Bonding & Dispensing

Application

Bonding or dispensing — what is the difference?

Both applications use the same cell technology: a robot guides a dispensing head along a programmed path and applies precisely defined material quantities. The difference lies in purpose:

In both cases the robot controls four critical parameters simultaneously: path geometry, application speed, dispensing pressure or volumetric flow, start and end points.

Why automate?

• Precision: path accuracy ± 0.5 mm — hard to achieve manually and impossible to maintain consistently.
• Material savings: manual application is conservatively over-dimensioned. Robotic dispensing reduces material consumption by typically 15-30 %. On one production line this is 8,000-20,000 € per year in material costs.
• Consistency: no fatigue effect, no shift-to-shift variation, no operator-dependent scatter in bead or dot quality.
• Ergonomics: materials often contain isocyanates, solvents or respiratory-irritant substances — the robot has no health risk.
• Documentation: every batch, every bead, every consumption logged electronically. Basis for traceability in automotive, medical and pharma.

Material types and their requirements

• 1K materials — pre-filled cartridges or drums. Simplest cell configuration, no mixer needed. For silicones, greases, thermal paste, cyanoacrylate.
• 2K materials (bonding + potting) — adhesive and hardener are mixed in the correct ratio via a meter-mix-dispense system (MMD). Static mixer at the dispensing head. After mixing, limited pot life — cell design must accommodate it (needle purging, purge cycles).
• Hot melt — molten adhesives. Heated material supply, insulated hose, heated dispensing head.
• Low- vs. high-viscosity materials — determines pump type (gear, piston, time-pressure dispensing) and needle cross-section.

Cobot or industrial robot — two variants

The choice comes down to batch size, workpiece size and cycle rate:

Typical applications — bonding

• Body bonding and structural joining in the automotive sector
• Windscreen and glass bonding
• Electronic subassemblies: displays, camera modules, sensor assemblies
• Lightweight construction: CFRP/GFRP composites in aerospace, sports, mobility
• Furniture and wood bonding (edge banding, veneer bonding)
• Medical device assembly (catheters, disposable products)

Typical applications — dispensing

• Silicone gaskets on housings, electronic enclosures, automotive sensors
• Potting of control units, sensors, LED modules
• Thermal-paste application on heat sinks and power electronics
• Grease and oil dispensing in gearbox and bearing production
• Sound deadening in automotive bodies
• Seam sealing after welding (automotive underbody coating)

The NEXOS configuration

• Robot — cobot or industrial robot depending on the variant (see above).
• Dispensing system — gear, piston or time-pressure pump depending on viscosity and accuracy requirement. For 2K: meter-mix-dispense unit with static mixer. Established brands: Nordson, Graco, Vieweg, Preeflow, ViscoTec, Sulzer Mixpac.
• Dispensing head with valve and exchangeable needle. For 2K: static mixer as a consumable.
• Material supply — cartridges, drums, pressure tanks; heated for hot melt.
• NEXOS.Cube as the cell frame. In the stainless-steel variant for hygiene-sensitive applications (medical, pharma, food).
• Workpiece fixture — modular fixture plate, vacuum clamping or customer-specific fixture.
• Needle cleaning and purge station — for uninterrupted operation with 2K materials.
• Extraction for solvent-containing materials.
• Optional: NEXOS.LinDrive as 7th axis — for long seams or two parallel workpiece stations.

Sequence of a typical cell

1. Load and fixture workpiece (operator or robot handling)
2. Cycle start, robot moves to start point
3. For 2K: purge cycle through the static mixer, discard the first quantity (check material ratio)
4. Dispense — robot travels the path, dispensing valve opens on point, volumetric flow per program
5. Path end: close valve cleanly (prevent drip), robot moves to standby position
6. Needle cleaning on material change or during standstill
7. Remove workpiece, curing follows (often outside the cell)
8. Order confirmation with time stamp and material batch number

Why it pays off

Market data (2026) for dispensing/bonding cells:

• Cobot cell: investment 60,000-140,000 € (robot + dispensing system + cell). Typical payback <12 months, often within 6-9 months through material savings alone.
• Industrial-robot cell: investment 150,000-400,000 €. Payback 1.5-3 years in series operation.
• Material savings: 15-30 % less consumption = 8,000-20,000 € per year per line (depending on material cost).
• Scrap reduction: uniform application → fewer defective parts, less rework, fewer customer complaints.
• Market growth: the Robotic Dispensing segment grows from 11.6 bn USD (2023) to 19.6 bn USD (2033) — a strong adoption trend.

Scalability

• Stage 1 — single cobot cell with 1K dispensing and cartridge change
• Stage 2 — 2K expansion with MMD system and purge station
• Stage 3 — 2 workpiece stations in parallel or rotating
• Stage 4 — vision and adaptive path tracking for workpieces with production tolerances
• Stage 5 — integration with NEXOS.DSP for material consumption monitoring, batch traceability, dispensing pump failure prediction

Expansion options

• Vision system for path correction — camera scans workpiece tolerances, path is adapted dynamically
• Bead inspection — downstream camera checks bead for interruption, height, width; NOK parts are automatically rejected
• Weighing plate for spot-check volume verification of the application
• Automatic needle cleaning and needle change — second-precise cleaning, longer service life
• Digital twin via NEXOS.XR — test new workpieces virtually, collision checking, programming without cell downtime

Key sizing parameters

• Material: 1K or 2K, viscosity (mPa·s), pot life for 2K
• Application type: bead, dot, area coating; bead cross-section or volume per dot
• Workpiece geometry: 2D flat or 3D contour; decides cobot vs. gantry
• Cycle rate in workpieces/hour and number of parallel workpiece stations
• Cleanliness requirement — cleanroom for medical/pharma; ATEX for solvent-containing adhesives
• Existing material supply — cartridge, drum, central dispensing
• Curing process — at room temperature, in an oven, with UV; follows the dispensing cell

Safety & environment

• Solvent-containing adhesives — extraction, ATEX zone review, potentially explosion-proof design
• Isocyanates (2K PU) — avoid skin contact, extraction per TRGS 430
• Cleaning agents — usually solvent-based, in a closed circuit or with a drip tray
• Material disposal — 2K residues (from purge and mixer) are hazardous waste, ejected into a collection container