FAI for Custom RTV Molds: What First Article Shows

If you are approving a custom RTV silicone mold, pull the packet apart before you look at the dump. First article exists to prove that this resin production mother, this platinum or tin skin, this jacket / mother-mold support shell, and this trim made a cavity that matches the drawing and a dump that matches the fill-weight. It is not a capability study. It is not a PPAP unless you asked for one. It is not an AS9102 form unless you are in that system and you specified it. Most food, craft, and industrial RTV jobs need the substance of FAI, not an aerospace form number.

The tool you are approving still followed photos, sketch, or CAD, then a 3D-printed pattern, often a temporary silicone flip, a resin production mother, then batch RTV. The mother is not the pattern. The flip is not the product. Free DFM. CAD revision about USD 50 when a balloon forces a file change. Prototype usually 3-7 business days after CAD lock. Production MOQ 20 pieces per design. LSR part FAI against a model that was tuned on RTV is a fake pass. Do not mix them. On this site the path is photos, sketch, or CAD, then a 3D-printed pattern, often a temporary silicone flip, a resin production mother, then batch RTV. The mother is not the pattern. Free DFM. HTV/HCR compression mold tooling is also quoted on RUUIPON. HTV/HCR compression mold tooling stays on RUUIPON.

What the packet has to contain

Build it in this order. If a shop skips a layer, the rest is decoration.

1. The drawing you will hold them to, ballooned. Every dimension and note you care about gets a bubble number. Balloon flash max at the split, Shore of the cavity, fill-weight or pocket volume, post-wait of the dump, and the fits that actually mate. If you send a pretty CAD PDF with no balloons, you will get an "FAI" that measured five easy outsides.

2. Material identity. RTV grade and manufacturer, lot/batch, mix 1:1 or 10:1, hardness target, platinum vs tin. A cert that says "silicone, RoHS" is not a material cert. For 21 CFR 177.2600 or LFGB sections 30/31 claims, the cert must match the cavity compound. We do not invent an FDA-approved factory stamp.

3. Process state of the measured dumps. As-cast or after a named wait, at what temperature (23 C is the usual lab state). Platinum shrink is about 0.1-0.3%; tin is still moving. Measuring the wrong state is a fake pass.

4. Dimensional / fill-weight report against the balloons. Method named: scale, optical, caliper, water volume. Soft Shore 10A-20A wants contact strategy, not a macho CMM program copied from a steel housing. Record actuals, every pocket, not pass/fail ticks only. Outer-row 3-6% heavy vs center is sag.

5. Visual standard. Flash, voids, inhibition stick, jacket registration. Photos with the same lighting you will use in incoming.

6. Tool identity. Mother rev, pattern rev if it still exists, jacket number, cavity count. An 8-cavity FAI that reports one pocket is a 1-cavity FAI with seven strangers.

That is the packet. Everything else (full capability, GR&R, biocompatibility reports) is extra and must be named at RFQ.

Common mix-up: photo-only FAI of the hero pocket

A passing photo of a nice bear does not prove pocket 8. Pull from a continuous short run, not the three prettiest dumps in a bowl. ISO 3302-1 on the balloons is a drawing class if the article is rubber, not a substitute for a fill-weight map. If your email still says "master, box, keys, jacket" as the FAI object, you are listing shop furniture. FAI the cavity and the support shell you bought.

How to run it on the bench

1. Freeze drawing rev and balloons before the pattern is printed. FAI against a moving rev is theatre.
2. Complete tryout until the dump window is boring: mix, vacuum, jacket, peel.
3. Pull first-article dumps from a continuous short run.
4. For multi-cavity, pull from every pocket. Report every pocket. If a pocket is blocked, the FAI says so.
5. Measure after the agreed wait and after the agreed trim. If you will ship untrimmed, measure untrimmed.
6. Hardness on a thick enough section of the skin, or on a companion slug, because a 1 mm lip will lie on a durometer.
7. Pack the packet with the mold, cavity-tagged, plus living-mother custody note.

If fill-weight fails, stop. Do not "FAI the next lot." Either the support shell, the mother, or the pour is wrong. Recast or re-support, then new first article. Partial waivers belong on a signed deviation, not in email.

Silicone-specific traps

Softness. A Shore 10A skin will move in a vise. Fixturing and low-force probes are part of the method.

Flash as a dimension. If flash max is 0.15 mm at the split, it is a balloon, not a vibe.

Shrink vs LSR samples. Platinum RTV dumps are a different shrink story than heat-cured LSR. Do not FAI an RTV tray against a model that was tuned on LSR steel, or the reverse.

Sag. Straightedge on the jacket back. 0.5-1.5 mm edge dish is a missing support shell.

Inhibition leftovers. Sticky first articles on platinum are a chemistry fail. They do not belong in the dimensional table.

Family tools. Each unique pocket is its own first article, even if the PO thought it was one dump.

Typical shop values

Reference values only. Confirm material-specific limits against the supplier’s technical data and agree project acceptance criteria before production.

Worked example: 12-cavity bear packet

A 12-cavity 18 mm bear, 4.0 g target, food-contact, about 2,000 dumps a month. Balloons: fill-weight, flash at split, Shore of skin, chin radius. Platinum 10A-20A, mix 1:1, vacuum degas, jacket / mother-mold support shell. First article: twelve weighs, straightedge on jacket, photos of the split land. Hero-pocket photo was refused. A parallel LSR FAI form with gate remnant balloons was the wrong packet.

Stay on this page / skip this page

Stay when you are approving an RTV tray and need the packet named before anyone says "looks good."

Skip if you actually need FAI of vulcanized LSR/HCR parts - a different RFQ - ask us. Skip aerospace form numbers unless you specified them. A one-off artisan dump can skip the form and still keep the substance (weigh, wait, every pocket).

We will not quote photo-only FAI of the hero pocket. We will not measure a dump still warm from the table. We will not FAI LSR against an RTV-tuned model. We will not raise Shore A first to fix a fill-weight miss - fix the support shell. We will not skip a blocked pocket in the report.

Related: DFM checklist, remote audit, gummy trays, contact.

What to send

• Ballooned drawing with the RFQ, not after tryout
• Dump material; ship state: wait, trim, temperature
• Every cavity reported - yes or no
• Form: shop table vs your template vs a named aerospace standard if you actually need it
• Food-contact path if needed: 21 CFR 177.2600 and/or LFGB sections 30/31

Put on the PO: "First article = ballooned drawing + RTV cert (grade/lot) + fill-weight/actuals per balloon per pocket + visual photos + jacket/mother ID, measured in the ship state (wait/trim yes or no). No photo-only FAI." Send balloons and dump material to [email protected] or contact.

FAQ

Does a passing FAI prove 10,000 dumps? No. It proves the recipe can hit the drawing. We do not sell a cycle warranty. Capability and incoming sampling are separate.

Can I approve from a cavity photo? No. A photo of pocket one is not first article. Weigh every pocket in the ship state.

Is this AS9102? Only if you specified that system. Most RTV food and craft jobs need the substance, not the form number.

What if pocket 7 is blocked? The FAI says so. You do not average the other eleven and call the tray released.

When does the prototype clock start? CAD lock. Then usually 3-7 business days. MOQ 20 after the packet passes. DFM is free. CAD revision about USD 50 when a balloon forces a file change.