Apply a FIPG polyurethane gasket to an electrical cabinet door by defining the enclosure seal and compression requirement, cleaning and fixturing the coated door, conditioning the matched two-component PU system, calibrating both material streams, teaching a continuous CNC path, dispensing and curing the bead, then inspecting the complete contour in the intended enclosure. Release the process only after real doors pass the specified enclosure test.
A cabinet door gasket machine can repeat a stored path, but it cannot correct an oily powder-coated surface, a warped door, an unsuitable foam system or uneven latch compression. Treat the door, coating, chemistry, metering system, fixture, path, cure and enclosure test as one validated process. The material supplier’s technical and safety data control ratio, temperature and cure conditions; the cabinet drawing and applicable test plan control the finished seal.
- Freeze the enclosure and gasket acceptance specification
- Prepare the coated door and sealing land
- Condition and identify both PU components
- Fixture the door and establish the dispensing datum
- Calibrate output, ratio, nozzle and path
- Dispense one controlled continuous contour
- Cure and handle the gasket under defined conditions
- Inspect the bead and test the assembled enclosure
1. Define the Cabinet Seal Before Programming the Machine
Start from the released door and enclosure drawings. Identify the sealing land, hinge side, latch points, corners, welds, studs, cut-outs and any surface steps. State the cured bead width and height, contour-position tolerance, allowed start-stop joint, adhesion requirement, cosmetic limit and minimum clearance from hardware. Also define how the gasket will be compressed when the door closes. A dimensionally attractive free bead is not enough if one latch crushes it while another edge barely touches.
Write separate acceptance levels for the machine, the gasket process and the enclosure. A machine factory acceptance test can prove metering, motion, recipes and alarms. Process validation proves that the selected chemistry adheres, cures and repeats on production-intent doors. The final enclosure test proves the assembled product. IEC 60529 covers degrees of protection provided by enclosures; it is not a dispensing recipe and an IP claim must come from the responsible product test, not from the machine specification.
| Input to freeze | Why it matters | Required evidence |
|---|---|---|
| Door and enclosure geometry | Sets contour, fixture datum and compression gap | Released drawings and production-intent sample |
| Target bead section | Sets output, path speed and nozzle choice | Width/height limits and approved section gauge |
| Coating and surface condition | Controls wetting and adhesion | Coating specification and cleaning work instruction |
| PU material system | Controls ratio, viscosity, reaction and cure | Current TDS, SDS and supplier process window |
| Enclosure performance | Defines the real sealing result | Named test method, sample plan and pass criteria |
2. Prepare the Door and Sealing Land
Inspect the coated door before it enters the cell. The sealing land should be dry and free of oil, silicone, dust, release residue, loose powder, corrosion and handling contamination. Confirm that the coating is fully cured and compatible with the chosen polyurethane. Use only a cleaning method approved for that coating; an aggressive solvent can soften the finish or leave a film that creates a delayed adhesion failure.
Measure door flatness and the local height of welds, hems and hardware near the contour. Do not use a thicker bead to hide uncontrolled sheet-metal distortion. Rittal publishes electrical enclosures with an all-round foamed-in PU seal, which confirms the application route, but its construction and rating are evidence for that enclosure only. Your door, coating, latch system and test duty need their own validation.
3. Condition the Two-Component PU System
Identify both material lots and confirm shelf life, storage history and the material supplier’s approved processing window. Condition the polyol and isocyanate to the specified temperatures and use circulation or agitation only as directed. Temperature changes viscosity, and viscosity changes pump loading, mixing and bead laydown even when the HMI values stay unchanged. Keep moisture and foreign material out of tanks, transfer lines and the mixing head.
FIPFG means that a fluid or thixotropic sealing system is metered, mixed and deposited directly on the part, where it reacts into a soft foam gasket. The Sonderhoff FIPFG process description explains the interaction between the two-component chemistry, CNC-controlled mixing head and freely foamed contour. Use that as process background, not as a substitute for the TDS of the exact cabinet-gasket system selected for the project.
