From Enquiry to Repeat Order: A Realistic Timeline for a Custom Filter Programme

A buyer asks for a custom filter in March, expects stock in June, and finds in July that the sample was approved late because the artwork was not, that the tooling was not started until after approval, and that the first production batch could not ship because the barcode prefix had never been issued. None of these are manufacturing failures. They are sequencing failures, and they are predictable.

This guide sets out the actual order of events in a custom filter programme — oil, fuel, air, hydraulic or coolant — from first enquiry to repeat order. For each stage it identifies what sets the duration, what commonly stalls it, and what the buyer can do from their side to keep it moving. It is written for distributors, fleet operators and private-label brands sourcing from a Chinese filter manufacturer.

The sequence, and why it cannot be compressed arbitrarily

A custom filter moves through seven stages, and each one produces something the next stage needs as an input. That dependency is what makes the sequence rigid. You can run stages in parallel where they do not feed each other — artwork can be prepared while the sample is being built — but you cannot approve a sample before you have built it, and you cannot build a production batch before the drawing is approved.

Stage 1: Feasibility and routing

Feasibility answers one question: can this part be built on an existing platform, or does it need new tooling? The answer determines the entire schedule, because tooling is the longest single stage and the one least tolerant of later changes.

Three routes are possible, and they differ in cost and risk far more than in price per unit.

A factory that quotes without telling you which route your part falls into has not yet done the feasibility work. Ask for the routing decision explicitly, in writing, with the reason. It is the single most useful sentence in the early correspondence, because it tells you whether you are buying a configuration or a development project.

Stage 2: Tooling or configuration

Where new tooling is required, this stage dominates the timeline and carries the most risk of rework. Moulds for end caps and housings, dies for metal components, fixtures for assembly and gauges for inspection are all made to the approved drawing — which means the drawing has to be right before tooling starts, not after.

Ask two questions before tooling starts: who owns the tool, and what happens to it if the programme ends. Ownership determines whether you can move the part to another supplier later, and it is worth settling in writing while the relationship is still easy.

Stage 3: Sample build and approval

Sample build is short. Sample approval is often long, and the delay is usually on the buyer’s side. A sample that arrives without a dimensional report invites a round of questions; a sample that arrives with one can be approved against a checklist.

Approval should test four things, in this order:

1. Fit — it installs on the machine or housing without force and seals without leaking.
2. Form — dimensions and interface match the approved drawing within stated tolerances.
3. Function — media efficiency, valve cracking pressure, collapse and burst ratings meet the specified values.
4. Presentation — marking, packaging and labelling match the artwork that will be printed.

Test function before presentation. A programme that discovers a media problem after the packaging has been printed has paid twice for the same delay. If the sample passes fit, form and function, give written approval and move artwork in parallel, not afterwards.

Stage 4: Pre-production and artwork

This is the stage most often ignored in planning and most often responsible for a late first shipment. Nothing here is difficult; everything here has a dependency on information that lives outside the factory.

• Barcode and prefix — a GS1 company prefix has to be registered and issued before any label can be printed. Registering one is not a same-day process.
• Artwork proof — approve a physical printed proof, not a screen image. Colour references and material finish only read correctly on the substrate.
• Label compliance — destination-market requirements for language, country of origin, and any regulated warnings.
• Carton specification — quantity per carton, dimensions, gross weight and carton marking, matched to your warehouse slotting.
• Document set — which certificates, test reports and origin documents the shipment must carry, and which are chargeable.

Stage 5: Production, inspection and release

Production duration is set by batch size and by material availability, particularly media. A media grade that is standard for the factory is available off the shelf; a specialised synthetic grade may need to be ordered in, and that order has its own lead time.

Ask for the inspection record as a deliverable, not as a favour. A batch that ships with the record attached can be received and put away; a batch that ships with documents to follow sits in a warehouse accruing storage cost while somebody chases paperwork.

Stage 6: Logistics and first arrival

Mode selection is a trade between cost and time, and for a first order the calculus is different from a repeat order. On a first shipment you are also buying information: whether the packaging survives, whether the documents are correct, whether the batch matches the sample.

Incoterms belong in this stage and should be agreed in the quotation, not negotiated at booking. FOB, CIF and DDP place the risk and the administrative burden in different places, and a programme that assumed DDP but was quoted FOB discovers the difference at the moment of shipment.

Stage 7: Repeat order

The repeat order is the stage where all of the earlier work pays back — if the records were kept. A programme with an approved drawing, a frozen specification and a retained reference sample reorders in a fraction of the original time, because nothing needs to be re-established.

Three records make the difference:

The five stalls that cost the most time

Across custom filter programmes, delays cluster into a small number of causes. None of them is a manufacturing problem.

1. Blank fields on the data sheet — the factory fills them by assumption, the sample proves the assumption wrong, and a cycle is lost.
2. Artwork and barcode started after approval — weeks of administrative lead time added to the end of the programme for no reason.
3. Drawing revisions issued verbally — the factory builds to the last written drawing; verbal changes produce a sample nobody approved.
4. Approval testing done out of order — packaging approved before function is verified, so a functional fix invalidates the packaging.
5. Media availability assumed — a specialised grade ordered in after the production slot is booked moves the shipment, not the order.

How to compress the critical path

There is no way to make a mould faster by asking. There are several ways to remove work from the critical path.

A programme that does all seven typically lands its first production batch in the time a less organised programme spends getting to an approved sample. The saving is not in the factory; it is in the buyer’s preparation.

Frequently asked questions

How long does a custom filter programme take in total?

For a part built on an existing body with a different element or marking, first production is commonly achievable within about six to ten weeks from a complete enquiry. Where new tooling is required, add the tooling lead time, which is usually the largest single block in the schedule. Both figures assume artwork and approval are handled promptly.

Can sampling start before tooling is finished?

Only where the sample can be built without the tooled parts — for example, a hand-built element in a machined body that approximates the final housing. Such a sample verifies media and valve behaviour but not the tooled geometry. It is useful for de-risking performance early, and it does not replace the tooled sample.

Who owns the tooling?

It depends on the agreement and should be settled in writing before tooling starts. Common arrangements are factory-owned tooling amortised into the unit price, buyer-owned tooling paid for up front, and shared arrangements for high-volume programmes. Ownership determines your ability to move the part later, so treat it as a commercial term, not a technical footnote.

What happens if the sample fails?

A functional miss returns to the drawing: the specification is amended, the revision is numbered and issued, and the sample is rebuilt. A failure that indicates the route itself was wrong returns to feasibility. The distinction matters because one costs a sample cycle and the other costs a tooling decision.

How large should a pilot batch be?

Large enough to fill a production run without a partial shift, and small enough that a problem discovered during the run is affordable. For most filter lines that lands in the low thousands rather than the low hundreds. Ask the factory what batch size fits its line, then size the order to that number rather than to a round figure.