Draft Lives on the Resin Master, Not Dump | RUUIPON

Draft on an RTV job is a property of the *master* you will pull out of the cured rubber, and of the walls that master prints into the cavity. If the resin print is a zero-draft brick, the cavity is a zero-draft brick. Peeling the dump later does not add the degrees you skipped. Buyers send a dump STEP with injection-molding draft on the *part*, then a master STL with straight walls, and expect the rubber to invent a taper. We draft the master at DFM — typically talking 1–3° on walls that must still read — then pour. A sibling page covers when peel can substitute for draft on a glove. This page is only: put the taper on the pattern.

RUUIPON marks that taper in Bao'an, Xinhe Blvd, Shajing, since 2018. Mix is 1:1 or 10:1 by weight. Prototype is 3–7 business days after CAD lock of the drafted master, not after "the dump looks drafted in SolidWorks." Production is MOQ 20 pieces per design. Simple 3D is USD $50 when that CAD scope applies. Platinum shrink after a full cure is typically about 0.1–0.3%. Peel-versus-draft on the tool: draft angle. Steel/LSR *parts*: wydsilicone.com.

Does not apply when the object already needs a split because of a closed loop — draft on a doomed one-piece will not save an arm-against-torso. It also does not apply to a steel HCR/LSR cavity. Food trays still want draft on deep logo wells so the dump does not tear serifs; no grease, no tin for chocolate.

Pull the master first, then the dump inherits the negative

You demold twice. First you get the resin master out of the RTV. Then, every cycle, you get the dump out of the cavity. Both moves see the same wall. A reverse taper on the master becomes a hook in the rubber and a scuff on every later piece.

Jacketed walls cannot stretch. If a mother mold is holding a straight 40 mm wall, peel does not substitute. Add 1–3° on the master or split. Inner cores and plugs pull along an axis; they need draft even if the outer skin is 10A.

Injection-style draft on the *dump file* is often the wrong direction for a master we pour around. A part drafted for a steel cavity is not automatically a pour-ready pattern. We will remodel. That is the $50 CAD scope when it applies.

The RUUIPON Mold Structure Decision still gates: flat back → open-back; peelable undercuts → glove; if not → two-part / plug / core. Structure first. Draft second. Shore last.

flowchart TD
  A[Incoming dump CAD + master STL] --> B{Master walls drafted 1-3 deg?}
  B -->|yes, direction checked| C[Pour plan]
  B -->|no, zero-draft brick| D{$50 CAD on the master OR split}
  D --> E{Jacket will lock the wall?}
  E -->|yes, still zero| F[We would not pour]
  E -->|draft added or split| C
  C --> G[CAD lock]
  G --> H[3-7 business days prototype]

The photo that would prove a draft call: master on the millimetre scale showing the taper, cavity copying it, first dump leaving without a scuff. A dump render with green draft faces is not a master.

ISO 3302-1 M2 is a size class. It does not grant zero-draft jacketed walls.

Deep recessed letters on the master need draft plus a floor. Texture that is a mushroom is a hook, not a grain. We would not keep a reverse-taper logo "because the dump CAD had 2° on the outside."

Failure: scuffed wall, torn lip, master stuck in 20A

Symptom: master will not leave the flask; or it leaves and the first dump scuffs a white stretch on a 40 mm wall.

Cause: zero-draft master inside a jacket; reverse taper on a logo well; FDM stair-steps acting as tiny hooks.

Confirm: dye the wall, pull once, look for wipe. Caliper top vs bottom of the master. If the master is a straight brick, stop arguing Shore.

Fix: add draft on the master and recast, or split. Do not raise Shore as the first move — a 40A brick on a zero-draft wall scuffs harder. Sanding FDM hooks is a master fix, not a dump SOP. Loaded sag of about 0.5–1.5 mm is still jacket work after the taper exists.

Typical shop values

Caption: Typical shop values, not a named PO.

