Mould Steel and Shot Life: How Long an Injection Mould Lasts

How long does an injection mould last?

Judge useful life by the mould's ability to produce parts that meet your agreed dimensions, appearance and function. Specify the required output and quality rather than relying on calendar age or a steel name.

For the life obligation, define whether a shot means a completed moulding cycle. Record the number of operating cavities and count acceptable parts separately. Ask whether trial runs, start-up cycles and production with blocked cavities count towards the supplier's stated life.

When buying from China, ask what output this particular tool must deliver, using which resin, and under what circumstances repairs become chargeable.

SPI mould classes 101–105: a specification framework

The Plastics Industry Association publishes Customs and Practices of the Moldmaking Industry. Its public catalogue describes classifications and approximate lifespans intended to reduce confusion when quoting or ordering moulds.

The catalogue does not display the detailed class requirements. The table therefore lists verification questions rather than verified class definitions. Obtain the agreed publication edition before specifying a class; no class-specific cycle limits, production categories or hardness minima are asserted here.

Request evidence of compliance with the agreed class requirements and write the supplier's life obligation separately into the purchase order.

P20, 718, H13 and S136: what the steel name tells you

ASSAB's material-selection guidance discusses machinability, polishability, toughness, wear resistance and corrosion resistance. Use the proposed product's technical literature to assess suitability for the application.

Specify the cavity and core material separately from the mould base, slides and replaceable inserts. Request exact product designations for the critical components.

The cited manufacturer literature does not provide a universal finished-mould shot-life range for each quotation name. Obtain a tool-specific life obligation rather than assigning a lifespan from the name alone.

Aluminium or steel?

Uddeholm describes Alumec 89 as suitable for prototype tools and short or medium production runs not subjected to high pressures or abrasive plastics. Its brochure identifies machining and thermal-conductivity advantages. These statements concern that product and do not establish the life of every aluminium mould.

Compare the proposed aluminium alloy and steel product against the required output, wear resistance, toughness, corrosion resistance and surface finish. Include expected design changes in the purchasing decision.

Ask the toolmaker to compare both routes against the same resin, geometry, finish and expected output. Identify any proposed steel inserts and include their replacement costs in the comparison.

Why the same steel can give different mould life

Disclose the resin, fillers and additives before material selection. ASSAB's guidance distinguishes wear resistance, corrosion resistance and toughness, and explains that increasing hardness generally improves wear resistance while decreasing hardness improves toughness.

Review gates, thin cores, sliding surfaces, cooling and ejection with the toolmaker. Request design and trial evidence separately from material certificates, and agree how performance will be assessed during production.

Define failure to meet the life obligation using measurable criteria, such as unacceptable flash, dimensional drift or surface deterioration. Distinguish routine consumables and replaceable inserts from major cavity repairs or complete tool replacement.

Use the separate guide to factory tooling maintenance and retirement when agreeing maintenance records, storage and retirement arrangements.

What to specify in the purchase order

Turn the supplier's life claim into an explicit obligation with a defined scope. The following items are purchasing recommendations, not statements that a standard automatically supplies these contract terms.

Address commercial control alongside production requirements. See injection mould tooling cost and ownership for payment, ownership and transfer considerations, and sourcing injection moulds and tooling from China for the wider buying process.

If you sell in the US or EU

US food-contact products — FDA guidance explains that a food-contact material's regulatory status depends on its constituent substances and their applicable authorisations, specifications and conditions of use. Define the intended food-contact use and obtain supporting material evidence; selecting a mould steel alone does not establish finished-article compliance.

US customs valuation — the US customs regulations require the value of qualifying assists to be added to transaction value to the extent not already included. Buyer-supplied tools and moulds can qualify when provided directly or indirectly, free or at reduced cost, for producing goods for export to the US. Ask the customs representative to check valuation and apportionment using the tooling agreement, invoices and production records.

US additional tariffs — USTR's Section 301 search uses the product's tariff subheading to identify relevant Section 301 actions and additional duty. Check an imported mould separately from the moulded goods. Ask the customs representative to check the complete applicable tariff treatment; the Section 301 search is not a calculation of every import charge.

EU product requirements — European Commission guidance states that CE marking is required only for products covered by the relevant rules and must not be affixed to other products. Identify the finished product's applicable requirements before approving the tool; a mould class or steel certificate alone does not establish product conformity.

Great Britain example: tooling costs and import VAT

Suppose a buyer pays for a mould that remains in China and imports the parts into Great Britain using Method 1 transaction-value valuation. HMRC requires relevant tooling payments, or the appropriate value of tooling supplied directly or indirectly free or at reduced cost, to be included where not already included in the goods price. Apportionment needs to be considered; a separate tooling invoice does not by itself exclude the cost.

HMRC's import VAT guidance adds applicable import charges, excluding import VAT itself, and relevant incidental expenses to customs value. Provide the customs representative with the tooling agreement and payment records so the valuation can be checked. This example assumes no duty rate, VAT rate or allocation method.

Compare the specification behind the quotation

Before choosing a supplier, compare the proposed material, supporting evidence, construction, life obligation and repair exclusions on the same basis. Ask suppliers to explain differences before comparing prices.

Prepare the drawing, resin specification, intended market, expected output and existing offers for a quotation review.

Sources

The industry publisher's public catalogue supports the existence and stated purpose of its classification publication, not the detailed class requirements. Manufacturer literature supports the product-property descriptions. Regulatory and customs statements draw on the official FDA, USTR, European Commission, HMRC and US customs regulation sources listed below.

The linked CBP publication could not be retrieved during this review; the US assists statement was checked against the official eCFR provisions instead. Manufacturer examples are not supplier endorsements or mould-life guarantees.