Shift handover is where problems start: a fix for plastics units

Six in the morning, at the punching machine. The night lead mutters that press seven has been playing up and to keep an eye on it. The morning lead hears 'press seven'. He misses that a hot runner zone on one cavity keeps sagging because a thermocouple lead has worked loose, and that the night crew bumped its setpoint by hand at three. By ten the short shots are back. The morning setter burns an hour repeating fiddling the night shift already did.

In most moulding and extrusion plants, defects, settings and tool quirks travel between shifts by word of mouth. Some of it arrives intact. Much of it evaporates. The next crew meets the same gremlin, cures it again and passes it on just as loosely.

• An identical fault resurfaces on the same press at roughly the same hour daily.
• A tool runs with altered values recorded nowhere.
• Pallets wear red hold tags that nobody on the present shift can account for.
• Maintenance is summoned twice in one day for the same dripping water fitting at the mould.
• A dryer dew point alarm was muted overnight, and the day crew discovers splay streaking every part.
• A resin lot or masterbatch is swapped mid-shift, and the successors learn of it only when the parts change hue.
• The day lead first hears of a buyer's complaint from the dispatch clerk.

Every repeated diagnosis devours machine hours, resin, purging compound and the crew's patience. Rejects from a fault one shift already understood are the most pointless scrap a plant makes. Quality holds linger because nobody knows why a pallet was tagged. Shifts begin blaming each other. Eventually the morning crew distrusts whatever the night crew says, and the night crew stops bothering to say it.

• Changeover is a scramble. The departing crew wants the bus, while the arriving crew is still pulling on gloves and ear plugs.
• The outgoing lead is drained. After eight or twelve hours, a lengthy form is the last thing anyone completes properly.
• No overlap is rostered. If nobody's hours include handover time, it happens at the gate or not at all.
• Nobody owns it. Where the supervisor doubles as setter, it is unclear who speaks for the shift.
• Old jottings go unread. A register exists, but nobody leafs back through the week, so the same items sit there unresolved.
• Phone messages scatter. Voice notes on a group chat get buried under tea orders and leave pleas.

Date, shift and the names of the outgoing and incoming shift leads.
Machines running: press or line number, mould or die, resin and lot, colour.
Settings changed this shift: machine, what was changed, from what to what, and why.
Defects seen: machine, defect type, time first seen, what was tried, whether it is solved.
Holds and quarantine: pallet or tote numbers on hold, reason and who placed the tag.
Breakdowns and maintenance calls: machine, fault, ticket raised, current status.
Material and utilities: dryer, chiller, compressor or water problems, resin lots opened.
Pending: mould changes due, first-offs awaiting approval, customer calls to return.
Signatures of both shift leads after walking the problem machines together.

The page is filled during the shift, as things happen, not at the end. That single rule makes the difference between a useful record and a hurried summary.

1. 1

   Appoint one voice per shift

   One person speaks for the shift and owns the page. If the setter doubles as supervisor, write that down.

2. 2

   Plan a short overlap at the machines

   Ten to fifteen minutes when both leads are on the floor, scheduled into the roster rather than taken from the crew's break.

3. 3

   Stroll past the troublesome machines together

   Every open defect and altered setting is examined at the press or line itself, never merely described at the gate.

4. 4

   Sign, then brief the crew

   The incoming lead signs and reads the open items aloud at the start-of-shift huddle, so operators know which press to watch.

5. 5

   Review repeat items weekly

   The production manager reads the week's pages and lists any item that appeared on three or more shifts. Each becomes a maintenance or process job, owned by someone, with a finish date.

6. 6

   Keep the pages

   File them by month. They become the best training material the plant owns for new setters.

Handover discipline is easier to recruit than to instil. In process technician hiring for plastics, add a short written exercise to the interview. Describe a chaotic night: a jammed ejector plate, a damp resin lot, a hold pressure raised to chase short shots. Ask the candidate to draft the handover entry. Some will record the altered value and the reason. Others will scrawl 'press had problems'. Ask, too, about the last fault they passed to another shift, and how. A talent acquisition partner can fold this into selection for setters and shift leads.

Shift handover is among the five people patterns described for plastics units on our hub. How rotation and overlap fit inside the roster is covered for injection moulding attendance and shifts. Keeping logs and registers in order is tackled in the records routine for small-part moulders. When one setter's absence leaves a shift exposed, see a few technicians decide quality.