Customized sealing solution for the EV wallbox

 

The reference material FERMAPOR K31-A-9675-2-VP and B-4 (B component) is used for this purpose by leading manufacturers. It is a 2-component polyurethane sealing foam that cures at room temperature and compensates for component tolerances during sealing. If necessary, curing can be accelerated by using a annealing oven.

For outdoor use of the wallbox, the two-component silicone sealing foam FERMASIL-A-91-VP2 and B-91 (B component) can be used as an alternative.

Alternatively, we can also customize our material systems to meet your component requirements and specifications. Influencing factors are, for example, the pot life before foaming starts and the curing time, as well as the viscosity, hardness and adhesion properties.

Thanks to the mixed-cell foam structure, the closing forces when installing the polyurethane foam gasket are low.

The contour-accurate foam application into the groove of the two- or three-dimensional wallbox housings is carried out with the robot controlled Formed-In-Place-Foam-Gasket (FIPFG) technology of our DM 502 mixing and dosing machine – in a fully automatic, precise, safe and efficient way.

The different reaction phases of the sealing foam in the chronological sequence

 

Reference material

    FERMAPOR K31-A-9675-2-VP   FERMASIL-A-91-VP2
    FERMAPOR K31-B-4 (UL 50e)  FERMASIL-B-91
Mixing ratio   4 : 1 1:1
Pot life time   38 sec. 56 sec.
Tack-free time   3.5 min. 5 min.

Viscosity of the A component

  1,800 mPas 15,000 mPas
Density of foam   0.34 g/cm³ 0.30 g/cm³
Hardness (Shore 00)   64 52
Temperature resistance   from -40 to + 80 °C from -60 to +180 °C
Pretreatment   Plasma, Corona or Primer

Primer P8 or TEROSON SB450

In addition to the reference products, we develop material systems according to your individual requirements. Influencing factors include pot life until start of foaming, curing time, and the viscosity, hardness and adhesion properties.

 

Repeatedly open and close the wallbox for maintenance purposes while maintaining the sealing effect

When the wallbox housing, which consists of two parts, is assembled, the foam gasket is compressed evenly over the entire length of the component contour, resulting in a high level of tightness with excellent long-term behavior.

Due to its excellent shape recovery characteristics, the mixed-cell foam structure of the polyurethane seal can still be compressed well even after years (tested according to DIN EN ISO 1856). It is therefore possible to repeatedly open and close the wallbox for maintenance purposes while maintaining the sealing effect of the foam gasket.

 

Cross-section of a polyurethane foam bead – unpressed (without groove)

Silicone foam bead unpressed in the groove

 

Cross-section of a polyurethane foam bead with approx. 50 % compression

Silicone foam bead in the groove with approx. 30 % compression

 

 


Mixing and dosing system with 3-axis linear robot and shuttle table for sealing EV wallbox housings with sealing foam

 

 

Flexible and fully automatic – fully in line with your requirements

The reference configuration for sealing the wallbox housings shown here consists of the DM 502 mixing and dosing system and the MK 825 PRO precision mixing head, as well as a 3-axis linear robot and the WT 1-LEVEL shuttle table for picking up parts.

The placement of the wallbox housings on the shuttle table plate is carried out by a machine operator, who can also check the parts for quality, or alternatively by a Pick & Place robot. In the latter case, an optionally installed camera or sensor system could carry out the quality control of the parts. Parts are then machined in continuous shuttle mode of the two shuttle table plates in one plane.

The highly dynamic LR-HD 3-axis linear robot or alternatively the highly efficient LR-HE plus ensures contour-precise guidance of the mixing head above the EV wallbox housing.

During this process, the sealing foam is inserted very precisely into the groove of the two- or three-dimensional wallbox housing. Immediately after the dosing cycle, the applied material expands by several times its volume and the room-temperature curing of the material begins. This results in a seamless, soft-elastic foam gasket of the desired foam hardness with an almost invisible coupling point.

Even with short cycle times and high unit numbers, the material application process using the FIPFG method is carried out with high dosing precision and repeat accuracy. As a result, you get foam gaskets of consistently high quality.

Thanks to the automatic logging of dosing program data, all process data can be traced and evaluated by the machine operator via the CONTROL 2 operating panel while production is running.