How often should a Case Mould parting line be cleaned?

Every 5,000 shots; poor water or hot melt shortens that to 3,000.

Why repair a score of only 0.02 mm?

That depth already opens a path across the sealing face, and flash grows with each shot.

What flow drop justifies stopping the press?

Fifteen percent below the acceptance baseline; by the time temperature rises, dimensions have moved.

Can a bent ejector pin be straightened?

No. Concentricity is lost, the bore wears oval, and later pins lose clearance.

Can the three checks share one shutdown?

Yes quarterly, but the 5,000-shot clean usually falls due earlier.

Case Mould Maintenance: Parting Line, Water Lines, Ejector Pins

Quick answer: Three checks carry most of the risk on a Case Mould: the parting line, the water circuit and the ejector pins. Set intervals by shot count, with a fixed limit for each: 5,000 shots for the parting line, one quarter for descaling, 10,000 for pin straightness.

Setting the Service Interval for a Case Mould
Parting Line: Clean Every 5,000 Shots
Water Lines: Quarterly Descaling and Temperature Spread
Ejector Pins: Bend and Return Checks at 10,000 Shots
Tooling, Consumables and Downtime
FAQ

1. Setting the Service Interval for a Case Mould

Wear tracks clamp cycles, melt temperature and water quality, so calendar schedules drift. Anchor on the shot counter: an 800-tonne press at 900 shots a day reaches 5,000 in five days, while lids on a 300-tonne machine take half that.

The three failure modes are unrelated: the parting line is a sealing boundary where steady flash means a gap has formed, water lines lose heat transfer as scale builds, and pins bend before they break.

Part	Interval	Limit	Action
Parting line	5,000 shots	0.02 mm score	Grind or weld
Water lines	Quarterly	Flow down 15%, spread over 3 °C	Descale, reseal
Ejector pins	10,000 shots	0.05 mm bend	Replace pin

The interval only holds if the counter is read: mount it on the fixed half, reset at each changeover, and copy the value onto the service card.

2. Parting Line: Clean Every 5,000 Shots

Cleaning restores the contact band, not the shine. Lock off, pull sprue residue, then scrape overflow with brass or bamboo along the cavity edge. Abrasive paper is forbidden; a hand scratch becomes a channel for melt. Blow the vents clear; they run 0.02 to 0.03 mm deep.

Read damage as depth, position and direction with red lead bluing or a 0.02 mm feeler; if the blade enters, the tool is out of limit. Damage on the cavity sealing face beats the outer land, because only the first makes flash.

Depth	Symptom	Treatment	Downtime
under 0.02 mm	Bright spots, no flash	Lapping paste, one direction	1 hour
0.02–0.05 mm	Fine flash	Oilstone, bluing check	4 hours
0.05–0.1 mm	Continuous flash	Local weld, then grind	1 shift
over 0.1 mm	Visible step	Re-machine or new insert	2 shifts

Work paste in one direction only; circular motion spreads a score into a hollow. Close dry three times at thirty percent of clamp force, since a large face tilts and crushes the band just repaired.

3. Water Lines: Quarterly Descaling and Temperature Spread

Circulate five percent citric acid for forty minutes, neutralise, rinse for fifteen. Treat cavity and core separately; acid run in series weakens and the second half is wasted. Case tools carry 8 to 12 mm channels, and 0.1 mm of scale costs about twenty percent of local heat transfer.

Judge flow against the acceptance record; a fifteen percent drop triggers action. Inlet-to-outlet spread should stay within 3 °C. Pressure-test at 6 bar for ten minutes and allow 0.2 bar of decay. Drain before winter; trapped water freezes and splits a channel.

4. Ejector Pins: Bend and Return Checks at 10,000 Shots

Every 10,000 shots, retract the plate, pull each pin and lay a straight edge along it; light underneath means a bend. Replace anything past 0.05 mm rather than straightening it, since a straightened pin wears the bore oval and ruins the pins that follow.

Fit clearance at 0.02 to 0.03 mm, roughly H7 against g6. Too loose and melt grips the pin; too tight and heat seizes it. Deep cavities push length-to-diameter past fifteen, so pins sit on a drafted face. Set stroke from the deepest demoulding point plus 5 to 8 mm, and replace springs once free length shrinks five percent.

5. Tooling, Consumables and Downtime

Keep a service box split by area: brass, oilstone and W10 paste; citric acid and a flow meter; a straight edge and spare pins. Re-torque M8 bolts to 25 N·m.

Full service takes about ten hours; split it: cleaning at changeover, descaling quarterly, pin inspection on nights. Record tool number, shot count, tasks and next due count on one card that travels with the tool.

Conclusion

Maintenance on a Case Mould follows a shot-based timeline, not a monthly tick sheet. Hold the parting line at 5,000 shots and 0.02 mm, water at a fifteen percent flow drop and 3 °C of spread, pins at 10,000 shots with stroke and spring checks. Put thresholds and records on one card, and service becomes a task that can be handed over.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.