How often should a Case Mould be serviced?

Answer: By shot count, not calendar: gauge at 5,000, measure at 20,000, polish at 100,000, and service fully before restarting an idle tool.

Can clamping force press existing flash shut?

Answer: Only temporarily. Ten percent more force holds 0.1 mm of flash, but it returns at 0.3 mm in two weeks. Grind the blocks flat, 0.05 mm a pass.

Does the water circuit have to come apart?

Answer: Usually not. Citric acid at 5 percent and 40 °C, circulated 40 minutes, clears scale under 0.2 mm; a blocked branch needs plugs out.

A pin snapped inside the cavity, is the Case Mould lost?

Answer: No, but stop at once. Closing on a broken pin dents the cavity face, and polishing 0.1 mm out changes wall thickness. Burn the stub out by EDM.

How detailed should the service record be?

Answer: Enough to trace shot count, part batches and material removed at each repair.

Case Mould Care: Three Wear Lines and Four Daily Numbers

Quick answer: Care of a Case Mould is triggered by three measurements: a 0.05 mm feeler at the parting line, 0.10 mm of ejector clearance and a 3 °C water split. Cross any and the press stops, far cheaper than repairing flash.

The Three Wear Lines in a Case Mould
Four Numbers to Write Down Every Shift
Cleaning Order for Parting Line and Cavity
Water Circuit: Scale Removal and Flow Limits
Replacement Limits for Ejectors and Guides
Four Moves That Take 300,000 Shots to 500,000
FAQ

1. The Three Wear Lines in a Case Mould

A Case Mould fails in a fixed order: parting line, then ejector bores, then the cavity.

Location	Limit	Check interval	What follows if ignored
Parting line	0.05 mm feeler enters	5,000 shots	Flash to 0.4 mm
Ejector pin and bore	0.10 mm clearance	10,000 shots	Whitening, punch-through
Leader pin and bush	0.08 mm clearance	10,000 shots	0.2 mm offset gouges cavity
Sprue bush bore	0.15 mm of wear	20,000 shots	Stringing, 6 s added

The parting line fails on the rest blocks, not the sealing face: 0.02 mm short, and clamping force crushes the edge. Ejector bores come second, where melt past 0.10 mm cures into a ring the next ejection scrapes.

2. Four Numbers to Write Down Every Shift

Daily inspection needs no teardown, only four readings: clamping force, mould temperature, water split, cycle time.

Case Mould: shrink-wrapped black cases on a wooden pallet, green floor by a yellow aisle line, a worker bent over a bench, red pipes above

Clamping force holds within 3 percent: 590 to 610 t on a 650 t press, and below 560 t check oil temperature.

Mould temperature follows the resin: PP at 40 to 60 °C, ABS at 60 to 80 °C, and 8 °C under setpoint means restriction.

The water split is the most useful of the four: 3 °C healthy, 6 °C half the flow gone, 8 °C a blocked channel.

A cycle gaining 3 seconds is rarely the press, and plotted per shift the fault seldom survives two days.

3. Cleaning Order for Parting Line and Cavity

Wrong order damages a tool more than skipping the job. Six steps apply whenever a Case Mould leaves the press.

Lock out power, wait for 60 °C; solvent on a hot cavity starts cracks.
Blow the parting line with 0.4 MPa air, inside out.
Scrape resin with copper; abrasives never touch the parting line.
Wipe the cavity with anhydrous ethanol; acetone hazes polish.
Apply rust preventive at 5 μm and store closed with a 2 mm gap, or springs stay loaded.

The routine takes 40 minutes. Shops that skip step four polish again within three months.

4. Water Circuit: Scale Removal and Flow Limits

The water circuit never alarms; it just stretches the cycle until scale reaches 0.2 mm.

Case Mould: hundreds of black plastic latch parts piled on a grey bench, two hands lifting one part to check flash, white bags beside

Two readings decide it: flow per circuit and the temperature split. A 10 mm channel should carry 8 L/min; below 5 L/min it needs descaling.

Descaling needs no teardown: circulate 5 percent citric acid at 40 °C backwards for 40 minutes, then flush to neutral pH.

After descaling, flow returns to 8 L/min and the split to 3 °C, winning back 4 to 6 seconds a shot.

5. Replacement Limits for Ejectors and Guides

Ejectors and guides are consumables: replace on dimensions, not feel.

Part	New-part baseline	Replacement limit	Stock ratio
Ejector pin, 6 mm	0.02 mm straightness	0.3 mm wear	20 percent
Leader pin, 25 mm	58 HRC surface	0.08 mm bush clearance	2 per tool
Leader bush	H7 bore	0.05 mm oversize	2 per tool
Return spring	Length on record	5 percent shorter	4 per tool
Nitrogen cylinder	120 bar precharge	108 bar	1 per tool

A 6 mm pin worn 0.3 mm loses a tenth of its section and bends, scraping its own bore. Leader pins and bushes go in pairs, or a new pin wears a band and clearance returns to 0.08 mm in a fortnight. Nitrogen at 120 bar down to 108 bar drops ejector force a tenth and crowns thick walls.

6. Four Moves That Take 300,000 Shots to 500,000

A Case Mould rated for 300,000 shots often reaches 500,000 if four moves happen early.

Inserts come first: rest blocks, sprue bush and ejector-plate bushes become replaceable, cutting a repair from three days to four hours.

Second, log three service levels: gauge at 5,000 shots, measure clearances and torque bolts to 45 N·m at 20,000, polish at 100,000.

Third, control the water. Softened water under 200 μS/cm and a quarterly filter change keep the cycle from drifting.

Fourth, control storage: below 60 percent relative humidity, closed with a 2 mm gap, rotated quarterly so leader pins stay evenly loaded.

Inserts cost most and pay back fastest: converting at 300,000 shots usually buys another 200,000.

Conclusion

Care of a Case Mould is measurable: three wear lines give the stop signal, four readings give the trend, water and ejector parts set the ceiling on life. Post the limits beside the press, and 500,000 shots from a 300,000-shot Case Mould becomes normal rather than lucky.

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.