Used Injection Moulding Machine Nozzle Fit: Check the Sprue Bushing Before Buying

Before buying a used injection moulding machine for an existing mould, compare the installed nozzle and the tool’s sprue bushing as a pair. Ask for the seat profile, the two melt openings and the usable nozzle reach from a shared reference plane. If the seller proposes another tip, identify it by part number and make the completed fit and trial part of the purchase terms.

Conceptual illustration. The diagram identifies the checks to request and provides no dimensions for a particular machine or mould.

Start with the mould that needs to run

Get the current sprue bushing drawing from the toolmaker or the measurements of the installed part. An older drawing may describe a bushing that has since been replaced. On the press side, ask for the offered machine serial number, injection unit identification, and a clear record of the installed tip or extension. Include the drawing revision and units on both sides. If you are moving several tools, start with the deepest recessed seat or any tool with a different seat profile.

Component maker DME identifies seat radius and opening size as separate fit checks for its three-plate extension bushing. MISUMI’s dimensional reference illustrates nozzle curvature, hole diameter and projection from the fixed platen. Use these references to identify what to measure. The machine and tool drawings determine the actual dimensions and acceptance tolerances.

Use one fit sheet for the machine and tool

Check	Ask the seller for	Ask the toolmaker for	What closes the item
Seating profile	Installed tip profile and radius where applicable, with a photo of the contact surface	Seat profile and radius or approved mating tip drawing	Toolmaker confirms the intended contact geometry. Any damaged or worn surface is assessed separately.
Melt path	Diameter at the nozzle exit and tip type	Diameter at the bushing inlet and any specified offset or fit requirement	Both openings align as intended. Confirm the transition and expected sprue release with the toolmaker.
Reach and clearance	Usable projection from the fixed platen with the proposed tip fitted, plus its outer envelope	Seat depth from the mould mounting face and dimensions of the locating-ring opening	The technician checks the two datums against the assembled machine, including clearance through the ring.
Trial	Guarded observation and an agreed run using the fitted tip	Expected sprue release and a sample acceptance criterion	Record the tested configuration and results, including any visible leakage or sprue sticking.

Agree who owns a mismatch before the machine ships

When the toolmaker specifies another tip, ask the machine supplier to confirm its compatibility with the installed nozzle body and any heater or sensor arrangement. If the seller proposes an extension, have the parties check its reach and outside clearance with the actual tool. Write the part number, installer, inspection evidence and retest responsibility into the offer. Leave any unproven fit item open if the tool cannot be tested until arrival.

Use the full mould fit checklist for tie-bar, platen and opening dimensions. This nozzle check also belongs in the inspection scope when comparing equipment from the used machine sourcing catalogue.

Questions to settle before purchase

Does the locating ring prove the nozzle will reach the seat?

The ring helps locate the mould. Confirm the nozzle projection, seat depth and clearance separately against the assembled tool and press.

Can I specify one seat radius and orifice difference for every mould?

Use the drawings or approved component data for each pair. Special nozzles and extensions can have different requirements. For a hot-runner tool, obtain the hot-runner supplier’s machine-side inlet drawing.

Ask GEEPOW about a used machine for your existing mould. Include the installed bushing drawing, seat depth and resin, plus the candidate machine model or serial number if you have it.