix has released a new technical white paper, “Closure Panel Hem Adhesive Optimization: Controlling Process Variation to Improve Joint Quality and Reduce Manufacturing Defects.”
The white paper provides practical insights into the challenges associated with hem adhesive dispensing on closure panels such as doors, hoods and liftgates, while exploring strategies for improving process capability, reducing variation and achieving more consistent adhesive application.
Why Hem Adhesive Process Control Matters
A robust hem joint depends on achieving the right adhesive location and volume throughout the dispensing process. However, manufacturers must contend with numerous sources of variation, including panel dimensional tolerances, fixture variation, robot positioning, material properties and changes in dispensing system performance.
When adhesive volume or placement moves outside the desired process window, manufacturers can experience:
- Excessive adhesive squeeze-out requiring manual skiving
- Insufficient adhesive coverage and hem-joint voids
- Over-hem sealer bubbles and cosmetic defects
- Increased rework and repair
- Additional labor and production costs
- Potential long-term corrosion concerns
Many dispensing systems operate passively, delivering a predetermined amount of material without continuously verifying the actual bead being applied. This makes it difficult to compensate for normal manufacturing variation and maintain consistent hem fill.
Moving From Passive Dispensing to Adaptive Process Control
The white paper examines how Adaptive Process Control (APC) can help manufacturers move beyond simply setting a dispensing process and hoping it remains stable.
Using real-time sensor data, process logic and automated adjustments, APC can continuously monitor the dispensing process and compensate for normal variation. Coherix 3D Volume Adaptive Control (VAC), for example, learns the dynamic behavior of the dispensing system and adapts to changes in material properties, viscosity, environmental conditions and other process variables.
The white paper also explores complementary technologies such as Lateral Tracking, Z-Tracking and Auto Repair, which can help maintain accurate bead placement, control nozzle-to-part distance and address adhesive gaps during production.
Proven Results in a Closure Panel Study
The white paper includes results from a detailed automotive closure panel study involving nearly 1,000 assemblies. The study evaluated adhesive volume and location, hem fill, squeeze-out and under-fill before and after optimization with APC technology.
The results demonstrated measurable improvements in adhesive process control, with multiple zones brought within specification and significant reductions in both over-filled and under-filled conditions.
The study highlights an important point: successful closure panel optimization requires more than advanced sensing and APC technology. Robust tooling and fixtures, dimensional control, accurate robot paths, capable dispensing equipment and experienced engineering teams all play an important role in establishing a stable manufacturing process.
Once that foundation is established, real-time sensing and adaptive process control can help maintain performance despite normal production variation.
Download the White Paper
If you are responsible for automotive body engineering, closure panel manufacturing, adhesive dispensing or process quality, this white paper provides practical guidance for identifying sources of variation and improving hem adhesive process capability.
Download the “Closure Panel Hem Adhesive Optimization” white paper to learn how controlling adhesive location and volume can help reduce defects, minimize manual rework, improve first-pass yield and create a more consistent closure panel manufacturing process.