Silicone Gummy Mold Manufacturing, Master to RTV Tray

If you're buying a silicone gummy mold from us, manufacturing means pouring a food-contact platinum RTV tray that a depositor can fill and a dump station can empty.

We're not pouring tin-cure into a 3D-printed bear and calling it done, and we're not injecting LSR into a heated steel tool unless you separately ordered a molded silicone *part*. Production chemistry here is platinum addition-cure RTV (A/B), poured against a finished master in a mold box, then held by a jacket so Shore 20A-class rubber keeps pitch on the belt. Then we post-cure, trim, wash, and qualify the article under 21 CFR 177.2600 extractives and/or LFGB/BfR XV.

Shop sequence: master, box, pour, jacket

The RTV tray is the product. The master is how we make it.

1. Master: CNC aluminum, machined resin, or SLA/DLP fully UV post-cured, washed, and barrier-coated so platinum doesn't inhibit. Layer lines print as cavity texture.
2. Mold box / flask: sets pour height, wall thickness, and a square back for the jacket.
3. Registration keys: pips, bushes, or CNC bosses if the tray splits or a face reseats in a frame.
4. Platinum RTV pour: degassed A/B, poured to box height, cured per the grade. That's the working face.
5. Support jacket: resin, fiberglass, printed shell, or an aluminum/PC carrier so the cavity doesn't balloon under the shot or cup on the belt.
6. Trim, post-cure, wash, volume check.

Logos live in reverse on the master. Hairline serifs fill with RTV and then trap gelatin, so we radius relief on the pattern, not with sandpaper after the pour. Texture language (VDI 3400 / MT 11000 on a metal master) only if the show face needs matte versus gloss.

Common mix-up: quoting an LSR plate as if it dumps pectin

A lot of RFQs treat "silicone gummy mold manufacturing" as LSR injection of a plate from a steel production tool. In the shop that usually means you've been sent a cold-runner, heaters, and a part-tool FAI — none of which dump candy. Aluminum or steel LSR injection tools with a cold-runner mold silicone *articles*. Mixing that line item with an RTV tray is how lead times and food-contact specimens get scrambled.

Tin-cure RTV is condensation-cure and the wrong food-contact, sensory, and wash start. Soft platinum one-ups (hand peel, no jacket) are the right *sample* family; they aren't the production tray until Shore, thickness, register, jacket, and post-cure match the line. Peroxide leftover stocks exist in industrial rubber; for dual-market sensory, platinum is the realistic pour.

Post-cure and the article you actually ship

After demold we trim flash so slurry can't sit on a ragged box lip, then post-cure in a ventilated oven scaled to thickness. A 2 mm cavity floor and a 12 mm jacketed back don't share a lazy bake. Skip it and 177.2600 flasks and LFGB volatiles are a different, dirtier article. Wash as production will wash — the regulation expects a cleansed article — then inspect volume, pitch, flatness, flash, color, and tears.

The food-contact file is this SKU, this color, this RTV grade, this post-cure. A natural plaque doesn't qualify a red production tray. US: 21 CFR 177.2600 extractives. Germany/EU: LFGB/BfR XV. Dual-market: both. Don't print "FDA approved." HS for export of silicone articles often lands in 4016.99 or 3926.90; ask the forwarder, don't invent a code here.

Register, stiffness, first article

A tray that looks like a gummy mold on a table can still miss every nozzle. We need locating holes or bosses that match your carrier, a flat back or a designed flex axis for a roller dump, a rigid jacket (or firmer RTV back + softer face) when one Shore can't stay flat and still dump, and stacking ribs so wash racks don't oval cavities. ASTM D395 screens set; your stack is the plant test. Hybrid faces in aluminum or PC need a designed food-contact bead, not kitchen tin-cure.

A first article isn't a pretty bear. It's pitch and envelope against your drawing, cavity volume (water or check slurry) against the piece-weight plan, dump of *your* slurry at a stated temperature (or a stand-in gel you accept as mechanical only), flatness after post-cure and wash, flash, and article identity. Mechanical dump doesn't prove pectin release. Formula, nutrient load, and any cannabinoid question stay out of our traveler.

What to ask when you're buying the manufacturing PO

• Is the master CNC, machined resin, or SLA, and who barriers it so platinum doesn't inhibit?
• What's the box pour height and the jacket material (resin, fiberglass, aluminum, PC)?
• Shore of the face, and is there a firmer back or a rigid jacket?
• Post-cure recipe scaled to floor *and* jacket thickness?
• 177.2600 extractives and/or LFGB on *this* tray, not a spatula?
• Recast of the face against the same master if it wears — is that a line item?

