A second source is often discussed after something has already gone wrong: a late shipment, a lot that failed incoming inspection, or a supplier that announced a price change. At that point every custom silicone part looks like it needs a backup. In practice, qualifying an alternate route takes engineering time, samples, and inspection effort, so it pays off for some part numbers and not for others.
This page is about the decision before the qualification work starts: which custom silicone parts justify a second source now, which can wait, and what to settle internally before you contact another supplier.
Start from the consequence of a missing part
The useful question is not “do we have only one supplier?” but “what happens on the line or in the field if this part is unavailable for one reorder cycle?”
A second source is usually worth qualifying when:
- The part stops assembly or shipment of a finished machine and there is no practical substitute in stock.
- The part is replaced in service, so spare-part demand continues after the original project ends.
- The silicone part is custom (own drawing, own extrusion die or mold), so no catalogue equivalent can be bought quickly.
- Repeat demand is steady enough that the qualification effort is spread over many future orders.
It is usually lower priority when the part is a one-off build, demand is ending, a standard size from stock is an acceptable fallback, or the current safety stock already covers a realistic requalification period.
Look at how hard the part is to match
Qualification effort depends on what the part has to prove. Two custom silicone parts with the same annual spend can need very different work.
Relatively simple to move:
- Tubing or profiles defined by a clear cross-section, length, and hardness, where fit is checked with ordinary gauges.
- Die-cut or simple molded gaskets whose function depends on a few dimensions and an agreed material family.
More work before a switch is safe:
- Molded parts with tight fit features, inserts, or several cavities in the current tool.
- Seals where performance depends on installed compression rather than free-state dimensions alone.
- Parts approved mainly against a physical reference sample rather than a complete drawing.
- Parts with project-specific documentation or market requirements.
The harder the match, the earlier you need to start. A second source for a difficult part is rarely ready in the week it is needed.
Check whether your own package is ready
A common reason second-source projects stall is on the buyer side: the drawing is out of date, the approved sample is the only reference, or nobody has written down which features receiving actually checks.
Before you approach another supplier, it helps to confirm:
- The current drawing revision matches what is actually being delivered.
- Fit-critical features are marked, separate from cosmetic preferences.
- The approved reference sample is identified and kept under control.
- Incoming inspection notes exist for the features that have caused problems.
If these are missing, fixing them first often has more value than starting a qualification, because the same gaps will make any new supplier’s samples hard to judge. See Drawing Revision Control for Silicone RFQs and Reference Sample Control for Silicone Parts.
Decide what the second source is for
“Backup supplier” can mean different things, and each changes the scope:
- A standby route that is sampled and approved, then ordered occasionally to stay active.
- A split of repeat volume between two routes on an ongoing basis.
- A planned transfer away from the current route over several orders.
A standby route that never receives an order tends to lose value: drawings change, people move on, and the approval no longer reflects current production. If you choose a standby arrangement, plan how and when it will receive real orders.
A simple way to rank part numbers
For a list of custom silicone parts, a short internal ranking is often enough:
- Impact if unavailable: line stop, delayed shipment, or minor inconvenience.
- Matching difficulty: simple cross-section, molded fit features, or sample-only approval.
- Demand outlook: ongoing, spare parts only, or ending.
- Package readiness: drawing current and critical features marked, or not yet.
Parts with high impact, ongoing demand, and a ready package are the natural first candidates. Parts with high impact but an unready package usually need documentation work first. Low-impact parts with ending demand rarely justify the effort.
Once a part is selected, the practical steps for the RFQ itself are covered in the Second-Source Evaluation Checklist for Custom Silicone Parts.
Where Forvard Tech fits
Forvard Tech reviews second-source inquiries for silicone gaskets, custom silicone profiles, molded silicone parts and silicone tubing from the drawings, samples, and inspection notes a buyer already has. Sampling scope, documentation, and quotation are confirmed per project after that review.
If you have a short list of parts you are considering for a second source, send the drawings or sample references through the RFQ page and note which parts matter most. We will tell you what is clear and what still needs confirmation before sampling.