Isocyanates can cause serious occupational exposure. The UK HSE’s isocyanate control guidance requires assessment, control and review and emphasizes ventilation, appropriate protection, training and health controls. Build closed transfer, extraction, spill response, waste handling and maintenance isolation around the current SDS and local legal requirements. Automation does not make uncured PU chemicals harmless.
4. Fixture the Cabinet Door From Functional Datums
Locate the door from datums that also control its relationship to the cabinet opening. Support thin panels so they do not sag or oil-can under their own weight. Clamp outside the sealing land and avoid changing the door shape. Add mistake-proofing for mirrored doors, left/right hinges and rotated loading. If the production family contains many sizes, use adjustable stops with a recorded position or dedicated nests with positive identification.
Set the dispensing Z datum from the real coated surface, not from an empty worktable. A fixture can repeat while the workpiece height changes, so verify door seating before every pour. Run a dry path at safe clearance after a new program, fixture service or door revision. Confirm that the head clears hinges, studs and clamps through the complete contour and that the operator cannot start a mismatched recipe.
5. Calibrate Ratio and Output With Physical Measurements
Verify each component stream at the intended operating point using the material supplier’s approved procedure. Collect timed outputs, weigh them with a calibrated scale and compare the actual A:B mass ratio with the approved recipe. Then verify mixed output. A correct total mass does not prove a correct ratio because two drifting streams can still add to the expected total while producing a sticky, brittle or slow-curing gasket.
The current Machinepu FIPG cabinet-door PU gasket dispensing machine page publishes a 0.3-5 g/s application range, 5-30 mm adjustable gasket-width range, travel up to 30 m/min and stated repeat accuracy of ±0.05 mm for its listed configuration. These are equipment-envelope values to reconfirm at quotation. They do not guarantee a cured section, adhesion, cycle time or enclosure rating with an unspecified material and door.
| Setup variable | Verification method | Failure if uncontrolled |
|---|---|---|
| Individual A and B output | Timed mass collections at production conditions | Wrong ratio or unstable cure |
| Mixed output | Repeated weighed shots | Bead-section drift |
| Nozzle identity and stand-off | Documented tip plus physical height gauge | Wandering, flattened or splashed bead |
| Path speed and acceleration | Saved program plus reacted corner sections | Heavy corners or thin exits |
| Start-stop timing | Cured joint inspection and sectioning | Gap, bulge, string or unmixed spot |
6. Teach a Continuous Contour and Control the Join
Place the programmed contour in the center of the approved sealing land. Keep nozzle height and orientation stable, use smooth velocity transitions and slow only as much as the smallest radius requires. When an axis decelerates while material output stays constant, mass per unit length rises and creates a corner bulge. When it accelerates faster than material delivery responds, the bead becomes thin after the turn. Tune motion and output as linked variables, but change one controlled factor per trial.
Select the start-stop point where the joint can be inspected and where local compression is stable. Program valve timing and overlap so the ends merge without a gap or oversized lump. Do not hide the joint behind a hinge before proving it. The related PU dispensing equipment range can help compare motion envelopes, but the cabinet trial must prove access, stand-off and the reacted joint on the real door.
7. Dispense, Cure and Handle the FIPG Bead
Release the cycle only when material temperatures, calibration status, tank conditions, door identity, fixture seating and program revision are within limits. Establish homogeneous mixed flow at the validated purge location before entering the saleable door. Follow the contour without an unplanned pause, protect the wet bead from dust and contact, and collect uncured waste in the approved system.
Keep the door level or in the validated orientation through the reaction and cure interval. The site’s polyurethane foaming process guide explains mixing, reaction and rise, but actual cream time, tack-free time and handling strength come from the selected material and plant trials. Do not stack, close or package doors until the gasket can withstand that handling without imprint, stretch, contamination or permanent deformation.
8. Inspect the Gasket and Test the Assembled Enclosure
Inspect the entire contour under consistent lighting. Measure cured width and height at defined straight sections, corners, height transitions and the start-stop joint after a fixed conditioning time. Check contour position, continuity, surface condition, adhesion and interference with hardware. A vision system can map position and width; a non-contact profile sensor can measure height; destructive sections remain useful during setup and FAT.
