Hot Melt Glue System Stops: Clogs, Skips and Open Flaps

Key takeaways

• The same glue system problems appear on case erectors, case packers, cartoners and some labellers.
• Code "glue system" as a cause across machines, so its total shows up in one ranking.
• Glue skips cost Quality first; nozzle clogs and refills cost Availability.
• Char from glue held hot too long is behind many clogs.
• Plan the heat-up time before the shift instead of losing it at start-up.

Hot melt glue systems stop packaging lines in a few predictable ways: clogged nozzles, char in the tank or hoses, glue running low, and temperature out of range. What you see first is glue skips and open flaps; the stops come when the crew clears a nozzle, refills the tank or waits for the glue to heat up.

Fabrico, an OEE and light MES platform, logs each stop with its reason and ranks losses by money across machines, so the same glue problem on three different machines can add up to one priority. This guide covers where hot melt sits on a line, why it stops, how it shows up in OEE, and how to code it.

Where does hot melt glue sit on a packaging line?

• Case erectors: sealing the bottom flaps of each case.
• Case packers: closing and sealing the top flaps. See our case packer OEE guide.
• Cartoners: closing carton flaps. See cartoner OEE.
• Some labellers, such as wraparound labellers, use hot melt to hold the label. See labeller OEE.
• Tray formers and wraparound packers.

Each machine reports its own stops, so glue problems are spread across several machine reports. On any one of them, glue may not look like a top cause. Added together, it often is.

Why do hot melt glue systems stop?

• Nozzle clogs. Small particles of char or debris block the nozzle, so the bead gets thin, uneven or stops.
• Char. Glue that is overheated, or held at temperature for a long time with little use, can degrade and form char that later clogs filters and nozzles.
• Tank low. The tank runs low between manual refills, and a big refill of cold glue can drop the temperature.
• Heat-up. After a cold start or a long stop, the system needs time before it can glue properly.
• The wrong glue. A glue that does not suit the board, the line speed or the room temperature bonds poorly.
• Pattern settings. After a format change, glue timing or position can be wrong until it is adjusted.

How do glue problems show up in OEE?

A clog usually announces itself: skips and open flaps rise for a while before the crew stops to clear the nozzle. Watching rejects is the early warning.

How should glue system stops be coded?

Use one cause, "glue system", on every machine that glues, with a few reasons under it:

• Nozzle clog
• Tank low or refill
• Heat-up wait
• Glue skip reject stop
• Glue pattern setting after changeover

Keep the machine as a separate field. Then you can rank glue problems by machine, and also see their total across the line. Our guide to Pareto analysis for downtime shows how to rank causes.

What does a week of glue stops look like?

Sample line (illustrative numbers, not a customer): a line with three machines that use hot melt glue, one week.

• Per machine, glue costs the erector 68 minutes, the cartoner 24 and the case packer 60. On each machine's own report, it sits somewhere in the middle.
• Across the line, the glue system is 152 minutes a week. Ranked as one cause, it sits well above any of the three per machine figures.
• The cartoner also rejected 1,400 cartons for glue skips, which do not appear in the minutes at all.
• Fifteen nozzle clogs on three machines suggest a shared cause worth checking first, such as char from long idle periods at temperature. One fix could help all three machines.

Which fixes reduce glue system stops?

• Avoid char: do not hold glue at full temperature during long idle periods. Many systems have a standby setting; use it where yours does.
• Refill little and often, or use an automatic fill where one is fitted, so the tank level and temperature stay steady.
• Clean and change nozzles and filters on a schedule, before clogs start.
• Plan the heat-up before the shift starts, so the line is not waiting for glue at the first case.
• Settings per format: glue timing and position written as centerlines and checked at each changeover.
• The right glue for the board, the line speed and the plant temperature, agreed with your glue supplier.

Where Fabrico fits

Fabrico is a computer vision enabled Manufacturing Performance Platform. OEE and light MES come first, with computer vision on stops.

• Automatic downtime logging on every machine that glues.
• The operator confirms the reason in one tap, so a nozzle clog and a tank refill get different codes.
• Losses ranked by money across machines, so a cause that is small on each machine but big on the line comes to the top.
• A camera clip as evidence for a stop, where a camera watches the glue station or the flaps.
• OEE live by line and shift, rejects included.

You start with a pilot on one line, with a baseline and a decision date agreed in advance. There is no free plan and there are no tiers: each plant gets a quote. Read how a light MES starts on one line in our light MES guide.

Frequently asked questions

Why do hot melt glue nozzles clog?

Usually from char, degraded glue that forms when glue is overheated or held hot for a long time with little use, and from debris in the tank or hoses.

How do I reduce glue skips?

Keep nozzles and filters clean, keep tank level and temperature steady, and check glue timing and position after every format change.

Should glue problems be coded on each machine?

Code them on the machine where they happen, but under one shared cause, "glue system", so you can see the total across the line.

Do open flaps count against OEE?

Yes. Rejected or reworked cases and cartons reduce Quality, even when the line never stopped.

How long should hot melt take to heat up?

It depends on the system and the glue. Measure it, and plan it before the shift starts so production is not waiting for it.

See your glue stops in a demo

Bring one line and a week of stop data. We will show glue stops across every machine and what they cost.

Request a demo · Contact us