Injection Molding Service China | Prototype to Production

Which injection moulding programme fits your part

Pick the route before asking for a price, or the quotes will not be comparable.

Route	Tooling	Fits	Confirm first
Prototype or bridge	Aluminium or soft steel	Design validation, market tests	Tool life in shots
Pilot single cavity	One cavity, hand loaded	Low volume, early sales	Unit cost ceiling
Multi-cavity production	Hardened steel, 4–16 cavities	Steady annual programmes	Cavity balance, spare inserts
Family tool	Same part set, one tool	Kits sharing colour and resin	Each cavity fills fully
Dedicated high cavitation	32+ cavities, hot runner	Caps, closures, consumables	Shot life, maintenance access

Matching the press to your part

Clamp tonnage — the projected area the quoted press covers, with margin.
Shot capacity — part plus runner inside the barrel's shot volume.
Tie-bar spacing — whether your tool physically fits.
Screw and barrel — confirm the screw suits your resin, especially filled or FR grades.
Takeout — robots and conveyors change labour content per part.
Capacity — compare presses under injection molding machines and plastic machinery.

What actually moves the unit price

Cycle time — cooling dominates; wall thickness decides it before tooling starts.
Cavitation — more cavities spread press time, but raise tool cost and balance risk.
Resin and yield — confirm whether regrind is allowed and at what ratio; see regrind ratios and property loss.
Start-up scrap — who pays while the process stabilises.
Secondary operations — assembly, printing and packing are rarely in the piece price.
Tool amortisation — billed separately or recovered into the piece price; read what drives injection mould cost.

Quality evidence to require before shipment

First-article inspection — each drawing dimension with its measured value.
Setup sheet — the parameters your approved parts were moulded at; see reading a moulding setup sheet.
Material traceability — resin lot, compounder and COA for your delivery.
Capability data — measured across a run, against the class in ISO 20457 general tolerances.
Defects and warpage — sink, flash, knit lines and bow; start with moulding defects and warpage causes.
Tool maintenance — who maintains the mould and how shot counts are recorded.

Mistakes that cost buyers the most

Approving a T1 sample as production. Trials are for finding problems.
Freezing geometry before the resin. Filled grades shrink unevenly.
Tolerancing every dimension as critical. It raises scrap and price.
Comparing quotes that assume different cavitation, resin or secondary operations.
Skipping the tooling clause. Ownership, storage and transfer in writing — see mould ownership and transfer.
Moulding a hollow part when blow molding fits, or a low-volume shape that CNC machining delivers cheaper.

Frequently Asked Questions

What volume justifies a hardened production tool?

Ask each molder to quote the soft and hard tool separately against your annual volume, then compare payback; the path is in prototype to production tooling.

Can a Chinese molder run my existing tool?

Usually yes, and it is the fastest route to a second source. Provide the tool, drawing and process sheet, and settle ownership and customs paperwork in writing first.

How do I compare two quotes that look different?

Normalise them: same model, drawing, resin, cavitation and annual volume, tool itemised separately. Ask for the assumed cycle time and scrap rate — those explain most gaps. More in negotiating plastic part prices.

Is a family tool cheaper than separate tools?

One tool costs less than several, but every cavity must fill and cool in the same window, and one damaged cavity stops the set. Weigh it with family moulds versus single-cavity tooling.