Close the door in the intended enclosure and verify compression around the complete perimeter. Use pressure-sensitive evidence, a controlled gap method or another validated technique to find weak contact before environmental testing. Then perform the specified enclosure test on the responsible sample plan. The PU machine buyer’s guide can structure utilities and scope discussions, but neither a dry run nor a visually smooth gasket proves dust or water protection.
Common Cabinet-Door FIPG Defects and First Checks
Map every defect to its position on the door and compare it with corners, welds, fixture supports, the path join and latch locations. Change one factor at a time and retain the failed door with its material lot, recipe revision and inspection data. Random edits to speed, output and ratio at the same time destroy the evidence needed to identify the cause.
| Defect | Check first | Do not assume |
|---|---|---|
| Heavy corners | Axis deceleration, output response and local stand-off | Reducing the whole shot is the only fix |
| Gap or lump at the join | Valve timing, overlap, purge state and nozzle cleanliness | A closed door will hide the discontinuity |
| Bead lifts from coating | Cleaning, coating cure, compatibility and contamination | Longer cure creates adhesion |
| Sticky or brittle region | Separate outputs, ratio, mixing, temperature and moisture | Correct total shot proves correct chemistry |
| Leak near latch or hinge | Door flatness, gap, compression and local bead section | The dispensing path is necessarily wrong |
| Bead shifted on one model | Part ID, fixture datum, loading orientation and program | Robot repeatability proves correct location |
Build the FAT Around Real Cabinet Doors
A useful factory acceptance test includes the smallest and largest planned doors, the tightest radius, representative coating, approved or agreed trial chemistry, production nozzle and intended fixture. Test cold startup, normal repeated cycles, a planned pause and restart, recipe change, refill, alarm recovery, purge and warm production. Record individual-component calibration, mixed-shot repeatability, material temperatures, program revision, cure conditions and all dimensional results.
Assemble agreed doors into representative cabinets and apply the specified compression and enclosure test. If final material, coating or cabinets are unavailable, label the FAT boundary honestly: metering and motion may be accepted while reacted-gasket and enclosure performance remain open for site validation. Retain approved samples, section photographs, raw measurements, recipe export, training record and a signed list of remaining responsibilities.
Frequently Asked Questions
What does FIPG mean on an electrical cabinet door?
FIPG means formed-in-place gasket. A metering and mixing system dispenses reacting material directly along the cabinet door’s programmed contour, where it cures into the gasket. For a foamed polyurethane seal, FIPFG is the more specific term: formed-in-place foam gasket.
Can the same cabinet door gasket machine run different door sizes?
Yes, if every door fits the machine envelope and the correct fixture, nozzle and stored path are selected. Each model still needs an approved recipe and inspection plan. Use part identification and recipe interlocks so a smaller door cannot be run with a larger door’s program.
How should a FIPG gasket corner be programmed?
Use a smooth path through the allowed radius and coordinate travel speed with material output. Prove the result on reacted beads because axis motion and metering response are different systems. Section the corner and the straight section after it to detect both material accumulation and a thin exit.
Why does a PU gasket fail to bond to a powder-coated door?
Check coating cure and compatibility, cleaning method, oil or silicone contamination, storage time, material condition and the interval between cleaning and dispensing. Do not assume extra cure time will repair an incompatible or contaminated interface. Confirm adhesion with the coating and PU suppliers on production-intent panels.
Does a foamed-in-place gasket guarantee an IP rating?
No. The gasket is one part of the enclosure system. Door stiffness, flange geometry, hinges, latches, compression, openings and assembly also affect protection. Only the responsible test of the complete enclosure against the specified standard and configuration supports an IP claim.
A reliable electrical-cabinet FIPG seal comes from a controlled door, coating, chemistry, metering, path, cure and compression system. Freeze the acceptance method first, calibrate both material streams, teach the contour from functional datums, verify the reacted bead at every critical location and release production only after representative assembled enclosures pass their specified test.