Drafts we would not skip

We would not recommend pouring a zero-draft resin brick inside a rigid printed jacket and hoping 10A will stretch.

We would not recommend applying injection draft to the dump CAD only, then sending an undrafted SLA as the pattern.

We would not recommend reverse-taper serifs on a chocolate well. Couverture tears; we will not grease the well to hide it; we will not switch to tin.

We would not recommend "add draft in the rubber" as a pour trick. Rubber copies. It does not taper a brick.

A tooling charge is not unrestricted ownership of the drafted master CAD. Recasts follow the locked taper unless you pay to change it.

Worked example: 60 mm resin box, 0° master, 2° dump file

Craft resin box, 60 × 40 × 25 mm. Buyer STEP for the dump showed 2° (injection habit). The SLA master was a straight wall. Platinum 20A block, printed jacket. Master stuck; operators pried a lip tear. Recast: $50 CAD applied to put 2° on the *master*, same dump OD at the rim, lock, wash/UV/seal. Prototype 3–7 business days after that CAD lock. Production MOQ 20 of that design. Related: resin molds.

Release spray is still not draft. A platinum-compatible release after a passing slug may help a sacrificial print leave, but a 90-degree FDM ratchet will still tear 10A. CAD the taper.

We would not copy a plastic-injection 1–3° rule onto a food gummy cavity and then forget the master. Two drawings on the RFQ: master peel, dump pull. If purchasing only has one "draft" field, they will pick the wrong object.

Open-back magnets often need a vertical scrape wall. That wall is a dump convenience and a master lock. Break the scrape land with a tiny taper or accept a split at the rim. Say which.

Prototype 3–7 business days after CAD lock of those walls. MOQ 20 per design. USD $50 CAD when that scope applies. Mix 1:1 or 10:1. Platinum shrink about 0.1–0.3%. Jacket if loaded sag would be about 0.5–1.5 mm. ISO 3302-1 M2 as a common dump class. Steel draft on LSR lives at wydsilicone.com.

Mix-up: the dump file is the master

The dump is what you cast later. The master is what we pour around. Draft the object that has to leave the rubber first. The other mix-up is treating peel on a glove as a license for reverse-taper logos on a jacketed tray.

What to ask when you're buying the taper

• Which file is the master, and which is the dump?
• Jacketed walls or open-back peel?
• Logo wells: raised or recessed on the dump, and a millimetre depth?
• Food vs craft — chocolate stays platinum, dry, no tin?
• After CAD lock, 3–7 business days, then MOQ 20 / design?

Related: DFM review, contact.

RFQ copy-pack — draft the master

Paste into [email protected]:

Object: RTV mold I pour into, not an LSR/HCR part Master file vs dump file: name both Walls: current draft deg, or ask us for 1-3 Jacket: yes / no / ask us Dump: resin / PU / plaster / chocolate (no tin, no grease) Logo depth mm if any File: STEP / STL / photos with a millimetre scale CAD: mold-ready STEP OR USD $50 3D if that scope applies Prototype 3–7 business days after CAD lock, then MOQ 20 per design

Send the master walls, not a dump render with green faces. We lock the taper — not a blank free quote. Phone +86 135 3006 2969. Licheng Technology Industry Park, Xinhe Blvd, Shajing, Bao'an. Shop since 2018.

FAQ

Can I skip draft because silicone peels? On some open-back gloves, peel substitutes. Jacketed walls, cores, and reverse-taper logos still need draft on the master. See the sibling draft-angle page for peel cases.

Should I draft the dump CAD the way I would for injection? Draft the master we pour around. Injection direction on the dump file is often the wrong object. We will check.

Will adding 2° change my dump size? Yes, unless we hold a named OD. Call the critical millimetres. ISO 3302-1 M2 is not a secret hold.

Does a harder Shore replace draft? No. Harder rubber scuffs a straight wall. Jacket and taper first.

Does adding draft restart the 3–7 day clock? Yes. CAD lock includes the master taper. MOQ 20 per design after the witness.