DFM Before Tooling: RTV Calls Before Rubber | RUUIPON

DFM on a custom RTV mold is not a polish pass and not a brochure about machines. It is the set of calls you make before rubber hits the box: open-back vs keyed split vs plug vs core, draft on walls that must still read, island width on logos, jacket yes/no, and whether the STL's units are millimetres. If you skip that gate, you pay for a master that only looks good on screen and then tears on demold 1. Soft Shore does not delete a hook.

RUUIPON marks those calls in Bao'an (shop since 2018), then you KEEP or FLATTEN, then CAD lock starts the 3–7 business day prototype. Production MOQ 20 pieces per design. Simple 3D is USD $50 when that CAD scope applies. The service-desk version of the screenshot is DFM review. This page is why you do it before tooling, not after the first torn pour.

Does not apply when the file is already a locked STEP from a previous PO with no geometry change — that is a recast, not a DFM. It also does not apply to LSR/HCR *part* DFM in a steel tool (flash land, cold-runner, shut-off). Those drawings go to wydsilicone.com.

What we mark before anyone mills a master

1. Units. Open the STL in millimetres. A 25.4× earring is a units miss, not an "artistic scale." Silent units stop the review.
2. Pull vector. Cookie-tray peel vs a second direction. Soft Shore does not invent a second direction.
3. Undercuts. KEEP or FLATTEN on each hook. If peel is unsafe, we name two-part, plug, or core — the same Mold Structure Decision used on complex resin: flat back → open-back; else deep undercuts + peel? if no → split/plug/core; large wet casting → mother mold.
4. Islands. Hairline serifs fail first. About 0.3 mm is the talk; we would rather thicken a letter than ship a stamp you throw away.
5. Draft. About 1–3° on walls that must still read. Peel substitutes for draft on some gloves; it does not on jacketed walls, deep logos, or cores. Details: draft angle.
6. Jacket. Loaded sheet or wet mass: mother mold. Edge sag of 0.5–1.5 mm is a missing jacket, not a Shore miss.
7. Dump. Pour chemistry and peak °C belong on the RFQ before Shore.

A thumbs-up on WeChat with no KEEP/FLATTEN marks is not CAD lock. Lock is the snapshot after those marks.

flowchart TD
  A[File in mm plus dump name] --> B[DFM marks: units, pull, undercuts, islands, draft, jacket]
  B --> C{Buyer KEEP or FLATTEN?}
  C -->|Marks missing| D[Not lock — do not mix A/B]
  C -->|Approved snapshot| E[CAD lock]
  E --> F[Master / box / vacuum pour]
  F --> G[3-7 business day prototype]
  G --> H[Dump test then MOQ 20]

Typical shop values

Caption these as typical shop values.

ISO 3302-1 M2 is a rubber-article class on the drawing. It is not the word "precision" and it is not a substitute for DFM marks.

We would not recommend

We would not recommend pouring A/B on a hooked STL because the buyer is in a hurry. Hidden hooks discovered on demold 1 are a CAD reopen, not a free Shore nudge.

We would not recommend treating DFM as a vibe check ("you have machines, so it will be fine"). Name open-back vs split vs jacket in writing.

We would not recommend skipping DFM to "save" the $50 simple 3D line. That line is modeling when CAD scope applies. DFM is the gate. Skipping it costs a master.

We would not recommend quoting this as an LSR part DFM. Different object, different site.

A tooling charge is not unrestricted ownership of the marked CAD. Say who keeps the file if you need the recast in your building.

Worked example (anonymized)

A jewelry STL, 22 mm pendant, bail as a closed loop, UV resin dump. The email said "one-piece, 20A, ship next week." DFM: units mm (good); pull vector cookie-tray (bad — the bail traps rubber); KEEP on the bail would require a split or a flatten of the loop. Buyer chose FLATTEN the bail to a hook that peels. CAD lock after that screenshot. Simple 3D at USD $50 because we rebuilt the bail. Prototype in 3–7 business days. First UV dump released. Had we mixed A/B on the closed loop, the 3–7 day clock would have bought a scrap glove. MOQ 20 per design after the dump test.

The photo that would prove the gate: screenshot with KEEP/FLATTEN arrows on the bail, next to the first dump. A factory-gate pan of "our CNC" proves nothing about DFM.

Common mix-up: DFM is extra NRE you can cut to win the PO

Purchasing drops the DFM line to match a trader's number, then discovers the split on demold. The trader's number was an open-back cake mold. Yours was a hooked bust. You were never comparing the same tool. Put structure on the RFQ so the PI has a named jacket and a named split. Related: design service, undercuts and splits.

What to ask when you're buying

• Will I get KEEP/FLATTEN marks before anyone mills a master?
• What starts CAD lock — my thumbs-up, or the marked snapshot?
• Is simple 3D USD $50 in scope, or is the STEP already mold-ready?
• Jacket yes/no for this dump mass?
• Who owns the marked CAD after the tooling charge?

Related: DFM review service, design service, draft, contact.

RFQ copy-pack — DFM before rubber

Copy to [email protected]:

• STEP or STL in millimetres, units stated
• Dump and peak °C
• Known hooks, bails, through-holes, hollows
• Preference: open-back / split / flatten / shop to mark
• Logo file if letters must survive
• Simple 3D: USD $50 when that CAD scope applies
• Quantity: prototype after CAD lock, then MOQ 20 per design
• Custody of master and CAD after tooling charge

Matched next step: send the file so we can mark KEEP or FLATTEN, not a request to "start the mold." Phone +86 135 3006 2969. Licheng Technology Industry Park, Xinhe Blvd, Shajing, Baoan.

If the pour is food-contact, DFM still happens first; the 21 CFR 177.2600 pack is a later article test, not a reason to skip KEEP/FLATTEN.

FAQ

Is DFM the same as the $50 3D fee? No. USD $50 is simple 3D when that modeling scope applies. DFM is the structure gate (split, draft, jacket, islands). You can need both, either, or neither if the STEP is already mold-ready.

Can we DFM on a call without a file? We can talk. We cannot KEEP/FLATTEN millimetres. Attach the STL or the scaled photos.

If I accept your split mark, can I still change it after the first pour? Yes, but that is a new CAD lock and a new 3–7 day pour. It is not a free tweak on the existing rubber.

Does a high-tear 10A skin skip DFM on undercuts? No. Soft high-tear rubber still cannot peel a closed loop. Structure first. Shore second.

When does production MOQ 20 start relative to DFM? After you approve the prototype that came from the locked CAD. DFM is before tooling. MOQ 20 is after the dump test. Do not multiply an unmarked STL to twenty tools.