Repeat orders for moulded parts: keeping a running schedule with the buyer

Moulded parts are bought again and again. The buyer's planner calls them off in batches, a few thousand at a time, and expects them on the day. Keep one schedule that both of you can see. Split it into what is firm, what is planned and what is only a forecast. Then act on each band differently: mould the firm quantities, book resin for the planned ones, and only note the forecast. When the planner can see your stock and your next press slot, the repeat order arrives before the shortage does.

Why a moulded part needs a shared schedule

A machine shop can ring the buyer before the last lot runs out, and our post on re-order routines for machined parts sets out that call. Moulding has three costs the call alone does not solve.

The mould has to be set on a press of the right tonnage, and while it sits there that press runs nothing else. A colour change means purging the barrel, and going from black back to white eats hours of press time. Special grades, such as a flame-retardant polycarbonate or a matched masterbatch, are bought in bags and some take weeks to arrive. A call-off that lands without warning can collide with all three.

The buyer wants something too. Their line stops if your parts are late, and they are tired of ringing to ask. A shared sheet answers both sides without a call.

Three bands: firm, planned and forecast

Agree the meaning of each band with the planner before you fill a single row.

1. Firm. Quantities on a purchase order or a schedule release the buyer has confirmed in writing. You mould these, in the colour order that wastes least material.
2. Planned. The buyer's best estimate for the weeks after the firm band. You book resin and masterbatch for these, and you hold a press slot. You do not mould them.
3. Forecast. Everything beyond that. You note it, use it to plan machine hours and mould maintenance, and spend nothing on it.

One more rule sits across all three. Mould ahead of the firm band only by the buffer the buyer has agreed in writing: a stated quantity per part, and what happens to it if the part changes. If there is no such email, there is no buffer.

The sheet itself

One tab per buyer, one row per part, and the weeks across the top. The figures here are illustrative.

BUYER: electrical fittings maker     PLANNER: (name)     UPDATED: (date)

Part / rev       Colour  Resin   Wk1     Wk2     Wk3      Wk4      Wk5       Wk6
Plate 2M rev E   White   PC-FR   8,000   8,000   6,000    6,000    (8,000)   (8,000)
Plate 2M rev E   Ivory   PC-FR   2,000   -       2,000    -        (2,000)   -
Back box 3M      Grey    PP      -       5,000   -        5,000    (5,000)   -
Band                             FIRM    FIRM    PLANNED  PLANNED  FORECAST  FORECAST

Our stock today:  Plate white 3,100 | ivory 400 | back box 0
Agreed buffer:    Plate white 4,000 (email of date) | others none
Resin booked:     PC-FR for Wk3 and Wk4, arriving Wk2
Press and mould:  Mould 14 on press 6; maintenance stop in Wk5
Revision flags:   Plate 2M rev F under trial at buyer. Build no rev E past Wk4.

The last five lines are where the sheet earns its place. The planner sees your stock, the buffer they agreed to, the date resin lands, and the week the mould comes out for maintenance. The revision flag stops either side building parts that are about to be superseded.

What you give, and what you ask for

Update the sheet whenever stock, a resin delivery or a release changes, and send the link with a two-line note saying what moved. A sheet the planner trusts is one that is never stale.

In return, ask for four things. The planner moves quantities between bands as soon as their own schedule shifts. The revision flag is filled the day a new drawing goes for trial. Model changes and plant shutdowns are mentioned the moment they are planned. And the buffer agreement is reviewed whenever the part changes.

Show the buyer only their own parts. Your press loading for other customers stays off the shared sheet. Neither the planner nor their purchase team needs it, and it invites a conversation about why their part is not first.

Imagine: a Pantnagar moulder and a switch maker in Haridwar

Imagine a moulder in SIDCUL Pantnagar supplying switch plates and back boxes to an electrical fittings maker in Haridwar. The details are illustrative.

A slow fortnight left two presses idle. The owner moulded twenty thousand white plates ahead of the forecast, to keep the operators busy. Three weeks later the buyer moved to revision E, with a new emboss on the face. Revision D was finished, and the stock sat in the moulder's store. The same week, an urgent ivory call-off arrived while the press was full of white material, and the changeover cost most of a shift.

The owner and the buyer's planner then set up the sheet above. Firm, planned and forecast were defined in an email. A buffer of four thousand white plates was agreed, with the buyer taking any buffer stock left at a revision change. Colours ran white, then ivory, then grey on each campaign, light to dark. The revision flag went in the day revision F went for trial. The old revision D stock was cleared slowly, partly against service spares the buyer agreed to take, partly as scrap. It was the last stock moulded on a guess.

When a shared schedule is not worth the trouble

Skip it for a buyer who orders twice a year. A calendar reminder will do. Keep it to yourself if the buyer shares forecasts with three moulders and plays them against each other. In that case, build your own version from their call-offs and mould only firm quantities. A buyer who will not name a planner, or never updates their rows, is telling you the account runs on price. Account management and key account growth is worth the effort only where the buyer engages.

Build one tab first

Choose the buyer whose last call-off caught you short. Build the tab from the last few releases, add your stock and resin lines, and ask the planner which band each quantity belongs in. The route from first enquiry to repeat business is on the plastic manufacturing page. If your largest account has no shared schedule yet, or you want it kept as part of customer retention, tell us what you need.