How Custom RTV Silicone Molds Are Made

A custom RTV silicone mold is not cut from a mood board, and it is not "CAD, then resin, then pour." Send photos, a sketch, or CAD. Free DFM. CAD revision is about USD 50 when we edit your 3D. After CAD lock we typically 3D-print a pattern, often flip a temporary silicone tool from that print, cast a resin production mother, then pour batch RTV - the cavity you dump chocolate, pectin, resin, wax, or soap into. Prototype is usually 3-7 business days after CAD lock. Production is MOQ 20 pieces per design. RUUIPON has poured that path in Bao'an, Shenzhen, since 2018.

The resin production mother is the hard production tool we pour batch RTV against. It is not the 3D-printed pattern. The temporary silicone flip is not the product. A jacket / mother-mold support shell is a different noun: it keeps a Shore 10A-20A skin from ballooning under a wet dump. CNC of a pattern, or a pour-on-print, stays a valid DFM choice when we name it - we do not collapse every job to CAD then resin then RTV.

The object you buy is the last pour

Four objects show up on the same traveler. Mixing the nouns is how a buyer pays for a pretty print and thinks they bought twenty trays.

Stay on this sequence when you need a cavity you pour into. Open an HTV/HCR compression-mold RFQ on RTV vs HTV if you need the steel/compression tool. Skip as an HTV product RFQ here. if the carton is a vulcanized part.

Shop path after CAD lock

1. Photos, sketch, or CAD. Free DFM. CAD revision about USD 50 when we edit your 3D.
2. CAD lock: millimetres, logo depth, fill line, Shore band, and structure are signed.
3. 3D-print a pattern. Wash / UV / seal when the print would inhibit platinum.
4. Often: flip a temporary silicone tool from that print.
5. Cast the resin production mother. That mother is the production tool, not the pattern.
6. Pour batch RTV. Split / plug / core, plus a jacket / mother-mold support shell when a 10A-20A skin would balloon.
7. Weigh A/B to the grade ratio (1:1 or 10:1), vacuum until the foam collapses, pour, cure, pull, then dump the real material on the prototype.

Platinum RTV linear shrink after a full cure is typically about 0.1-0.3%. Tin-cure is more forgiving of a dirty pattern and keeps moving in storage. Neither chemistry is LSR injection. Draft talk is about 1-3 degrees on walls that must still read. Structure follows the RUUIPON Mold Structure Decision: flat back? open-back. Deep undercuts that will not peel? two-part / plug / inner core. Large wet dump or Shore 10A-20A? jacket / mother-mold support shell.

Common mix-up: treating the print as the mold

A lot of RFQs treat an SLA figurine on the desk as a production cavity. The print still has layer lines, often inhibits platinum, and has no support shell. It can be the pattern after wash, full UV post-cure, and usually a barrier coat. Production still wants the flip-and-mother path when that is how we protect the face. Catalog copy that says CAD, then resin, then RTV - skipping the flip - and treats the first hard copy as if it were already the production mother. We will not quote that shortened sentence as the shop path.

Mix, vacuum, and the witness dump

Shop order on the bench after the resin production mother exists: release the mother; weigh RTV A/B; mix; vacuum-degas until the foam collapses; pour a thin stream; cure; demold; inspect; fit a jacket / mother-mold support shell when the skin is soft; dump a witness in your compound. A cavity photo is not the last step. A measured witness plus a written recast / refinish / release decision is.

Some small pours use a thin stream and vibration when a chamber is missing. That is a compromise against trapped air, not the default when the pocket has serifs. If the first witness misses, the next step is a pattern or mother refinish, a recast, or a new quote - named, not guessed.

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: 6-cavity fruit tray

A gummy line wanted a 6-cavity fruit, 22 mm tall, food-contact, about 1,000 dumps a month. Free DFM named a two-part skin plus a jacket / mother-mold support shell so the sheet stays flat on the depositor. After CAD lock we 3D-printed the pattern, flipped a temporary silicone tool, cast the resin production mother, then poured platinum RTV in the 10A-20A band. First article was a dump-weight check on all six pockets, not a photo of pocket one. A later logo change is a recast against the living mother if nobody sanded the face "to clean it up."

Stay on this page / skip this page

Stay when you need a pour cavity and want the shop sequence named before anyone prices rubber mass. This page is how we make that cavity.

Skip if you already know the object and only need Shore or layout - use what a custom mold is or Shore. Skip if you need finished HTV/HCR/LSR parts - that carton is a different RFQ - ask us. An HTV/HCR compression mold (the steel/compression tool) stays on a RUUIPON RFQ; do not use this how-made page to price that tool.

We will not quote platinum against an unwashed, under-cured print. We will not skip the flip-and-mother path in the written sequence just because a catalog collapsed it to CAD then resin then RTV. We will not mill an LSR part tool from the same uncompensated file and call both "how the mold was made."

Related: what custom molds are, RTV vs HTV, manufacturer, contact.

What to send so we start the right path

• Object: RTV pour cavity (this page) or HTV/HCR compression tool (other RFQ) or finished part (an HTV product or mold RFQ here, or ask us if you need a high-volume LSR cold-runner tool)
• Photos, sketch, STL, or STEP
• Dump material and peak temperature
• Quantity now; prototype after CAD lock, then MOQ 20 / design if you stay on RTV
• Known undercuts, logos, hollows
• Destination market if food-contact papers may apply (21 CFR 177.2600 extraction and/or LFGB sections 30/31)

Send the file and the dump to [email protected] or contact. WhatsApp +86 135 3006 2969.

FAQ

How are custom silicone molds made if I only have a 3D print? The print can be the pattern after wash, full UV post-cure, and usually a barrier coat. We still often flip a temporary silicone tool and cast a resin production mother before batch RTV. A printed figurine on a desk is not a cavity.

Do you go CAD, then resin, then RTV only? No. That sentence skips the pattern-vs-flip-vs-mother split. The resin production mother is the hard production tool. It is not the 3D-printed pattern and it is not the interim silicone.

Is the last step a photo of the cavity? No. A measured witness dump of your compound, plus a written recast / refinish / release decision.

Can you pour RTV as a shortcut to an LSR mold? We can pour an RTV cavity to study shape. We cannot skip a later LSR part tool if production is molded LSR parts. That parts PO stays an HTV product or mold RFQ here, or a different LSR-tool RFQ - ask us.

What is MOQ and the prototype clock? MOQ 20 pieces per design after approval. Prototype usually 3-7 business days after CAD lock. DFM is free. CAD revision is about USD 50 when we edit your 3D. Those three numbers are the RTV card - do not paste them onto an HTV/HCR compression-mold RFQ.