Example

A recent-style job on this sequence is a 12-cavity fruit, 20 mm tall, 2.4 ml, platinum RTV Shore 25A poured on a CNC aluminum master, resin jacket, post-cured, then water-filled at corners and center before the plant runs pectin. Recast of the face is priced against that master, not as a new LSR production tool.

When this manufacturing sequence is the wrong PO

If you actually want a factory-pressed LSR or HCR *plate* from a steel production tool (a molded silicone article), that's a different quotation — heated cavity, often a cold-runner, not a master-and-jacket pour. If you only need a 1-cavity kitchen peel to freeze a formula, skip the production jacket and the pin pattern. Tin-cure craft kits aren't a cheaper version of this sequence; they're a different chemistry.

Related reading: what tooling means on an RTV PO, cavity DFM, custom RTV molds.

First-article and manufacturing RFQ

Copy this before we pour.

• Master: CNC / machined resin / SLA (UV post-cure + barrier coat)
• Box pour height, wall thickness, jacket material
• Shore of the face; firmer back or rigid jacket?
• Cavity count, dump height, nozzle pitch
• Target grams or ml; slurry family for the dump trial
• Post-cure scaled to floor *and* jacket thickness
• 21 CFR 177.2600 extractives and/or LFGB on this color/thickness
• Recast of the face against the same master: line item?

Send the STL or master photos, target grams, nozzle pitch, and tray envelope. We'll review pour height, jacket, and whether a one-up dump belongs in the price before the production array.

We would not recommend quoting an LSR plate as a pectin dump tray

We would not recommend treating "silicone gummy mold manufacturing" as LSR injection with a cold-runner. That molds silicone *parts*; it does not dump candy. We would not skip post-cure because the gummy isn't baked in the cavity — 177.2600 and LFGB see the rubber article. We would not use tin-cure as a cheaper pour or a hybrid-jacket bead.

flowchart TD
  M[Master CNC / resin / barrier-coated SLA] --> X[Mold box: pour height, square back]
  X --> A[Platinum A/B, vacuum degas]
  A --> C[Cure, demold, trim]
  C --> J[Jacket: resin / FG / Al / PC]
  J --> P[Post-cure scaled to floor AND jacket]
  P --> W[Wash as production will wash]
  W --> V[Volume map + pitch + article identity]

Typical shop values: master-to-tray platinum RTV pour

| Item | Typical shop value | | --- | --- | | Piece-weight target | 4.0 g (cavity volume × measured slurry density; fill-to-brim or fill-to-line stated) | | Outer-row vs center | 3–6% heavy if the loaded tray sags under the nozzles | | Loaded-tray edge sag | 0.5–1.5 mm without a flat jacket | | Cavity Shore | 10A–20A platinum RTV skin + rigid jacket | | Platinum linear shrink | 0.1–0.3% (cut the master so poured pitch lands) | | Mix | Platinum 1:1 or 10:1; vacuum degas | | Post-cure | Scaled to 2 mm floor vs ~12 mm jacketed back — not one lazy bake |

Caption these as typical shop values, not a measurement on your PO.

FAQ

Is platinum RTV the same manufacturing route as LSR plates? No. Platinum RTV is poured against a master and usually jacketed. LSR injection uses a heated metal tool, often with a cold-runner, to mold silicone *parts*. Use RTV when you need a flexible depositing tray; use LSR/HCR only if you actually commissioned a molded article.

Why post-cure a gummy tray if the gummy isn't baked in it? Post-cure is for the rubber article: volatiles, extractives, sensory. 21 CFR 177.2600 and LFGB/BfR XV see the finished, cleansed tray. Jacket and floor thickness set the bake. The gummy's set temperature is a separate process.

Can you recast a worn tray instead of cutting new steel? If the master and jacket still register, a new platinum RTV face is the normal repair. If the master was sanded "to clean it up" or lost, you're back to CAM. A recast isn't an LSR remold.

Does a master FAI replace food-contact testing? No. Master inspection proves reverse geometry. Food-contact proves the poured, post-cured tray. You need both for an article that will touch candy or vitamin gummies.

Where does tin-cure belong in this flow? It doesn't. Tin-cure RTV isn't the production chemistry, isn't the prototype chemistry we want on a food-contact sample, and isn't a repair bead for hybrid jackets.