Injection molding lead time, from quote to delivered parts

The five clocks inside a lead time

A supplier who answers "how long?" with one number is either quoting a repeat order or guessing. A new injection molded part runs through five separate clocks, and only some of them are ours.

1. The quotation. An RFQ with a STEP file and a stated annual volume gets a reply from an engineer within 24 to 48 hours: a price, a lead time and any design notes that would reduce either. An RFQ without geometry or volume gets a question back instead, and the clock restarts when it is answered. How to get an accurate injection molding quote lists what a complete one contains.

2. Design review and tool layout. Before steel is cut we return a design-for-manufacture review of your model and a tool layout drawing covering parting line, cavitation, gate and runner, ejection, cooling and any actions. Your approval of that layout is the last inexpensive point to change anything, and it is also the step most likely to sit in an inbox for a week.

3. The tool build. Steel is ordered and machined, then EDM, polishing and texturing. This is the 4 to 8 weeks, and the next section explains which end of it your part will land on.

4. Sampling and approval. First shots (T0) are measured against your drawing and reported. Where a dimension needs it the tool is adjusted, then T1 samples go to you for sign off. How long approval takes is on your side of the table; a program with its own incoming inspection and a PPAP submission takes longer than a buyer who checks three critical dimensions.

5. Production and transit. Once samples are signed, production parts leave within 3 working days of the purchase order, then spend whatever time the lane takes: days by road inside India, weeks by sea to the United States.

What puts a tool at 4 weeks or at 8

The spread in tool build time comes from the tool, not the press. A single cavity two-plate tool with a straight pull and a standard finish sits at the short end. Each of these moves it toward the long end:

• Cavity count and family tools. Every cavity is machined, fitted and balanced; a four-cavity tool is more work than one cavity cut four times over.
• Actions. Undercuts need slides or lifters, each a mechanism to design, machine and fit.
• Hot runners. They remove the runner and suit high volumes and cosmetic gates, and they add a manifold to specify, source and commission.
• Finish and texture. An SPI A grade high gloss is hand polishing on hardened steel; a VDI 3400 or Mold-Tech texture is a separate process step. The surface finish guide explains the grades.
• Steel. Aluminium (7075, QC-10) is the fastest to cut and suits hundreds to a few thousand cycles. P20 pre-hardened is the production default. H13 hardened or stainless can involve an imported blank or a specialty coating, which adds a sourcing line to the schedule; ask which steel in your quote is sourced how.

Steels, tool types and designed tool life up to 2,000,000 cycles are set out on injection molds and tooling.

Where schedules actually slip

In our experience the lost weeks are rarely machining time. They come from four places, and all four are avoidable:

• An incomplete RFQ. STL instead of STEP, no drawing for critical dimensions, no volume. Each gap is a round of email before a firm number exists.
• A layout waiting for approval. Steel is not cut on an unapproved layout, so every day it waits is a day added to the end.
• A change after steel is cut. Moving a boss, adding a rib or switching resin grade is a tool change. PA66 unfilled and PA66-GF30 shrink differently and cannot share a tool without rework, so nominate the grade on the drawing, not just the family.
• Resin availability. Commodity grades are stocked domestically. Several engineering and high-performance grades are imported, and their lead time can exceed the tool's; see materials and raise the grade at quotation.

Worked schedules, new tool to parts at your dock

A buyer in South India. Tooling 4 to 8 weeks, dispatch within 3 working days of the production order, then about 5 to 7 days by full truckload to Chennai or 3 to 8 days part load to Peenya. That is roughly 5 to 10 weeks from tooling order to parts at your dock, plus however long your own sample approval takes. The city lanes are on the Chennai and Peenya pages.

A buyer on the US East Coast. The same tooling window, first article samples by air in 5 to 8 days, then 40 to 55 days at sea for production. A first production shipment reaches an East Coast port roughly 10 to 16 weeks after the tooling order, plus sample approval, as set out for Georgia buyers on injection molding supplier for Georgia. After that first shipment the lead time is the sea leg, so safety stock is planned around seven to eight weeks of pipeline.

These are typical figures. Carrier, season, port congestion and your approval loop all move them, so the quotation names a date for your part and this page is the reasoning behind it.

How to take weeks out

• Send a STEP file, a drawing with critical dimensions and tolerances, the resin grade and an annual volume in the first RFQ.
• Name one person who can approve the tool layout, and book the review before the layout arrives.
• Freeze the design before steel is cut. If it is not frozen, run CNC or 3D printed parts until it is.
• For a low volume or a bridge tool, ask whether an aluminium tool fits your cycle count; it cuts faster and costs less.
• Fly first article samples even when production goes by sea.
• Keep the tool on our floor between runs. You own it, and a repeat order then leaves within 3 working days instead of waiting on a tool transfer. Ownership terms are on how it works.

When the lead time rules us out

If you need parts sooner than a tool can be built, roughly under 4 to 6 weeks for a new part, injection molding is the wrong process for that first batch, from us or anyone else. 3D printing or CNC machining will get a few hundred parts to you first, and the tool follows once the design is released. And if a US line needs weekly just-in-time replenishment with no stock held, a molder a truck ride away will serve it better than a sea lane; our process is built for stable, released designs where tooling cost and piece price matter more than a short replenishment loop.